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Difficulty stabilizing 200gr Nosler Part

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/22/2007 at 05:59
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I cannot seem to stabilize 200gr Nosler Part bullets in my 300H&H rifle. Any comments or help on this subject will be appreciated. I have shot enough 178 gr Hornady and 200gr Sierra Gameking bullets to know that they stabilize.

Why will the Noslers not stabilize? Is it that the Noslers (flat base) have to much bearing surface? I do not have a runout gauge so I cannot check concentricity. I do however take the utmost care during the reloading process. The rifling is 1:10 checked.

I have read a fair amount regarding the loading for a 300H&H using our local powders and I am right within all the specifications. So there is nothing glaringly wrong.

According to the tables the 200gr should be doing about 2750 ft per sec.

 

I am also posting quite a few targets, as a picture paints a thousand words or something like that.

The first two pictures are of 178 grainers, the next three 200gr Sierra Gameking and the last three the dreaded 200gr Noslers. In all cases I have fired a minimum of 5 rounds as per Graysteel and Dale’s request.

Take a careful look at the last target and you will see why they insist on 5 shots. Look at that 3 shot grouping…… Now if I photoshopped those other two holes out maybe the Noslers would work for me!!!!!

I am not looking for target accuracy, but 1 ˝ inch would make me happy. Any comments???help????

 



Edited by 8shots
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/22/2007 at 10:31
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have you checked 200 and 300 yds groups the bullet may not have stabalized by 100 yds. partitions are not known for accuracy, have you checked a different lot # ?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/22/2007 at 10:57
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No I have not checked longer distances. I thought that the Sierra boattails may in fact give the short distance stability problem.

Maybe the answer lies in your statement - "Part are not known for stability" and no matter what I try it will not work.

I have purchase 3 x 50 boxes but did not check lot numbers. They are a bit expensive for me to purchase diff lot numbers. Either these work or they get tossed.

Thanks for feedback.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/22/2007 at 15:42
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8shots!!!!!.......................That is somewhat of a strange problem you have there!!! The same rifle you had spent the money on too? Assuming that nothing else is wrong; scope, barrel, stock, bedding, brass, bullet uniformity, COL, etc., I would concentrate on changing the bullets and your powders around and try different combos. If your groups tighten up by changing and using different combos, then your particular rifle does not prefer the 200 gr.partitions with that particular powder you are using. Also, I`ve read that certain barrels just need more rounds through them to shoot better. If after experimenting and you still get lousy groups, then you may require another barrel. However I`m sure, that the least of your problems is your Leupold scope???? LOL!!!!!..............For my newer 300 WSM Ruger Frontier 16.5" barreled compact, about 3 months ago, I loaded up some 200 gr. Accubonds for the first time. 100 yard groups were a consistent 1.20", outside to outside or less for 3 shots. Chrono`d MV was 2828 fps. using 69gr. of RL 19 (max. load)..........Switch to the 200 gr. Accubonds and see what happens!! If your groups tighten up, then forget the Partitions. You are really gonna have to do some playing around with this one!! Have some coffee and contemplate!!! 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/22/2007 at 23:10
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I don't think checking at a longer range will do you much good. Rate of spread generally doesn't decrease with range. It usually only increases. In other words, once the bullet is traveling on a line that is not parallel with the bore it will tend to continue on that line.

I agree with the general view. I would suspect the bullets themselves maybe a bad lot like Dale suggested, maybe they just don't like the power load. As changing the bullets tightens the group, I would try either a different lot or significantly dropping the power load to see if that changes anything. Just my two cents.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/23/2007 at 10:50
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when a projectile is at the change pt in stability it will cork screw around the trajectory flight path as well as pitch and yaw. Some are just worse than others. slow motion 44 mag cleary shows, and 38 super loads in 160 with twist rates below 1/9 where a problem for many years. I have a steyr PSS that shoots 200 gr SMK even better at 300 yds than 100. ranges past about 500 are different.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/23/2007 at 13:49
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Certainly, the helical path mentioned can be an issue with any spin stabilized rounds, but my understanding is the total dispersion from that is fairly small compared to other factors. I would be surprised if the dispersion from a helical path in this case would exceed 1" maximum. (I would be really interested folk's thoughts on helical path dispersion numbers) Also, I don't see much elongation of the holes, so I wouldn't think there could be too much precession present. I am not disagreeing with Dale's point; I just still have the feeling that because the variance to so large, less subtle causes may also be playing a role.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/23/2007 at 14:56
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closer to 4" in 44 and up to 9 in 38 super, my PSS would run about 3 at 100 yds. keyholing in 38 super. also 64 gr wsp .224 will give about 2 in at 100 yds in slower than 1/12 twists. and slower than 2600 fps. and keyholing about 1 in 10.

Edited by Dale Clifford
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/24/2007 at 12:49
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Thanks for your feedback on this one. Yes I need to drink a cup of coffee and think it through. My intentions are to try both the very top end load or around 2900 ft per sec, and the bottom end, around 2400 ft per second. If neither gives a positive answer, then the box is going out of the window. I will then have to rethink my premium bullet strategy. Maybe go for 180gr, but that is another problem for later.

Graysteel this is my newly rebarreled rifle. The 200gr Sierra Gameking seems to perform ok for hunting. 180 gr performs very well, even putting me into second place in a shooting comp a while ago.

My guess is that this rifle do not like the Nosler for some reason. The Barnes X apparently is also difficult a bullet I am told. I thought of going to Barnes X, but a reliable shooter friend says it will give me the same level of frustration. So there must be something said for each make of bullet and how a rifle responds to it.

I will be out of shooting this week-end, but hope to report back week-end next about upper end and lower end loads on the Nosler.

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/24/2007 at 13:52
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I would certainly be interested to hear your follow up. Speaking of follow ups... Dale, those are interesting numbers you posted, do you have a feel for the length per rotation of the helix for any of those rounds? It would be interesting to get a feel for rate of procession in those rounds.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/24/2007 at 15:22
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a close look at the coupled differential equations sierra uses for their ballistic programs shows that they can be combined to give 2nd order quasi-peroidic differentials  of the Duffings types, and as such the "system" dampens out at some point (the trajectory of the differentials or phase diagram forms a spiral or degenerating helix). the 44 period of oscillation as far as I can tell from the slow mo's is about 2 ft. My impression of the 38 super is about 3 feet from, playing with keyholing, and the 64 grs .233 about 5. this obviously points to velocity as being a big determinate (not in the matrix sense). I have no idea on the stey-- with a 1/12 twist it came as a suprize, but I rarely use 308 past 600 yds. preferring bigger stuff. I suspect the center of mass plays the largest role.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/25/2007 at 02:20
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Dale, please repeat yourself, but in English this time!!!!

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/25/2007 at 08:50
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Dale, thanks very much for the info. 

8Shots, basically he pointed out the path is one of a helix that has a continually decreasing diameter. The bullet doesn't simply stabilize at some point during the orbit, but actually tends to approach the center axis.

This is a correction of my statement (better model) that suggested the error was an additive process  i.e. (Diameter of the Helix + Angular Variance)

In the model I suggested, a moderate diameter helix combined with a small angular variance would tend to produce a round that had an apparent decreasing MOA variance, but still had an increasing total variance. In other words, the bullet impact may be 2.5 inches off at 100m - 2" from the helix and 0.5" from the angular error. And the bullet may be 3 inches off at 200m - again 2" from the helix and now 1' from the angular error.  In this case the bullet is displaced by 2.5 MOA at 100 and 1.5 MOA at 200. The MOA decreased, but the total error still increased from 2.5 to 3.

Dale points out this is a 2nd order function, meaning the rate of change also changes. He also points out that the rate of change is approaching zero. This means the round is forming a tightening (decreasing diameter) spiral around the axis of the bore (approximately). In this case it is possible to actually have a both the MOA and the total dispersion decrease at longer ranges. For example, if the helix starts with a diameter of 4 inches, and there is an angular error of 1 MOA, the bullet could seem to be 5 inches off of target at 100m. However, at 200m the helix may only have a diameter of 1 inch, so that the total maximum dispersion would be 1" + (1 MOA @ 200m)  resulting in an error of 3" rather than 4". The apparent MOA has decreased and the total dispersion has also decreased. The rifle has become more accurate not just in measure of angle but also in absolute spread.

He also points out that from the slow motion video's it appears the diameter of the helix is such that this is a likely outcome.


Edited by Graysteel
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/25/2007 at 10:48
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Thought I said that.

 

If a system can be reduced to a "control system" many tools become available, rather than using hit or miss (no pun intended) "experiments". LTI (linear time invariant-laplace transforms) are ideally suited for this stuff. Spring oscillations, beams and such mimick the behavior of almost any system. The description of the ballistics of projectivle by Sierra and others in this stuff (JBM) require numerical computer computation (affectionately referred to as numanal) using solvers that iterate a variable thru a matrix of input values. For the sake of simplicity these are then given in tables using each of the coupled variables "plotted" against the first input, usually time or distance along an x axis. (frequency if they are waves). Because of the readership and the goal of the use for this information they are never plotted against each other (phase diagrams) as the information has little to do with the outcome of the shot. Perturbation simulations can then be "injected" at this point to see "at that  point" when center of mass causes instability (bifurcation parameter) and the projectivle becomes a hockey puck or a badmitton birdie.

Graysteel's "translation" is right on and add that at some point the projectile "wants" to become more accurate but the perturbation by outside forces takes over and one sees the statistical dispersion that accompanies long range shooting endeavors.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/26/2007 at 13:00
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Originally posted by Graysteel Graysteel wrote:

......... Dale, those are interesting numbers you posted, do you have a feel for the length per rotation of the helix for any of those rounds? It would be interesting to get a feel for rate of procession in those rounds.

 

I too have wondered about those numbers!

 

I have looked real hard at those target pictures and I can only see 'perfect' nose forward bullet holes.  (One does look a bit funny until you realise that it crosses an inked and un-inked zone on the target.  The 200gr Nosler Part. bullet holes all look very true.

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/26/2007 at 13:23
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8shots, I think you and I should just go hunting!

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/29/2007 at 14:32
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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/30/2007 at 02:29
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Thanks for that Dale.  This is fun!
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/30/2007 at 03:02
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Thanks for all the feedback. Dale thanks for that website. Will have a closer look when I have time.

303Guy, I also looked at possible keyhole effect etc, but the bullets seems to punch straight. Anyway, this coming week-end I will try the higher end loads etc.

Man, you are welcome for a hunt. Just bring lots of ammo!

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/30/2007 at 03:47
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Originally posted by Dale Clifford Dale Clifford wrote:

get some beer and peanuts.

 

http://www.nennstiel-ruprecht.de/bullfly/index.htm#Figures

 

Good site, thanks Dale!

 

Doug

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/31/2007 at 23:57
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Originally posted by 8shots 8shots wrote:

Man, you are welcome for a hunt. Just bring lots of ammo!

 

Ahhh ...  memories of the African bushveld!  That looks like great hunting you are doing!  Good to see those pictures.  I had forgotten what it was like.  So very different to my wet, wet, hunting conditions here.  Our biggest danger here is slipping in the mud or getting lost - and you can get hurt!  Easy to go down a steep slope and break a leg or worse.  Happens often.  Guys go out hunting or just for a hike and don't come back.  They get lost or injured.  Sometimes they don't get found for days and then sometimes they don't survive.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: November/01/2007 at 04:35
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Funny, we were talking in a PM about Nieu Zeeland hunting. Our Nov 2007 Magnum has a full length article on NZ hunting with pics of Red Stag, Wallabies, Thar and feral pigs!! It is written in Afrikaans, sou it won't be of value to post it on the forum.

Edited by 8shots
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: November/01/2007 at 07:01
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Great pics there 8shots, I hope you get that whole thing sorted out bro. Good luck
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: November/02/2007 at 08:23
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Well, I dressed in my most effective camo this morning and sneaked out to the rifle range. I had loaded up the night before 6 rounds of 165 gr capstan bullets to 3000fps, 5 rounds of Sierra Gameking to 2850 - 2900fps and my famous Nossler Part to the same as SierraGamek.(fps taken of load tables, not chronied) This meant charging up the case with some secret help from my PM buddy (thanks you know who you are).

I also increased the OCL by 1mm to cater for the additional pressure.

I post the targets as I shot them, with some explanations. Shots 1 and 2 on the 165gr was from a cold, reasonably well cleaned barrel ie light copper removal was done.So I feel shots 3 to 6 may be the ones to look at.

On the Nosler Part, shot two I felt was a flincher, as the rifle now has a healthy handshake and at 25x the scope seems a bit larger then I like!

The Sierra Gameking performed the worst. The shot with a question mark next to it is just that, also a possible flincher.

My conclusion is that I now have a load that will work for me on the Nosler. Obviuosly some more shootig will show if that 1 shot was indeed a flincher or just wishfull thinking on my part.

Thank you all for your comments and interest, hopefully you enjoyed this little excercise as much as I did!!!

 

 



Edited by 8shots
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: November/03/2007 at 14:23
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8shots,  having a closer look at these target holes, you can distinctly see the yaw.  Some paper seems to show it up better than others.

 

The following are pictures from another site with similar problems. 

 

 

 - notice the circular pattern? These are 55gr BT.  The second target (zoomed in more) are 60gr flat base.  (In 223)

 

Now for one of your targets!

 

 

This is your only group that 'looks' like it might have a yaw induced circular pattern.  Your others do not show this so this one may just be a coincidence.  The second picture with the holes that show yaw might be seen as 'circular' -if you squint at it.

 

Of course, this does not solve your problem - it was just for interest!

 

 

 



Edited by 303Guy
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