6bra Fireforming Tubb TMS AR Comp

[urbanrifleman]

Took my Rock Creek 1-8 6br prefit with about 1200 rounds and rechambered it with my fingers to 6bra. Headspace to 4 short. Bone stock Remington 700 single shot from Buds Guns trued by hand by my smith. Jewel trigger. Stock made from CMP 40X stock by my buddy Terry Tabor.

Tubb said shot several TMS bullets to clean up the throat. So I did.

Fire forming AR Comp 29.2 to 29.9 with 108 Berger. Jumped 25 thou.

Shot with Tubb bipod and squeeze bag. Tubb brake.

 

[urbanrifleman]

Best group after about 25 rounds post TMS rounds.

 

[urbanrifleman]

Groups immediately preceding that group.

 

[urbanrifleman]

Keep in mind these are not benchrest groups. Bipod and squeeze bag. Scope is 20 power.

 

[KenOath]

Coming along nicely..

 

[urbanrifleman]

Coming along nicely..

No load work up. I have no idea which load shot the best, they all shot tiny. Velocities were single digits. Range from 2825 to 2855 from low to high. All shot tiny.

 

[22DASHER]

Welcome to the fun of anything based off the 6 BR case. Pretty hard not to get them to shoot.

 

[urbanrifleman]

Welcome to the fun of anything based off the 6 BR case. Pretty hard not to get them to shoot.

I've been shooting 6br for about a decade. The 6bra seems to be even more forgiving.

I posted to show the TMS bullets didn't ruin my barrel. Quite the contrary. And AR comp flat shoots.

 

[Okiehunter67]

Did the TMS move the lands out any??

 

[urbanrifleman]

Did the TMS move the lands out any??

The lands ended up right where they should have been after break in. If it did, it wasn't much. Maybe a thou or two. Hard to tell. Break in will move the lands a bit.

 

[urbanrifleman]

More fireforming testing. 108 Bergers AR Comp.

In rows:

29.2
29.4
29.6
29.9
30.2

29.6 and 29.9 shot the best I suppose. None sucked. Certainly not bad for a bipod.