Velocity for 115 berger

[tightneck]

I just finished building a 6mmAI with a 7twist PacNor for a highpower shooter. We were at the range yesterday working up a load with 115 DTAC's and 115 Bergers. Found a nice load at 3125 with the DTAC's but the Bergers blew up before they got to 50 yards at this velocity. So much for the Bergers, but my question is at what velocity will they remain intact in the 7 twist?

 

[Mudcat]

Interesting. I blew one up last weekend at about 2850fps,guessing on these as I have not chrono'd my 37.0gr H4350 in a 6XC yet) out of a Krieger 1/7 twist. Went about 50-100 yards and POOF! Not exactly something I want my bullets doing in a match!!!

Anyone got some info??

 

[tightneck]

Interesting. I blew one up last weekend at about 2850fps,guessing on these as I have not chrono'd my 37.0gr H4350 in a 6XC yet) out of a Krieger 1/7 twist. Went about 50-100 yards and POOF! Not exactly something I want my bullets doing in a match!!!

Anyone got some info??

Wow, That's not good news at all. I can't believe that Berger would have the recommended twist listed at 7, if the J4's won't stand up to it. Eric, are you listening? Its a complete waste of time to shoot them if you can't push them to 2850 and KNOW they aren't going to blow up.

 

[mikecr]

Tightneck
Using a rule of thumb I made up for Bergers a while back, I predict 2970fps 7tw limit ..

KRPM LIMIT =,0.308-cal)*238.095+290
Velocity Limit then equals 1.38889*KRPMlimit*TWIST

So for the 115 berger:
KRPM LIMIT = 305
Max Velocity = 2,970fps

Course this is a general number.. Independant of barrel & bullet lot. It's based on heaviest per cal bullets only.