More MG42 teething problems... (PICS AND VID)

[MauserMatt]

Took the '42 to the range again today and decided I want to put at least 200 rounds through it.. Well, I probably cleared the weapon of live rounds that didn't go off more than I shot it... I THINK I have the charging handle problem solved.. Just had to square off the edges a little bit for that... But here's the newest..

I think the biggest problem is the ammo. The Yugo stuff doesn't like to pop the primers. So of course had dimpled primers that the K98 had no problem with. Then I had this:



Here's a video of what happened:

http://www.youtube.com/watch?v=FF00dVjL2ds[/video]

(Yes that is a live round sticking out there with another round in the chamber)

And this is what that particular cartridge looked like when I pulled it out of the chamber:





There was also still powder in this cartridge. I must note also that the barrel gate popped open on me this time too. I've never had that happen either..

I then started getting the barrel gate to pop open every few times and that's when I stopped shooting. I don't want or need an OOB explosion...

I think the problem of dimpled primers will be solved once I upgrade to Pirates new bolt system. The barrel gate though I have no idea...

[JBaum]

I'm not following here... did the first shell come apart and leave the front part in the chamber, then the second shell impaled into the remaining part of the first shell?

[Bil]

Was there a cartridge case also in there? Did a base rip off and then feed another? From the video it looks like you may have pulled on the charging handle and put a round into an already loaded gun,that may have been what we heard then.It seems there should be another case.Or did this cartridge go off before it was in battery,swelling the case? Did your trigger assy fail?If this blew the door open,you may have bent it,or jammed the latch.Either way,lucky no one was hurt!Let us know what you find out. ---bil just watched again,big and slow.It looks like the barrel door popped open when you fired.This caused the barrel to be mis-aligned.You then fed more into it-see the cartridge sticking out the side at the very end of film

[Pirate]

does the round with the blown primer have flash holes? I don't see them in the photo. as far as the yugo ammo goes the 50's stuff has deep primers and doesn't work reliably in my gun. I like using the steel cased romanian as it is more tollerant of excessive headspace.

[sdk1968]

Matt,

def looks like you double clutched him there...

how much do you have latching on the barrel door? (mines pretty tight when it closes.)

do you have any pressure from your recuparator on your barrel when its installed?
(mine has a little pressure on it, the barrel has to be pulled out by the barrel door, it wont just fall out)

im a rookie at these, could just be YUGO ammo.

and one thing about Pirates FCG & bolt: it WACKS a primer! its running Romanian and Turkish with no problem.

[xano]

My 2 cents. It looks like on the last round the gate popped open and then you had an ftf. You then charged the gun again pushing the gait out even further. I think you should check the engagement of the gait door and get as much bite as possible. The spring on the latch gets weak and moves with recoil if not adequately secure. Make sure the gait is not bent. From the looks of things I don't think so.

[MauserMatt]

To clarify, no shells were broken in the chamber or otherwise. The picture of the bullet is the same bullet that you see in the first picture. That bullet just fell right out of the chamber. AND the pictures were taken of what you see in the video. All of this happened with 1975 Romanian ammo. The only problems I had with the Yugo was duds.

Right after these pictures were taken we were able to load up and keep shooting for a little bit. And then the barrel gate popped open again for no apparent reason. So we stopped shooting then. My latch has always been pretty tight, which is really what surprised me about it popping open like that..

Since it was put together I've probably run about 300-500 rounds through it without the barrel latch popping open..

My recuperator puts a little amount of pressure on the barrel, I do have to use the latch to get the barrel out.

My setup is a Pirate bolt and a Wiselite AR FCG gripstick.

[JBaum]

flash holes are visible in the top picture at 3 and 9 o'clock. It's berdan primed, so there there are two flash holes on opposite sides.

[sdk1968]

ok thats exactly the same year Romanian i have....

ive not ran that many rounds thru mine yet (only 100)
hammered that first 100 out pretty quick just to see if it would jam up.

and your gate latch was tight.. wow im gonna be a little more careful next time out with mine. LOL
my barrel is pretty snug in there as mentioned before, you actually have to pull to get the barrel out of the recup.

one of the guru's will surely have the answer as to how much pressure is really supposed to be in this area.

but that round in the video looks like it just bounced off of the one that was still in there and hit the latch set up.

[MauserMatt]

What I would REALLY like to know is how the primer got popped out of there without igniting any powder??? I can shake the round and hear the powder bouncing around.... What causes this??

[Pirate]

Matt, did you find the primer? that is why I asked about the flash holes. look inside your bolt to see if there is primer material in there. one of the main problems I had with the ar fcg was blown primers, but only the part where the fp hit it blew out. it looks like the primer exploded. you should pull the bullet and see what the powder inside looks like. the second round may have bent the bbl door.

[MauserMatt]

Never did find the primer..

The barrel door looks fine. I don't see any flash marks or bent metal... The door still latches strong...

I'll try to get some time and pull the bullet tomorrow and snap a pic..

[42rocker]

Have to guess if this 2008 problem got fixed or not. Brought post up because on nice pics and interesting problem. I would rather read about this stuff and learn how to deal with it in the field.

Later 42rocker

[TactAdv]

Four years late and all..... ;-)

Typically, primers that dislodge like this are the result of a defect in the manufacture of the case at the primer pocket. It is not at all uncommon that the piercing operation that forms the anvil hole of the Berdan system fails to fully pierce the case head, or can even be blocked by some obstruction during manufacture. This is more likely with Berdan system than Boxer due to the nature of the anvil and flame path.

If that happens, the primer will simply back itself out of the (closed off) hole there as you show, there is certainly enough energetics effect in a primer to overcome any crimping used to retain it and it simply dislodges.

The other possibility is just the opposite; that there was little to none crimping or retaining force on that particular primer annulus and when it ignited all its energy sought the path of lead resistance; there is often a thin seal at the apex of a Berdan flash-hole as an additional environmental seal, meant to be pierced by the primer action on ignition.

Lots of possibilities.

-TomH