Well I'm sitting here recovering from rotator cuff surgery & am ready to be put in a straight jacket! Can't do anything so my mind is working overtime. I had the brain fart of getting 358 Winchester ballistics in an AR15 size platform by necking down the 450 bushmaster to 35 caliber. Neck length would be equal to caliber or maybe a bit less if need be. I think that case capacity of a 35/450Bm is about equal to the 358 Win. Can anyone run this on quick load & tell me if this is a worth the effort?

35WSSM will get you there but the Bushmaster case won't. Just neck up the 30 RAR will get you the same place as your concept but if you want a double stack the 358 Gremlin is the way to go. 180's at 2,350.

Thanks for the info Boom. Now I'm learning that the 450BM has a bad habit of cracking the bolts on AR15s due to the case head size.

The 30 RAR platform was designed to take more punnishment so maybe buy a 30 RAR and have two barrels. A 308 and 358 but I see a nice niche for a 375-30 RAR. Think 458 SOCOM performance but better BC.

That is probably a more realistic way to go Boom but I was wanting to do it in an AR15 size platform not the larger AR10.

The 30 RAR is an AR 15 length and style rifle but beefed up especially in the bolt area if I remember correctly but on a regular AR15 bolt the 358 Gremlin is worth a look at. There are WSSM bolts for 2.25" length and that works ok single stack from Olympic Arms.