question's about yugo sks's

[jon1996]

hello,
i just got two yugo sks's, i really like them, i am getting ready to clean them, i noticed on the gas tube there is a small hole drilled into it, what is the purpose behind this?, and what is the little round lever on top of the gas tube for?
thanks,
jon

 

[Stasher1]

Don't know about the hole, but the lever is for shutting off the gas so you can launch grenades.

 

[DMK]

It seems to me that the hole is to bleed off excess pressure. I guess they make the hole in the barrel a little larger than it needs to be for reliability then allow the excess to bleed off from the tube.

The FAL does this except that it has an adjustable sized bleed off hole where the size on the SKS is fixed.

IIRC, the AK also has a hole in the tube.

 

[K40]

you will notice after a trip to the range you will have to clean the bayonet off where this hole vents, espcially if you have any lubricant in the tube..my guess is the piston cycles past this vent, then discharges the excess pressure - instead of the rod lodging the slide and slide cover in your jaw