What's your twist? I think you have to be real careful when you crowd it as hard as we were. There were 6-8 guys here with 6x.284s, all 1-14" twist, all with barrels from the same maker, same batch, cut with the same reamer.
The guy who got it all started went up to 55 grains of Varget under a 60 grain Sierra. He claimed over 4300 fps. That seems way overboard but they gave me 5 rounds to test in my gun ... no problem pressure signs and they grouped under half inch.
All of my ammo, and that load above, were in Norma 6.5-.284 cases necked down, with Fed 210M match primers.
That bullet has a low BC so I went off in another direction. I wound up mostly shooting the 70 grain ballistic tip over 58 grains of RL19. Sometimes I'd swap in the 65 grain VMAX but keep the load the same. The accuracy wasn't quite as good but the splatter was greater.
I played with the 75 grain VMAX some, with H414 for some reason I don't recall now, and ran into pressure issues.
I didn't have any problems with pressure, case life was normal, when I lost cases it was to neck splits, not primer pocket problems (other than those 75 grain vmax / H414 loads).
The guys who worked all this crap out told me to expect about 400 rounds barrel life. I was at 800, still shooting good, but figured it was a good time of year to rebarrel (and be without my gun) so I did that earlier than necessary and went with .220 swift next time around. I'm guessing accurate life for my rifle, the way I was loading and shooting it, would have been 1500 rounds or more.
Anyways, I'm not sure I'd want to crowd it that hard if I had a 1-12 or 1-10 twist. I'd for darn sure work up real real carefully.
One of the guys in the group had one with a 1-7" twist. Someone .. Berger, I think, makes a 115 grain VLD, and there are several in the 105-107 grain range. He also had a .243 AI with an identical barrel. He wasn't able to gain anything useful over the .243 AI with the VLDs, about 50 fps before he'd begin blowing primers and sticking his bolt.
I come away from that 2-3 year period when we were working with them a lot is that as a quick twist VLD-driver, the 6x.284 is not a net gain, you burn a lot of powder, from expensive brass, with shorter barrel life, more recoil, and don't gain much velocity. On the other hand, with a slow twist for varminting use, it may be a lot more useful. My gun comfortably pushed the 70 grain Nosler as fast as my swifts would push a 55 grain bullet, but the 6mm 70 grain has a much higher BC, a lot more frontal area for more "slap" on target, and better SD. Certainly at a higher cost, though. Whether it's worthwhile is a personal choice.
I'm on the cusp of building another. I can't decide whether I'm going to do a 6x.284 with a 1-14" twist to handle those same bullets again or do a .22-250 AI with a 1-12" twist to drive 60s comfortably.
On varmints, the two most vicious chunk splattering things I've ever owned are that 6x.284 and my current .204 ruger, both exceed the splatter capacity of the .22-250 (I've had 5) and .220 swift (I've had 4) by a noticeable margin on the size varmints I shoot. I 'spect the big .22s would whup the .204 on slightly larger critters but they'll never touch the 6x.284.
Tom
