New Posts New Posts RSS Feed - Sensitive barrel?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Check GunBroker.com for SWFA's No Reserve and No Minimum bid firearm auctions.

Sensitive barrel?

 Post Reply Post Reply   Topic Search Topic Search  Topic Options Topic Options
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 07:43
8shots View Drop Down
Optics Jedi Knight
Optics Jedi Knight
Avatar
Lord Of The Flies

Joined: March/14/2007
Location: South Africa
Status: Offline
Points: 5754

I had a new barrel fitted to a Sako 300H&H. The barrel is 24" 1in 10 twist. I have started tuning the loads to match the barrel (which is pillar bedded, free floated by a proffesional stock maker).

I firstly found that new brass has to be fully resized before it fits in the chamber. Brass fired previously through a different rifle also has to be fully resized. Brass once fired through the new barrel only needs to be necksized and fits perfectly.

Using the exact same load specs, except that the brass has either been fully resized or fire formed and necksized, I found that the results are very different.

Fully resized not fired before brass = 4 inches and worse grouping.

Once fired brass and neck sized only = 1and a half inch grouping.

What is going on here? Is the chamber just reamed to very tight specs. Other then the issue with fire forming the brass first, everything else seems OK.

Any comments??

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 08:31
RONK View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire
Avatar

Joined: April/05/2007
Location: United States
Status: Offline
Points: 3199

 

  Are you using two different sizing dies; one full length and one specialized neck-sizer?  If so, it could be a bad full-length die. Neck-sizing usually gives better accuracy, but there shouldn't be that big a group by full-length sizing only, since your barrel shoots quite well otherwise.

  Just for kicks, slide a cardboard shim under the barrel at the fore-end tip to put some upward pressure on it and shoot a few with your best ammo. Post results.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 08:42
8shots View Drop Down
Optics Jedi Knight
Optics Jedi Knight
Avatar
Lord Of The Flies

Joined: March/14/2007
Location: South Africa
Status: Offline
Points: 5754

I am using two different dies. Both dies worked well with previous barrel, so I doubt if it is the dies playing a role. A gunsmith friend of mine has an extremely accurate 308 custom rifle. I have seen him put 5 touching. He tells me that he has to fireform all of his shells. He in fact makes cheap lead bullets with a low powder load to blow the cases to fit the chamber.

So I am curious to know if this is "normal" for rifles with tight chambers or is something else at play, like maybe a crooked neck ream?? The brass coming out of the new barrel looks straight and nothing obvious can be seen.

The experience with the poor grouping of not previuosly fired brass is consistant over a number of firings.

The rifle also is very sensitive regarding OAL and amount of powder. Groupings go way out when any one factor is only slightly changed.



Edited by 8shots
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 09:36
Dale Clifford View Drop Down
Optics Jedi Knight
Optics Jedi Knight


Joined: July/04/2004
Location: United States
Status: Offline
Points: 5087

the chamber is a very "loose" chamber. when full length resizing the brass is being moved to min. dimension, and on firing the firing pin is pushing the case forward until the shoulder or bullet is touching depending on the OAL dimension, (a 300 HH with min. shoulder I'm quess its the bullet and why your showing such a range with OAL). on firing the case is sealing and pushing the web area back, but not as much as seen as a sharp shoulder. This was a common problem when the almost straight case HH was in its top of popularity, and one of reasons for the 300 win mag. If yur using the gun for target the camming action of the bolt should be used as much as possible in building neck sized fire formed cases that are difficult to close the bolt.

a five shot, neck sized, very very tight case, chamber fit case. (pulled last rd)

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 09:55
8shots View Drop Down
Optics Jedi Knight
Optics Jedi Knight
Avatar
Lord Of The Flies

Joined: March/14/2007
Location: South Africa
Status: Offline
Points: 5754

Thanks for explanation Dale.

I have tried to make this hunting rifle a target rifle. The only thing in which I succeeded was to drive my wife up the wall. I went the route of re-barreling and tuning this or that and never being satisfied.

No more. This is a hunting rifle and I am happy to get 1inch groupings. I am also OK with it if I have to fire form all my brass.

For target shooting I have ordered a Rem700 VSF in a 308.

 

Great shooting above Dale! Is that rifle for sale!!!

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 17:54
RONK View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire
Avatar

Joined: April/05/2007
Location: United States
Status: Offline
Points: 3199

 For a rather slender barrel such as you have, !-1/2 inch groups are nothing to sneeze at anyway; plenty accurate for most hunting.

  That is great shooting Dale Clifford .

 

  8-shots, I don't think Dale shot that group with a 300 H&H. If you look closely, it is noted 140 SMK at the top. To my knowledge, Sierra does not make a .30 Match King in that weight. Could be wrong tho'...Correct me here Dale?

 I'm also going to venture that it was fired from a rifle with a somewhat heavier barrel contour than the Sako you posted above. Just don't see too many pencil-barrelled belted magnums that put them all into the same hole.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 17:58
pyro6999 View Drop Down
Optics Retard
Optics Retard
Avatar
OT TITAN

Joined: December/22/2006
Location: North Dakota
Status: Offline
Points: 22024
looks like 190 or 192 or 195 smk  to me
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 18:02
pyro6999 View Drop Down
Optics Retard
Optics Retard
Avatar
OT TITAN

Joined: December/22/2006
Location: North Dakota
Status: Offline
Points: 22024
heres a 30 cal i shoot
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 18:45
hot30 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: December/27/2006
Status: Offline
Points: 378

8shots, look at the case wall thikness of your new brass compared

to that of your old brass. could the new stuff be "thicker" at the neck.??

might be some pinching going on if its thicker. your full length die will

size allittle different on thicker brass( the neck expander)....... Your

neck sizer is without the expander..??????????

 

  Anyway, I would say your doing quite well, what do you want a CANNON

to do about accuracy..  Hollow point boat tails.!!!!!!!!!!!!!!!!!



Edited by hot30
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 20:06
RONK View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire
Avatar

Joined: April/05/2007
Location: United States
Status: Offline
Points: 3199

Originally posted by pyro6999 pyro6999 wrote:

looks like 190 or 192 or 195 smk  to me

 

 

  Dale's target picture? Top left target? Penciled in? You read something other than 140 gr. SMK?  O.K., I better get my eyes checked...



Edited by RONK
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 20:27
Dale Clifford View Drop Down
Optics Jedi Knight
Optics Jedi Knight


Joined: July/04/2004
Location: United States
Status: Offline
Points: 5087
6.5x284 cooper 140 gr SMK. 2900 fps, just used to illustrate when neck sizing really pays off. its part of the erosion test started last spring.  The 300HH biggest advantage is it's ability to feed and chamber even under the worst of conditions. 8shots--you didn't pick a cartridge that is the easiest to work with in a target sense. You will find the 308 more forgiving and without the strange happenings.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 20:44
pyro6999 View Drop Down
Optics Retard
Optics Retard
Avatar
OT TITAN

Joined: December/22/2006
Location: North Dakota
Status: Offline
Points: 22024
sorry the image quality on my end looks very fuzzy. this computer i have is 7 yrs old

Edited by pyro6999
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/14/2007 at 21:16
RONK View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire
Avatar

Joined: April/05/2007
Location: United States
Status: Offline
Points: 3199

Originally posted by Dale Clifford Dale Clifford wrote:

6.5x284 cooper 140 gr SMK. 2900 fps, just used to illustrate when neck sizing really pays off. its part of the erosion test started last spring.  The 300HH biggest advantage is it's ability to feed and chamber even under the worst of conditions. 8shots--you didn't pick a cartridge that is the easiest to work with in a target sense. You will find the 308 more forgiving and without the strange happenings.

 

  Yeah that all makes sense. For serious target work 8shots also needs a heavier barrel, hence my suggestion to shim the forend to try and tighten the groups a bit more. Or possibly a lot more with a bit of luck. Really nice (and nice-looking) hunting rig regardless.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/17/2007 at 03:01
8shots View Drop Down
Optics Jedi Knight
Optics Jedi Knight
Avatar
Lord Of The Flies

Joined: March/14/2007
Location: South Africa
Status: Offline
Points: 5754

Thanks for all the feedback. You are all correct in that this rifle will not be a target rifle. I have given up on that quest and ordered a Rem700VSL in a 308 cal.

I was however just trying to understand the "strange" behaviour for case preference.

However, just to prove it can be done, I participated in a shooting competition this week-end. Distances from 200m, 100m and 50m. I ended up second out of 86 contestants, using the 300H&H! Walked away with a few nice prizes.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/17/2007 at 10:18
Dale Clifford View Drop Down
Optics Jedi Knight
Optics Jedi Knight


Joined: July/04/2004
Location: United States
Status: Offline
Points: 5087
congrats!!!
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/17/2007 at 20:33
RONK View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire
Avatar

Joined: April/05/2007
Location: United States
Status: Offline
Points: 3199
 Good for you! That's gotta be pretty satisfying!  
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/18/2007 at 04:30
303Guy View Drop Down
Optics Apprentice
Optics Apprentice


Joined: September/02/2007
Location: New Zealand
Status: Offline
Points: 55

8shots, is that S385 a ball or extruded powder?  I had difficulty with Somchem ball powders when loading for 223 and 303.  I abandoned it for the older MR200 (pretty good stuff), for both 223 and 303.  My 223 shot 3 MOA with factory ammo and 1 1/4 MOA with reloads, getting down to 3/4 MOA with match bullets.  Have you considered heavier bullets?  My understanding is that the 300H&H was designed for heavies.

 

Congrats on your shooting!

 

 



Edited by 303Guy
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/18/2007 at 05:15
8shots View Drop Down
Optics Jedi Knight
Optics Jedi Knight
Avatar
Lord Of The Flies

Joined: March/14/2007
Location: South Africa
Status: Offline
Points: 5754

Thanks for all the nice remarks. I do feel vindicated, as I drove my wife nuts in the process of getting the rifle sorted out. At least I came home with the meat! Literally, as part of the prize was 2kg of beef fillet!

303Guy, the S385 is extruded.

For target shooting I think the 178gr is about perfect as it gives a relatively flat trajectory and can still buck the wind.

For hunting I use the 200gr Nosler Part, which is enough to knock down anything I hunt. However, the heavier bullets are more difficult to stabilize. I struggled a fair amount last time round to get the right powder combo and seating depth.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/18/2007 at 10:32
Dale Clifford View Drop Down
Optics Jedi Knight
Optics Jedi Knight


Joined: July/04/2004
Location: United States
Status: Offline
Points: 5087
don't know if this has been covered before (to lazy to read back) but 200+ gr 308 need 11 or faster twist rate.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/18/2007 at 13:56
303Guy View Drop Down
Optics Apprentice
Optics Apprentice


Joined: September/02/2007
Location: New Zealand
Status: Offline
Points: 55

Dale,  8shots did say his twist is 1 in 10.  I know little about the 300 H&H but I did have the impression that it is a good shooter so I am quite intrigued that there is a difficulty.  I am reloading for a vaguely similar geometry case - the hornet - with a huge bullet jump and thought I would have accuracy problems with mag fed loads but found it to be quite forgiving and have found a way of making the bullets enter the rifling nice and straight.  Nothing to do with the 300.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/18/2007 at 15:03
Dale Clifford View Drop Down
Optics Jedi Knight
Optics Jedi Knight


Joined: July/04/2004
Location: United States
Status: Offline
Points: 5087
not knocking the 300, just that the less the shoulder the harder to work with the cartridge, like hornets here, cz, 10 in taurus rev, T/C in k hornet. all 3 favor 40 gr vmax.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/20/2007 at 03:04
8shots View Drop Down
Optics Jedi Knight
Optics Jedi Knight
Avatar
Lord Of The Flies

Joined: March/14/2007
Location: South Africa
Status: Offline
Points: 5754

Unfortunately I cannot comment if it is the cartridge or the barrel that makes it difficult to work with, as I inherited the rifle. When I recieved it the barrel (original Sako barrel) was pretty shot out. So I replaced the barrel and all of my load development has been done on a non-factory barrel. So the doubt allways sets in, is it the barrel or is it the calibre (shape of the case).

Off course, also to show that it can be done, Ben Comfort won the 1000yds Wimbledon Cup in 1935 with the 300H&H!!!

I have a 30-06 Heym (also .308) that is a dream to load for. Takes anything I feed it and gives me sub MOA as long as I keep the speeds at the top end and the bullet just off the lands.

 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Similar Threads: "Sensitive barrel?"
Subject Author Forum Replies Last Post
Rangefinders weather sensitive? trigger29 Laser Rangefinders 2
Is IMR Powder more heat sensitive? garyalarson Reloading & Ballistics 6
20 in barrel for 1000 yards?? bigpapa4045 Firearms 55
1-4 scope/barrel issue chase102798 Tactical Scopes 5
Scope barrel/objective threads striped brbob1 Rifle Scopes 2
Short barrel 308 ammo recommendations Lockjaw Reloading & Ballistics 33
Barrel scope gap luka7777778 Rimfire / Airgun 11
Seekins barrels? koshkin Firearms 8
Calculating barrel twist rate and BC 8shots Firearms 1
Which bullet for barrel break in? M7025-06 Firearms 10


This page was generated in 0.328 seconds.