Bartlein Gain Twist Barrel Report

[Black Diamond 408]

I installed my 375 cal Bartlein "T" twist or Gain twist barrel and chambered it in my 375 Snipetac caliber. The barrel starts off at 1 turn in 16" twist at the breech, speeds up to 1 turn in 7.75" at the muzzle,31" long. This barrel is intended for the new style Alum tipped high BC bullets, but for barrel break in I will be using the 350gn Sierra Matchkings.

Viersco Custom repeater action
double helical fluting on bolt
Manners MCS T2 carbon stock
Bartlein stainless barrel, 31"
Detachable 5 shot magazine system
30 moa scope base
8-32x56 nightforce scope
Jewell trigger
17.25# with Bipod

Starting test results were done during shoot n clean barrel break in.

Retumbo powder
fed 215 primers
350gn Sierra matchking bullet, seated to touch lands.

130gns powder
2919 Ave fps ES 5 .780 group

132gns powder
2949 Ave fps ES 8 .665 group

134gns powder
3001 Ave fps ES 7 .195 group
This group was fired with no cleaning between shots. Shot 1 was clean barrel, 2-3 and 4 were
in a ragged hole.

I am working up to the top load as I break in the barrel, all of the test loads show no pressure signs. I was shooting 140gns in another one of my rilfes chambered for the same case. I will take my time getting to the top load while break in of the barrel. Once this is done I will switch over to the 370gn Alum tipped bullets and stretch out the range to 500yds.

Dave

 

[Ernie]

Dave,
Beautiful rig-Can't wait to see it stretch its legs a little more with those HAT's

 

[yotefever]

Thanks for the report, I've been real interested in the gain twist barrels.

 

[Master Diver]

Dave,

That sure looks great.

Lots of D&D in getting thoise LGT barrels to work.

Keep up the great work

Can't wait to get my rifles from yougun)

Cheers,

Master Diver

 

[Pdvdh]

Cool stuff. Nice lookin rifle.

Gotta feel pretty good about the three shots in one hole. Hope to hear some more as you continue on to the 370 gr Al tipped bullets.

 

[Crane]

I want it!

 

[groper]

whats happening on this front dave? i wouldnt have thought the jacketed bullets would not have survived at a velocity much past 3000fps with an exit twist of 7.75in... how fast did you get them to go and did you experience any of them flying apart?

 

[Black Diamond 408]

The Match Kings dont come apart at vel of 3200 through my barrel, but the twist is way too fast
for this bullet type. Accuracy is not good at any distance so i stopped all tests with that bullet, no use waisting them. I have tried several solids through it, except for the extreme 7 cal bullets. I am not going to re throat this barrel just to test a new bullet that might not work. The bullet that i found to
be totally amazing is the 350gn Predator solid, i can push them over 3200 if i desire. Accuracy is amazing, groups have been sub .5 moa at distances past 1100yds. I fired several 1400 yd groups in the wind to 7", and this rifle is a hunting stlye with repeater magazine. Not a bench rest rifle at all.
The whole set up is under 17#