Long Range Hunting Online Magazine

Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Rifles, Bullets, Barrels and Ballistics


338 LM Improved w/ gain twist barrel

LinkBack Thread Tools Display Modes
Old 01-01-2011, 02:52 PM
Gold Member
Join Date: Mar 2004
Location: Las Vegas, NV
Posts: 550
Re: 338 LM Improved w/ gain twist barrel

I shot 8 more of the 276s again today, to verify velocities so I can add more info to the mix from yesterday's range session. Today it was nearly identical as yesterday for weather. I shot my last 295 6.5 Caliber as teh 100 yard zero calibrator and get the ball rolling. I then shot 8 of teh 276s, watiing 2-3 minutes between shots.

The load was not a developed one, but simply one that I know was going to be safe (it was 2.0 grains less then what had popped/leaked on my yesterday). Anyway, the load produced an average velocity of 3,106 fps an ES of 30, and was a 1.0 minute load. Given that teh minute was mostly verticle, I suspect a real accurate load is nearby, but not the 103 grains of Retumbo that I was using. I also think that today's velocities confirms my estimate yesterday of 3,150 to 3,200 fps for the top tested velocity.

FYI until I can do more at distance elevation and drop testing with known loads and color coded bullets, I'm calling the ball on BC on the ZA 6.5 at 3,200 fps as roughly .940. That does not suck too bad at all... But since that speed is not one thatI can or want to replicate it is likely of interst only to the 338/408 shooters where I believe 3,300 - 3,400 fps is easily within reach.

Noel wanted me to also mention that given my recent success with the 6.5 caliber ZAs, he wants me/us the start testing the 7.0 caliber projectiles as soon as he can get some produced.

When I get them and shoot them, I'll let you know what they do.

Reply With Quote
Old 01-02-2011, 09:35 AM
Platinum Member
Join Date: Feb 2004
Location: Pennsyltucky
Posts: 2,625
Re: 338 LM Improved w/ gain twist barrel

Jeff, thanks for all the info, i'm sure most of us fund this stuff very interesting. my question would be how you determined to use a 5.4" exit twist? this just seems flat out way outside the box and was just wondering if it was determined you needed something this fast. did Noel or someone with experience recommend this fast a twist?
Reply With Quote
Old 01-02-2011, 12:55 PM
Silver Member
Join Date: Jan 2008
Posts: 414
Re: 338 LM Improved w/ gain twist barrel

My goodness Dave, where have you been for the last two yrs. There have been lots of tests run on this class of bullet for at least that amount of time. None of it has been kept secret and it is still available for you to review on various threads both here and on Snipershide. Granted, I did most of the early testing and I may not have the " Experience " needed to perk your interest; however, if you care to spend the money and time to acummulate the barrels, cases, copper etc to do your own tests Im sure the bullets will act the same whether fired by a vastly experienced person such as yourself or some inexperienced hillbilly like me. Better yet why dont you amble on down to the house and I will let you use my stuff to verify how these things act. I still have a few of each of the various prototypes and several twist rates. I bet you will leave more experienced, even if the experience was handed to you from a dumb-ass like me you may find it usefull. Oh, by the way have you noticed even with the jacketed bullets, longer bullets require tighter twist.
Reply With Quote
Old 01-02-2011, 02:35 PM
Gold Member
Join Date: Mar 2004
Location: Las Vegas, NV
Posts: 550
Re: 338 LM Improved w/ gain twist barrel


Yes I had input from both Noel, Agustus, and Frank at Bartlein, in figuring out the 5.4" exit twist on that barrel. I suspect a 5.0" would be better, as with the very long solids (as in 6.5 calibers or LONGER in length) I'm not sure you can ever twist them too muhc. Its not like they will come apart; nowI have had some go unstable like the ones I test ed the other day, but they dop not go poof after leaving the muzzle, just kind of wobble then carwheel off into the netherworlds never to be seen or heard from again.

The good news is it looks like there are several folks moving aggresively into the solids realm, and I'll be testing and shooting lots of the bullets this coming spring and summer. I'll be noting which ones work and which ones don't from my rifle. All in all its a learning curve for both myself and the manufacturers.

Reply With Quote


Thread Tools
Display Modes

Similar Threads for: 338 LM Improved w/ gain twist barrel
Thread Thread Starter Forum Replies Last Post
338 Lapua improved barrel length & twist rate ? Kiwi Greg Long Range Hunting & Shooting 7 07-27-2010 02:54 PM
Bartlein Gain Twist Barrel Report Black Diamond 408 Rifles, Bullets, Barrels and Ballistics 7 06-30-2010 09:09 AM
Gain twist rifling - pro's and con's GaryJones Rifles, Bullets, Barrels and Ballistics 2 03-10-2005 10:45 AM
Gain Twist Barrels TGScott Rifles, Bullets, Barrels and Ballistics 2 12-01-2004 10:13 AM
Gain -Twist barrels BC SHOOTER Rifles, Bullets, Barrels and Ballistics 1 01-11-2002 01:41 PM

Current Poll
Do you archery hunt for elk?
YES - 32.04%
66 Votes
NO - 51.46%
106 Votes
Not yet, but I plan to. - 16.50%
34 Votes
Total Votes: 206
You may not vote on this poll.

All times are GMT -5. The time now is 09:16 AM.

Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC