Another gas port question
Posted 10 May 2009 - 07:49 AM
I read through all the threads on gas ports, and there seems to be a discrepancy in the "correct" number to have. I understand that the total gas flow is based on overall port diameter, and two large ports can allow more gas than four small ones.
The question is, how many ports are the newer Saiga's shipping with? I thought it was four "diamond" looking ports, but am also seeing posts from new owners that have three "round" ports. I can't believe that the number would be varying...even on a russian assembly line. There must be a standard design that they are sticking with...for now at least.
Can anyone shed light on this once and for all?
Posted 10 May 2009 - 08:40 AM
"I can't believe that the number would be varying...even on a russian assembly line."
The variation is from 1 and a half (partially obstructed) to 4 (the four are round ports in a diamond pattern).
The short and sweet is... It's a $250 shotgun manufactured with all the attention to detail of a $250 shotgun.
It only costs $500-$600 here since It can, for well under $1000 total cost, be built to compete with $2500 and up DD shotguns.
Posted 10 May 2009 - 11:10 AM
The 22" full choked version, also imported by the previous importers, had a triangular pattern of three holes. The longer the barrel, the fewer ports that are needed to cycle the bolt, due to the increased back pressure created by the pressurized gasses remaining behind the shot column in the barrel for a slightly longer period of time.
Even with these older models, there was some variance in hole patterns and numbers.
The original Saiga shotgun...the 410..only has one large port, just like the AK rifles it was based on. The first ones did anyway...I'm not sure about the new ones. Mine is the very first model and didn't even have a gas adjustment.
These newer guns, the ones Tony made the "vodka special" comment on one time, and it stuck...lol.....only have two ports. I just fixed one of these the other day for a member here. When I pressed off the GB, I was surprised to find these two ports were not noticeably larger than the ones in my 4 port gun. I've heard some people say that this was a change that Izhmash made on purpose, and those guns came in like that on purpose...not because of a mistake (or too much vodka at break time...lol). I think that's BS. If they do them on purpose, then they were not meant to be put on the American market, hence the warranty repairs... The ammo they use in Russia is more powerful than the weak ass shit we use over here. Those guns were either made that way on purpose, and got mixed up with guns to be exported to the US, or they fucked up and forgot to drill the third hole. That still doesn't explain why there are still '08 guns turning up with 4 ports. Maybe they did screw up and the three holers were supposed to be 24" barrels...
Either way....for the damn gun to work right with standard equipment, and cheap low brass ammo, it needs at least three ports.
It is actually possible to overgas the gun if you make the ports too large, so be careful working on these yourself. On the 2 port gun I fixed the other day, it was not even cycling high brass buckshot, even on the highest setting with gunfixr's gas plug. It would stovepipe every time. With wallyword low brass it would not even completely pull them from the chamber.
Every other trick had been tried before deciding it needed port surgery.....
1. It had the upgraded gas plug
2. It had the upgraded piston, or "puck", from KA
3. It had the FCG polished
4. ...the reduced tension hammer spring
5. ...the bolt and carrier polished
6. ..."the feed ramp mod"
7. It even had the front recoil spring replaced with a lighter one from a 1911
After closer inspection I found why it still didn't work any better, even after all that.
The damn GB was partially covering one of the two holes.
So I took it off and enlarged, and even polished the edges of the main port in the GB. I also angled the holes back slightly more (with a 5/64" bit) to give the gas more pressure directly backwards.
At this point, with all the other mods that had been done, I could have most likely put it all back together and it would have cycled fine. Just to be sure though...I drilled another 5/64" hole just between and to the rear of the existing two (triangle). I angled and polished the rear of the main gas block port, to be sure it was letting all the gas flow efficiently.
Reassembled it all, and test fired it...it made a HUGE difference...
The low brass shells (Federal 3 Dram 7.5 shot) that wouldn't even clear the chamber before, ejected four to six feet out and forward....even on setting two (which is like setting one on a factory shotty). I had to turn it all the way to one (almost no gas) to get them to stovepipe.
With the high brass (Winchester 9 pellet 00 Buck), it had no problem at all cycling and ejecting 6 feet, on the lowest setting (1). But with the gas plug turned up to 2, and 3, it was cycling so fast the shells didn't have time to even clear the ejection port before getting munched by the returning bolt...(see pic at bottom). I am assuming this is the case...since turning the gas adjustment down, instead of up, solved the issue. It munched the high brass on settings 2 and 3 before switching to one (minimum).
If my assumption is correct, this gun is cycling so good now it needs to be turned down some for the high brass or they won't be able to eject fast enough. The lighter recoil spring that was used, trying to help the prior cycling problem, now needs to be taken out and replaced with the heavier factory spring. That will most likely balance things out perfect and the gun won't be over gassed for the recoil spring. If it still has any probs with munching high brass, like 3" turkey loads for example, then the KA piston can be flipped around backwards, or the factory one put back in there, and that will fix it.
First...a three port gun converted to four ports...
DSC00395.JPG 78.74KB 51 downloads
IMAG0007.JPG 122.65KB 24 downloads
Taking the "Vodka" out of a Vodka Special...lol
Vodka_Special_lol.JPG 189.57KB 33 downloads
Vodka_Special_2.JPG 101KB 27 downloads
Enlarge_GB_Port.JPG 90.08KB 24 downloads
Polish_GB_Port.JPG 101.02KB 20 downloads
Polish_GB_Port_2.JPG 87.12KB 17 downloads
Start_Third_Hole.JPG 69.92KB 20 downloads
Drill_Third_Hole.JPG 58.43KB 17 downloads
Polish_Barrel_Port_Area.JPG 58.56KB 17 downloads
Clean_up_ports_inside___w__bronze_brush_on_drill.JPG 62.67KB 16 downloads
Clean_up_2.JPG 76.35KB 11 downloads
Clean_Bbl.JPG 49.77KB 15 downloads
Un_Vodka.JPG 82.69KB 17 downloads
Stovepipe_Munch.JPG 68.42KB 15 downloads
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