shooter51@verizon.net

Gunsmithing question

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Is it possible to slow the cyclic rate of a blowback operated 7.62 X 25 subgun?

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Mike Todd to the service desk??

 

Like on a PPSH 41?

A heavier bolt will definitely help slow down the ROF.

Unfortunately I don't know anyone who either made one or is making any currently.

 

R.L.

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The easiest way is to sell the PPSh and buy a Zastava M56... ;) 

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Depending on what gun anybody with a mill or lathe should be able to install a tungsten insert to simply make the bolt heavier. I'm sure it would take some tuning but I don't know why that wouldn't work.

Adjustments to spring weight might be easier though. 

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You got  game B san, actually it's a PPS43, for theater work. I had been considering a combination of both methods mentioned, but thought I would ask this body of smart pigs, before I start making chips. Will have to adapt a spring tension gage, any estimate of pounds pressure at full compression? Stock spring rate?

I worked with a material called Mallory metal, used when spin balancing components, very dense, but much easier to work than tungsten (sp ?) and much cheaper.

Any thing else I should know before I slice and dice?

 

Thanks, Paul in da swamp

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CAREFULL THERE ! when playing with springs one can get themselves in real trouble if the wrong window is opened. its always easy to speed one up by making the bolt travel shorter or slow one down by adding weight but initial spring tension should stay VERY close to the original design.  BOTH examples listed IE; PPSH AND PPS-43 fire slightly b-4 full bolt closure. any change in the design force can be catastrophic . the low pressure 9mm luger caused no problems but during the past flurry to convert open bolt sub guns to semi auto only closed bolt. EVERY EXAMPLE of PPSH I know of shot much has blown up damaging the extractor and many times the BOLT. some virtually exploded the FIRST ROUND  pushing the front of the extractor thru the front of the receiver because the bolt and spring rate for the full auto, applied to the closed semi variation allowed the round to exceed proof pressure , ALL the "PRE IGNITION" was removed. in that case, adding to the bolt was no help so we added spring weight and got some relief rut too much and failure to feed kicked in. of the 8 guns I worked on 2 receivers and 4 bolts were severely damaged and more than 15 extractors broken looking for the "CURE"  3 ended up "so/so" at best. the PPS -43 was a bit better , I think the HAMMER added just the right amount of resistance and helped , but we still lost extractors and changed them all to 9mm in the end.


I only accept postal money orders. contact me DIRECTLY before sending any funds                                           email  myoldiron@outlook.com        

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GUY'S , I MUST APOLIGIZE FOR MY PREVIOUS POST IN THIS THREAD !   I always strive to be COMPLETLY correct when expressing my opinion in both personal AND mechanical discussion.  Consequently  I sometimes go TOO deep attempting to describe a solution OR a  problem.  after more thought on the matter this was certainly one of my worst attempts.  IN FACT, WHEN ADDING WEIGHT TO AN OPERATING SYSTEM OR SPRING RATE , ONE WILL NEVER CAUSE A SAFETY ISSUE IT WILL JUST CEASE TO OPERATE!  looks like its happening again, so I will cease and desist here. good luck with the project MIKE

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I only accept postal money orders. contact me DIRECTLY before sending any funds                                           email  myoldiron@outlook.com        

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