Mac 11/9 custom work -sear work

[Generalzip]

I’ve seen posted that C&S metal works does for sear engagement upgrade for the Mac 11. If you were to replace the stock sear with a Lage one and the bolt with a FTF one, would this upgrade still be recommended? I just bought a Mac and the previous own said he put a mag in and that was enough to send the bolt home and runaway the entire mag. Luckily nobody was hurt. He since replaced the bolt and the sear as described above and said it hasn’t happened since in 2-3000 rounds.

I want to have the safest Mac possible as I will be letting other shoot it. So given the current configuration, would this upgrade be recommended? I want to have a semi feed ramp installed on my Uzi and the Mac refinished as well so figured would send both in at the same time for this work.

I’m from Texas so any reputable shops that could do all the work. Someone pointed me to Adams armament.

 

[ScubaLoser]

If the previous owner installed a Lage sear in it you’re fine. You can visually see if the sear is worn out, and Lage is written on the sear as well to confirm it’s actually a Lage one.

Read the description of the Lage sear here:

Lage Manufacturing

www.max-11.com

 

[Gaujo]

Sometimes the problem is the little pivot thing the sear sits on. I had this problem, and eventually had runaways with a lage sear. I had to lightly file that little thing and then the same sear no longer had a problem as it could now sit properly.

 

[Generalzip]

If the previous owner installed a Lage sear in it you’re fine. You can visually see if the sear is worn out, and Lage is written on the sear as well to confirm it’s actually a Lage one.

Read the description of the Lage sear here:

Lage Manufacturing

www.max-11.com

My understanding is that it’s not just the hardness of the seer but also the dimension/positioning of it. They went from 380 to 9mm and didn’t make any changes even though there’s more recoil and a heavier bolt. My understand was the area of dear engagement was not enough. Unless the Lage sear is dimensionally different it would not account for this issue

 

[Generalzip]

Sometimes the problem is the little pivot thing the sear sits on. I had this problem, and eventually had runaways with a large sear. I had to lightly file that little thing and then the same sear no longer had a problem as it could now sit properly.

Could you possibly post a pic of what you filed down and how much?

 

[Gaujo]

I'd have to take the gun apart, but it was this little thing under the sear that the sear pivots on. Looked kind of like an ar-15 front sight. Filed it eeeeever so slightly.

You can see it in the next to last picture here, right under the tip of the red arrow

MAC-11.info

www.mac-11.info

I cannot remember now if I filed the tip or the sides of it, but I believe it was the sides, that the front two legs of the sear pivot on. This effects the presented face of the sear so proceed with extreme caution. Vegas SMG was actually the one that suggested trying this, said these little pivots weren't always welded in perfectly geometrically. Miss that guy!

 

[Generalzip]

Hmmm since it’s part of the actual receiver it seems I’ll def send it off to have it done by a professional.

 

[skoda]

If you have a new sear and bolt and it doesn't run away then don't worry about it. If you are running a steel bolt the rate of fire is so fast that a runaway will empty the magazine so quickly that most newbies probably won't know what happened. You could always keep a spare sear and bolt in your range kit if you are really concerned about it.

I have had to reweld and reshape my Lage sear after a few billion rounds. I've had to dress the notch on my CFW bolt too.

While you're at it replace the safety inside and out. Especially the inside part, it's terrible. Get a few buffers while you're at it.

 

[JwestAK]

Hmmm since it’s part of the actual receiver it seems I’ll def send it off to have it done by a professional.

While I can't help with the overall issue. The part is he talking about is the sear stud. I would not file on it because it is welded into the receiver.

You would achieve the same result by profiling on the bottom side of the sear itself where it stops on the sear stud. Since that part is easily replaced, it wouldn't be a in depth repair.

(Image borrowed from Lage Manufacturing)

 

[SecondAmend]

After replacing two sears, to minimize wear and tear on the sear and on the bolt sear notch, now when shooting centerfire ammo I usually just do mag dumps (mag loaded to ten or so rounds). But I'm mostly shooting .22 now anyway.

 

[Generalzip]

If you have a new sear and bolt and it doesn't run away then don't worry about it. If you are running a steel bolt the rate of fire is so fast that a runaway will empty the magazine so quickly that most newbies probably won't know what happened. You could always keep a spare sear and bolt in your range kit if you are really concerned about it.

I have had to reweld and reshape my Lage sear after a few billion rounds. I've had to dress the notch on my CFW bolt too.

While you're at it replace the safety inside and out. Especially the inside part, it's terrible. Get a few buffers while you're at it.

I’ve got all the spare parts you can imagine. The concern is a runaway gun is absolutely unacceptable to me under any circumstance and I’m willing to pay any amount of money to have the gun adjusted and tuned to ensure it never happens again including preventative maintenance on sears etc every 3-5k rounds. I’m not concerned with a couple hundred dollars in parts to ensure someone doesn’t get killed.

The problem was the previous owner said just insert in the mag was enough to trip the sear and empty the mag. He was not prepared for it at all and was lucky it was pointed down range. Had it been someone less experienced or strong they certainly could have been killed. I don’t know about you but “it’s probably fine” is not good enough for me in this instance. Hence why I’m asking for gunsmiths that are known to be able to correct this issue permanently to ensure it never happens again.

ETA: hope I didn’t come off as an ass. I’m just driving the point that a safe firearms is of absolute highest priority to me.

 

[Generalzip]

While I can't help with the overall issue. The part is he talking about is the sear stud. I would not file on it because it is welded into the receiver.

You would achieve the same result by profiling on the bottom side of the sear itself where it stops on the sear stud. Since that part is easily replaced, it wouldn't be a in depth repair.

(Image borrowed from Lage Manufacturing)

Makes sense. I assume this would make the sear protrude up slightly more increase sear engagement. This would result in a much safe firearms at the cost of a grittier, more creep trigger. That’s an easy choice in my opinion considering the mac trigger sucks anyway. The gun has since been replace with Lage sear, internal and external safety, select fire competition trigger. I’ve also bought the improved Lage trip, selector switch, and spare disconnector and all pins and springs for the FCG. My intent is have it shipped somewhere while in ATF jail to be inspected completely, any repairs made, and refinished.

Who’s the best gunsmith for Mac’s in the country? Time and money is not of concern as long as the work is top notch and competency is there. If they know uzis well this is a plus as I want to install a semi feed ramp in my vector Uzi.

 

[JwestAK]

Makes sense. I assume this would make the sear protrude up slightly more increase sear engagement. This would result in a much safe firearms at the cost of a grittier, more creep trigger. That’s an easy choice in my opinion considering the mac trigger sucks anyway. The gun has since been replace with Lage sear, internal and external safety, select fire competition trigger. I’ve also bought the improved Lage trip, selector switch, and spare disconnector and all pins and springs for the FCG. My intent is have it shipped somewhere while in ATF jail to be inspected completely, any repairs made, and refinished.

Who’s the best gunsmith for Mac’s in the country? Time and money is not of concern as long as the work is top notch and competency is there. If they know uzis well this is a plus as I want to install a semi feed ramp in my vector Uzi.

I'm new to the transferable MAC world. However when I had questions about my gun, Sam at Practical Solutions was able to answer them. To my knowledge he is one of the top guys in the game. However I'm sure people who have more experience have other options as well.

 

[skoda]

The problem was the previous owner said just insert in the mag was enough to trip the sear and empty the mag. He was not prepared for it at all and was lucky it was pointed down range. Had it been someone less experienced or strong they certainly could have been killed. I don’t know about you but “it’s probably fine” is not good enough for me in this instance. Hence why I’m asking for gunsmiths that are known to be able to correct this issue permanently to ensure it never happens again.

ETA: hope I didn’t come off as an ass. I’m just driving the point that a safe firearms is of absolute highest priority to me.

Rule #1 ALWAYS applies. If you don't follow Rule #1 then you shouldn't have a firearm in your hands. If you are taking inexperienced people shooting it is your responsibility to teach them Rule #1 and to constantly monitor that they follow Rule #1. Relying on a sear and other parts is always a recipe for disaster. A part that worked ten million times before can fail the next time you use it.

And sorry, I didn't notice the part in your first post that the gun went off when the magazine was inserted ( which is one reason why we have Rule #1). I thought that it was a standard trigger off run away. I wasn't being flippant about your problem but this is a fairly simple mechanism with a limited number of failure modes. Basic diagnosis methods will reduce that to one or two likely causes and from there a solution.

If you are really questioning the basic safety of your particular gun* you should try to find out why it did what it did for the other guy as just replacing parts is no assurance of a fix. Obviously when the mag was inserted the impact of the mass bottoming out caused the bolt to be released and for some reason the sear didn't catch the bolt after the first round was fired (not that it would matter if it was ONLY one round that was unintentionally fired). Did the previous owner have their finger on the trigger? (they probably won't admit that) That failure smells of a bad sear and possibly the corresponding surface of the bolt. Do you have those parts? If you do look at the sear and bolt for damage in the mating surfaces. If you don't have the parts and don't feel qualified to diagnose/test the gun with the new parts then spend the money to take it to a good gunsmith** and have them check it out. They can't guarantee that it will never happen again but they might make you feel better about the gun. Good luck.

*not a bad thing to do for M11/9s especially those made in 1986 before the ban

** any decent smith that has experience on MACs can do it, ask some local smiths first, but Practical Solutions is probably the most experienced with the idiosyncrasies of MACs

 

[Generalzip]

I trust his finger was not on the trigger as he’s been shooting for over a decade and owns a few MGs. He did keep the parts. He said the bolt looked worn on the sear area.

There technically is a way to essentially assure it will not happen again. That’s by adding material with proper hardness to the sear such that it has “excess” engagement on the bolt. So long as the heat treatment was good on the bolt and sear it should last a lifetime of shooting. This is what C&S metal Works apparently used to do? Of course if you put a million rounds through it, it will fail again but in doing something similar to as I described, you nearly eliminate the sear and bolt as being the next most likely failure points.

Other weapons do not have this issue and the designs similar. Think sten, Tec 9, Uzi etc. the sear is ultra important on an open bolt weapon for obvious reasons.

I sent an email to practical solutions and will let you know their reply.

 

[m11stuff@hotmail.com]

"Runaways" don't typical just happen and dump a whole mag'. It starts with shooting a burst, but an extra round or two fires after you release the trigger. Then, three of four rounds after you release the trigger. It will get progressively worse until it dumps a whole mag'. You need to look at the edge of the sear, the sear notch on the bolt and the selector/sear pin hole in the lower. Most runaway bolts I have seen were caused by a rounded off/worn sear notch on the bolt.

Runaways can also be caused by weak ammo not fully cycling the bolt back far enough to catch the sear.

 

[MitchWerbellsGhost87]

I'd have to take the gun apart, but it was this little thing under the sear that the sear pivots on. Looked kind of like an ar-15 front sight. Filed it eeeeever so slightly.

You can see it in the next to last picture here, right under the tip of the red arrow

MAC-11.info

www.mac-11.info

I cannot remember now if I filed the tip or the sides of it, but I believe it was the sides, that the front two legs of the sear pivot on. This affects the presented face of the sear so proceed with extreme caution. Vegas SMG was actually the one that suggested trying this, said these little pivots weren't always welded in perfectly geometrically. Miss that guy!

This is called the “Sear Stud”, the height of the stud directly affects the height of the sear. The lower the stud, the higher the sear.

In my experience with SWD M11/9s the runaways always seem to occur because the sear surface on the bolt gets peened out and worn down and starts to jump the sear instead of catching on it. It gets to a point where the bolt will snap shut on you if you so much as look at it the wrong way. This can be easily remedied by picking up a newly manufactured CNC bolt assembly from Practical Solutions. The improved LAGE sear will help as well but in my experience it’s really the soft improperly heat treated SWD OEM bolts that only last a couple 1000 rounds (or less) before they start failing to engage the sear.

 

[Gaujo]

I may have actually ground the sear. If you want to try I'll take it apart and check. Otherwise send it to Sam at Practical solutions.

 

[Generalzip]

This is called the “Sear Stud”, the height of the stud directly affects the height of the sear. The lower the stud, the higher the sear.

In my experience with SWD M11/9s the runaways always seem to occur because the sear surface on the bolt gets peened out and worn down and starts to jump the sear instead of catching on it. It gets to a point where the bolt will snap shut on you if you so much as look at it the wrong way. This can be easily remedied by picking up a newly manufactured CNC bolt assembly from Practical Solutions. The improved LAGE sear will help as well but in my experience it’s really the soft improperly heat treated SWD OEM bolts that only last a couple 1000 rounds (or less) before they start failing to engage the sear.

Based on what was described to me I think this is the best answer of what happened in this particular case. Would it not be wise then to slightly file the sear stud or part of the sear to slightly increase sear height say 1mm additional? Just to be extra safe and prevent this? Also ensuring sear to bolt contact is perfectly perpendicular would help too I’d imagine.

 

[Homer]

I'm definitely not an expert but reading this and from years of reading peoples problems and people marking mags to diagnose problems, was the run away with any mag or just one mag?