3 port Saiga-12 not cycling low brass...drill out ports?

[Ruly3 0]

I'm progressing with my Saiga-12 build, but still unable to cycle low brass...every shell (Winchester Universal 7 1/2 shot) results in an FTE. I have Pauly's Glass Bolt and Ice Rack Supreme. I have a CSS puck and a TAC-47 Autoplug. Forward tigger group, etc. Everything is well lubed and installed. Still can't cycle low brass.

 

My Saiga-12 has 3 ports and I am able to check the diameter with the Pauly's wire guages. The .07 slides right in all 3 ports with a tiny, tiny bit of play... the .08 dosen't fit. I thought I read somewhere on this forum that my 3 ports should be .09. If that's the case...I'm way undergassed and need to drill out these ports with a 3/32 drill bit. I know that once I drill, there is no going back.

 

Can anyone confirm my thoughts so that I can finally complete this build...

[vulcan16 971]

The Auto Plug will not help cycle a under gassed S12.

Is your hammer re-profiled correctly?

Go ahead and remove the gas block, you may find a hidden 4th port.

Port sizes are .093 for 3- .076 for 4 ports.

I drill the gas block open a little with a 11/32 bit instead of doing the D ring mod.

[Paulyski 2,227]

^^ What he said,

If you're at 3 that are barely over .07" as indicated by the Port Gauges that I include in GlassBolt, you're fighting a lost cause.

That's why I include the Port Gauges.

3 that the .08" fits in with a bit of play tend to run decent if tuned well, but if you indeed do only have 3, you're pretty far under gassed for weak-weak stuff..

I recommend really working at getting the .07 in, then really working to see if you can get the .08". That's because carbon/lead mixture clogs the ports starting to form on the outside, and working in, so once your gas is right, use the perspective next smallest gauge, and keep it in your cleaning kit to use as a cleaner.

 

Also, a big ol' list of things to check at the gun and refine was just sent in a PM before I saw this thread, so here goes;

 

 

a troubleshooting list;

 

Are you running a Twister Puck? If so toss it & get a CSS Performance Puc. Pucs/pistons have gas check grooves for very good reasons. First off they center the piston as it moves, second they help with the seal as high presser gas vortexes in the check grooves as it tries to blow by. The twister screwed up by eliminating 1 gas check groove, and made the one they left too big. :/

 

Second, are you running a UTG quad? If so, test the weapon with the top rail removed. The top rail can clamp down on the gas system. Sometimes they must be clearanced to avoid this. The S-12 HATES shit clamping down on the gas system.

 

-Hit up the extractor slot fix

 

-Try a CSS Performance Puc as this can help by lengthening the stroke slightly, this really helps if the gas block was set too far forward slightly, or if the op-rod is set short. Same difference. (ensure it rattles a tiny bit when installed in a clean gas system. If not, file a tiny bit off of the nipple, checking VERY often until you get a tiny bit of play.)

 

-Slide the carrier back & fourth on the rails without the hammer or any springs in, to find if you have any high-points of resistance. If so, address the spots where it drags, BY HAND.

 

- Add a couple drops of oil on the recoil spring's guide-rod where the rear slides into the front section as it compresses as the weapon cycles. You may be surprised how much resistance can come from there if un-oiled and it wears wrong. Maybe AK's run dry fine, but the S-12's not an AK. It's AK based. AK's use a different guide system there.

(I understand Jack Travers of JT engineering has a guide rod that addresses and improves this. I've yet to test it personally)

 

-Check locking lug embutments in the trunnion to ensure there's no foreign matter jamming up in there.(paper wadding from older ammos is notorious for this)

 

-Is the gas block canted? This can cause a lot of resistance as the cycle begins because the carrier's askew as the cycle begins.. Canted gas blocks need to be addressed.

 

-Check the I.D. of the gas block. It shouldn't be much more than .8270". An oversized I.D. gas block will let gas blow by. This is another reason I like the CSS performance Puc. It's slightly larger than the factory.

 

-Next is rare, but can be an absolute nightmare.... At times, the barrel hoods are too thick and they jam on the shell's rim. remove the bolt & carrier, take a steel hulled shell, and drop it in the chamber. If the rim jams on the barrel hood at all, that's an issue. You should be able to drop a shell in, and it should fall down into the chamber all the way, then if you shake the weapon up and down with the muzzle pointed to the ground, the shell should freely be able to hop up & drop down in the chamber as you shake the weapon. An undersized chamber can also cause issues the same way. The shell gets jammed in there, then fires, expands slightly, then robs tremendous power from the cycle as the bolt attempts to extract it.

When this happens, people sometimes think the weapon has locked up.

If anybody here experiences this, do not hit the charging handle with a hammer. That's how my vertical charging handle installations started, for a guy who did just that & broke it off. If the weapon seems "locked up" look in receiver through the safety, and ensure the hammer is in the upright position so you know you don't have a timebomb.

Then release the extractor off of the shell by lifting it with a small Flathead screwdriver (or knife). Chances are, once you lift the extractor you will be able to pull back the charging handle, then you can get the shell out with a ram-rod.

If you're skilled you can fix a barrel-hood that's too thick & is progressively jamming up on the rim of a shell, but if it's the chamber that's undersized, please don't try to hack that shit out with a dremel.

That's what gunsmiths are for.

 

-Also, polishing the chamber doesn't hurt. Run a course, then medium, then fine Dremel Abrasive Buffs down the chamber with the extension wand (about 2 times each) then polish with a wool-pad with compound.

-If while you're set up, you want to hit the rails, just the course abrasive buff will work, and it will leave a surface conducive to lubrication retention.

 

And as always, test with the factory mag & Factory gas plug.

[Squishy 1,149]

If 4th port is there is one can be nearly impossible to see. If you take a paper clip and feel around back toward the threaded opening you might find it. Here's a photo that shows the rough location...it's the arrow pointing up;

 

 

This doesn't address the under gassed problem but it's good to know what you have.

 

I assume you followed the "dial in" on the auto-plug.

[evlblkwpnz 3,418]

No plug will help cycle a under gassed S12.

Is your hammer re-profiled correctly?

Go ahead and remove the gas block, you may find a hidden 4th port.

Port sizes are .093 for 3- .076 for 4 ports.

I drill the gas block open a little with a 11/32 bit instead of doing the D ring mod.

Postfixer....

[rickyblaze 8]

I had recently bought the Tac-47 auto plug and while my S12 would shoot the value pak 8's and 7 1/2's it had to be on setting 2 and shouldered tight . Then it would not always cycle them from a drum or hip shooting. I took off my gas block thinking I might have the hidden 4th hole after trying to set up the Auto plug and failing. What I found were 3 ports. I don't know for sure what the holes were before I started but I drilled them out to .096 and then the Autoplug set up problem was fixed. Now it shoots with fail any failures, kinda cool having a mixed load mag with no failures.

[Ruly3 0]

OK...I disassembled everything...took off the gas block... I confirmed 3 ports only mesuring .07. I re-drilled all three with a 3/32 bit to .093. I also enlaged the porthole in the gas block with some jewelers files because one or the barrel ports was obstructed just barely at .07 and most definetly would be at .093.

 

So now I'm curious on recomendations to reinstall the gas block...should I tap it in with a chisel again similar how it was suggested to remove it?

[gunfun 3,931]

Remove the gas adjustment plug so that you are not hammering against the threads- a few bad stories there.

 

Be careful not to lose the detent and spring when you do this.Put the stock on the floor and clamp the barrel up, or have a friend hold it. Put a block of wood or soft metal like brass or aluminum against the gas block where the adjustment plug would go.and tap it on back to about 3/8" from home. Then put the gas tube back and be careful to keep it in the grooves each time you hit it. you don't want to munch the end if it falls out a bit and gets crooked. Check each time you hit with the hammer. as you get close be careful not to go too far and pass the pin grooves. Hopefully you scribed a mark on the block and barrel before removing to preserve orientation. Make sure you don't leave it with a canted block before you put the pins in. Carefully look to make sure the alignment is right.

 

It is also helpful to use 800 grit sandpaper to shiney the barrel up, and add a bit of grease for an easy installation.

[Ravan 17]

Thank you for this thread, took my gas block of tonight, 3 holes, at .079. This thread was a great help.

[TORKIT 20]

After I did all of the above mods and was still getting stove pipes "FTE's" with low brass I ended up tuning my recoil by replacing both main springs with performance springs from CSS, they are a much softer spring, now it finally works, also made a recoil buffer pad but its not needed for low brass.

[Ruly3 0]

So my Saiga-12 is back together tonight after all the drilling and filing. I cleanned up to bare metal the surfaces where the gas block presses on to the barrell, sprayed some Rem oil on it and used a 2" nylon mallet to tap the gas block back in (without the puck/plug installed)... that was easy. Now I need to get it to the range a test fire some cheap Winchester Universal 7 1/2 shot. Thanks everyone! I'll report back soon with the results...

Edited October 24, 2012 by Ruly3

[poolingmyignorance 2,191]

After I did all of the above mods and was still getting stove pipes "FTE's" with low brass I ended up tuning my recoil by replacing both main springs with performance springs from CSS, they are a much softer spring, now it finally works, also made a recoil buffer pad but its not needed for low brass.

You might try reinstalling your factory sporting and up grading to JT 's recoil rod, sometimes the hammer drags the spring robbing it of cycling power. To me this is a better fix that allows use of full purer loads. Worth a look at least.

[bitters 6]

So my Saiga-12 is back together tonight after all the drilling and filing. I cleanned up to bare metal the surfaces where the gas block presses on to the barrell, sprayed some Rem oil on it and used a 2" nylon mallet to tap the gas block back in (without the puck/plug installed)... that was easy. Now I need to get it to the range a test fire some cheap Winchester Universal 7 1/2 shot. Thanks everyone! I'll report back soon with the results...

 

Good luck man, I'm in a similar situation. Hopefully all goes well for you.

[Pro2A 17]

that was easy. Now I need to get it to the range a test fire some cheap Winchester Universal 7 1/2 shot. Thanks everyone! I'll report back soon with the results...

From what I've learned here, I would go with cheap "something else", as the majority opinion is that winchester is the dirtiest, most fouling ammo of all.

[Nephilim7 107]

I believe Federal Bulk is known to be dirtier than Winchester Universal by far. Federal makes a nasty, waxy black substance in the gas block...

[lbsrdi 1,078]

I have heard that also. All I really buy is federal and I have never had any real fouling in the GB. My ports are undersized factory drilled, the gun is completly flawless with undersized( and partially blocked) ports. I never experience GB fouling to speak of, love my factory ports and factory springs.

[gunfun 3,931]

Winchester is much cleaner burning, but federal cycles better. Winchester bulk seems to have more variation in quality and power shell to shell.