Wildcat chamber to cartridge clearances?
Hi everybody.
I am considering a new semi-wildcat 35 cal cartridge and AR15 build.
First my question, then the details.
How much clearance between the chamber and the cartridge is acceptable at the case head?
I want to build a 358 something mostly for hunting Hogs in southern Arkansas, but it could also double as a Deer gun.
My thoughts are to use existing chamber reamers and loading dies, to avoid the high cost and wait time of custom tooling...
So two options.
1: 358 Win- run it in 1.700" in a standard .358" AR barrel, then cut the base off of stock 358 Win dies for case forming and loading. RP 308 win case capacity is 47gn H2O. Should be able to load to 46Kpsi
2: 350 Rem Mag- run it in 1.700" in a standard .358" AR barrel, then cut the base off of stock 350 Rem dies for case forming and loading. 450 Bushmaster case capacity is 54gn H2O. Should be able to load to 38.5Kpsi.
The only problem I forsee is the base of a 450 Bushmaster case is .500". Measuring down 1.7" from a 350 Rem Mag case shows .505".
Is this going to be too much slop, and will it cause problems when loading to 38.5Kpsi?
The 358 Win option seems to be the simpleist to do. Case forming is basically, cut the case, run it into the die, trim to length and you are done. Any 308 based case should work and cases are fairly cheap and will always be availible.
The 350 Rem option needs a few more steps. I tried running a case directly into the 350 die, but the neck folded up on me. So I ran a case into a 416 Taylor die to start a neck, then ran it into the 350 die and it worked perfectly. The neck is too thick, so it'll need turned. I have the Hornady tool, just need the 35 cal mandrel. 450 Bushmaster cases are much more expensive and who knows if they will go out of production in the future?
I am thinking of limiting myself to 180-200 grain bullets and make the cases as long as possible to seat a 200gn bullet, cast or jacketed, and still be able to fit into an AR15 magazine.
I have some Hornady 200 Interlock and FTX. I found some Speer 180s at Midway, they had a limit of 2, so that's what I ordered. For cast, I'm looking at the Lee 35-200.
I found an AR barrel manufacturer that said they would make me a barrel if I supplied a formed case to set the headspace with.
I ran several powders through Quickload
The 358 case should do
180- 2310fps
200- 2140fps
The 350 case should do
180- 2330fps. If I can find AR Comp, it might go 2410fps
200- 2170fps If I can find AR Comp, it might go 2240fps
One thought I had was with the 6.5x55 Swede, the base is .480", but some US ammo companies make ammo for it from 06' based brass with a .470" base.
I downloaded some pics:
http://www.lsstuff.com/pics/guns/358...ck/358r-01.jpg
http://www.lsstuff.com/pics/guns/358...ck/358r-02.jpg
The bullets will be seated deeper, that's just as far as I could go without cutting down the dies.
Now go ahead and shoot holes in my plans...