1919 A4 Forums banner
1 - 20 of 22 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter · #1 · (Edited)
Fairly new here and recently purchased a Maremont M2HB that may have a few issues. The gun has probably been in storage for the last 20 years in a dealer vault. The setup on this gun is similar to a MG52; meaning there is no bolt latch or release. The backplate only has a slide safety and a butterfly trigger between the spade grips. I cleaned everything up internally but seems to have a mild hangup when the bolt moves forward after cocking the charge handle. If the charging handle is racked with the top cover open the bolt will "fly" forward after closing the top cover. It is nearly impossible to release the bolt slowly and not slam. I thought the hang up could be a weak Bolt Drive Spring or a faulty Barrel Buffer Assembly so I replaced both with NOS parts but the issue still remains. The dealer I bought this from insists there isn't an issue with the gun other than it needs to be "broken in" and fired. The gun has very little wear on it and appears near new internally but I have still hesitated to fire the weapon to err on the side of safety. Any help or opinions would be appreciated.
Link to some pictures : http://s1237.photobucket.com/user/sl65amg2008/library/M2?sort=3&page=1
 

·
Registered
Joined
·
4,704 Posts
Never had, or handled an M2HB. If it's anything at all like it's little brother, with the top cover open, pull back the handle. That bolt should stay locked back every time until the top cover is closed, or upward or downward pressure is put on the extractor arm knocking it's grip on the interior rail loose. On a 1919, if it don't firmly engage every time, something is wrong.
Closing the top cover should disengage it from the rail, letting it fly to battery quite forcefully as it's designed to.
When using any auto loading arm for real with loaded ammo, never 'ride the bolt'. Let it fly freely after full retraction.

Other, better and more experienced folks will be with you shortly.

This has not been a public service announcement.

Welcome to the forum. Please be very careful.:)
 

·
Registered
Joined
·
1,665 Posts
I had a problem with my bolt not wanting to slide all the way forward. Check the angled stud bits that hold on the retracting side group. The angled bits are hand fitted. On my gun they had been swapped in the last tear down. It took a while to figure that one out.:rolleyes:
 

·
Registered
Joined
·
1,665 Posts
Oh, and don't slam the bolt home with no barrel in it, according to a maintenance comic I came across. It is rough on the Barrel extension.
 

·
Registered
Joined
·
1,467 Posts
Rugman is right on on the function of the top cover releasing the bolt.

Check for hangups with the backplate off and no buffer spring. see if the bolt slides back and forth freely. I spent A LOT of time at this stage of the build getting everything nice.

FA weapon?? Not seeing denial islands.

Above all be very careful. A mistake on many weapons might hurt you. A mistake with this bad boy will kill you.



Karl
 

·
Registered
Joined
·
7,251 Posts
...looks like a semi-auto...

Maybe it's my bi-focals...but I see 2-denial islands,so this is probably a semi-auto weapon. Karl is correct and all the internals should be checked one-at-a-time. Complete function should be done without the recoil rod/spring assembly and the spades off the gun. Make sure to lube the parts with 30W motor oil and then look for areas that show wear marks. Make sure that any sharp areas are dressed with a stone or break them with a few swipes of a fine file. It will take a few take-downs to get everything operating smoothly. Don't get discouraged....there is a price to pay for shooting an M2HB. Also...don't discount any tips...everything needs to be looked at. Get the military manual for the operator (gunner) and a field maintanince manual for specific areas to look at. Keep asking questions...we all learn from the knowledge of others.
 

·
BeltFed GURU
Joined
·
4,433 Posts
L999here,
It is not a semi !! I know because i sent him over here in the first place ! I felt a "fresh set of eyes" and different minds would help him more than i could :D . There are aspects i do not think about because they are second nature to me :confused: .
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #8 ·
Thanks to everyone for the input and thank you Belt Fed Frog for directing me to this sight; you have been a wealth of information to me for many years. Sorry about the picture post being so large, I'm not sure how to link up thumbnails. There is a photobucket link which should give you a look at the gun from many angles if you need more pictures. Belt fed is correct, it is a FA M2 or at least that's what the paperwork says. If Rugman and Karl are correct about the top cover releasing the bolt then there may not be a problem at all. I ASSumed that since there was no bolt latch that the bolt would ride forward with the charging handle every time, wether the top cover was open or closed. But what has been happening is the bolt stays back every time the charging handle is pulled and is either released by giving the gun a bounce if the top cover is already closed, OR if the top cover is open when pulling the charge handle back the bolt runs forward upon closing the top cover. So now I question if there is any problem at all???? Is it functioning as it should and is my lack of knowledge the only problem?
 

·
Watercooled Addict
Joined
·
2,146 Posts
First off, welcome. Next, if the gun is tight, take it apart and lube it well with oil. something more the consistency of vactra light way oil rather than rem oil. Lube anything that moves, especially the sides of the sideplate where the bolt and the barrel extension rub, as well as where these parts rub on one another. I actually prefer grease on the breech lock cam and lower side of the breech lock where it rides on the cam.
It sounds as if your gun is dry and tight. The bolt is sticking slightly and the jarring of the internals from closing the topcover on an open bolt is putting enough downward pressure on it to allow it to run home. It could be that your breech lock cam is a little too loose also allowing the cocking stud to rub in the slot in the right side plate. You do want the cam a little loose though(think playing card thickness between the bottom plate and the bottom of the breech lock cam.

Also you need to have a barrel in the gun when testing this as without one to hold the internals in proper geometry, all sorts of strange things with alignment and binding can happen.

Thirdly, never close a topcover on an open browning of any type as you are forcing the drive tab on the feed lever closed on top of the bolt rather than into its slot where it is supposed to be, thereby causing bending, burrs and general bad juju!

Lastly, even with a barrel in the gun do not let the bolt fly forward on an empty chamber. This causes undue stress on the barrel extension and can lead to cracking which can lead to separation, which can lead to everything coming out the rear of the gun upon firing with enough force to kill you and the next guy behind you. You must however not ride the cocking handle forward when loading the gun. Stick belt into gun double loop first and cycle twice. First time ride the handle to avoid bolt banging on empty chamber and second cycle release it completely while it is fully rearward allowing it to fly home and properly load.

I am making an assumption that you know about the proper setup, timing and headspace of the gun. These must be checked frequently and religiously because they change as parts wear and replacing any part will change either or both. I check mine at least every two belts when at a shoot.
Headspace can cause nice dangerous explosions, and timing can cause some horrific ones. Please get proper training on both if you are even remotely unsure. Also make sure barrel lock spring is correct and functioning properly. I have been near one that blew because the spring became weak and allowed the barrel to unscrew. Gun was headspaced and 30 rounds later it blew. The barrel had rotated over 1 turn in 30 shots.

Be safe and have fun.
 

·
Watercooled Addict
Joined
·
2,146 Posts
frog,
It took me a minute to realize there was a link to an album. I thought you had gone crazy for a second!

Its the more current version of the hb only buffer. They work fine but can become worn where the shaft reciprocates through the hole in the plate and this can cause binding. At this point the hole will be visibly egg shaped if that's the case. This gun doesn't look to have very many rounds through it so I would imagine that is fine. It would take enough rounds that only a few armies on earth could afford the ammo to wear it that much.

On a different note, if the drive spring rod is as bent as it looks in the picture with the buffer in it, that will cause a noticeable bind in the bolt.
 

·
BeltFed GURU
Joined
·
4,433 Posts
Jmann ,

That is what i meant about fresh eyes !! I had him get an oil buffer and drive spring from MG Dave because i was a bit worried about the batter ring on the back plate . As far as Crazy well yes and no :tongue::rofl::rofl:


I knew you would see things clearly and catch /touch on things that never crossed my mind ,i did not see the bend in the drive spring rod :D:urtheman::thumbup:

Sadly i am going blind :(
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #13 ·
JMANN thanks for the input. I think you may have found the issue and I will be checking into it as soon as I get home from work. It makes perfect sense that the issue is the breech lock hanging up on the breech lock cam due to dryness/tightness. I did change out the bolt driving spring with a NOS spring because it looked bent to me as well and it did seem to help but did not clear up the hang up issue completely. When I pull the charging handle back all the way and release it the bolt will move forward slightly before it hangs up. If I bump the gun with the heel of my hand it will "creep" forward ever so slightly with each bump until it finally releases and slams home. I think this creeping forward is the breech lock riding up the ramp on the breech lock cam. I will pull the breech lock and lube it as well as the breech lock cam. When I first received the gun I ran all parts through my parts washer and reoiled all the parts but I didn't remove the breech lock so there may be a lack lubrication between the breech lock and the barrel extension as well as between the breech lock and the breech lock cam. I have a feeling this may solve the hang up issue.
 

·
Registered
Joined
·
7,251 Posts
...and it was my bi-focals acting up....LOL. Sounds like the problem areas have been addressed,especially with lube and the breech lock. I had to re-think everything the first time I operated my FA M2HB,as I was not used to the bolt locking to the rear on an empty gun. Had to re-read the manual and refresh my memory. It had been almost 15 yrs since I was at Nellis AFB on the range with a FA M2HB. Amazing the stuff you forget....LOL...
 

·
Watercooled Addict
Joined
·
2,146 Posts
Just to add to something that might be causing confusion. The bolt should not stay back on this gun regardless of whether the topcover is open or not. On a m2hb gun the only two ways the bolt should stay back is if
1. the gun has the bolt hold open device installed to allow for single shots, which this one clearly does not, or
2.If you manually reach into the open topcover with your spare hand while retracting the action and place the point of the extractor into the notch ground into the rivet on the lsp which is there for this purpose.
Either way you dont want to close the topcover with the bolt back because once the topcover is opened the feed arm will index back to its retracted position thus not be able to line up with the drive slot in the bolt without bending upward and jumping time. It is sort of like dragging the needle across a record rather than laying it in the groove(for those of us old enough to remember such).
 

·
Registered
Joined
·
4,704 Posts
Just to add to something that might be causing confusion. The bolt should not stay back on this gun regardless of whether the topcover is open or not. On a m2hb gun the only two ways the bolt should stay back is if
1. the gun has the bolt hold open device installed to allow for single shots, which this one clearly does not, or
2.If you manually reach into the open topcover with your spare hand while retracting the action and place the point of the extractor into the notch ground into the rivet on the lsp which is there for this purpose.
Either way you dont want to close the topcover with the bolt back because once the topcover is opened the feed arm will index back to its retracted position thus not be able to line up with the drive slot in the bolt without bending upward and jumping time. It is sort of like dragging the needle across a record rather than laying it in the groove(for those of us old enough to remember such).
I will consider myself stuck in the time out corner.:(

Would that have applied to a semi gun??

Shuttin' up.:eek:
 

·
Watercooled Addict
Joined
·
2,146 Posts
I will consider myself stuck in the time out corner.:(

Would that have applied to a semi gun??

Shuttin' up.:eek:
Didn't mean to embarrass you. I know your response was well intended, and I know a lot of folks do it this way, but there are also a lot of top overs with burrs and gouges on the feed arm and gouges in the bolt. On a .30 the back edge of the extractor cam has a small u shaped cutout for the leading edge of the extractor to rest in and hold the bolt open. More times than not when they are cycled with the top over open, the extractor comes to rest in that little detention and the bolt stays open. The .50's have a rivet in the side plate with the same notch in them but for whatever reason they usually have to be manually guided into the notch to stay open.
long rambling story short, those notches are there to hold the gun open and show clear. However the bolt should be retracted and extractor depressed to allow bolt to be eased forward before the top cover is lowered. Slamming the top closed with a bolt held back in one of the notches drives the extractor down and out of this notch, thus releasing it, but not in a way intended because the feed shuttle is out of time with the bolt. This is especially true on the.50 where the feed arm has a spring that brings the shuttle back to center when the top over is raised.
 

·
Registered
Joined
·
4,704 Posts
I'm a grown man (more or less), I can take it.:eek: I'll try not to muddy waters I don't know anymore.;)
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #19 ·
Progress

Well it looks like we are headed in the right direction. After careful oiling and greasing the bolt will "ride home" after cocking and releasing the charging handle 4 out of 5 times. So I still get the occasional hangup, but before the oiling of every part I could find including the breech block and cam it would hang up everytime. So I am not too concerned anymore. There is still something I must be missing or things are just a little tight. The dealer that I bought it from claims it just needs to be broken in and needs to be fired.

Is it OK to grease the barrel support since there is a hangup at the very end of the bolt closure?

I also saw the notch in the rivet on the LSP to lock the extractor into to hold the bolt open..... a very helpful piece of information.

Thanks for the help
 

·
Legendary Donor
Joined
·
1,683 Posts
m2 problems

jmann is right get plenty of proper instructions on this. these are not to be played with.
take your time and read up real good. there are plenty of cd's on this gun out there. the m2 board used to be a good place to get one. don't know now.
the kits are getting harder to get so the board has less use than it used to.
tomt
 
1 - 20 of 22 Posts
Top