300 Mag version of 6BR-AI (BRA)!

[SHall]

Meet the 300 Short Ackley Magnum, made from the parent 300 RSAUM case using Norma brass. I made the body taper the same as my 6BR-AI and same 40 degree shoulder. I actually started this project several years ago when 300WSM Norma brass was in very short supply and impossible to find. But you could find 300RSAUM Norma brass easily and a lot cheaper. Norma WSM was going for about $2. a piece if you could find it. 300RSAUM Norma brass was $1.19 to $1.27. My thought was to get WSM velosity and have a more stable case than either. 40 degree shoulder basically stops brass flow. No donuts and no case trimming!
Below I added the reamer drawing of the “Short Ackley Magnum “. And no I did not name it after my name, SAM, it just came out that way. Also, for comparison a 300 RSAUM Print. The “SAM” powder capacity is right between the RSAUM and the WSM but duplicates (at least) WSM velosities. It hold about 2g less of H4350 then the WSM and about 2g more than the RSAUM. Any of the Short Mags pound you pretty hard, so I had R.A.D. (Recoil Aided Devise) added the winter. You still feel the recoil by more of a push, but it doesnt jar and hurt you as bad.

(Its late, I will write more this weekend if anyone is interested?) Samuel Hall

 

[bcarico]

It sure does look mean with that 40degree shoulder. Who made your dies? I may need me a barrel spun up for one of these. Is that what Hunter was kicking butt with last season?

 

[Sniper338]

I pretty much like the look of anything improved or AI...

 

[rardoin]

Your design is very similar to the 300 Sherman Short magnum which is parented by the 300 saum case. I have a 7 SS mag reamer inbound any day now. The SS case, like your AI version looks like a magnified 6BR case. I understand the 300 SS is very easy to tune and has a broad charge weight window of precision. I would expect the same from your design.

 

[dogdude]

300 ''SAM''...very cool .

 

[Mulligan]

Sam,
Thanks for the information, looking forward to more discussion.
CW

 

[SHall]

I shot the smallest group I have ever fired with any caliber at my 500 yard range with the Short Ackley. I always shoot 4 shot groups testing. I shot a .185 one afternoon at 500! It has not duplicated it, but it did it once! The main problem I am encountering is finding really good 308 cal LR VLD bullets. Just about every custom bullet maker is tooled up to make 6mm’s (103-105g) for LR. I know some guys are having luck with Berger, Sierra etc. Maybe I have not found that magic lot, but not me so far, no luck.

It sure does look mean with that 40degree shoulder. Who made your dies? I may need me a barrel spun up for one of these. Is that what Hunter was kicking butt with last season?

Hunter won the only match he shot with it at 1000. I loaded my best VT’s in my 300 SAM and he shot it in some bad conditions and shot a 5 inch something 10 shot in HG.
Whidden made the FL sizing dies and did a great job. The seater is a straight line Wilson cut with my reamer.

 

[Chuckhunter]

Sam just curious, what is wrong with the V.T. 204, that's an impressive 500yd. group but I know it's about consistency and the agg's. Inquiring minds want to know.

 

[Joe Salt]

Looks nice I really like the 40 degree shoulder. Good luck buddy.

Joe Salt

 

[SHall]

Sam just curious, what is wrong with the V.T. 204, that's an impressive 500yd. group but I know it's about consistency and the agg's. Inquiring minds want to know.

The 204’s shoot good, I just had an old lot of 207’s that were outstanding when it came to 10 shot aggs. I am out of those though.

 

[SHall]

Alex Wheeler has a design very similar to mine. Best I remember the body taper is 10 thou per inch where mine is the minimal Ackey reccomended at 7 thou per inch. There is not a dimes worth of difference in the field between th e two though. Tom Mousel has been experimenting with it. To be honest I probably would not do this project again, I would just stick with the WSM with Norma brass. Alex thinks the Improved will agg better over a season because of better effiency of the case design. I do love the case and 40degree advantages though! Looks like a big brother to the 6BR-AI!

 

[Alex Wheeler]

I have a couple, one is your basic 300 saum AI, 40deg with .010" tpi. The other is tightened up at the base for ADG saum brass, so it has slightly less taper, but not enough to have an effect on anything. My main reason for doing them was to be able to use the excellent ADG brass which I put on the same level as Lapua. But if it can run the same nodes as the WSM with less powder (it can), it will agg better in my opinion as well.

 

[Evan]

Mostly just curious, but has anyone tried going a touch smaller? Push down the shoulder 0.010 or 0.020 to drop the capacity 5gns or so? I'm curious how much capacity is actually needed to get everything up to speed as the WSM has always seemed too big, although that allows folks to run a bit less pressure - good for brass and barrels.

EDIT: In looking at it, I'm basically describing a 300-6.5 PRC AI but without better brass available that's not a terribly promising option for BR.

Double EDIT: ADG makes 6.5 PRC brass, so maybe...

 

[jonbearman]

Love that Indian Blanket stock. Very cool.

 

[Capt. Oblivious]

That stock is awesome and that 300sam looks very very nice. I realy like it

 

[Kurz]

Thank you for posting your process and targets for us to cogitate on. I will point out though that you could use the initials ASM instead, Ackley Short Magnum...



Seriously though, this is a good example to use for those times when the haters and kvetchers always ask, "Do we really need another .30 caliber cartridge?", substitute 6mm or 6.5mm instead.

This process is not about developing a brand new cartridge but it IS a process of refinement. It's these smaller refinements that ultimately lead to the better (improved) configuration which produces the most efficiency and accuracy.

Thanks for putting your time, effort and money into this project.

 

[SHall]

Most of the time I refer to it as the 300 SA (Short Ackley). I dont even like having it be associated with my name. I plan on wringing it out at 1000 yard matches this year if our demoncrat governor opens up NC anytime soon.

 

[Alex Wheeler]

I understand in these times where socialism is gaining popularity and capitalism is looked down on, some may fear that there may be some profit involved for those who give away information. I assure you there is none. Do not fear.

 

[Evan]

Most of the time I refer to it as the 300 SA (Short Ackley). I dont even like having it be associated with my name. I plan on wringing it out at 1000 yard matches this year if our demoncrat governor opens up NC anytime soon.

Maybe call it the 300 Smackley (Short Magnum Ackley)?

 

[Alex Wheeler]

This is Sam's thread and I dont want to intrude but I think the abilities of the case are FAR more important than the name, this brings back memories of the BRAI/BRA. Its why I have not talked about this case. Why people care so much about the case name I'll never understand.