Rounds between stoppage for NFA machine guns

Machineguntony · September 15, 2014, 11:21 PM

I was reading an article that stated NFA machine guns, due to their age, encounter various issues. The main issues are stoppages between rounds and maintenance issues.

Empirically and anecdotally, I think the above paragraph may be supportable because I saw, at a police academy, a genuine and new MP5 factory gun being run with 20 magazines, and it had zero stoppages.

I used to always get a stoppage. I usually get a FTF (usually a double feed) a few times per range session.

For the first time in my NFA ownership, I took 2500 rounds to the range, this weekend, and had zero FTF, FTE, double feeds, etc. All 2500 rounds ran flawlessly. Prior sessions I would always have some sort of stoppage. Maybe it is because I am becoming better at reloading. I don't know the reason, but I'm curious as to whether I will have a stoppage next time I go. I was shooting my M16s and MP5s. No stoppages.

Do you guys encounter stoppages on your machine guns? Every gun jams, I understand, but it appears that machine guns jam more frequently.

mboylan · September 16, 2014, 09:22 PM

Pre-86 was no different. Lots of stoppages and fixing.

kawasakifreak77 · September 18, 2014, 05:32 AM

2500 rounds in one trip? Good lord!

Though sounds like you've got peerless reliability with whatever weapon you have there so kudos, man.

tirod · September 19, 2014, 11:17 AM

IIRC the M4 is about 3.600 rounds between stoppages demonstrated. That's using LC issue ammo.

Colt has an interesting video of them shooting an M4 continuously mag after mag, and it blows up after about 850 rounds.

What's the difference? "Fire a burst of 8" as the Army teaches and you reduce the potential overheating that creates damage and causes the problem to begin with. Not to forget the average combat load of the Infantryman is less than 400 rounds.

The legendary Filthy 14, which as only been cleaned twice, has gone over 55,000 rounds as a carbine class loaner. It's had parts replaced, the MRBS is unknown, but it's still in use as far as we know. Since it can't shoot full auto, it's a good reference point in comparison to the M4.

It depends on the amount of rounds and how much time. Too much ammo too soon and you get Wanat - is that gun designed to do it? A Jeep load of ammo and a water cooled .30 in a fighting position can take a lot more punishment.

So, spell out exactly how it is going to be used, or abused, and you will soon see the answer. Mean rounds between failure requires spelling out how many rounds and what downtime there is between them. Each type action is different and there is no one answer. Comparing numbers with no idea of what the rate of fire is doesn't mean a thing.

Machineguntony · September 19, 2014, 03:43 PM

I took 1000 rounds to the range and had two stoppages, both being failures to eject. So I must have gotten lucky, in that I didn't have a stoppage in 2500 rounds.

I am not shooting all the rounds out of one gun. It is out of multiple guns.

From what I am told by a dealer, for NFA machine guns, the stoppage rate of about 1 in 500-1000 is about average, depending on the gun (something like a mac11 will have a much higher rate of stoppage than a good m16).

At a cyclic rate of about 600 rounds a minute, 1000 or 2500 rounds only comes out to be about 1-2 minutes of trigger time. Most of the time is spent reloading the mags.

boltomatic · September 19, 2014, 04:46 PM

Auto's are finicky. Ammo is usually the biggest culprit, both the gun and ammo need to be tuned for the same rate of fire for reliable function.

medalguy · September 28, 2014, 09:21 PM

I took my 1919A4 out last week and went through 1600 rounds (2 full cases) without a problem, except one time the belt got slightly twisted and that caused a stoppage. Otherwise, all I did was properly headspace and pour about a pint of ATF down into the guts before starting shooting. Oh yeah, fired bursts of 10 rounds or less at a time, and let it cool down slightly (5 minutes) between 200 rd belts. Baby likes to be run wet and she likes to smoke. A lot.

I have a 1921 Thompson that I shoot frequently, and as long as I run 230 gr FMJ it works well too. I rarely have any problems with that one either.

M14 also works well with full power (GI) loads but doesn't like my target load 7.62, not enough oomph to work it FA.

I've found that most often, feeding issues are the result of not enough power, not using the ammo the gun was designed for (SWC doesn't work in any Thompson I own), or lack of sufficient lube.

September 15, 2014, 11:21 PM	#1
Machineguntony Senior Member Join Date: June 22, 2013 Posts: 1,277	Rounds between stoppage for NFA machine guns I was reading an article that stated NFA machine guns, due to their age, encounter various issues. The main issues are stoppages between rounds and maintenance issues. Empirically and anecdotally, I think the above paragraph may be supportable because I saw, at a police academy, a genuine and new MP5 factory gun being run with 20 magazines, and it had zero stoppages. I used to always get a stoppage. I usually get a FTF (usually a double feed) a few times per range session. For the first time in my NFA ownership, I took 2500 rounds to the range, this weekend, and had zero FTF, FTE, double feeds, etc. All 2500 rounds ran flawlessly. Prior sessions I would always have some sort of stoppage. Maybe it is because I am becoming better at reloading. I don't know the reason, but I'm curious as to whether I will have a stoppage next time I go. I was shooting my M16s and MP5s. No stoppages. Do you guys encounter stoppages on your machine guns? Every gun jams, I understand, but it appears that machine guns jam more frequently. __________________ Sent from Motorola DynaTac 8000x

September 18, 2014, 05:32 AM	#3
kawasakifreak77 Senior Member Join Date: December 16, 2007 Location: St. John, Ks. Posts: 267	2500 rounds in one trip? Good lord! Though sounds like you've got peerless reliability with whatever weapon you have there so kudos, man. __________________ Looking for oddball ammo. Tracers, AP, whatcha got?

September 19, 2014, 03:43 PM	#5
Machineguntony Senior Member Join Date: June 22, 2013 Posts: 1,277	I took 1000 rounds to the range and had two stoppages, both being failures to eject. So I must have gotten lucky, in that I didn't have a stoppage in 2500 rounds. I am not shooting all the rounds out of one gun. It is out of multiple guns. From what I am told by a dealer, for NFA machine guns, the stoppage rate of about 1 in 500-1000 is about average, depending on the gun (something like a mac11 will have a much higher rate of stoppage than a good m16). At a cyclic rate of about 600 rounds a minute, 1000 or 2500 rounds only comes out to be about 1-2 minutes of trigger time. Most of the time is spent reloading the mags. __________________ Sent from Motorola DynaTac 8000x

September 16, 2014, 09:22 PM	#2
mboylan Senior Member Join Date: March 31, 2011 Posts: 120	Pre-86 was no different. Lots of stoppages and fixing.

September 19, 2014, 11:17 AM	#4
tirod Junior member Join Date: January 21, 2009 Posts: 1,672	IIRC the M4 is about 3.600 rounds between stoppages demonstrated. That's using LC issue ammo. Colt has an interesting video of them shooting an M4 continuously mag after mag, and it blows up after about 850 rounds. What's the difference? "Fire a burst of 8" as the Army teaches and you reduce the potential overheating that creates damage and causes the problem to begin with. Not to forget the average combat load of the Infantryman is less than 400 rounds. The legendary Filthy 14, which as only been cleaned twice, has gone over 55,000 rounds as a carbine class loaner. It's had parts replaced, the MRBS is unknown, but it's still in use as far as we know. Since it can't shoot full auto, it's a good reference point in comparison to the M4. It depends on the amount of rounds and how much time. Too much ammo too soon and you get Wanat - is that gun designed to do it? A Jeep load of ammo and a water cooled .30 in a fighting position can take a lot more punishment. So, spell out exactly how it is going to be used, or abused, and you will soon see the answer. Mean rounds between failure requires spelling out how many rounds and what downtime there is between them. Each type action is different and there is no one answer. Comparing numbers with no idea of what the rate of fire is doesn't mean a thing.

September 19, 2014, 04:46 PM	#6
boltomatic Member Join Date: March 25, 2014 Posts: 98	Auto's are finicky. Ammo is usually the biggest culprit, both the gun and ammo need to be tuned for the same rate of fire for reliable function.

September 28, 2014, 09:21 PM	#7
medalguy Senior Member Join Date: August 31, 2009 Location: New Mexico Posts: 1,033	I took my 1919A4 out last week and went through 1600 rounds (2 full cases) without a problem, except one time the belt got slightly twisted and that caused a stoppage. Otherwise, all I did was properly headspace and pour about a pint of ATF down into the guts before starting shooting. Oh yeah, fired bursts of 10 rounds or less at a time, and let it cool down slightly (5 minutes) between 200 rd belts. Baby likes to be run wet and she likes to smoke. A lot. I have a 1921 Thompson that I shoot frequently, and as long as I run 230 gr FMJ it works well too. I rarely have any problems with that one either. M14 also works well with full power (GI) loads but doesn't like my target load 7.62, not enough oomph to work it FA. I've found that most often, feeding issues are the result of not enough power, not using the ammo the gun was designed for (SWC doesn't work in any Thompson I own), or lack of sufficient lube.