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357AR

20K views 77 replies 14 participants last post by  moleman 
#1 · (Edited)
Here is what I've been working on this past winter with a lot of imput with several members over at weaponsguild. An ar15 based off of a 357 maximum rimless loaded to 223 pressures. I started with a home made chamber reamer (because standard 357max reamers won't work) and a 357 test barrel and once I got the bugs worked out I sectioned the test barrel and bought a Green Mountain blank to turn down. I haven't run it over a chronograph yet, but I was able to go above what Quickload shows for a 158gr bullet @ 2250fps without any signs of high pressure. I'm currently working up loads for 180gr bullets. Here's a few pics.
 

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#29 ·
I updated the pistol thread, but not this one. I used the 18" 357AR rifle as allowed in the MI shotgun zone this past season. Put a 3-9 Nikon scope on it and sighted it in. Made a heart/lung shot on a 6pt opening day with a Hornady 180gr SSP bullet. The bullet went through the deer and buried itself in the ground. I'll have to go back in the spring with a metal detector to find the bullet. I was very pleased with how it performed.
 

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#31 ·
Sure, as long as they're the right diameter. But I'd check with the bullet manufacturers for specific recommendations at whatever velocity you're expecting.

Paper targets don't care, but a proper hunting bullet needs the correct core hardness and jacket thickness to make a clean kill.
 
#32 ·
I only ever worked up to 250gr bullets at a max of around 1600-1700fps, so it's likely a 300gr bullet is going around 1400-1500fps on a guess. If you weren't stuck with the COL of the 223 and sat the bullet out further you might gain back a bit of velocity. Bullet construction and the speed it is driven at is also a good point. That's why I went with the Hornady 180gr SSP (single shot pistol) bullet to try first. It was designed to open up at lower velocities. MOST of the 357 hollow points lighter than 158gr would likely also perform poorly on deer as they'd be too lightly constructed for the velocities they'd get driven in this cartridge.
 
#34 · (Edited)
Yep, one of the first bullets I tried left over from a ruger 357 I had back in the early 90's. The feed ramps need a little more polishing and smoothing out so that the soft wide blunt tip doesn't catch anything v/s a 158gr XTP that has the jacket all the way to the hollow point. I've only ever shot the 158Gr SJHP at paper and they shot well. The old (80's vintage hornadys) SJHP looked very much like the ones in your pic. Couldn't seem to find a pic of them on this computer, but I think there is a pic in the 357max barrel thread over on WG. So far I've shot the 158gr SJHP & XTP, 180gr SSP & XTP, and 200gr sierra rn. The best feeding so far in order is the 180gr SSP, 200gr rn, tie for 158 and 180 xtp. I have some 140gr xtp bullets and some GC 210gr cast bullets to try once it warms up some.

So far case forming has been the only pain as I've been lathe turning the cases to get he neck thickness correct. After using a 44amp case reaming die to make some 444-1BG cases I'll be making a reaming die for 357AR as well. It's a lot faster.
 
#36 ·
The 357AMP (Auto Mag Pistol) is based off of the 308 or 44 automag case IIRC and wouldn't be legal for me to hunt in the shotgun zone since it is a bottleneck case. Google it, it's been done before.

Back to the die stuff. The expander dies and cases are for the 357AR, but the reamer dies (top pic) are for the 44 automag that I'm using to form the longer 444-1BG since it's basically a longer 44 automag. It is the type of die and reamer I'll attempt to make soon to make case forming easier. The 357AR cases will have a wrinkle in them from where the shoulder was unless you roll it out. It's mostly cosmetic and is visible in the pic of the cases with the expander die and stems.
 

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#40 ·
Same here. It seems like the biggest thing you can do with the standard 5.56 setup. Other than the barrel everything else should work mags, BCG,etc. I think the right powder could push it faster but it seems like a nice effective thunker. Not quite a thumper but way more effective than the poodle shooter. Some 350gr subsonics would probably really put some slapdown on a critter and be downright quiet with the right can then it could be the 357 blackout.
 
#38 ·
I ended up cheating and got one of the GM gunsmith 9mm blanks to use to make the reamer die out of. It was reasonably priced and already had a hole through it that would work for the floating pilot reamer(pic). The 4140 should also get hard enough for the amount of use it will see, and I'll still have more than enough left over to make a 9mm barrel for something. I'll have to make a reamer similar to the 44 automag case reamer in the earlier post.
 

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#39 ·
I'll probably remake the reamer and the die, but there is now a reamer die in 357AR. The reamer turned out ok, except I will have to make another expander arbor to expand the cases up a little bit so they stick to the die walls and don't start turning once you get the reamer in about 1/2". I used a standard 9mm reamer, but custom made case reamer like the 44 automag one a couple posts up would be easier to use with a tap handle and have a non-fluted area for better side load support from any torque from the tap handle. I also tried out a new threading tool which broke and boogered up the threads a bit, so I went back to my old one. I used a section of a 1" 4140 GM blank and hardened it when I was done. The pic shows the reamer used to make the die and the die with a case and a reamer in it. This die will make case forming a little easier and faster.
 

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#41 ·
hvymax, the only thing that needs modified is the mags. I haven't found a metal mag that works yet as you have to remove the bullet guides at the front of the mags or else they will try to single stack in the front and double stack in the rear. Pmags , thermomelts (they still suck and are flimsy) , and the polymer/steel Bulgarian mags can all have the bullet guides removed and work. There may be others, but those are the ones I've tried. Here's a couple pics of a USGI and modified Pmag. The 30rnd mags will only hold about 23-25rnds before the curve of the mag makes the cartridge base to low for the bolt to pick up, and the 20rnd mags do best with 18 or less. The best combination is a 20rnd Pmag with a 30rnd follower in it.
 

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#42 ·
Slowly plugging away on 4 more 357AR barrels. The two mostly done ones still need muzzle threads, the extension modified, torqued on, final headspace, gas port and Parkerizing. The one in the lathe has been turned down to .980" from 1.2", threaded for an extension and is about to get rough chambered. There's still one pistol barrel hidden in the 1.2" dia blank.
 

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#43 ·
Got a little bit more work done on them in the past two days. All are profiled, one still needs the muzzle crowned and threaded 5/8"-24tpi, two need short chambered and all need final headspace, parkerized and a gas port. The barrel 2nd from the bottom is the one that was being threaded in the Cushman chuck that I found out was bad (in this thread) http://www.gunco.net/forums/183-tool-shed/63472-old-iron-3.html so it will end up slightly under 16" and will get a muzzle brake welded on.
 

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#45 ·
Not sure how a 45-06 Is going to work out you will have some very very thin necks an about zero taper .
even with a .430 bullet there is not much taper less than a 444 marlin.

You might want to consider 6.5 swede brass as its slightly bigger at the base .

To bad starline does not make that 45 raptor brass longer its 1.800 " it has almost zero taper if any .
 
#49 ·
Not sure how a 45-06 Is going to work out you will have some very very thin necks an about zero taper.
True. On the other hand, 30 years ago it wasn't unusual for people to use .308 or '06 brass to make heavy duty .45 ACP brass, or .45 Thompson, .451 Detonics, etc.

.44 AMP requires internal reaming for a .429/.430 bullet, so I imagine a .451 bullet would need proportionally more reaming.

Some of the aulde phartes on the bullseye and race gun forums might have some pointers.
 
#46 ·
Yeah the walls will be about straight. I have those 45 barrels and if I get the right donor I am thinking integrally suppressed bullpup semi auto that takes BAR mags. I like Moleman's 357AR as well. If the right parts fall in my lap I might have to do one as well. Again I would probably go with a big honking hunk of subsonic lead though. My printer will need more ink for all of the evil form 1 ideas I have.
 
#47 ·
You guys are watering down the soup, those barrels are beautiful!

That short one looks like it wants to be blind pinned with maybe a spot over it. Tiny recess, maybe two pops with the mig. Should be good to go.
 
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#48 ·
Still pisses me off that it ended up under 16" by about 1/8"-3/16". The barrel on the bottom is 17" so with a pinned/welded on flash hider on the short one it will be GTG. The 17" barrel has been crowned (11 degrees) and threaded 5/8"-24. CDNN had the 5/8-24 flash hiders for $8 so I got one for each barrel.
 
#52 ·
Getting near the end of the tunnel! I work slow, and haven't had much shop time lately but have made some progress. Got them all chambered, and threaded. Test fired them all on the 4th, rechecked H/S again, blasted them, caliber marked them, drilled the gas ports and a dimple 180 degrees out for the gas block setscrew. They'll need degreased again, touched up with the abrasive blaster and then into the park tank. Already fished the park tank out of the rafters. Just need a free day to finish them up. Debating blind pinning the brake on the 15-7/8" barrel or using it as a pistol barrel.
 

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#57 · (Edited)
Made some more cases recently from 5.56 LC-13 brass and thought I'd show the steps. A couple of guys have made the cases from 357Max brass which just involves changing the rimmed case to rimless, but I like using cheap 223 and 556 brass. So here's the steps:

1. trim to 1.640"-1.650" and debur

2. anneal

3. lube inside the case and expand case mouth with skinny expander

4. expand case body with blunt expander

5. resize

6. roll case shoulder wrinkle away (optional)

7. turn necks/ream to .0105" case wall thickness

8. trim to final length 1.595" and tumble

9. load/shoot


This method seems to work very well as I had no split cases out of the 40 or so I formed recently. Usually I've had 5-10 split out of 100 when using once? fired range mystery brass. Any flaw in the case mouth of the parent case will result in a split, so the initial trim and debur really cuts down on losses. This batch of LC-13 cases probably would of been fine without turning/reaming, but I've had others like FC cases that wouldn't chamber without turning so I just turn them all. Really all you're reaming or turning off is where the base of the bullet would be.
 

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#60 ·
Recently while at Cabelas I saw a Pmag 10rnd mag. So I picked up one for the rifle I'm making for my boy. Pmags are probably the best mag for 357AR as the bullet guides are easily removed. 10 minutes with wood chisels and sand paper removed all but a hint of the bullet guides and let the rounds seat normally. Previously I used a 20rnd Pmag with the bullet guides removed and added a block of wood inside of the mag spring to limit the capacity like you would on a shotgun. I may block this one to 5 to 9 rounds as the gun can't hold more than 10 total.
 

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