30-06/.357 Auto wildcat project.

[texaswoodworker]

This is just an idea I've been kicking around, and one I'd like to experiment with in the near future.

How about a 30-06 that has had it's neck and shoulder cut off, necked down (long neck) to .357, and that has an OAL short enough to function in an AR-15. I really don't have a reason for doing this. I just want to do it for the heck of it. I just think a .357 caliber wildcat designed specifically for cast bullets and the AR-15 platform would be pretty cool. How would I go about doing this? Are there places I could send a few rounds to have the pressures tested? I think I could find someone to make the dies easy enough, and I could probably find someone to make the reamer too.

[DeanWinchester]

The bolt head is gonna be the weak link. You're not leaving yourself much material in the bolt head.
I see where you're going with it, but you'd be better served with an AR-10 in .358 Winchester

[country gent]

I bored a AR15 bolt face out for a guy to accept 6ppc cases once. It could be done and the machining wasnt the issue BUT the wall thickness between locking lugs on the bolt was pretty thin. I found out later that he had issues with front of lugs breaking down to face. Another even bigger issue with this is the barrel stub in the extension would be very thin around the cartridge/chamber. The AR10 would be a much better cantidate for this conversion. as the bolt is bigger and so is the barrel stub under the extension. Keep in mind also that it needs to be safe to full pressure loads as even though you plan on only cast loads and pressure what about after your gone and the rifle is passed down or sold?

[texaswoodworker]

I've seen AR-15s chambered for .223 WSSM which has a rim diameter of .535" vs the 30-06's .473". How are they getting those to work without these sort of issues? If sizing up to an AR-10 is what's needed, I can do that. It would let me use a longer case too. As for pressures, I'm not 100% sure what they would be yet. Especially since this is just an idea at this point. I'd like for it to stay round 45,000-55,000. I'm not sure how well cast bullets would hold up past that.

[runfiverun]

I'd just look at the 35 gremlin before I went to all that trouble.

[texaswoodworker]

I'd just look at the 35 gremlin before I went to all that trouble.

Kind of takes the fun out of wildcatting. :p

Like I said, this project really doesn't serve a purpose. I want to do it just for the heck of it, plus it would be neat to have a cartridge I designed.

[lancem]

This is just me but I think it would be easier to do one at a time. I'd get something like a handy rifle in 357 then have a reamer made for the case you want and then you will have a good platform for testing your wildcat cartridge. Once you have all of it's issues figured out then move to fitting it into the AR platform. That way it's a rather low cost project to see if the cartridge is even going to work or say be better than something that has already been invented.

[texaswoodworker]

This is just me but I think it would be easier to do one at a time. I'd get something like a handy rifle in 357 then have a reamer made for the case you want and then you will have a good platform for testing your wildcat cartridge. Once you have all of it's issues figured out then move to fitting it into the AR platform. That way it's a rather low cost project to see if the cartridge is even going to work or say be better than something that has already been invented.

That is a good idea. Thanks. :)

[sthwestvictoria]

I'd just look at the 35 gremlin before I went to all that trouble.

There is also the russian 9x39mm - the SKS round necked up to 9mm:
http://en.wikipedia.org/wiki/9x39mm (http://en.wikipedia.org/wiki/9x39mm)

[OKSaddletramp]

CG, why didn't you just use a 7.62 x 39 bolt? Since the PPC cartridges are based on that case, it should have been a simple matter of replacing the bolt on a standard carrier and replace the barrel.


I bored a AR15 bolt face out for a guy to accept 6ppc cases once. It could be done and the machining wasnt the issue BUT the wall thickness between locking lugs on the bolt was pretty thin. I found out later that he had issues with front of lugs breaking down to face. Another even bigger issue with this is the barrel stub in the extension would be very thin around the cartridge/chamber. The AR10 would be a much better cantidate for this conversion. as the bolt is bigger and so is the barrel stub under the extension. Keep in mind also that it needs to be safe to full pressure loads as even though you plan on only cast loads and pressure what about after your gone and the rifle is passed down or sold?

[jmorris]

A 458 socom bolt would work it has the same rim diameter as the 30-06.

There also was a wildcat built by cutting the neck off a .223. Sort of like the 300/.223 rounds (aka 300 blk) but not necking down and using a 357 bullet.

[rockrat]

Your 357 round sounds alot like the 357 auto mag round.

You could use a 450 bushmaster bolt.

I think for the WSSM rounds they use an oversize bolt/extention.


I have wondered about running a 35 rem reamer in short and using 7.62 x 39 brass with the corresponding bolt. One of those many projects I might get to one of these days.

[texaswoodworker]

Your 357 round sounds alot like the 357 auto mag round.

You could use a 450 bushmaster bolt.

I think for the WSSM rounds they use an oversize bolt/extention.


I have wondered about running a 35 rem reamer in short and using 7.62 x 39 brass with the corresponding bolt. One of those many projects I might get to one of these days.

I originally wanted to make it similar to the .357 Automag, but a little hotter. I'm playing around with the idea of changing the parent case. 6.5 Grendel (or 7.62x39mm) or .50 Beowulf may work well. I did a little research and found that .458 SOCOM has the same rime diameter as 30-06. Using a rim that size will work if you keep the pressure low. 35,000 PSI max. Since that would be difficult to do while getting the velocities I'm wanting, using a round with a smaller rim as a base would be a good solution.

[jmorris]

Getting the 7.62x39 to feed 100% without the curved mags can be challenging.

You could always go the AR-47 route though.
http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=558

[texaswoodworker]

Getting the 7.62x39 to feed 100% without the curved mags can be challenging.

You could always go the AR-47 route though.
http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=558

I was thinking of straightening out the walls like on the 6.5 Grendel. Should also increase case capacity. I've seen those before, and they are pretty neat.

[jmorris]

What about a 30 AR necked up to 357? It operates at 55k psi.

[texaswoodworker]

Just checked out the spec on it. Looks good, but it has the same sized rim as .308, .458 SOCOM, 30-06, ect. I wounder how they managed to get away with that much pressure when the 458 SOCOM is limited to 35,000 PSI to keep from damaging the bolt. Do they use a larger bolt?

[jmorris]

Rim diameter has no relation on how much pressure a case can operate at. .223 has a max pressure of 62,366psi, with a rim smaller in diameter than 9x19.

The parent case of the 30 AR and 450 bm is the 284 Winchester (max pressure of 64,000 psi). Like the 458socom they have a rebated rim too.

If they were not worried about tearing the rim off during extraction or reloading they could rebate the rim all the way to .223 diameter.

[Pinsnscrews]

so, basically, you want to make a Rimless .357 Herrett ;-)

http://i27.photobucket.com/albums/c167/wyckedflesh/DB2E2F2D-8289-41BC-9792-4DEB2008A651_zpsykwrcbmw.jpg

[jmorris]

Bob Milek and Steve Herrett made a rimless version to use in the XP-100, from a 308 case.

http://www.handgunhunt.com/tech/t11/

The 2.4" OAL won't fit in an AR mag though.

[texaswoodworker]

Rim diameter has no relation on how much pressure a case can operate at. .223 has a max pressure of 62,366psi, with a rim smaller in diameter than 9x19.

The parent case of the 30 AR and 450 bm is the 284 Winchester (max pressure of 64,000 psi). Like the 458socom they have a rebated rim too.

If they were not worried about tearing the rim off during extraction or reloading they could rebate the rim all the way to .223 diameter.

Huh, I'd been told that those sort of pressures with a rim that large would damage the bolt. If that's not the case, it looks like we have a winner for a parent case. That is just about exactly what I was needing. A large case capacity and a decent amount of pressure. :D

Thanks. :)

[texaswoodworker]

so, basically, you want to make a Rimless .357 Herrett ;-)

http://i27.photobucket.com/albums/c167/wyckedflesh/DB2E2F2D-8289-41BC-9792-4DEB2008A651_zpsykwrcbmw.jpg

Give or take a little, and yeah. :) My design will be short enough to fit in an AR-15 though. ;)

[texaswoodworker]

So I looked into .30 AR some more. They do make AR-15s chambered for them, but they do not use standard uppers. They use redesigned uppers with beefier bolts (AR-10 maybe?) to withstand the pressure.

[jmorris]

They use unique uppers, bolts, barrel extensions and nuts, likely why they are not popular.

Your original idea of a blown out 7.62x39/6.5 grendel looks like a good plan or a 30 Remington/6.8 spc, if you want to keep as many "stock" parts as you can.

[scb]

Here's one that was discussed for a while. Never went anywhere. It's a 6.8 SPC necked up to .358. The "nice' thing about this one is I believe it could be loaded with readily available 357 Herrett dies, just a different shell holder. Of course it would use a 6.8 bolt head. I bought a .357 Herrett barrel and dies for my Contender to see if I could make some casings but since the "SAFE ACT" have sort of lost interest.
http://castboolits.gunloads.com/showthread.php?90803-Cast-Boolits-AR15-Upper&p=1131098&viewfull=1#post1131098

[Pinsnscrews]

Sadly, they really only made a rimless version of the .30 herrett, called the .300 herrett using the .308 case. I have, though, considered trying to form up some .357 herrett using .308 cases, but the bottom of the case is too wide for the dies. Not sure if it will form properly or not. I was thinking of talking to Mike Bellm about making me a barrel and adjusting a set of .357 herrett dies that use the full diameter of the .308 case. Was thinking of calling it the .357HRL (Herrett RimLess)

[2ndAmendmentNut]

An AR 10 in 358 Winchester would be pretty sweet.

[175lt2]

I'm so glad I stumbled onto this thread, I have been wanting to do something like this for a while.
Until reading it here I didn't know that a necked up 7.62x39 already existed, my design is based on that case but a little different. I want a case with a little less taper than the 7.62 for better feeding from ar mags and a long neck for boolits, of course that means cases will need to be fire formed but not a big deal. My idea should resemble a fatter long neck 300 whisper in 35 cal.
I figured that the case volume is lost in making a long neck will be gained back with the reduced taper. I think case volume will be a smidgen more than 357 max, of course this is all theory until I start making metal Chips fly but I have all the parts and a 17" scrap of 357 barrel blank so I think I will start in the new year, any input will be appreciated, I'll keep you all posted on the progress.

[KLR]

Register at weaponsguild.com forum and look up the 357AR builds by user Moleman.

[DanWalker]

I had an AR upper in 7.62x39. It absolutely refused to feed anything but spire pointed bullets, due to the case taper. You should most definitely blow out your wildcat case to get rid of that. 6.8 spc mags work fine for 7.62x39 so magazines shouldn't be a problem. The round you are describing sounds a LOT like the 358 GREMLIN.

[175lt2]

I had an AR upper in 7.62x39. It absolutely refused to feed anything but spire pointed bullets, due to the case taper. You should most definitely blow out your wildcat case to get rid of that. 6.8 spc mags work fine for 7.62x39 so magazines shouldn't be a problem. The round you are describing sounds a LOT like the 358 GREMLIN.

yeah it does sound like the gremlin, It looks like I'm trying to re invent the wheel.
seems there isn't much that hasn't already been tried when it comes to wildcats, I'm still going forward with it. I thought about buying another barrel too, I recently picked up a bunch of mauser actions, I would feel safer doing load work in one of them rather than the Ar. I also need to do more reading on the gremlin.

[lar45]

I have, though, considered trying to form up some .357 herrett using .308 cases, but the bottom of the case is too wide for the dies. Not sure if it will form properly or not.
The 357 Herrett is made with 30-30 brass. The 30-30 brass has a smaller body than the 308.

Maybe you could try running a 358Win reamer in part way to make a shorter chamber, then cut down some 358Win loading dies so a custom reamer and dies wouldn't be needed?

[Pinsnscrews]

Lar45, that is what I wanted to talk to Mike Bellm about. He would know what reamer would do the job the best.