I thought I would share my initial experience with the (new to me) 6mm BR Ackley Improved chambered in a 1k IBS rifle and rebarreled rem 700 fire forming / field rifle.
At the end of last benchrest season I knew I would need to rebarrel over the off-season as my base to ogive had become 1.850+ on the dasher. The rifle was still shooting and tuning reasonably well at over 2k+ rounds down the tube but I was simply running out of brass to hang on to the projectile. Honestly I wasn't ready to jump on the BRA bandwagon just yet but after much contemplation and discussion with my gunsmith Shawn Williams of North Ridge Rifles ... I decided to go for it!
I knew I wanted a bore rider chamber as I have used them in the dasher configuration and really enjoyed how it tuned and some of the flexibility it offered. I asked Shawn what he thought about the idea and he informed me that one was already on order from JGS... perfect!
Now for the good stuff... We did a 0.268 nk 6mmBR Ackley on my bat 3L action and a matching chamber on my rem 700 action. Both chambers came out perfect. I can fire a piece of brass in the rem and bat, measure both, and have both measure under 0.0005 variation base to shoulder datum. I fire formed 200 pieces of brass in the rem 700 using the cream of wheat method. I used 8gr of Alliant Unique with 15gr cream of wheat, capped with 70% paraffin 30% petroleum jelly melted together and allowed to dry on a cookie sheet (makes for a nice playable slightly sticky wax). The lengths turned out more consistent than I ever managed with this technique with the dasher. The shoulder comes out crisp with a slight radius. All base to shoulder measurements were consistent when taken with a hornady comparator. (I should mention all cases were neck turned and annealed prior to forming)
After the cases were sonic cleaned, tumbled, and annealed... I moved on to an initial break in / ladder test just to find working pressure parameters. I have been playing with HBN coating and barrel treating for a little while so I figured I would try it just for the heck of it during this time. I started with the rem 700 in 0.3gr graduations with H4895. I started at 29.6 and ended at 31.6 when I saw light ejector marks for 2976fps. (HBN coated hybrids, and treated barrel that was salvaged from last year's dasher barrel... which started life at 28.6"... now I'm sure it is a couple inches shorter with the rechamber)
I then moved on to my bench gun with the new 8 twist Krieger and the same ladder test only this time I made it to 32.4gr and 3060+ fps before I saw a light ejector mark. (32.4 did not read on my chrono but 32.1 did for 3051fps). Both rifles produced a nice little ragged hole at 150yds during this test with a few just slightly out at the lower charge end. The rem appeared to cluster from about 30-31gr and the bat liked just about everything from 30-32gr... which is nice. So far I am enjoying what this little cartridge has to offer! I will post more as I get into serious tuning... but initial results are promising!!! More to come!...
James Bradley
At the end of last benchrest season I knew I would need to rebarrel over the off-season as my base to ogive had become 1.850+ on the dasher. The rifle was still shooting and tuning reasonably well at over 2k+ rounds down the tube but I was simply running out of brass to hang on to the projectile. Honestly I wasn't ready to jump on the BRA bandwagon just yet but after much contemplation and discussion with my gunsmith Shawn Williams of North Ridge Rifles ... I decided to go for it!
I knew I wanted a bore rider chamber as I have used them in the dasher configuration and really enjoyed how it tuned and some of the flexibility it offered. I asked Shawn what he thought about the idea and he informed me that one was already on order from JGS... perfect!
Now for the good stuff... We did a 0.268 nk 6mmBR Ackley on my bat 3L action and a matching chamber on my rem 700 action. Both chambers came out perfect. I can fire a piece of brass in the rem and bat, measure both, and have both measure under 0.0005 variation base to shoulder datum. I fire formed 200 pieces of brass in the rem 700 using the cream of wheat method. I used 8gr of Alliant Unique with 15gr cream of wheat, capped with 70% paraffin 30% petroleum jelly melted together and allowed to dry on a cookie sheet (makes for a nice playable slightly sticky wax). The lengths turned out more consistent than I ever managed with this technique with the dasher. The shoulder comes out crisp with a slight radius. All base to shoulder measurements were consistent when taken with a hornady comparator. (I should mention all cases were neck turned and annealed prior to forming)
After the cases were sonic cleaned, tumbled, and annealed... I moved on to an initial break in / ladder test just to find working pressure parameters. I have been playing with HBN coating and barrel treating for a little while so I figured I would try it just for the heck of it during this time. I started with the rem 700 in 0.3gr graduations with H4895. I started at 29.6 and ended at 31.6 when I saw light ejector marks for 2976fps. (HBN coated hybrids, and treated barrel that was salvaged from last year's dasher barrel... which started life at 28.6"... now I'm sure it is a couple inches shorter with the rechamber)
I then moved on to my bench gun with the new 8 twist Krieger and the same ladder test only this time I made it to 32.4gr and 3060+ fps before I saw a light ejector mark. (32.4 did not read on my chrono but 32.1 did for 3051fps). Both rifles produced a nice little ragged hole at 150yds during this test with a few just slightly out at the lower charge end. The rem appeared to cluster from about 30-31gr and the bat liked just about everything from 30-32gr... which is nice. So far I am enjoying what this little cartridge has to offer! I will post more as I get into serious tuning... but initial results are promising!!! More to come!...
James Bradley