Okay, Now I'm Stumped

[Ductapeman 1]

My boss, knowing that I have converted a Saiga-12 or two, brought me his brother-in-law's S-12 to look at because it was short-stroking. My first thought was "Vodka?"-- we pulled apart the gas system and discovered four gas ports, only two of which were deep enough to actually see any daylight through (and not very much daylight at that). "Aha," I say to myself, and drill out the ports to .077" and slap it back together. Now-- it still short-strokes. Any ideas from you guys on what to check next? Any ideas would be most welcome! Thanks-- Lee

[Billybobf 50]

Hammer profile?

[Matthew Hopkins 1,065]

have you tried shooting 00 bucks or slugs?

[Billybobf 50]

Ok, how does it feel when pulling it back? Also there has been rumors of vodka special gas plugs before.

[YOT 3,743]

You been around since '06 and haven't read the stickies yet???   

[lbsrdi 1,078]

Sounds like you are getting sufficient gas through the ports, may be some odd issue with the gun. Is it converted? Have you tried more powerful loads? I would take the whole thing apart and take some time inspecting it for anything that seems out of the ordinary, like a factory mistake.

[RED333 1,025]

You been around since '06 and haven't read the stickies yet???   

My very thoughts!

[gunfun 3,931]

 4 @ .078" is often, but not always enough.

 

Check your ammo. it should be 3 dram eq: 1200 FPS, 1 1/8 oz of shot. Parts other than FCG should be factory, gas plug on #2

 

Then cycle the bolt a hundred times to break in the spring. Then make sure your hammer face is profiled, and your rails deburred with sandpaper. Test again. 

 

Increase ports by .002" and re test with the above ammo until it works. You should acheive 100% reliability with ports between 4  @ .078" and 4 @ .093". Don't go bigger, and keep the angles or even make the angle flatter. 

 

5 @ .077 would be better if there is room. But sort out the friction first. The links in my sig line show how to do the testing, and the trigger link shows what a properly profiled hammer looks like. 

drop in hammers are not fully profiled.

[Ductapeman 1]

Thanks to all, I will pass the word, as the project is no longer in my hands. I appreciate all the help! Also, I did look, but saw nothing specific about what I was looking for-- but then too, I no longer spend as much time here as I used to, so I may have missed something. You have my full permission to think whatever you want, since you will anyway.

[gunman1 1,753]

Red Green..............