I think I'm going to have to admit defeat.

[Ian]

On the chamber. Brad asked about a pound cast, which I didn't do because the gas port is actually in the throat and I don't want to extrude alloy into it. I've been thinking more on this too, and then I watched THIS.

I remember talking on the phone with the builder before ordering one of these and he described his chambering process. There was some issue doing it the traditional way. Seeing a barrel blank chucked up in a CNC three-jaw chuck kinda made me scratch my head. Hopefully he trued the OD between centers before boring the chamber , but even so, how many of you will put your money on a three-jaw chuck ever being anywhere near true to center? I hear that if you get within .005" of center you have an EXCELLENT and well above average chuck.

I haven't slugged the bore at all, but it does feel like 6-8" toward the chamber end is tighter on a tight patch than the rest of it. Likely it has a little bit of reverse taper but I'll have to slug it to find out for sure.

It just baffles me that a little bit of crookedness or reverse taper could make this thing group so terribly, I would expect something glaringly obvious to be wrong to make it so bad.

I'll do some more checking, thanks for the suggestions.

 

[Ian]

OK, I just checked the chamber and barrel out again. Instead of a traditional pound cast I drove a soft lead 500-grain bullet into the chamber and throat and back out again. I can't find anything out of whack, crooked, off center, nothing. I even looked again at the bullet from a squib load I had a while back, it stopped in the throat and made a perfect impression. Nothing is crooked odd looking about it. The barrel appears pretty straight when reading the light rings. I went ahead and cleaned and slugged the barrel and if there is any restriction near the breech end it is very slight. The only thing that is amiss is those faint lead streaks on top of three lands at the muzzle.

The muzzle crown is pretty shallow, looks like 90° included angle. I wonder if that could be the problem?

 

[Brad]

A little restriction would be enough possibly? Very low pressure round doesn't have enough pressure to keep the bullet obturated fully. Harder might help due to spring back after being constricted.

Might be a place for some very cautious lapping. Maybe use the Tubb final finish if they make a kit in .452. Hate to use a grease based abrasive as it might be more prone to migration into the gas system and action.

Ever think the upper is cursed? Know any witch doctors?

 

[Lost Dog]

Life's too short to wrestle with a weapon that causes this much aggravation. Trade or sell it and get something else. Your blood pressure will be much better for it as well.

 

[358156 hp]

I agree with Brad that a little light lapping would probably be beneficial. I do notice that you're using LEEs 230 gr TC bullet. Have you tried other designs? I had one of these moulds years ago, and never was quite happy with it. I'm not doing my LEE hatin' act, but perhaps the rifle doesn't appreciate that particular design.

 

[Ian]

I've tried ten different bullet designs and I forget how many different powders, and three different alloys. Probably put near 1200 test rounds downrange in the past couple years. I'm sticking with the TC bullet for now because it works pretty well in all my other guns and satisfies the need for quantity bullets cast and lubed easily.

I also have a couple of excellent RFN designs that work well in my other guns. I'd be using the Accurate 45-230L in ALL of my .45s if it would feed in the AR, but it gets torn up by the bottom two bolt lugs.

Here in a few minutes I'm going to go run some neck-sized loads through this thing and see if that doesn't help.

 

[quicksylver]

Did I miss the part where you said you tried different size bullets?...451 ,452 etc

 

[Ian]

I forgot to click "submit" earlier. I hadn't really considered lapping, it actually has a pretty nice bore with very uniform boring marks. The grooves also have boring marks, which had me scratching my head for a bit until I remembered it's a button-rifled barrel.

Quicksylver, I can only shoot either .451" or .452" bullets in this one. The only ones that work reliably at .452" are these tumble-lube bullets due to the undersized microbands, the chamber is very tight at the front.

Three trips to the range, nothing worked. Partial sizing, matched brass, going back to HP-38, all a bust. Gun was squeaky clean and lubed after all the work last night, now it's so gummed up the last box of 50 went through it with me pushing the bolt into battery about every third round with both hands. Two more magazine springs shattered as well, so I'm down to one that works and it's almost a single-shot. I'm really quite beside myself on this whole deal, so I'm putting it up for a while until I feel like spending a couple more hours cleaning it all up again so I can shoot jacketed bullets out of it.

I'm throwing in the towel and resuming my search for a .45 ACP carbine that will shoot cast bullets.

 

[quicksylver]

Sorry Dude that..su#^*

 

[Ian]

Win some, lose some. So it goes. The thing is an absolute joy to shoot with jacketed ammo, so there's the silver lining.

 

[Brad]

Does it stay as a jacketed bullet shooter or does it get the heave ho and go away?

 

[Ian]

I would have sold it a long time ago except I put that awesome multi-cam paint job on it...and the lower is homemade and unserialized so I CAN'T legally sell the whole thing. Some brake cleaner would take care of the paint on the upper, though, and I could turn it loose with the magazine well adapters and five magazines....four of them now with broken springs. If I could get $800 for it I would sell it in a heartbeat, but I don't think that's gonna happen. It's a cool little carbine so I think I'll just hang onto it and look for something else to shoot. If I get the magazine springs replaced it will continue to be a fine carry-around rifle, just not much of a range toy.

 

[358156 hp]

I figured you had tried other designs, but I thought I'd throw it out there anyway. Perhaps you can rebarrel the darn thing, or recut the original barrel to something like 460 Rowland. I've been wanting to do a Rowland equivalent for some time. 45 Super, and 45-08 come to mind too.

 

[Brad]

You aren't defeated, you just haven't won yet.

The mag springs breaking would piss me off. Springs like that shouldn't break. Sounds like a defective product to me.

 

[fiver]

that's brittle stuff if they just break like that.
I'd be for sure be having a talk with the owner of the company about that.

the crown could be the trouble here.
it wouldn't take much to re-cut it and it wouldn't hurt anything.

 

[L1A1Rocker]

I'm throwing in the towel and resuming my search for a .45 ACP carbine that will shoot cast bullets.

When you get the time (and inclination) to pull that infernally tight handgun off, let's re-touch that crown.

 

[Lost Dog]

Ian, in my lifetime I've owned close to 200 firearms spread out over the years. And in that time I've recently had two that were real lookers but shot for crap. I spent more time, money, and effort on those two than they were worth. I hate to give up, but there comes a time when enough is enough and ya gotta face the fact that the weapon is a lemon and get rid of it. Hanging on to it will only lead to more frustration and being unhappy. Take it from an old timer that's been there. Life's too short to let a weapon get you all upset and unhappy. Get rid of it and get something else.

 

[Ian]

Well, I just got off the phone with Pro-Mag and they're going to send out new springs. Am awaiting a callback from their engineering dept. regarding the broken springs and probably will be sending them back for a look-see. The rep told me they have no history of issues with these particular springs, so that's interesting. Macon Armory told me when I bought this upper around two years ago that there were a lot of issues with the springs in the 15 rounders collapsing and not holding the bolt open, but that Pro-Mag was fixing the issue.

Gotta hand it to Pro-mag, the lady that answered the tech line was sharp, friendly, and intent on rectifying my issue.

Oh, and I bought some Rainer 230 RN copper-plated thingies to see if they shoot any better than cast.

 

[fiver]

hopefully they do.
if not you might be able to find a couple and maybe get some more information from them.

 

[358156 hp]

Ian, Have you been able to recover a fired bullet for examination? After this, I'm out of ideas too...