357AR (Max-Rimless) from 223/5.56 cases

[Moleman-]

Here are some 357AR (MaxRimless) cases made 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 in this batch. Hunting season is just around the corner and I figure I'll make another 100 or so since my son is also shooting them now. Usually I've had around 5-10 cases 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 since they are getting expanded up so much. 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. The two expander stems are made from a bolt (it's quick and easy) and some hardened drill rod. They just fit into a Lee 38-357 powder through die body

[Michael J. Spangler]

Subscribed for updates.
Will you get into any details on the AR build in this thread?
I'm thinking of changing my AR over to 300BO because it likes cast. I bet this would be a much better chambering.


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[PaulG67]

Now that is something that I would love to do in an AR, HOWEVER I live in Massa!@#$%^&*()_+_)(*@#^&*&^$#!@^&*(_)(*chusetts and it recently became illegal for me to enjoy my hobby in such a way.

[Michael J. Spangler]

I'm with you Paul. Fingers crossed and lots of phone calls and emails sent. We can beat this one. Will you be at the state house Saturday?
Not to hijack but goal has an announcement tomorrow and will be speaking on Howie Carr's show.

Hopefully we can come back to this thread and make moleman proud when we show off our 357ars


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[Moleman-]

I have enough pics to do a quick 357AR build thread in the "special project" area if it would be appropriate to put it there. I've only ever shot one type of cast bullet out of it and they shot well even though they weren't perhaps the best profile for a semiauto as the corners of the flat tips get rounded off going up the feed ramp. I'm working on a 44BGM AR10 to use this fall and many of the build steps are the same for each rifle.

[PaulG67]

I have attended several G.O.A.L. rallies in the past but will not be able to attend this one. I am having a health problem that will put me in Beth Israel hospital for about two weeks in the near future. Funny I will be in Boston just not the right time.

[badgeredd]

I have enough pics to do a quick 357AR build thread in the "special project" area if it would be appropriate to put it there. I've only ever shot one type of cast bullet out of it and they shot well even though they weren't perhaps the best profile for a semiauto as the corners of the flat tips get rounded off going up the feed ramp. I'm working on a 44BGM AR10 to use this fall and many of the build steps are the same for each rifle.

It would be absolutely appropriate to put up a post in the Special Projects" area. I will be watching for it.

[Moleman-]

It would be absolutely appropriate to put up a post in the Special Projects" area. I will be watching for it.

Got it put up http://castboolits.gunloads.com/show...-Rimless)-AR15

[SSGOldfart]

Human this is a idea that piques my interest to. I have Mike Bellum cutting a camber for shooting 357 Maximum Rimless
In a TC now,which is very close to your 357AT,I'd like to see your 44BGM AR10.

[Moleman-]

I looked at Bellum's site quite a bit when while making a test barrel to see if I could even get one to feed. It, and all of the links in it are a good read for someone with a 357Max. Still gathering parts for the 44BGM ar10. The barrel is headspaced and I started on the barrel nut wrench today. Once it's closer to being done I'll start a thread on it.

[2wheelDuke]

Great thread (and your other one on the builds.) I know the possibility of a cut off .223 being turned into a .357 had been discussed for years, but I haven't seen much on anyone actually doing it.

I've been interested in the .300 blackout for a while now. It's a decent round, but I really feel that I got suckered a bit by the original writeups on it, namely the ones that compared it to 30-30 win and 7.62x39. Sure the blackout fills a niche that those 2 can't for people that want subsonic or short barreled performance, but that's a different issue. The blackout is adequate to hunt deer and hog in any area I can afford to go, and does allow me to run cast fairly easily in the AR platform.

This round interests me though. I've assembled AR's but I don't have the means to turn barrels and install extensions. It'd be interesting to see one or more of the companies run with this round as yet another contender for hunting with the AR.

[Moleman-]

I also would like to see a company run with it. It's not new or fancy but it does a good job of filling the requirements of the Limited Firearms Zone in southern Michigan and is not a hard kicking rifle for smaller shooters.

[nvreloader]

Moleman

Would it be better to anneal the case mouth/shoulder areas before,
you expand the neck/shoulder out to proper size?

Do you by any chance have a reamer chamber print for your case,
or know where I can find a chamber/reamer print?

I would believe that this case Head spaces on the case mouth, correct?

Another great use for the 223 case, never a shortage of cases.

Tia,
Don

[AggieEE]

Question about the 44BGM. How does that compare to the 44 Automag? If the length isn't too short to work through the mags that may be interesting.

[Moleman-]

nvreloader,
I've tried several different methods including annealing several times including between the two expanding arbors. Mostly it's the initial opening with the skinny expander that will split a once fired case at a nick or deep scratch on the neck/shoulder. Expanding up to 6mm or so first also helps a little, but not as much as trimming and deburring them first does. The above method is the one I've settled on as a good balance between time and case loss.

I made the first reamer going off of a saami print tweaked for headspacing off of the case rim and a longer throat. Actually got the useable throat way to long which I adjusted on my second reamer and added in .001" (.002" total) more chamber taper for feeding. I had Dave Manson make me a floating pilot reamer (he has his 357AR print on file). He felt there should be more chamber taper (.005") for feeding and a much shorter freebore (.075"). I chambered my pistol with the Manson reamer and used it during the 2013 deer season. Things I noticed were that it didn't feed any better or worse than my other barrels with .002"-.003" taper and the cases needed trimmed much sooner. The extra diameter from the looser chamber was letting the cases expand more which turned to extra length once the cases were resized. Perhaps if I had a custom die set made it wouldn't be an issue, but I want to keep it so it can be reloaded with an off the shelf die set. The lead bullets shown above also would not chamber in the pistol as they hit the rifling because of the shorter freebore and leade. With that in mind, I made a floating pilot reamer shown above in the wood box that I've used since with the specs below. Feeds well, chambers heavy lead bullets, shoots well, and can chamber .357" and .358" barrels.

[Moleman-]

Question about the 44BGM. How does that compare to the 44 Automag? If the length isn't too short to work through the mags that may be interesting.

I hunted with a lower pressure version last year in a 1891 mauser. It would push 265gr bullets to around 1985fps at 37Kpsi. The higher pressure version for the ar10 can beat a 444marlin with a similar length barrel if you want to go that route. I want to get a decent feeding lead gas checked bullet mold for it at around 300-325gr and wouldn't rule out possibly as high as 350gr. I've got a lower pressure 44x1.7" planned for an ar15 that the cast bullets would also get used out of. Still gathering parts for it and haven't made a reamer for it yet.

[runfiverun]

I have a 223 case I modified to take a 250gr 35 cal cast boolit and it is super simple to do.
it feeds from the magazine too.
it's only drawback is head spacing on the case mouth so it turns into a supersized 30 carbine.

[Moleman-]

runfiverun, what mold are you using? I've almost ordered the NOE 200grFN which I've shot or the 245rn which seems to be a similar profile to 200gr sierra rn that feed well out of my uppers. I also saw the MP 220gr WNFT which looks like it has a smaller diameter tip which might slide through the feed ramps easier.
Headspacing off of the case mouth so far hasn't been an issue. While not ideal it helps meet the case requirements set by the DNR and allows an easy semiauto build.

[runfiverun]

the saeco #248
the nose profile has a smaller meplat which helps feeding.
I use the same boolit in my 358 win.

anyway I decided to try making the cases and seeing if they would try to feed in the AR cause I had a couple of oopsie boolits there while I was loading them in some 357 max cases.
I just set the oal for the magazine and popped the beavertail and schunk they went right in till the boolit hit the chambers neck.

[Moleman-]

That's heavier than I really wanted to go, but I like the profile of it. How do they do in the Max?