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How to fix wonky rate of fire in PPSH-41


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#1 michaelkih

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Posted 14 December 2014 - 11:39 PM

So I have a C&R bring back PPSH-41.  It's a great gun, and always goes bang, but the rate of fire is all over the place, even with new S&B ammo.  the internals are mint, and the barrel is new looking inside and shiny.

 

I am looking for advice from other PPSH-41 owners.

 

Here is what I notice.

 

Sometimes it throws the brass 5+ feet in the air.  When it does this, the rate of fire is perfect and fast.  then it'll thrown some rounds just inches into the air and the rate of fire slows down.  It's as if some random bullets have less power, but I know that's not the case with new S&B ammo.  Could it be that the bolt is dragging on the round in the drum, or dragging while pulling the empty case out of the chamber?  Is this a problem that pops up with drums, but I not with stick mags?  I don't own any stick mags.

 

Same things can happen in semi auto.  I'll shoot sometimes, and it throws the brass nice and high and it shoots just one round.  Then every now and then a round only shoots a case inches in the air, then 2 rounds will fire with just one trigger pull.  As if the bolt didn't go all the way back to get caught.

 

I'm really not sure what the hell is wrong here.  I'm glad the gun runs, but I cant figure it out.  Spring, drum, brass vs steel case, etc???

 

Thank you for any help.


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#2 Mongo

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Posted 15 December 2014 - 12:28 AM

I had a similar issue with mine but it was due to the old surplus Yugo ammo I was using. I switched to Rommy surplus and it runs like a top and is much more consistent. I'm taking my out for the New Year shoot and will get some footage then.


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#3 michaelkih

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Posted 15 December 2014 - 01:39 AM

Interesting.  I just assume it can't be the ammo since it's new S&B.  I picked up 150 rounds of that steel cased Red Army ammo and 150 rounds of Prvi ammo, and a stick mag to try all out this week.  We'll see!


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#4 Mongo

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Posted 15 December 2014 - 10:21 AM

I have never used anything but a drum in my gun so that might contribute to it as the spring pressure changes the ROF changes. But my gun was definitely sputtering with the Yugo ammo and I can notice a definite difference in the recoil impulse between the Yugo and Rommy ammo.


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#5 michaelkih

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Posted 15 December 2014 - 12:41 PM

Thanks.  I just went and picked up the stick mag and it fits the gun, so I'm going to run to the range and test it out.  The other brands of ammo should be here Wednesday for me to try out.


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#6 Roland the Thompsongunner

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Posted 15 December 2014 - 01:05 PM

My ppsh does that once in a while. I think the drums may have something to do with it. I had some surplus ammo issues too like Mongo stated. The worse was bulgarian i think. Way too hot you could feel it beating the gun up and it sounded like an mg42. I have been shooting mine almost exclusively in 9mm now with mp40 mags. It runs real well with this setup. Its also way cheaper to shoot and you can buy ammo everywhere. Royal tiger has the kits for like 150 which is the barrel and mag adapter. Give that a try i think you will like it. I also shoot tons of blanks with mine with a junker barrel. Thats a lot of fun too at the reenactments. Keep it well lubed with a light oil too. That helps. Dan
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#7 av8tr

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Posted 15 December 2014 - 02:17 PM

Roland,

 

Not to hijack this thread, but did the Royal Tiger kit require any gunsmithing?  There website says it does.  I'm sure the barrel slides right in, but what about the mag adapter?

 

Incidentally, my PPSh-41 runs pretty consistently.  I've used stick mags and drums.  The ammo I have used was Privi Partisan.  Ammo seems to eject pretty high consistently as well.


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#8 av8tr

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Posted 15 December 2014 - 02:17 PM

deleted


Edited by av8tr, 15 December 2014 - 02:19 PM.

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#9 michaelkih

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Posted 15 December 2014 - 04:04 PM

Ok, so I tried the stick mag, and it was better, but still had some very minor fluctuations.  Put in the drum after, and it was just plain awful!  It fires all the rounds, but it's sounds and feels ridiculous.  I might need to tighten up my drum, but then I can't fill it up all the way because the recoil spring is too weak to push the first couple rounds.  Anyone have a source for new recoil rods and springs?  Replacing the original one after 72 years can't do anything other but help.

 

I'll try the Red Army and PRVI ammo later this week and report back.


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#10 michaelkih

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Posted 15 December 2014 - 04:04 PM

I assume you need to fit the barrel notch on that conversion kit.  That's easy.  Just be patient.


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#11 Roland the Thompsongunner

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Posted 15 December 2014 - 05:35 PM

The adapter kit does need some fitting but it is easy with some patience and a couple files. You may need to file the barrel diam to fit in the trunion and then the notch has to be cut. You can do all of this with hand files easily. The magwell adapter is the same. File slowly until it fits. Its well worth the effort. It took me maybe an hour to do each and I have been using them for about 10 years.

 

Sorry to hear you are still having issues. Try different ammo it may help. Also, I remember my gun was finicky when I first got it because the upper and lower receiver were not tight together. I had to tighten up the rear lock cap by bending the tab a fit to make it fit tighter. My problem was the bolt was jumping over the ejecter on the way back and wouldnt eject the shells right. Many would just clear the gun or fall back into the reciever. Check that the bolt fits snugly and that when you run the bolt back and forth and that the ejector is up inside the bolt far enough to catch the shell to kick it out. Dan


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#12 jl7422

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Posted 15 December 2014 - 07:45 PM

I had a similar problem when I first got my Ppsh.

 

After some investigation it turned out the ejector was a crude replacement, too tall and forcing the bolt to ride up and generally cobbling up the whole cycle--but never consistently. A replacement from a Polish kit fit perfectly and she runs 100% consistent on S&B or Prvi. It's too nice to shoot corrosive!


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#13 michaelkih

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Posted 15 December 2014 - 09:43 PM

It's interesting that you posted about the ejector.

 

I just now took the spring and rod out of the gun and held the trigger down so I could move the bolt forward and backward freely.  When it is all the way back it's sitting level, but as I push it forward slowly it does actually hit the top of the ejector and raise maybe 1/2 - 1mm.  Is this normal?  I've never seen a gun do this before.  Should I take a dremel to the top of the ejector and shave off 1/2mm so it glides over it freely or is this normal?


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#14 michaelkih

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Posted 15 December 2014 - 09:57 PM

Does this look like an original ejector?  I assume it is since everything else is original, but you never know.  You can see all the wear on the top where the bolt keeps hitting it and riding over the top.

 

http://i658.photobuc...zpse21013b6.jpg


Edited by michaelkih, 15 December 2014 - 09:58 PM.

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#15 jl7422

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Posted 15 December 2014 - 11:34 PM

What you are describing is exactly what mine was doing--bolt riding up over a too-tall ejector.

 

Like I say, I replaced mine with a proper factory part -- bolt then slid smoothly with no contact and problem solved.


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#16 Roland the Thompsongunner

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Posted 16 December 2014 - 07:27 AM

Its hard to say with seeing a bunch of angles, but it looks like it may have had some metal added at some point. The bolt should slide over it just clearing it but should not lift. That throws everything off when it does. Pick up another complete lower and switch it out. I think military gun supply has the parts kits for like 150 wothout the barrel. They are brand new polish parts and fit and function great. Well made. I always switch all my stuff out to shoot and keep the original parts and barrel off because they are all matching numbers. I only use the upper when shooting. Give that a try before modifying or switching out your ejector. It should help
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#17 michaelkih

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Posted 16 December 2014 - 11:40 AM

Will an older style pin upper like mine fit on the newer style pin lower that those parts kits are?
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#18 Roland the Thompsongunner

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Posted 16 December 2014 - 12:21 PM

I believe it should you just have to use the two piece pin instead to lock in place. I have older style lowers with the solid pins but never had an early upper. My gun is the two piece type.
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#19 michaelkih

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Posted 16 December 2014 - 12:56 PM

Thanks for your help.  I'll give that a try after I play with the drum tension and ammo choices a little bit this weekend.


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#20 michaelkih

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Posted 18 December 2014 - 11:03 PM

Tried the new parts and the different brans of ammo. 

 

Conclusion after going back and forth today.

 

-New spring helped a TON.  Was able to tighten the drum up two more full turns.

 

-Drums run ok with S&B

-Drums run perfect with PRVI, just slow

-Drums run perfect with Red Army, is fast, and shoots flames

 

-Stick runs almost perfect with S&B

-Stick runs perfect with PRVI, just slower

-Stick runs perfect with Red Army, is fast, and shoots flames

 

Finally conclusion?

 

Selling my S&B and buying a pallet of Red Army Standard.  Freaking ran amazing!


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