Loading for a polygonal 6mmBR

[oldjad01]

I just shot my new PacNor 26" 10twist polygonal SS 6mmBr barrel. Loads were 29-31gr Varget, CCIBR4 primers, new Lapua brass. Only hit 2900+fps with the 30.5 and 31gr loads. I was loaded off the lands a bit, will set the bullets .010" back of the lands to .010" into the lands for my next test. Checked the pressure ring on fired cases and it was only .0002" larger than the new cases. No primer, extractor, or bolt lift signs of course. Looks real mild. The poly bbls are reputed,by some) to be faster than the ballard rifling and so the pressure may not be coming up to give the 3050-3100fps that I have seen for that load. I guess I'll just keep upping the powder by .2-.3gr until I get the velocity or the pressure signs. BTW: the loads up through the 30gr,1.5")gave erratic velocities and patterns, not groups. The 30.5g was .9", the 31g <.5. Looks like I need a little more powder, but the increase in velocity is only a couple of feet from 30.5 to 31grs.
Any suggestions on this would be appreciated. Seems that the Vmax, varget, Lapua brass and CCIBR4's are working for most everbody that I have heard use it. I realize no load works in every rifle. I do want to try some BIB and Berger 90's and a couple of more powders for a casual silhouette load, but the Vmax are what I would like for Varmits.
Thanks, JimDee
BTW: the bbl has a grand total of 20 rounds through it.

 

[Forum Boss]

I assume you're talking about the 87gr 6mm Vmax. If you can live without the polymer tips, try some Berger 88 gr Match High BC FB. I've found that recent lots are more consistent than Hornady's Vmax. You can also shoot the 90gr boattail from a 10-twist. The 80gr Bergers are also super-accurate but the V-max is a better bullet in the wind.

I just had dinner this evening with two other 6BR shooters. We were all laughing at the facts that we have jugs of Varget that we've given up in favor of other powders.

If you're shooting the 87gr V-Max,hence the 10-twist), I suggest you try AA 2520 or Hodgdon 4895 for max velocity, N135 for accuracy.

 

[JohnJ]

Iv got a 1/10 twist BR and it doesn't like varget at all...i was getting silver dollar groups at 200 yards so i try ed some AA 2460 that i have for my 7mm int and now i have ben able to get 4 shots to touch and one just outside the group....at least this power looks promising for me with the 87 vmax and 88 bergers....i dint know what the velocity is as im just working on groups now...now all i need is more range time to work on the loads

Johnj

 

[oldjad01]

Thanks for the advice. I've got a jug of 2520 and some H4895. I'll give it a try. JimDee