MG42/59 Booster cone needed.

[JBaum]

Besides that, there's something sticking out of the front receiver bushing the same color as the barrel bushing, but smaller around.

[Spiggs]

Thanks Gentlemen for all the assistance.

Ive decided to try fabricate the part from scratch, even though I don't have the measurements of an original part.

What I want to do is effectively try "shrink down-copy" a Yugo M53 booster to fit the Italian gun.
Using the Yugo booster as a template. Ive taken the measurements on the beretta/Breda and have tried to calculate how much smaller to build the new booster. Lets see if I can come up with something that actually works and wont destroy the gun

I will keep you all posted as soon as ive managed to build the part.

Regards

[Blanksguy]

Spiggs,
I have taken the liberty to "barrow" the photo TactAdv posted earlier to remind you that you do not have to manufacture a new Flash-Hider........just the small-flat-Booster-"Disk" that sits inside the front of the Flash-Hider.
Please look at the short/flat-part (Booster-Disk) that is sitting between the Flash-Hider and the Barrel-Bearing in the photo below. A better photo of these parts would help.........you'll just have to find on or possibly write to the manufacturer in Italy............or maybe post a WTB Ad on the French MG42 Board at:

http://mg34mg42.forumactif.org

I believe that this is a similar to how the Italians set up their Armeli-(?) in 5.56x45mm that looks similar to the MG42, but smaller......or possibly their conversion set for the MG42 in 5.56x45mm (?).

Regards, RichardS.
US Army, Retired

[Der Alder]

I tried blowing up Tact's pic with the booster to help see it a little better. The disk shaped booster (as I'll call it) is a little more visible, you can see the unique barrel bearing as well that slips out of the front??...which explains why the barrel is still in with it removed?

Is there a diagram/parts list anywhere for this set-up?

But like Blanks said, it doesn't appear to be a booster cone per say, but a nozzle disk that works in conjunction with the bearing and FH'er....at least that's what it looks like to me.

[TactAdv]

Richard....Sorry, I just stopped back in and saw your post.......

Answer is.....I don't know! Like I said this earlier version seems very hard to find much information on. All I know about Italian service guns is in alignment with more standard versions.....

I am clueless.

-TomH

[TactAdv]

".....believe that this is a similar to how the Italians set up their Armeli-(?) in 5.56x45mm that looks similar to the MG42, but smaller......or possibly their conversion set for the MG42 in 5.56x45mm (?)."


Hey Richard, NO, the CETME Ameli is delayed blowback ONLY, no muzzle booster. I had a Pre-May86 Dealer Sample at one time. It is excactly the same as the CETME Modello 'L' AR. Here's a picture showing the alternate muzzle brake/FH offered. Straight off the Modello 'L'. And another picture. Actually, there are quite a few parts that will interchange between the 'L' and the 'Ameli'.

The 5,56mm conversion set was made by SMAL/Luigi Franchi, s.P.a. It was NOT muzzle boosted either, although all the problems it suffered in service were all directed back to the lack of cartridge impulse power to work the heavy lock mechanism......so, probably would have been a good idea, maybe, to re-capture some of the escaping muzzle gasses and put them back to work.

The ONLY one of these conversion sets I have ever seen was for sale at the War & Peace Show in the UK a few years back......NO ONE wanted it.....EXCEPT the group of American guys I was with and we were all scheming on how to get this back in one piece.......

-TomH

[bmg17a1]

Other MG42 types have a booster with an expansion chamber in front of the muzzle bearing, which is most evident in the one piece booster design of the Rheinmetal versions and evolution of the MG3 and later. Unless that disc is pressed up against the face of the muzzle bearing and has an exit hole the same size or larger, the disc in front of the barrel bearing and behind the booster can dramatically overdrive action of the gun.
Without an actual PB booster/FH to copy, at the least alter or copy a one piece MG3 booster to fit and see what that does with driving the action. Experiment with just making the booster part first, and forget the FH until you have a booster pattern that works correctly. Then make the final part and add the FH.
Duplicating the expansion chamber of an MG3 booster is no cake walk!!!
There is no shortcut with making a part such as this and the more you know the better off you will be and the less potential to damage the gun. FWIW

Bob Naess

[Spiggs]

Ok, this is what ive managed to come up with for the moment. Hoping to get a chance and test it by the weekend.

It fits perfectly. You see how different my attempt at the correct part is vs an original Yugo m53 booster.

[Spiggs]

[JBaum]

The size of the nozzle hole controls the amount of recoil on the barrel. Having the nozzle hole smaller than needed will be hard on the gun, and possibly damage it over time.

Ideally, the nozzle will only be small enough to make the gun work, so it might be a good idea to make a few of these with different sized holes (larger than the 9.5 shown on the drawing), and use then largest one that the gun will successfully function with.

11mm is the size specified in the manuals as being for .308 (7.62 x 51mm) ammunition.

[Spiggs]

I've taken the advice and changed the 9,5mm to 11mm I'm also going to make one at 10,5mm just in case, I can always machine it out later. I hope it works! As I mentioned before, I'm hoping to test it out this weekend.

[Spiggs]

So! I just couldn't wait. Went to the range today for a short bit just to test her out.
Decided to load one round in the belt and fire it. After the first round I pulled off the front end to have a look see. No issue's. Loaded another round and tried the same again. No issue so far. I thought just for good measure send one more down range and have a look again. All was ok.

After that I decided to load just two rounds in the belt, same procedure, check out the front end and no issue! I decided to try three rounds in a belt at a time and then have a look. Still seems ok. I ran about 30 rounds like this. No issues. However I haven't tried a full range session with a few barrel changes just yet.

I have gotta admit I was nervous as hell, had visions of the gun exploding in my face.
Out here is so difficult to get a licence for something like this that if destroyed I could litteraly kiss this gun goodbye. It is also the only one in private hands in my country.

I think I should sharpen up the inner radius on the recoil booster just to have a better fit. I think its also time to case harden the part when its right just for good measure. I must admit im also a little worried that the "expansion chamber" inside the booster may just be a little shallow. The gun feels great so far though. No excesive recoil or anything like that. Perhaps I should try calculate the ROF with this set up to see if im inline with manufacturer specs or not. Im guessing if she runs a little fast then she is been fed by to much "boost" and I should work from there!.

I have obviously yet to try the light bolt just yet. Im also thinking of installing the anti bounce spring in the bolts just to be safe.

[Spiggs]

[Spiggs]

I forgot to mention, I made the booster out of EN30B

[Spiggs]

Mini update. She runs great. I just hope im not beating the gun up here.

Some of the shells have been getting hammered. They look like this.

[Der Alder]

The shells hit the front of the trigger guard with a lot of force.

Here is a good fix by Jbaum:
http://mg42.us/viewtopic.php?f=39&t=133 ... ass#p95303

[Spiggs]

Another mini update. Ive put 2000 rounds through her now. She runs like a well oiled sewing machine.
Not one malfunction at all.

Ive made two cones. One with a 9,5mm hole and one with a 10,5mm hole.

These with the fact I have a light bolt and a heavy bolt give me a lot of versatility in terms of been able to choose a rate of fire.

Obviously the 10,5mm cone shoots a little slower than the 9,5mm cone

I managed a little over 1050 rpm with the 10,5mm/light bolt and about 1350 rpm with the 9,5mm/Light bolt combo.

She ticks over at around 700 rpm with the Heavy bolt/10,5mm set up and about 900 with the Heavy bolt/9,5mm combo.

might be time for a video soon.

[usmc8488]

Nice to here you have worked out all the "bugs". Thanks for keeping us updated on the forum.

Regards

[JBaum]

You do know that the heavy bolt shouldn't be used with the regular buffer, right? The heavy bolt takes a special buffer. Use of the heavy bolt without using the proper buffer WILL damage the gun. It seems that heavy bolts are not uncommon, but the heavy buffers are very difficult to find.

[Spiggs]

I forgot to mention that I do have the correct buffer for the heavy bolt and yes it is different. I will post pictures a little later.

I cannot tell you how much I enjoy this firearm. I have several belt fed weapons and I find I shoot this one the most. Followed by my PKM

My 42 is running flawlessly.