why no necked down 450 BM or 458 socom wildcats?

steve garrett

Active member
I have always hoped we get an AR 15 cartridge that is a huge step up from 223. to me this starts with case compacity of around at least 40 grains or more. I know there is different stuff out there, just nothing with plug and play parts from dies, barrels to mags etc. both the BM and socom look like they use a standard bolt gun bolt face of .473, some people have said the use of the .473 bolt face is too big for the barrel extension on an Ar 15 and leaves it too thin. the way the BM and socom appear to have addressed the barrel extension issue is by limited pressures of 35-40k psi. These cases hold close to 60 grains of water. Why couldn't some wicked .22 or .24 wildcats be based off them while holding pressures to the same levels?
 
Originally Posted By: Plant.One

wouldnt you end up with basically something very similar to a 22br or 22 Dasher?

that would actually be a great thing IMO, but I don't know what 60 grains at 40k psi looks like from a 20" ar barrel.
 
Originally Posted By: steve garrettI have always hoped we get an AR 15 cartridge that is a huge step up from 223. to me this starts with case compacity of around at least 40 grains or more. I know there is different stuff out there, just nothing with plug and play parts from dies, barrels to mags etc. both the BM and socom look like they use a standard bolt gun bolt face of .473, some people have said the use of the .473 bolt face is too big for the barrel extension on an Ar 15 and leaves it too thin. the way the BM and socom appear to have addressed the barrel extension issue is by limited pressures of 35-40k psi. These cases hold close to 60 grains of water. Why couldn't some wicked .22 or .24 wildcats be based off them while holding pressures to the same levels?

They keep the pressures down to about 36K MAX. Necking down would require multiple steps and annealing as it went along. It would also be so square up front that feeding would be an issue. That amount of powder/pressure while useful would never approach the velocities of the high intensity crop of cartridges we use today. The SOCOM was submitted for SAAMI but failed when they proof loaded it and it was busting bolts. (Per the fellows that submitted it I talked to personally.)

I believe the best practical size neck down would possibly be the 358 or 375. They are already being done.

There is a new upper coming out that fits an AR15 lower that would handle it with a shortened 308 size BCG but it would be a definite rarity in most safes.

Greg

Greg
 
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Originally Posted By: yotehunter243What's this new upper you speak of Greg?

CMMG had it at the SHOT and will be selling parts down the road but unfortunately It will not fit a standard lower. Oh well at least it does offer us a strong upper platform for some real blasters.

Greg
 
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Gl any more details on the cmmg upper? Are they going to use the br type cases? As for forming issues yes that would suck to form that much down. But hornady or someone else could make brass. I think I may have answered my own question though. I ran the numbers on quick load using the wssm case adjusted to 60'grains water. I couldn't find a load that ran any harder than something on the 6.8 case when limited to 40kpsi. Compared to a full loaded 6.8'varient. Basically 3400 from. 55, 6mm bore size. 6x6.8 does that already. It's the pressure limitation that really cripples these. If they could run up to 60kpsi then there would really be something to be had
 
The CMMG will take the pressure and the brass will be the weak link. Not sure about the BR but it would do fine in one of these IMHO. It uses a full size 308 extension so that is no problem. We have set up a 450 Bushy on an AR10 style platform and it can be a beast but used as issued it is a pretty nice little cartridge in of itself stuck in a normal AR. Those 10's are big boys and the CMMG will be a nice bridge when they sell uppers and lowers in the future.

As for commercial brass it is all doable but less than 100,000 pieces doesn't even get a yawn at that level. SAAMI wants that many available just to get up to being submitted. In reality being SAAMI does nothing to make a cartridge take off. The 25X45 is SAAMI and it is not burning down any houses for sales and other than Sharps making guns and a few barrel makers like BHW not a lot is going on there.

Greg
 
Originally Posted By: steve garrett But hornady or someone else could make brass.


good luck on that. they can barely supply 450 bushmaster brass.

[edit] i mean its not unobtanium, but i have yet to actually see any on a retail shelf. only online at the big boys like midway and brownells.
 
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