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shot-out

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Topic: shot-out
Posted By: Dale Clifford
Subject: shot-out
Date Posted: January/25/2007 at 13:14

Seems to be some incredible mis-information on shot-out, burn-out, eroded barrels and barrel throats. Some believe it happens, but not enough to affect hunting accuracy or use, some believe it doens't occur due to todays guns material, some are well aware of it etc etc.

So for fun (isn't that what its all about) I orderd a 6.5-284 from Cooper should be here toward the end of the week, a caliber noted for its short barrel life. Now image a cartridge that shoots about 15% more powder and about .1 small bore--- the 257 weatherby. Even with stainless barrels, 800 rds is considerd the bench turning point for this caliber. Please go to 6mmbr.com and read the info page on the 6.5-284 if you don't want to--don't make any stupid posts.




Replies:
Posted By: crispycritter
Date Posted: January/25/2007 at 15:27

Are you going to slow fire,allowing the barrel to cool or get it hotter than blue blazes ?

 

My understanding is heat from alot of fast shooting increases the erosion factor.



Posted By: Dale Clifford
Date Posted: January/25/2007 at 18:00
Slow or fast certainly has an effect, however the approx. total rd. count is constant. Would you like to see it go in a day?


Posted By: pyro6999
Date Posted: January/25/2007 at 20:44
i think you should define what kind of accuracy you consider is shot out are we talking like the gun wont shoot 1/2 inch groups at a 100yds or are you talking 5 rounds and only 3 of them could hit a 4x8 sheet of plywood or are we talking it wont shoot 5 into a 6"x6" square. i'm thinking this may have something to do with why you and i dont see eye to eye on the whole issue.

-------------
They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead"

343 we will never forget

God Bless Chris Ledoux
"good ride cowboy"


Posted By: crispycritter
Date Posted: January/26/2007 at 00:09
Didn't realize that I was stepping into a deep pile of debate. My bad.  ----note to self - read all threads before posting ------


Posted By: Dale Clifford
Date Posted: January/26/2007 at 11:20

Crispy-no please- continue your input. This forum is about the broadest range of shooters. Some sites are very specfic such as 6mmbr- which defines "shot -out"quite specifically- and others such as pyro who put a larger cone of fire on the group size.

pyro- I'm just to going perform the experiment and let the reader decide. The Cooper is here, have got everything but the dies. will send pics.

The controls I will impose are the following.

All reloading will be done on a Dillon progressive-If you can't do it on a Dillon I don't shoot it.

Brass will be Lapua, two lots 50 with outside neck turning and bumping the shoulder, 50 no neck turning.

Bullets will consist of match grade, sierra,berger, and hornady.

Targets pic will be given the OT every 100 rds. ( i got the gun for 1000 yd shooting-so the in between rounds will be used for this.

No groups will fired from a concrete bench set up at a range-all will be done prone at my range.

Powder will be R22 as was used by Cooper in their test group, charges will be thrown by volume and not weighed.



Posted By: pyro6999
Date Posted: January/26/2007 at 11:37
so are we suppose to tell you in our opinon as targets are posted when we would call the barrel "shot out" that sounds fair if thats what you were planning!!

-------------
They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead"

343 we will never forget

God Bless Chris Ledoux
"good ride cowboy"


Posted By: Dale Clifford
Date Posted: January/27/2007 at 12:17

yes, I plan to cut, the barrel back, and rechamber at the 800 mark regardless. Inbetweens the gun will be used for 1000 yd practice.

Why don't you give your version of shot out--approximation of course.

Perhaps someone else with practical accuracy, hopefully MacDonald with tactical, etc.



Posted By: RifleDude
Date Posted: January/27/2007 at 12:47
Dale, just out of curiosity, why wouldn't shooting be done from a bench?  If this is a test of accurate barrel life, wouldn't you want to remove as many variables as possible so that any variability seen in the results could be more directly attributed to the gun, not the shooter?

-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: January/27/2007 at 13:15

Thats why I'm not shooting of a pickup hood--just kidding. Accurate barrel life, which I'm sure is what pyrro is getting at is a relative term, while someone such 6mmbr. views it more in absolute terms (and the military). It would be impossible to remove all the variables to the point of making everyone happy. Prone is good compromise between concrete benchs and action shooters who use time pressure to measure accuracy.

Please-post your definition of accuracy and shot out--what variables you view as most important, and why.



Posted By: Dogger
Date Posted: January/27/2007 at 13:47
Have to agree with Rifledude.  If the intent of the exercise is to detrmine at what point a barrel is "shot out", i.e. no longer meets some definable criteria, you need the most stable rest possible to remove the human component.  For this test a machine rest would be even better.

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God save the Empire!


Posted By: Tip69
Date Posted: January/27/2007 at 18:14

I'm a hunter, not a target shooter (although, that could change)  and shot-out to me means I can't put a group within the size of a Deer heart at 200 yds!  Not sure how to quantify that at 100 yds...... does that equate to 1 - 2 inches? 

 

I hope to get into praire dogs this spring....... I think my idea of shot-out might change at that point.

 

I would think you would want to shoot from a solid rest as well.



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take em!


Posted By: pyro6999
Date Posted: January/27/2007 at 20:15
Originally posted by Tip69 Tip69 wrote:

I'm a hunter, not a target shooter (although, that could change)  and shot-out to me means I can't put a group within the size of a Deer heart at 200 yds!  Not sure how to quantify that at 100 yds...... does that equate to 1 - 2 inches? 

 

I hope to get into praire dogs this spring....... I think my idea of shot-out might change at that point.

 

I would think you would want to shoot from a solid rest as well.

 

i agree, either this needs some definement or the test would only be one man's opinion, shot out to dale probably isnt the same as shot out to me or rifledude



-------------
They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead"

343 we will never forget

God Bless Chris Ledoux
"good ride cowboy"


Posted By: Dale Clifford
Date Posted: January/27/2007 at 22:18

So far two types of shooting have been described. Platform, (snipers, pds, prone, bench) and shoot and scoot (hunting, active pursuit of quarry, action shooting). Each of which has their own definitional need. The solid rest would use the gun lock up like a rail gun in bench, with the scope mts. silver soldered to the action, the mount would be about 2 ft. high so I could set in a chair and the trigger guard would be drilled for a camera release. This could describe something like the unlimited class. But would it help the scoot and shoot people who know that statistically that a "good" shot doens't require this?

 

 

 

 

 



Posted By: crispycritter
Date Posted: January/28/2007 at 04:00

"Shot out" is gonna be hard to establish. As mentioned,a long distance target shooter and a 100yd. deer hunter are not going to have the same opinion.The hunter will think a barrel is still good to go while the target shooter is ready to chunk the barrel in the trash.

 

However, I think if you stay with the same load and shoot from the bench,you will be able to give an idea of IF,WHEN and HOW MUCH accuracy is affected and at what round count it happens. The reader can then determine at what point the barrel is "shot out" for their shooting needs.



Posted By: crispycritter
Date Posted: January/28/2007 at 04:21

Quote:

But would it help the scoot and shoot people who know that statistically that a "good" shot doens't require this?

 

 

 

 

Yes, I think it will since Rifle Ability and Shooter Ability are two different things. For example, if your test show that the barrel gives 6"-8" groups at 100yds. at XXX rounds, then the hunter knows not to attempt a 200yd shot. Even if the hunter is able to be accurate at 200yds, the rifle will not.



Posted By: Dale Clifford
Date Posted: January/28/2007 at 12:12
 How about the case when the rifle is not accurate and the hunter can't shoot and he gets the deer. If you shoot 10 shoots 1 inch to the aim point 10 inch to the right statistically you have 100%. I can tell you from a lot of previous shooting that the groups will never reach 6-8" except under incredible circumstances. The group size will go from the factory 3 shot group which is about 7mm to 1" and 1 1/2". Even in match grade .233 varmiters as an example that I consider "shot out" at 6000 to 10000 rds, they make really good uppers for select fire guns until about 20000 until you get some amazing flyers. Even if the groups started at  2-3" this is considered to be miltary ok. The difference in each case is how many rds.


Posted By: crispycritter
Date Posted: January/28/2007 at 13:18

Originally posted by Dale Clifford Dale Clifford wrote:

 How about the case when the rifle is not accurate and the hunter can't shoot and he gets the deer. 

 

 

I'd have to call that a case of pure d luck. Even a blind squirrel finds a nut once in a while.



Posted By: Dale Clifford
Date Posted: January/28/2007 at 15:58

pure luck (what ever that is) or not it is still part of the statistical process and must be considered. all things are possible some things are more probable.

take a look at the whackos in almost anything goes and add your own. After you read and hear enough of these types of things, it appears they happen more frequently than one would expect.



Posted By: Dogger
Date Posted: January/28/2007 at 16:20

Not sure how you would do this but if it's possible to determine what the nominal accuracy of a new barrel is after break in (e.g. shot scatter radius from point of aim equals .75" or 1.5 moa rifle fom the new barrel), then measure at what point it deviates from that nominal accuracy by some predetermined percent variance.  When it reaches this threshold it would be considered shot out.  The difficulty would be in coming up with this variance.

 

Hunting rifles may not have the same tight tolerances that a bench rest target rifle would have but that wouldn't matter here.  We would be judging the change in performance from each barrel so the variance between the two would not be the same.  Whethor or not the rifle was to be used for hunting Vs bench shooting this test would have to be done from the sturdiest rest possible.  We are not measuring the shooters performance. 



-------------
God save the Empire!


Posted By: Dale Clifford
Date Posted: January/28/2007 at 17:09
Excellent points. I'm suprized someone hasn't been more vocal about the break in method, than the control of the shooting technique. This is usually the topic of all kinds of stuff.


Posted By: RifleDude
Date Posted: January/29/2007 at 08:31

Dale, for the type of rifle you're evaluating (accurate varmint rifle), the accuracy expectations are higher than a typical hunting rifle, so I'd say "shot out" would be when aggregate group sizes get about 25% larger than observed when new.  And, you’ll also need to test based on aggs, not individual groups, so you have more statistically valid data.

Also, with regards to the bench issue, the very best test you could devise to determine accurate barrel life would be using a rail gun while shooting indoors or in an area that also eliminates the effects of wind.  Since this probably isn't practical, anything that gets closer to this ideal will improve the validity of the test results.  So, I really do think using a bench would be better so that the variation in data will be most closely correlated to the barrel, not shooter.  Not doubting your shooting abilities, but the results will be more meaningful if we know all other variables besides the rifle were taken out of the test as much as possible.  Especially since the accuracy expectations for this class of rifle are more stringent, and therefore, the definition of "shot out" would probably involve a smaller cone of dispersion, more difficult to sort out from human factors.



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dogger
Date Posted: January/29/2007 at 09:31

Dale/Rifledude:  is there any info available from barrel makers/rifle manufacturers that would provide an idea of what criteria they use to accept or reject barrels?  If there is, not sure if criteria is decided upon by tolerance measurements on the barrel itself or through live fire testing.

 

Would be nice to get other members ideas on what MOA is acceptable on a big game centrefire rifle at 100 yds.  I'm leaning towards 4-5 MOA max from a sold rest.  Don't care if the rifle is brand new or 50 years old.  Expectations will play a part here, i.e.  if I'm only ever going to shoot to a max 100-150 yds from an old 45-70 this may be ok.  If a have a 338  it has to be better than this.

 

Thoughts?



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God save the Empire!


Posted By: RifleDude
Date Posted: January/29/2007 at 10:02
Originally posted by Dogger Dogger wrote:

Dale/Rifledude:  is there any info available from barrel makers/rifle manufacturers that would provide an idea of what criteria they use to accept or reject barrels?  If there is, not sure if criteria is decided upon by tolerance measurements on the barrel itself or through live fire testing.

 

I don't know what factory barrel makers use as acceptance criteria from a tolerance standpoint, but custom barrel makers consider a "match grade" barrel to be one with a measured land & groove TIR (total indicator reading) of 0.0001" to 0.0002" across the entire bore, measured with an air gage.  Good factory barrel TIR would be around 0.001", which is the number I believe Kimber advertises as their acceptable tolerance (not saying Kimber has the best factory barrel, just that I remember they published something to that effect).  Factory barrels aren't finish lapped like custom barrels, so they aren't capable of achieving the same tolerances as customs on a mass production basis.  Notice the number of "0"s after the decimal point in those tolerances; that wasn't a typo.  A true "match grade" custom barrel is made to 5-10 times tighter tolerance for bore uniformity than the factory barrel example used above, and that's considered a very good factory barrel.  Rifle manufacturers throw around the term "match grade" a little too liberally.



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: January/29/2007 at 15:45

Cooper lists this tube as match chamber, which is easy, but as Rifledude pointed out, I doubt if it is Match grade barrel. I'll try to find out from them, although both Kimber and Cooper advertise lapped at the factory. 4-5 moa is usually the accepted standard for an action shooter type rifle AR-10 or ar 15 from standing under time pressure. I would demand much more from a hunting rifle. 2-4 inch groups are usually a standard for standing metallic silhoutte.

Also I think there is an assumption about bench that should be looked at. How about the rests, would a loose Hoppes be ok, or do we need Sinclairs stuff and how about rear gun support 



Posted By: RifleDude
Date Posted: January/29/2007 at 16:08
Originally posted by Dale Clifford Dale Clifford wrote:

How about the rests, would a loose Hoppes be ok, or do we need Sinclairs stuff and how about rear gun support 

 

No, a loose Hoppes or any other loose front rest would not be ideal.  As for rear support, a simple Protektor bunny ear or rabbit ear style bag would be fine and they are also inexpensive.  Rather than buying a really good front rest, which can get kinda expensive, unless you had already planned to get one anyway, simple sandbags provide almost as much stability as a good front rest.

 

Give me a PM if in fact you ARE looking for advice on a good front rest.



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Roy Finn
Date Posted: January/29/2007 at 16:16
Originally posted by Dale Clifford Dale Clifford wrote:

Cooper lists this tube as match chamber, which is easy, but as Rifledude pointed out, I doubt if it is Match grade barrel. I'll try to find out from them, although both Kimber and Cooper advertise lapped at the factory. 4-5 moa is usually the accepted standard for an action shooter type rifle AR-10 or ar 15 from standing under time pressure. I would demand much more from a hunting rifle. 2-4 inch groups are usually a standard for standing metallic silhoutte.

Also I think there is an assumption about bench that should be looked at. How about the rests, would a loose Hoppes be ok, or do we need Sinclairs stuff and how about rear gun support 

 

Cooper uses Wilson rifle barrels which are air guaged and finished lapped.



Posted By: RifleDude
Date Posted: January/29/2007 at 17:40
Originally posted by Roy Finn Roy Finn wrote:

Cooper uses Wilson rifle barrels which are air guaged and finished lapped.

 

Correct.  Unlike the other custom barrel makers, Wilson isn't a brand used by competitive benchrest shooters, but they do make a better barrel than what comes standard on most factory rifles.  Whether or not they're made to true "match grade" standards, I dunno, but they are very good barrels within the reasonable MSRP of Cooper rifles.



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: January/30/2007 at 11:23

The gun will be used for standing long range metallic target shooting (500 yds) which is more hunter directed, some 1000 yd although the stock really isn't up to it. Still waiting for the dies, and the scope mounts which are 8/40 and Leo and using turn in Leos. I don't like to use turn ins with this large of scope, a Nightforce 8x32 with NP-P2 ranging reticle.

What about the use of erosion gauges? Why not just measure the amount of erosion?

Hint-rifledude, following the lands with OAL, using bullets in cases, and measuring the migration.



Posted By: RifleDude
Date Posted: January/30/2007 at 12:13
Originally posted by Dale Clifford Dale Clifford wrote:

The gun will be used for standing long range metallic target shooting (500 yds) which is more hunter directed, some 1000 yd although the stock really isn't up to it. Still waiting for the dies, and the scope mounts which are 8/40 and Leo and using turn in Leos. I don't like to use turn ins with this large of scope, a Nightforce 8x32 with NP-P2 ranging reticle.

What about the use of erosion gauges? Why not just measure the amount of erosion?

Hint-rifledude, following the lands with OAL, using bullets in cases, and measuring the migration.

 

Yep, using an OAL dimension with a Stony Point OAL gauge, Sinclair chamber gauge or similar is one way of measuring throat erosion.  Another is physical inspection with a bore scope.

 

This sure is an expensive test!  I hope you were planning on buying and rebarreling a Cooper rifle anyway!  Whatever job you have to be able to afford this... can I send you a resume?!!!!



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: January/30/2007 at 12:27
You should see the one trying to make major with 9mm.


Posted By: pyro6999
Date Posted: January/30/2007 at 12:32
the only thing i wish we could change about this test is the fact that we arent using a run of the mill rifle, i cant afford to do this with my stuff but it would be a neat comparison if we had a higher grade rifle and a standard grade rifle same caliber same loads same barrel lengths etc. ruger 77 or rem 700 against the cooper. that would really grab my attention.

-------------
They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead"

343 we will never forget

God Bless Chris Ledoux
"good ride cowboy"


Posted By: Roy Finn
Date Posted: January/30/2007 at 14:37
Originally posted by RifleDude RifleDude wrote:

Originally posted by Roy Finn Roy Finn wrote:

Cooper uses Wilson rifle barrels which are air guaged and finished lapped.

 

Correct.  Unlike the other custom barrel makers, Wilson isn't a brand used by competitive benchrest shooters, but they do make a better barrel than what comes standard on most factory rifles.  Whether or not they're made to true "match grade" standards, I dunno, but they are very good barrels within the reasonable MSRP of Cooper rifles.

 

Yep, frankly I never heard of Wilson Barrels prior to my Cooper purchase. I do know they make two grades of barrels, one a OEM (WTF that means), and a "match grade" tube. I think that term is used far to much these days. And no, I don't think makers like Hart, Krieger, Lilja etc. have anything to worry about. I do know that each Cooper 22lr has to shoot a 1/4" 5 shot group or less prior to leaving the factory.



Posted By: Dolphin
Date Posted: January/31/2007 at 16:56
Well, that being said, my Marlin, or is it a Savage, cannot remember, .17 HMR, shoots 0.5 inch groups all day long with a cheapo scope and has a bull barrel, but nothing close to match or anything fancy and the same kind of accuracy with my son's rifle in a 22lr.  For that kind of money, that ain't bad at all.  Cooper makes a beautiful rifle, very accurate, but for right now, I will stick with my cheapos, unless I run into alot of cash.

-------------
D. Overton


Posted By: Dale Clifford
Date Posted: January/31/2007 at 19:54

I believe Wilson makes a lot of the barrels used on "match" AR-15 uppers. (if it's the same one).

Roy are those Briley titanium chokes on your Beretta- please go back and elaborate.



Posted By: Dale Clifford
Date Posted: February/02/2007 at 23:02

 

Target and group from Cooper

 

 

 

Jeez not another leo.



Posted By: pyro6999
Date Posted: February/02/2007 at 23:15

 i found this today quite intresting read, opened my eyes a little

 

http://www.riflebarrels.com/faq_lilja_rifle_barrels.htm - http://www.riflebarrels.com/faq_lilja_rifle_barrels.htm



-------------
They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead"

343 we will never forget

God Bless Chris Ledoux
"good ride cowboy"


Posted By: Dale Clifford
Date Posted: February/03/2007 at 10:15
The group from Cooper was a 3 shot group--what do you think is the correct--3,5,10?


Posted By: RifleDude
Date Posted: February/05/2007 at 08:40
The 3 shot test group from Cooper was fired at 40 yards, because that's the max distance they have available to them for testing in their facility.  A 3 shot group may give a good clue as to a rifle's accuracy potential, but 5 shot groups prove a rifles accuracy and is the gold standard for accuracy testing.  With a 5 shot group, there's almost nothing left to luck or chance, and fliers outside the group are easy to identify.  3 shot groups are fine for sighting in or load testing in a heavy recoil rifle, but they are not conclusive proof of average accuracy.  For the purposes of the test, 10-shot groups are unnecessary, and just burn up extra ammo.

-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: February/05/2007 at 10:02
Do I get to do it from 40 yds?


Posted By: RifleDude
Date Posted: February/05/2007 at 11:26

As long as all groups are fired from the same distance and you measure the average of several groups, it doesn't really matter, for the purposes of your test. 

 

You could use the average of five, 5-shot groups (aggregate) for each time you record data, like is done in registered BR competition.  This will average out some of the larger group sizes caused by fliers and factors other than the rifle itself.  If you don't use average or aggregate group sizes, you give too much weight to abnormal groups resulting from assignable causes like wind.  You could record average group size after, say, every 100 shots so you won't have to measure so many groups.



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: February/05/2007 at 12:05
Just kidding--- I'll be sticking to the criteria established in the first part of the post.  For practical shooting, (3 gun matches) and in particular ,gas guns, I prefer 10, because the function of the gun and heat become important factors. It also gives a very good idea of how fast the gun recovery for the next shot. (such factors of roll-off, whether weight needs to be added and where.) . In this test 5 shot groups with turned and unturned brass will be posted every 100 rds.


Posted By: RifleDude
Date Posted: March/26/2007 at 16:48
Hi, Dale.  Was just curious if you've made any progress on this barrel life test...

-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: March/26/2007 at 18:11

Yes, barrel break in is done (100 rds) , best load is around 50 grs. should be posting targets.

mostly waiting for a special order erosion guage from a place called beastwerk



Posted By: RifleDude
Date Posted: March/26/2007 at 19:25
Cool.  Let me know the details and your impressions of the erosion gauge when you have a chance to use it.  I might be interested in buying one.

-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: March/26/2007 at 22:13

http://www.beastwerks.com/Throat_Erosion_Gauge.htm - http://www.beastwerks.com/Throat_Erosion_Gauge.htm

 

cartridge shoots a lot like my 270's impression as flat as my Sako 7mm STW. recoil impression about the same. however bolt tolerances much tighter.

 

Lapua brass very consistent in necks (as usual) no need to neck turn at this time, will check run out again after 200 rds.



Posted By: 8shots
Date Posted: March/27/2007 at 04:52

Dale,

What do you mean by neck turning of brass? What and how do you do this? 



Posted By: Dale Clifford
Date Posted: March/27/2007 at 09:51

Unless a barrel is "match" grade the chamber and especially the neck is very seldom round. As the makers reamers wear down the barrels toward the end of a run can become elliptical. Each time the brass is fired it conforms, and sometimes the resizing dies will not bring the brass back to spec. Even if they do the neck, after many firings will have scallops. Neck turning provides a means for the reloader, who has no control of the brass in manufacturer, a way of correcting some of both problems with the gun and the brass. Another, and probably the best reason, is to control the amount of tension on the bullet. After firing and stretching, because of the flexibility of the brass, it rebounds back, not quite tight enough to hold the bullet but still small than the neck dimension in the chamber. Uniformity in the neck causes even tension along the complete surface of the bullet and the release to the lands is smoother. In fact some "stool" shooters merely seat their bullets by finger pressure alone, the necks have been turned so finely. Because the neck material is thinner is works the brass on resizing less and the case life doubles or triples, most Lapua brass once prepped will out last the life of the barrel.

Neck turning also helps brass that has not been annealed correctly and if done prior to, sometimes avoids the neck annealing which is a real pita.

The only cases I don't neck turn are the ones were the shooting system would more than likely not show an improvement-- select fire weapons, ak, you get the idea.

Neck turning is like a trigger job on a 1911 its about 80% on the most important list.

 



Posted By: Dolphin
Date Posted: March/27/2007 at 09:55
He means uniforming the thickness of the brass at the neck of the cartridge.  From what I have read, not done mind you, accuracy is not significantly improved.  See a recent article in either Rifle Shooter or Shooting Times.  DC will not like that I referred you to a magazine article, but the author showed quite nicely that in the particular caliber he was testing, that turning the neck of the brass made no improvement.

-------------
D. Overton


Posted By: Dale Clifford
Date Posted: March/27/2007 at 14:28
handloading  is just like gun cleaning many ways to accomplish the same ends no "correct" way, but if you don't get dirty it's just pissin in the wind.


Posted By: 8shots
Date Posted: March/27/2007 at 15:04
Thanks for info and replies.


Posted By: Dale Clifford
Date Posted: March/28/2007 at 22:37

deciding on lug lapping , dykemed up and after 25 cycles later hard to see small rub area at back of top lug due to flash glare, think I'll skip it.

 



Posted By: RifleDude
Date Posted: March/30/2007 at 15:23

Dale unless I'm misunderstanding the intent of your post, the part of the lugs one would need to lap would be sides facing the shooter when the bolt is closed that bear the rearward thrust.  The purpose of lug lapping is so all lugs bear evenly against the abutments in the receiver to prevent bolt head movement when firing.  The view you show is the sides of the lugs that slide against the lug races in the receiver.  To show uneven wear on the lugs after cycling the bolt, you would need to snap the pic while looking down the bolt body, with the handle end of the bolt toward the viewer.  Perhaps you know this and just wanted to show the bolt head all dykemed up, but you reference a rub mark that's hard to see because of glare.  Again, maybe I just misunderstood what you were pointing out in the photo.



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: March/30/2007 at 17:16
yep that's why i skipped it-- cooper already did it , the only part needing was a small contact area on the receiver raceway.


Posted By: Dale Clifford
Date Posted: March/30/2007 at 21:16

dropped a couple of kernals of r22 on the front part of the barrel that mates with the bolt, a quick and dirty way (more ways than one) to test the tolerance in bolt play. Some bolts will still close, this one will not close.

forgot to thank you for providing the explanation on bolt lapping.



Posted By: 1stscope
Date Posted: March/31/2007 at 12:30

If you want to use 5 shot groups then keep track of the average and range or standard deviation, chart it, and you'll see any trends up or down, plus increasing variation.

 

I'll guess that a given caliber will be most sensitive to the heaviest bullet that it can stabilize, which will depend upon twist, and that 'shot out' means when you can't obtain the desired accuracy with that load. At least that's the case in highpower shooting either the .308 or previoulsy the 30.06, where both seem like they'll shoot Sierra 168 gr HPBT well 'forever'. The .308 will deliver tighter groups but the accuracy with the Sierra 190 gr HPBT seems to start dropping at 2000 to 3000 rounds in the .308, depending upon how picky you are. The .308 typically has a 1:12 twist while the 30.06 has a 1:10, although some split the difference and use a 1:11 in the .308.  



Posted By: 8shots
Date Posted: April/01/2007 at 05:06
Dale and 1stscope, I do not want to steal this thread, so I will post a new one some time today, where my 30-06 seems to behave strangely. I would appreciate your comments. I think it points to a barrel on its way out.


Posted By: Dale Clifford
Date Posted: April/01/2007 at 09:45

oh boy a statistical study-- I'll plug the data into SPSS do some table pivots , plot s.d. of velocity, do a two tail ANOVA on mean group variation, plot number of shots vs. s.d. of velocity and group variation. From this we can calculate the derivative to see if the "gain" of the group size is linear or quadratic. Also, we can use the erosion gauge to measure the physical deterioation of the throat area, and plot it also. Then by correlating the throat erosion, and using maybe a t-test, see if erosion is an accurate predictor or group size. Something like that?

http://www.spss.com - www.spss.com



Posted By: 1stscope
Date Posted: April/01/2007 at 12:10

Yeah, you can do that, but just plotting data first helps to see thru the abstraction produced by most formal statistical summaries. Plotting by mean and range (or std deviation) by time helps to see trends, and the regular sample sizes simply later anlaysis.

 

Another more abstract charting technique is to plot mean vs variance, where you get groups in that space that sometimes enable different comparisons or trends to be seen. If you wanna get fancy you can do confidence intervals around the joint distributions of different groups, but by then you've already lost everyone on all points except for what they can see on the charts.

 

Correlating throat erosion vs group size and/or variation makes sense, as that's what the original question seems to be.    



Posted By: Dale Clifford
Date Posted: April/02/2007 at 10:24
Hmm--- back to square one I guess.


Posted By: RifleDude
Date Posted: April/02/2007 at 10:46
Dale, I personally think you're overanalyzing this test.  If you just use a shooting technique that eliminates as much of the human variable as possible,  measure average group size of 10 five-shot groups after every 100 rounds or so, and measure throat erosion with your gauge, this should tell you what you want to know.  I would highly recommend shooting from a bench on a good front rest and rear bag to provide the most stable platform for the rifle as possible so you are testing more of the rifle than the shooter.  After finding a good accurate load, I would thereafter not recommend introducing any new variables like different loads or modifications to the rifle, because these can mask what the barrel is really telling you.  As much as possible, let barrel erosion be the only variable in the test if determining practical barrel life is indeed the goal of the test.  There is some subjectivity involved here, as the acceptable accuracy level for this type of rifle is more stringent than a deer rifle, so I would personally base the criteria for "shot out" on when the average group size becomes 50% larger than the "reference" group size established early on in the shooting.

-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: April/02/2007 at 11:17
50% larger sounds fine to me-- usually I employ several tricks to enchance accuracy as the erosion increases, including chasing the lands, changing bullet weights, and changing powder charge levels, (sometimes powders). In this test r22 will be used through out, and the same charge, even though pressures will decrease, and same bullet type and weight, I will try to even use the same brand if possible to eliminate manufacturing differences. Just so we are using the same calculator then a 1 in. would then become 1.5 or are we doing "mark up on cost"  1/.5=2  ?


Posted By: RifleDude
Date Posted: April/02/2007 at 11:38

Yes, I was referring to the former calculation (reference group size plus 50%) rather than the retail cost markup example.  Good point! 

 

I was just thinking from a practical standpoint due to the expected application of the rifle, 50% might be a good benchmark, as in my mind this would become the point where I would rebarrel a varmint rifle.  If this were a benchrest rifle, you could probable consider a 10% increase in average group size as being "shot out".

 

Also, since we are just evaluating barrel life here, I would think chasing the lands would also mask real barrel life, as the purpose for chasing the lands to begin with is because throat erosion began to occur to the point that accuracy suffered noticeably.  To me, chasing the lands is no different than cutting off the barrel tenon and rechambering / rethreading in that both are intended to bring the bullet closer to pristine lands.



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: April/02/2007 at 14:07
probably wasn't clear-- no I won't use any mentioned techniques


Posted By: Dale Clifford
Date Posted: April/24/2007 at 18:35

left group 5 fouling rds. right group last four of 25 shot string, last of fireforming  begin as soon as stoney point erosion gauge set, up --- had a hard time connecting with werkbeast.



Posted By: Dale Clifford
Date Posted: April/24/2007 at 18:40

4/5 mile per sec. .224 Sako action  600 rds. first 5 shots fouling rds.

 

 

 

 

 

 



Posted By: RifleDude
Date Posted: April/25/2007 at 09:49

DC, I may have misunderstood your post, but were the 2 targets shown under your Sako .224 fired with the Sako and the ones in the prior post fired with the Cooper you're using for the test?  The reason I ask is the right group on the bottom set of targets looks like the same group as the fouler group on the left in the previous set of targets.  Or, maybe you are just showing one 5-shot "fouler" group from the Sako, and it was to the left of your Cooper groups?  Nevertheless, if those are .22 caliber holes, minus the fouling fliers, it looks like your rifle is grouping pretty well.

 

Nice wood on the Sako!



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: April/25/2007 at 10:37

Yea I posted that because I wouldn't have been able to tell the difference (in hole dia) between the two if I hadn't done it personally. They are the same group and to the left of those (on the target) is the .224. I used it as a test control, because I know (exactly--well mostly) what to expect on the target. So if the other gun does so and so and so on. I wanted to test the two guns as to the first 5 shots in terms of barrel break-in.

They were shot off a pickup hood at 107 yds (laser). It looks like I need to replace the heavy duty off road shocks on my truck, the groups are usually a little tighter.

top group cooper

bottom sako-cooper



Posted By: RifleDude
Date Posted: April/25/2007 at 10:50

Thanks for clarification, Dale.  You may have mentioned it somewhere in the thread, but do you have the 8-32X56 or 12-42X56 NF Benchrest scope on your Cooper, and which reticle are you using?

 

Nice hood shooting!



-------------
Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: Dale Clifford
Date Posted: April/25/2007 at 11:02
8x32 np-1rr although at 32 a bit much -- shot the groups on 20 to compare with the Sako



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