Yugo (Handguard) Gas Piston Question

[owenj492]

Except maybe the Albanian, are all other (handguard) gas pistons same length? Can I use a Chinese piston in a Yugoslavian handguard? I need one for a Yugoslavian M59/66 barreled receiver I purchased from GB:





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[Loose}{Cannon]

Only the gastube is dif on an Alby.  You should be able to use any piston minus a short one from certain chinese commercial models like the SKSs.

[owenj492]

Great, thank you for the quick answer! 

[Greatguns]

My recollection is the M59/66 is about .001" OD bigger than the others on the piston head and also ever so slightly shorter(like 1/32") due to the gas valve. IIRC the guy who was making them and selling on Ebay for a while back in the day determined that and made sure people made the distinction as to which they had before purchase so he could ship out the correct one.
Also, are you missing one or are you blowing gas out the tube? If the latter you may have a gas valve issue.

On another note, are you missing the receiver cover? I have an M59/66 cover if you need one.

[carls sks]

good info as always here. 

[Loose}{Cannon]

I would imagine that .001 isn’t going to make much difference. I have swapped gas pistons in just about every combinations imaginable.   🤷🏼‍♂️

[owenj492]

My recollection is the M59/66 is about .001" OD bigger than the others on the piston head and also ever so slightly shorter(like 1/32") due to the gas valve. IIRC the guy who was making them and selling on Ebay for a while back in the day determined that and made sure people made the distinction as to which they had before purchase so he could ship out the correct one.
Also, are you missing one or are you blowing gas out the tube? If the latter you may have a gas valve issue.

On another note, are you missing the receiver cover? I have an M59/66 cover if you need one.

Thanks for the offer, I have one for the Yugo.

[Greatguns]

I would imagine that .001 isn’t going to make much difference. I have swapped gas pistons in just about every combinations imaginable.   🤷🏼‍♂️

Tolerance is .002-.004" if it's more than that you get blow by and possible short cycle. So, the main thing is that the tolerance is correct regardless of the flavor of piston.

[owenj492]

On a hunch I compared my "spare" piston rod to two of my Yugo's (J-XXXXXX and S-XXXXXX), the piston from my two Yugo's are just barely shorter than my "spare" piston, then I compared it to two other Chinese I have (24 Million and 1991 CGA) The "spare" piston I have exactly matches the Chinese SKS pistons with 20 inch barrel.

[Loose}{Cannon]

Aint gonna matter when that sucker slams rearward with as much force as they do. In my experience, blow-by issues are 99% of the time related to internal gastube corrosion.