GPMG runaway gun

[TenaciousDave]

I have heard from several reliable sources of instances where an L7 has got so hot that it has carried on firing even though the trigger has been released, ie runaway gun. However, my gunnery instructor informs me that runaway gun only occurs on L37, ie vehicle mounted, when the trigger bar needs adjusting, and cannot be caused by overheating. Have I been lied to by my friends?

 

[The-Goose]

Quite probably Dave, they told you they were your friends!!

 

[Boxy]

Have heard of it with the co-ax esp on the old Scorps but never on a light role.

 

[smudge67]

This is very rare in a GPMG, almost impossible, as the breach is held to the rear when the firing stops. Unlike the SA80. This is done by design, to stop what you have described from occuring.

It is more likely that the gun hasn't been balanced correctly, or the safety sear has become worn. The most likely cause is that the weapon hasn't been cleaned properly, and the gas parts are coked, therfore there is not enough gas pressure to push the working parts back far enough to reach the sear, and hold it to the rear. It will then keep firing until it runs out of rounds, or you twist the link to jam the gun.

 

[Filbert Fox]

I have heard from several reliable sources of instances where an L7 has got so hot that it has carried on firing even though the trigger has been released, ie runaway gun. However, my gunnery instructor informs me that runaway gun only occurs on L37, ie vehicle mounted, when the trigger bar needs adjusting, and cannot be caused by overheating. Have I been lied to by my friends?

I cant believe that you are taking the word of your gunnery instructor over that of your mates!
Great mate you must be!

 

[Bad_Crow]

I've only ever seen this happen once and the armourer pretty much blamed what Smudge67 had to say ref build up of crap in the weapon.

The lad in question instead of snapping the link chose to open the top cover. Work the rest out yourself.

 

[Pluvia_Plumbum]

See this happen to GPMG SF, so not just a Vehicle mounted problem.

I would be changing Barrels every 400 rds. To avoid overheating. Now I'm no Armourer Techie but runaways are usually a combination of gas setting and fowling rather than a trigger bar adjustment methinks. awaits correction!

 

[hantsbloke]

I think barrels were suppose to be changed after 200 rounds of rapid fire, but it meant more cleaning barrels though, also with a very hot barrel you had a chance off a "cook off" ie a round exploding in the feed tray due to excessive heat, another reason not to lift the top cover

 

[ugly]

I had it happen twice, both at Hythe ranges 7 years apart. 1st was live firing No1 on the GPMG application of fire against that screen. It was put down to an incorrectly assembled gun. No blame attached, only belts of five were issued and no dramas occurred, 2nd was whilst running through some slick gun drills for the SF pln Cdr in 5 Qns. He showed me the gun aon the point, ran through the drills at his command but when I fired a 3 round burst it continued to fire all 20 rounds in the belt off. I held it steady and reported run away gun but didnt break the link as it was over very quickly.
He was impressed and admitted that a few of the guns were very worn and it was possibly that or incorrectly assembled.
no dramas again.
Rounds firing from heat are cook offs and cant occur technically speaking with the GPMG but rounds can prematurely fire just about in a hot chamber before its fully closed. Not seen this myself!
Failing to balance correctly means that the working parts wont always travel fully to the rear engaging the safety sear. This means that an incorrectly balanced gun can runaway!

 

[Bad_Crow]

See this happen to GPMG SF, so not just a Vehicle mounted problem.

I would be changing Barrels every 400 rds. To avoid overheating. Now I'm no Armourer Techie but runaways are usually a combination of gas setting and fowling rather than a trigger bar adjustment methinks. awaits correction!

Its just not realistic. On Telic 4 we got through 1100 rds before getting chance to change it. As you can appreciate it was fcuking humming.

 

[ugly]

I ruined two barrels at sennelager doing a crate of 2700 1 in 5 for a night defensive shoot and we were rotating barrels every 200.

 

[spike7451]

If the gun is'nt balanced correctly then it can go runaway.One of my Cpl's tried to stitch me up when the AEOD team had a runaway gimpy mounted on the Spartan/Scimitar.
Came unstuck tho cause when the Sgt checked the maintainance logs,the Cpl's signature was on it!And considering we only had 2 of them as well!!

 

[hantsbloke]

I did see a cook off once, No2 got some shit in his eye. You always know where you put the hot barrel down, normally ground went up in flames around it! The barrels were bloody hard wearing I seem to remember, we only tried to use the one on an SF shoot! I think they had a very good liner in them!

 

[Bad_Crow]

I did see a cook off once, No2 got some s*** in his eye. You always know where you put the hot barrel down, normally ground went up in flames around it! The barrels were bloody hard wearing I seem to remember, we only tried to use the one on an SF shoot! I think they had a very good liner in them!

Or in my case glues itself to the inside of your daysack.

 

[smudge67]

I think barrels were suppose to be changed after 200 rounds of rapid fire, but it meant more cleaning barrels though, also with a very hot barrel you had a chance off a "cook off" ie a round exploding in the feed tray due to excessive heat, another reason not to lift the top cover

A cook off won't occur on the feedtray. A cook off is where the chamber is so hot that the round being chambered "cooks off" before the breach is fully locked. This can happen when firing a lot of rounds without changing the barrels.

 

[steelrain]

the only one i've seen was due to the safety sear being worn away, it happened on my very first burst with the weapon, plt 2i/c told me he'd waited 20 years to see one, and i go and get one, on my first shoot

 

[Pluvia_Plumbum]

See this happen to GPMG SF, so not just a Vehicle mounted problem.

I would be changing Barrels every 400 rds. To avoid overheating. Now I'm no Armourer Techie but runaways are usually a combination of gas setting and fowling rather than a trigger bar adjustment methinks. awaits correction!

Its just not realistic. On Telic 4 we got through 1100 rds before getting chance to change it. As you can appreciate it was fcuking humming.

A slick crew can change out a barrel in about 7's and for SF thats why you get three. Mind you if your on a two way range sometimes the Pam is the last thing on your mind

 

[Bad_Crow]

See this happen to GPMG SF, so not just a Vehicle mounted problem.

I would be changing Barrels every 400 rds. To avoid overheating. Now I'm no Armourer Techie but runaways are usually a combination of gas setting and fowling rather than a trigger bar adjustment methinks. awaits correction!

Its just not realistic. On Telic 4 we got through 1100 rds before getting chance to change it. As you can appreciate it was fcuking humming.

A slick crew can change out a barrel in about 7's and for SF thats why you get three. Mind you if your on a two way range sometimes the Pam is the last thing on your mind

Ah but i have added bold to one important word

We'd have only managed to fcuk it up in some way and lost the gun. PS made the call and we wrecked the barrel instead. Well it would have been fine until it got familiar with one of my rocket pockets and my ECBA.

 

[galgenberg]

To avoid overheating. Now I'm no Armourer Techie but runaways are usually a combination of gas setting and fowling rather than a trigger bar adjustment methinks. awaits correction!

I personally would use No 3 or BB shot for Fowling.The use of the GPMG seems a bit excessive

 

[ugly]

I'd have that that eider down would fowl it up nicely!