6 Rem AI-0 freebore chamber
26" shilen 14 Twist
70g Nosler ballistic tips
51g of Win 760
Rem 9 1/2 primer
4100 fps on fire-formed cases, bug holes abound!
Work up to this load in your rifle, and if you are shooting a 8,9,10T barrel, you may not be able to reach this powder charge without excessive pressure. I had a 10T Douglas that was 100 fps slower, right at 4000 fps, still shot bug holes with the 70gNoslers
80g Sierra Blitz BT
R#19
CCI 250 or Fed 215
3800 fps
AA2700 is a great substitute for Win 760 and is one of the coolest burning powders made. N160 and N165 would be great choices also as they are cooler burning powders also.
A friend has an 8T with .070 freebore, and he is shooting the Berger 108's at 3350 fps and the Berger 95's at 3500 fps.
Back in the late '80s, I shot the barrels out of two 6/284's using 85g Sierra BTHP, IMR 4831, CCI 250 at 3650. Barrels lasted around 1200 rounds, as IMR 4831 with about 56g is not easy on barrels. I would do another but that reamer was set up for Winchester brass, not Lapua, and there are case dimensions to be taken into account.
In today's world, with shortages of all components, brass, and bullets, there are two easy buttons:
243 AI-you need to know if the reamer is SAAMI spec or CIP spec for norma and Lapua brass
6 Creed which is shorter than the 243 AI, brass, and dies are available
The 6/284 and the 6 Rem AI work best on long actions unless you are single feeding. I was hunting coyotes with the 6/284 and a repeater was a must. I had one on a short action, but never ever again, same on a 284 Winchester.
The 6 Rem AI is right at home with the AA2700, H414, Win 760, and H380 which give longer barrel life with 60-87g. The 6/284 likes a slower burning powder, which could be related to case fill. Pard I sold the reamer and dies to is using R#19 with the 85-88g bullets of various types, and simply loves it.