6.5 PRC/SAUM shortest barrel length

[khuber84]

How many rounds did you fire into 1 group to realize that?

It takes 2 rounds showing me pressure signs to know better if I want to try load to a high velocity.

 

[Murtobird]

Just finished my 18" 6.5 prc and took it out to distance. 18" 7.5 twist 6 groove carbon 6 barrel. It's for a tikka, and it's tq'd well past aftermarket spec. Went 140ftlbs so I'm sure the chamber dimensions varied after TQ from the usual 75-80ftlbs everyone else does with rebarrels. It shot 2 different lots of hornady 147 factory ammo at 2800 and it shot another company's ammo with 142gr bullet at 2775. (Rated 2820 from a 22") overall very impressed and I wouldn't hesitate to go 18" again.

Morning. Are you saying you torqued your barrel to your action at 140ftlbs and you think it made your chamber smaller? just did a cabon 6 22" barrel and shooting 156gn. bergers at 2771.

 

[yeti12]

Morning. Are you saying you torqued your barrel to your action at 140ftlbs and you think it made your chamber smaller? just did a cabon 6 22" barrel and shooting 156gn. bergers at 2771.

I tq'd it to 140ftlbs yes. I'm not saying for sure it did or didn't. The velocity is faster than it should be. The chamber really wouldn't be smaller, it would just be closer to the bolt face if anything.

When I have more time I'll figure it out, but for now I'm bouncing between it either "stretched" the chamber due to the threads being where the chamber is or it just squished the shoulder of the barrel or face of the action a tiny bit when tightening it.

3 different kinds of factory ammo chambered fine and spent brass from the factory barrel chambered so im not all that worried about it.

 

[Murtobird]

Copy. I am new to all of this, just find it interesting.

I wanted an 18" barrel but settled on the 22" because I could get it faster. I am thinking about my next build.

 

[khuber84]

The chamber is moving but MAYBE a few ten thousandanths(0003?) by torquing form 100 to 150#. The shoulder of the barrel stays put against the front the action. You're just stretching threads.

 

[yeti12]

The chamber is moving but MAYBE a few ten thousandanths(0003?) by torquing form 100 to 150#. The shoulder of the barrel stays put against the front the action. You're just stretching threads.

If that's the only movement, it's more than .0003" it should be .0017" based off how much it rotated from the additional tq.