Been working on this AR-15 build and loads for about 6 months now. It is basically a 358 Winchester in a little light weight AR-15 Carbine. The first version with a polymer lower and 16.5 inch barrel weighed in at 6.4 pounds even with its bull barrel. I soon found it necessary to add a recoil pad, steel tactical rings, a RRA Operator forend and a heavy tactical scope to bring its fighting weight up to 11 pounds so I could stand to shoot 50 rounds at a time.
It works with a full loaded PRI 6.8 mag with most of the front rib removed, 10 for 10 and 15 for 15.
The case is the 358 MGP, a rimless 357 Harrett based on the 6.8 SPC cartridge necked up to 35 caliber with the shoulder moved forward to about 50% of the neck. The case itself was developed by Mike Plinkington of www.MGPCustoms.com whom has barrels and dies for sale on the net. It has a ferocious muzzle blast, sounds like a cannon. The 16.5 inch stainless barrel has a 1-22 twist rate that is surprisingly accurate (.5 to .75 inches at 100) for the 200 to 115s, the groove diameter is 357 for pistol bullet use and the bore diameter is 350 so you can shoot 9mm, 357 and 358 bullets in it. It shoots cast bullets real well, I use powder coated 200gr hard cast to fireform the brass at 2,400 without any leading.
It is my truck gun, I figure it will stop a truck pretty easy, with a 200gr at 2,400 fps or a 180gr at 2,500fps. Plenty of folks are now using the cartridge on hogs and bear I build my 358 AR for a daylight hog gun at my farm.
These are some stats no group at any load level over 1.2 inches. The cartridge works with Lil Gun, 4227, 1680, H-110 and 296 The use of the AR action allows the cartridge to exceed the 357 Harrett stats by almost 50% with less powder and equals mid 358 Win loads found on the Hodgdon site with less powder an 8 inches less barrel.
200 RCBS Hard Cast powder coated 2,400
200 Horn FTX 2,370
200 Rem RN 2,350
180 Horn SSP 2,500
140 Hprn FTX 2,720
125 Rem JHP 2,780
This is a cartridge lineup and a picture of the new AR. Just got in some 180 Hornady JHP Power Shock bullets to try.
Ed
It works with a full loaded PRI 6.8 mag with most of the front rib removed, 10 for 10 and 15 for 15.
The case is the 358 MGP, a rimless 357 Harrett based on the 6.8 SPC cartridge necked up to 35 caliber with the shoulder moved forward to about 50% of the neck. The case itself was developed by Mike Plinkington of www.MGPCustoms.com whom has barrels and dies for sale on the net. It has a ferocious muzzle blast, sounds like a cannon. The 16.5 inch stainless barrel has a 1-22 twist rate that is surprisingly accurate (.5 to .75 inches at 100) for the 200 to 115s, the groove diameter is 357 for pistol bullet use and the bore diameter is 350 so you can shoot 9mm, 357 and 358 bullets in it. It shoots cast bullets real well, I use powder coated 200gr hard cast to fireform the brass at 2,400 without any leading.
It is my truck gun, I figure it will stop a truck pretty easy, with a 200gr at 2,400 fps or a 180gr at 2,500fps. Plenty of folks are now using the cartridge on hogs and bear I build my 358 AR for a daylight hog gun at my farm.
These are some stats no group at any load level over 1.2 inches. The cartridge works with Lil Gun, 4227, 1680, H-110 and 296 The use of the AR action allows the cartridge to exceed the 357 Harrett stats by almost 50% with less powder and equals mid 358 Win loads found on the Hodgdon site with less powder an 8 inches less barrel.
200 RCBS Hard Cast powder coated 2,400
200 Horn FTX 2,370
200 Rem RN 2,350
180 Horn SSP 2,500
140 Hprn FTX 2,720
125 Rem JHP 2,780
This is a cartridge lineup and a picture of the new AR. Just got in some 180 Hornady JHP Power Shock bullets to try.
Ed