The thrill of an unpredictable machine gun

[No Soup For You]

I need some help concerning a Powder Springs M10-45 that I have just acquired. I have no manual for it but I took it to the range tonight for the first time figuring its operation would be fairly simple. Call me crazy, but I'm certain that a weapon is not supposed to fire when the safety is engaged and the trigger is not being pulled.

Safety off, chamber a round, it wouldn't fire when I pulled the trigger. It would lock up...fiddled with all the switches, semi, full, safe, fire...nuttin'. I would have to pull out the clip, eject the chambered round and start over.

If I pulled the bolt all the way back until it locked, put in a mag and pulled the trigger, the bolt would slam closed and chamber a round but then it wouldn't function.

Here's the fun part...Safety on, chamber a round, it would immediately fire the first round chambered without the trigger being touched. This happened every time. Then it would function flawlessly until the clip was empty.
If I don't pull the bolt all the way back and let it snap forward...it fires the round chambered. If I slowly ease the bolt closed it will chamber a round without discharging, but then it won't function. This thing will ONLY work if I follow a procedure that causes it to discharge when I don't want it to.

Is this normal or did I get a lemon? I was a nervous wreck handling this thing; it was like diffusing a bomb.

[whiskerz]

The gun is open bolt. fires with the bolt held to the rear. chambering a live round with the bolt down is dangerous! try this take safety off set selector to fun. pull bolt to rear.pull trigger bolt should slam forward stripping a round from the mag and firing until you release the trigger or the mag is empty. If that don't work let us know. HTH W>;I in addition have a good handful of it when firing, my mac11 has a lot of muzzle rise;f

[Irishfly]

What he said. I won't get on a ;l about messing with an unfamiliar weapon but maybe you should do some research on the Mac internet page http://www.mac10.org/ . Lots of info there. That should help. Operates very differently than a closed bolt gun. BTW, where did you shoot here in Austin anyway? Looking for new places to exercise my AC556.


Good luck,
D

[Chris G Thomas]

Over the last couple months, I have been shooting Class III at the Austin Skeet Range, on 290 E, just past Manor heading East, anyway, you know the place...Stanley is totally cool with Class III.

During that time, I have broken in over 70 class III virgins there! I got a pile of new virgins lined up for there tommorrow at 2:00. Come by and lets have a nice Class III showing!

Come see what SRT did to my CAC9! Doug made it Quiet!!!

[Irishfly]

Thats where I get off too. Normally go out there with Steve Ou cuz he gots some cool stuff (M249, G3, numerous MP5's). Might show up with my KAC556F and some suppressors. Thanks for the invite.

Damian

[No Soup For You]

Reds Indoor Range allows class 3 on Thursdays only.

I'll try the open bolt suggestions. I messed with it for about an hour and I believe I tried every variation of bolt open, bolt closed with the safety and fire selector in all the various positions.

I recall that what happened with an open bolt is that...I pulled the bolt back, put in the mag, pulled the trigger, bolt snapped closed but wouldn't discharge the chambered round...If I pulled the trigger repeatedly it would click but no firing.

[CanadianGlockFan]

If you look at the front of the bolt, is the firing-pin a permanent, machined nub on the breech-face, or is there a hole for a separate firing-pin that has to be striker-fired? The "normal" way for a Mac-10 to operate is to pull the bolt back until it locks, insert a full mag, and then it'll be ready to go when you pull the trigger. There HAVE been some Class 3 conversions from the closed-bolt semi-auto Mac-10s though, so the configuration of your bolt and firing-pin should tell you which one you've got.

[r2kba]

I think you gotta mac that needs a doctor. Ya need to have it examined by someone that knows what they are doin before you have some AD's that result in injury.

Please don't keep messin with it untill someone checks it's internals.

[UZIFORME]

You need to go somewhere that someone who understands how the gun works to check it out for you.

Never Never chamber a round in an open bolt weapon.

[modgun]

1 - You have an open bolt gun, treat it accordingly and be careful. Many good suggestions already in this post.

2 - Check that bolt to be sure of what you got.

3 - If I remember correctly this problem has come up before but I dont remember what it was. Ask over at macguns.com and there are some links there to other mac specific boards.

[r2kba]

Also try subguns.com message boards, if you can't get a definate answer by someone in person at a range that KNOWS WHAT THEY ARE DOIN.


Mac's are great, I have a m11, but mis-handling, and lack of knowledge on how to fix, or diagnose a problem can get folks shot.

[Jakk]

Check the firing pin protrusion on the face of the bolt. As others have said, the "firing pin" is just a bump machined into the face of the bolt. I recently chipped the pin on my spare M10/45 bolt, and it stopped running. I would get light primer strikes, where this gun will usually give a *really* heavy primer indentation.

The bolt on the left is the original with the good firing pin protrusion. The one on the right is the damaged one. I imagine I'll have to get mine welded up and re-machined.
http://www.hunt101.com/img/144357.JPG

[No Soup For You]

Thanks for all of your helpful information. I've been able to determine that I do in fact own an open bolt MAC; it has the little nub on the bolt...and my gun is busted, which is disappointing. It's my first machine gun and I went through a lot of crap-ola to get it.

Does anyone know of a gunsmith in the Austin, Texas area that works on these sorts of guns?

[Jakk]

What exactly is broken on the gun? Is the "firing pin" chipped like mine? Or is it something else.

Replacement parts are relatively inexpensive for these guns. If it is a bad bolt, you might consider just buying a new bolt. That would probably be faster (and possibly less expensive) than having someone repair it. I've been busy with other things and haven't had the chance to look into what it will cost to fix mine.

www.cobray.com lists M10/45 bolts at $167.50. www.rpbusa.com has M10/45 bolts for $125. There are a few other places as well.

[Irishfly]

I have a feeling Terry Davis could do it but don't be in a hurry. I have heard he is really really slow but a good smith. That's what I have heard as I haven't had any of my stuff worked on by him. I tried but he wasn't there on 5 different weekdays that I stopped by in a two week period.

Hank Fleming is probably the best in town but you would have to ask if he could help you out. I think that he works on Class III stuff as he was in the back of "Just Guns" for years. He has done some trigger and stock work for me and is a very good smith.


Here are the numbers-

Terry L Davis Gunsmith
(512) 926-8082 3411 Andtree Blvd
Austin, TX

Hank Fleming Gunsmith
(512) 445-6339 1325 S Congress Ave
Austin, TX

Hank is no longer at 1325 Congress Ave but look his number up in the phone book.

Hope this helps. Guys we need to get together and start an Austin Class III club. Lots of us around here.

D.

[r2kba]

Try sksparts.com, FTFindustries.com which are usually cheaper than cobray.com.


Buy ya a new bolt, and you'll be back in operation it seems.

Ya sure that's all thats broken? And why did someone sell ya a gun that didnt work, and didn't tell ya!? ;g

[No Soup For You]

What exactly is broken on the gun? Is the "firing pin" chipped like mine? Or is it something else.

I can't see that anything is broken. The gun appears to be in exceptional condition for being almost 30 years old. No scratches and very clean internals. I don't have the expertise to indentify what part isn't doing it's job. I followed the directions suggested for operating an open bolt MAC...no joy.

I met a guy at the range this morning that used to have an open bolt M10 and knew quite a bit about the history of the MAC. He messed with it a bit and proclaimed it to be defective. He stripped it down right there but he couldn't see anything out of place.

From a locked back bolt, pull the trigger, it will strip a bullet off the mag and chamber it but it still won't fire. Yet if I pull the bolt almost all the way back and let it go..it will fire the chambered round and function just fine until I need to reload.

[CanadianGlockFan]

Originally posted by No Soup For You
From a locked back bolt, pull the trigger, it will strip a bullet off the mag and chamber it but it still won't fire. Yet if I pull the bolt almost all the way back and let it go..it will fire the chambered round and function just fine until I need to reload.
That sounds like a sear problem, then. If it fires from the "held-back" position, but not from the "caught on sear" position, probably either your sear or disconnector is screwed up. Since this like trying to diagnose a broken leg over the phone, your best bet is to take it to a Class 3 smith.

[No Soup For You]

I contacted Hank Fleming, a gunsmith that was recommended here. He's going to fix this ugly little brick for me.

Thanks for all the information.

[aggiegunner]

It sounds like a weak recoil spring to me. When it has to strip a round off the mag it loses energy and doesn't have enough to fire the round. When the round is already chambered, it doesn't lose this energy.

I bet if you replaced that recoil spring you would be fine...