6mm ARC (Bolt Action)

[CollarChoke]

Varget continues to group well with Alpha brass, 105gr Berger Hybrids seated to 2.400" COAL and this time Federal 205 primers seated -0.001" crush. These are numbers for a 24" 1:7.5 with 0.180 freebore (double saami spec for 6ARC), which lets me seat long and opens up case capacity.

For 5 shot groups ES is more valuable than SD, but for completeness:

28.2gr - 2677fps, SD 9.1, ES 19.6
28.4gr - 2713fps, SD 10.7, ES 31.2
28.6gr - 2730fps, SD 8.8, ES 23.6

No pressure signs and QuickLoad has my hottest load at around 60K PSI, so settling on the 28.6 Varget load, which will be less touchy than LVR in the summer I reckon and comfortably hits the velocity ballpark for my requirements.

 

[Mr. Wolf]

Varget continues to group well with Alpha brass, 105gr Berger Hybrids seated to 2.400" COAL and this time Federal 205 primers seated -0.001" crush. These are numbers for a 24" 1:7.5 with 0.180 freebore (double saami spec for 6ARC), which lets me seat long and opens up case capacity.

For 5 shot groups ES is more valuable than SD, but for completeness:

28.2gr - 2677fps, SD 9.1, ES 19.6
28.4gr - 2713fps, SD 10.7, ES 31.2
28.6gr - 2730fps, SD 8.8, ES 23.6

No pressure signs and QuickLoad has my hottest load at around 60K PSI, so settling on the 28.6 Varget load, which will be less touchy than LVR in the summer I reckon and comfortably hits the velocity ballpark for my requirements.

View attachment 8582836

Nice info and great groups.
Any crunching with the 28.6 gr (I realize that you have a longer free bore)?
Thanks in advance

 

[CollarChoke]

Nice info and great groups.
Any crunching with the 28.6 gr (I realize that you have a longer free bore)?
Thanks in advance

No crunch for me but I'm clearing the donut at 2.400" (0.035" off the lands), the pressure and crunch story would definitely be different on a SAAMI chamber spec load

 

[Rob01]

For comparison, here’s my 110 ATip load at about .030” off the lands and at 2.360”. Sits a little deeper but bullet boatail starts at the shoulder neck junction but a little more into the body of the case than above. I could load it a little longer but this is a SAAMI chamber.

 

[46caliber]

105 grain "Match Proven Compound Profile"
6ARC SAAMI chamber.

 

[67rschev]

No crunch for me but I'm clearing the donut at 2.400" (0.035" off the lands), the pressure and crunch story would definitely be different on a SAAMI chamber spec load

Amazing the differences in cambering , and how it can shape the load possibilities of the same cartridge. I'm slightly tight on SAAMMI print . 28 grains of Varget in summer put me into the high 2800s with105 hybrid at .020 off the lands. Sticky lift and loose primers . The loading hammered in winter and was perfect at 2820, but sped up on me and right out of the node . Eagerly watching your results . How many rounds on your barrel ?

EDIT : Had to look back, was with a 108 Berger not a 105 . Reference target

 

[CollarChoke]

Amazing the differences in cambering , and how it can shape the load possibilities of the same cartridge. I'm slightly tight on SAAMMI print . 28 grains of Varget in summer put me into the high 2800s with105 hybrid at .020 off the lands. Sticky lift and loose primers . The loading hammered in winter and was perfect at 2820, but sped up on me and right out of the node . Eagerly watching your results . How many rounds on your barrel ?

EDIT : Had to look back, was with a 108 Berger not a 105 . Reference target View attachment 8585540

That barrel has 489 rounds on it, 469 at the start of the last data gathering trip.

And for sure, I love 6ARC's size because it packs away so tiny so I've been on a quest to turn it into a 6GT-lite. It's a small velocity compromise but if I can consistently tickle 2750 with a nice moderate temp stable(ish) load I'm happy

It was @padom that sparked the idea of cutting a more bolt gun appropriate chamber and I've been very happy with the results. Will definitely run the same specs on any bolt 6ARC barrel going forward.