guncats 4 Posted March 16, 2011 Report Share Posted March 16, 2011 just curious.... does the 16" version have a larger gas port? Quote Link to post Share on other sites
brokenfeather 2 Posted March 16, 2011 Report Share Posted March 16, 2011 Not sure. What prompts the question? Quote Link to post Share on other sites
guncats 4 Posted March 16, 2011 Author Report Share Posted March 16, 2011 them PSL's can have cracking problem from too many heavy rounds, and the causes is said to be "too much gas energy". So some cut the barrel down to 18" which reduces the pressure duration/energy. if the saiga 16" has the same port size as the 22", does that mean the 22" is way way way over gassed? Quote Link to post Share on other sites
csspecs 1,987 Posted March 16, 2011 Report Share Posted March 16, 2011 Yes they have different gas port sizes. If you cut a 22" down to 18" it will eject empty cases very softly, almost to soft to function on some rifles. Quote Link to post Share on other sites
brokenfeather 2 Posted March 16, 2011 Report Share Posted March 16, 2011 That's very interesting. Triing to wrap my head around what u are saying. Which has the larger port size and what are the port sizes recommended per length! Quote Link to post Share on other sites
guncats 4 Posted March 16, 2011 Author Report Share Posted March 16, 2011 Yes they have different gas port sizes. If you cut a 22" down to 18" it will eject empty cases very softly, almost to soft to function on some rifles. thanks! that is what I want to hear Quote Link to post Share on other sites
guncats 4 Posted March 16, 2011 Author Report Share Posted March 16, 2011 That's very interesting. Triing to wrap my head around what u are saying. Which has the larger port size and what are the port sizes recommended per length! I suppose the less barrel length ahead of the gas block (less pressure duration), the larger the hole needs to be to deliver the same amount of energy to the piston. Quote Link to post Share on other sites
finlander 3 Posted March 16, 2011 Report Share Posted March 16, 2011 Well, I haven't had any problems with my ver. 21 that I had the barrel cut to 17". Even had a set screw installed to gas port/block because with suppressor on it still ejected too strongly to my liking (I reload). Quote Link to post Share on other sites
SOPMOD 254 Posted March 17, 2011 Report Share Posted March 17, 2011 http://www.youtube.com/watch?v=jVkz4aXIiDg Quote Link to post Share on other sites
brokenfeather 2 Posted March 17, 2011 Report Share Posted March 17, 2011 Well, I haven't had any problems with my ver. 21 that I had the barrel cut to 17". Even had a set screw installed to gas port/block because with suppressor on it still ejected too strongly to my liking (I reload). But wouldn't a suppressor actually add more back pressure to the ejection cycle. BTW could you describe what you had to go through to get a set screw installed to help control the pressure. Was the gas block remove or what? Quote Link to post Share on other sites
guncats 4 Posted March 17, 2011 Author Report Share Posted March 17, 2011 http://www.youtube.com/watch?v=jVkz4aXIiDg very interesting.... that video is a s308 with 1.6mm gas port. So, I wanted to see how big the gas hole is in my 22" S308, so I did some measurements. -- hole in gas block: a little larger than 4mm. -- hole in barrel:.......err, hmm, there is no hole? I put a optic fiber into the gas block hole, shine the light to the optic fiber, and no light can be seen in the barrel. Put the optic fiber into the barrel itself and wenth the whole length.... don't see any hole in the bore wall, either. and this rifle is bought slightly used. Do they make single shot Saiga's ? Quote Link to post Share on other sites
guncats 4 Posted March 17, 2011 Author Report Share Posted March 17, 2011 never mind, found the gas hole. it is larger than 1mm but smaller than 1.8mm. so 1.6mm it is. Cool! Quote Link to post Share on other sites
brokenfeather 2 Posted March 17, 2011 Report Share Posted March 17, 2011 never mind, found the gas hole. it is larger than 1mm but smaller than 1.8mm. so 1.6mm it is. Cool! Did you pull the gas block to do this? How did you determine the sizes in the gas block and the barrel. I would like to obtain the same information on mine but really don't want to pull the gas block if I don't need too. Thanks Quote Link to post Share on other sites
SOPMOD 254 Posted March 17, 2011 Report Share Posted March 17, 2011 A Kalashnikov is supposed top eject shells 12-18 feet when clean so that it will continue to eject shells reliably when it's dirty. The only time your ejection cycle is "overgassed" is when there is visible evidence of case rims being chewed by the extractor or peening on the carrier/rear trunion/recoil spring guide. My 18" functioned fine for a hunting or pleasure shooting weapon but for a fighting rifle positive ejection is paramount.I am building another but not until I get a 16in in hand for a gas port measurment. BTW I cleaned up the gas port hole with a 1.6mm drill bit. It is actually a hair smaller than 1.6mm(1.4mm?). Quote Link to post Share on other sites
brokenfeather 2 Posted March 17, 2011 Report Share Posted March 17, 2011 SOPMOD have a question for you and please don't think me a complete dunce. Question, did you have to remove the gas block to clean it out or can you actually get to it well enough without a dis-assembly to clean it (the port that is). I have a 16 inch 308 is there a way to measure the port in the barrel with a dis-assembly? If so I would be willing to let you know what mine measures. Thanks Quote Link to post Share on other sites
finlander 3 Posted March 17, 2011 Report Share Posted March 17, 2011 (edited) Well, I haven't had any problems with my ver. 21 that I had the barrel cut to 17". Even had a set screw installed to gas port/block because with suppressor on it still ejected too strongly to my liking (I reload). But wouldn't a suppressor actually add more back pressure to the ejection cycle. BTW could you describe what you had to go through to get a set screw installed to help control the pressure. Was the gas block remove or what? Yes, suppressor adds back pressure, that's why I had the set screw installed. Don't know how the smith did the drill&tap for the screw but it can be done with the gas block in place. Probably easier to do with the gas block removed though. Edited March 17, 2011 by finlander Quote Link to post Share on other sites
guncats 4 Posted March 17, 2011 Author Report Share Posted March 17, 2011 never mind, found the gas hole. it is larger than 1mm but smaller than 1.8mm. so 1.6mm it is. Cool! Did you pull the gas block to do this? How did you determine the sizes in the gas block and the barrel. I would like to obtain the same information on mine but really don't want to pull the gas block if I don't need too. Thanks the 4mm gas block hole size was measured using a small allen wrench with a short piece of silicon tubing at the tip of the short end. diameter of the silicon tubing (when on the allen) measured about 4mm,it was a snug fit into the gas block hole. for barrel gas hole size, I used two allen wrenches, and stick the short ends into the hole in the gas block. The smaller one (about 1mm at the widest points) stuck into the barrel (shined a bore light and saw it poking out), while the larger one (somewhere around 1.8mm) did not go through. of course it could be anywhere between 1 and 1.8, but since somebody already suggested 1.6mm as the official size, that must be it. Quote Link to post Share on other sites
guncats 4 Posted March 17, 2011 Author Report Share Posted March 17, 2011 (edited) A Kalashnikov is supposed top eject shells 12-18 feet when clean so that it will continue to eject shells reliably when it's dirty. The only time your ejection cycle is "overgassed" is when there is visible evidence of case rims being chewed by the extractor or peening on the carrier/rear trunion/recoil spring guide. My 18" functioned fine for a hunting or pleasure shooting weapon but for a fighting rifle positive ejection is paramount.I am building another but not until I get a 16in in hand for a gas port measurment. BTW I cleaned up the gas port hole with a 1.6mm drill bit. It is actually a hair smaller than 1.6mm(1.4mm?). so you are saying 18" is actually too short already? Edited March 18, 2011 by guncats Quote Link to post Share on other sites
brokenfeather 2 Posted March 18, 2011 Report Share Posted March 18, 2011 never mind, found the gas hole. it is larger than 1mm but smaller than 1.8mm. so 1.6mm it is. Cool! Did you pull the gas block to do this? How did you determine the sizes in the gas block and the barrel. I would like to obtain the same information on mine but really don't want to pull the gas block if I don't need too. Thanks the 4mm gas block hole size was measured using a small allen wrench with a short piece of silicon tubing at the tip of the short end. diameter of the silicon tubing (when on the allen) measured about 4mm,it was a snug fit into the gas block hole. for barrel gas hole size, I used two allen wrenches, and stick the short ends into the hole in the gas block. The smaller one (about 1mm at the widest points) stuck into the barrel (shined a bore light and saw it poking out), while the larger one (somewhere around 1.8mm) did not go through. of course it could be anywhere between 1 and 1.8, but since somebody already suggested 1.6mm as the official size, that must be it. Thanks for the detailed description. I appreciate it. Quote Link to post Share on other sites
SOPMOD 254 Posted March 19, 2011 Report Share Posted March 19, 2011 A Kalashnikov is supposed top eject shells 12-18 feet when clean so that it will continue to eject shells reliably when it's dirty. The only time your ejection cycle is "overgassed" is when there is visible evidence of case rims being chewed by the extractor or peening on the carrier/rear trunion/recoil spring guide. My 18" functioned fine for a hunting or pleasure shooting weapon but for a fighting rifle positive ejection is paramount.I am building another but not until I get a 16in in hand for a gas port measurment. BTW I cleaned up the gas port hole with a 1.6mm drill bit. It is actually a hair smaller than 1.6mm(1.4mm?). so you are saying 18" is actually too short already? Not exactly. I have talked with other owners and builders of 18" S308s and they say their rifles throw the brass to the moon. This makes me think that my gas block must have been stretched or some other problem that contributed to the soft ejection. I just put together my 3rd Saiga 308 and I am going to try it out at it's full 21" length and see how it groups and handles but if I don't like the extra length then it will probably become an 18" rifle as well since 18" is the ideal length for a 7.62 NATO caliber weapon(20" for 308 Winchester). Red Jacket has cut down several to 18" without opening up the gas port and they say they still eject sharply and still ding up the brass. Quote Link to post Share on other sites
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