Today I shot some brass cases in the AR and finished that lot in the bolt gun because of too much pressure in the 3 twist.@45-90 are these numbers with hybrid brass? Could I run these loads in normal brass? Or is there too much pressure?
The hybrid cases have more H2O capacity by 1 to 1.2 gr, depending on what case the 8.6 has been made from.
And I run them at QL 65,000 psi.
Brass is a bit lower, 58,000 psi area, but will take slightly higher pressures, but not for as long.
Alpha cases are available in 8.6 blk and are good for higher pressure loads also.
Every gun is slightly different and loads must be worked up to.
None of the 6.5 twist high velocity loads are safe in the 3 twist...I just did the experiment on that!
And damaged two cases long before reaching the 6.5 twist velocities!
Absolutely do not use any supersonic data from the 6.5 twist in the 3 twist... Brass or hybrid cases...It will be dangerously way over pressure long before reaching the 6 5 twist velocities.
If you desire that level of performance get a 6.5 twist barrel.
It can not be done with a 3 twist.
I have, as of today, retired my 3 twist forever, as it offers "me" nothing.
It just doesn't have accuracy, velocity, or versatility of the 6.5 twist.
So my whole post is to inform those not satisfied with the Faxon 3 twist, as I have been, in its performance, is to upgrade to the 6.5 twist instead of wasting time and money on tbe 3 twist.
This has been the easy button, almost all my load development is done.
I have it down for most every 338 bullet I'm likely to use, from 160 gr to 350 gr.
Have some 272 gr fmj and 250 SMK to try.
So all the rest of the data will be from the 6.5 twist, not much help for those staying with the 3 twist...also staying with the hybrid cases, they are working out really well, they take more pressure and have slightly more capacity.
The 6.5 twist McGowen has solved all my
8 .6 blackout problems, along with the hybrid cases. It just works with no problems.
If ya stay with the 3 twist you'll have to accept it's limitations, and do your best with what ya have.
These are my experiences with the 8.6, and what I have found out, through a lot of time and expense.
Just sharing the information and trying to keep people on the safe side, while introducing new information, like a different twist rate, that worked for me,... that may or may not be helpful to them...you have more choices.