kinda following the idea of the Knight's PDW with the 6X35 round I decided to try making one using existing materials and dies. I decided to try the 256 Winchester Magnum but in a rimless form.
This is the rimless 256 Winchester Magnum next to a .223 cartridge.
Right now I'm just loading the cases for fire forming so they are not max loads. The cartridge case is made from new Lake City .223 brass and when fire formed holds 23 grains of water which is equal to the original rimed case. I'm using 70 grain Sierra BlitzKing bullets and hope to get maybe 2400fps out of the carbine.
This is the AR I've built. The barrel is 11.5" long with a fake moderator pinned and welded to make it a legal 16+". I didn't want to spend the extra money to SBR this since I didn't know how it will turn out.
the magazines I use are the Magpul Pmags and the rounds feed smooth as silk. I have only fired test rounds through the setup but hope to go to the range this weekend for some operation and accuracy work. I've added a small scope to the carry handle since the picture was taken since I have bad eyes and could not use the iron sights that well. The front sight is there as a sight only and the working gas block is under the handguards in the pistol length position. If you look close at the upper handguard you can see a small hole drilled in one of the ribs -- that's for the allen wrench used to adjust the PRI adjustable gas block.