metroplex 0 Posted December 12, 2004 Report Share Posted December 12, 2004 I did this a few months ago (around August), but here's the full story again: I kept my original Robinson/Molot gas tube intact because I have never seen a bare gas tube like that for sale on the net, so it'd be hard to replace. I further modified my Bulgarian gas tube by enlarging all 8 holes to 1/4" in diameter vs the stock 1/8". The first thing you will notice is that the piston is kept cleaner especially at the cup/dish where its usually caked with carbon. It should be only a slight ridge of carbon near the top. I did some reading on WHY they vented the gas tubes and apparently on the full-auto rifles and SAWs (RPKs, etc...) a non-vented gas tube would slow down the bolt on the return trip due to gases still being present in the tube when firing at a high rate. For semi-auto rifles, this is not a concern and this is probably why you do not see it on many semi-auto rifles (Saiga, Vepr). Here are my observations: With a vented tube, my muzzle blast is significantly enhanced in broad daylight with regular Wolf (undercharged/underpowered) ammo. I've seen some videos of AKs being bump fired at night and my muzzle blast is brighter and larger than that in broad daylight. I've noticed the accuracy improving by 100%. I used to get 7-10" groups at 100yd, but with a vented tube I was getting about 4"-6" groups at 100yd using Wolf and counting 10-15 round groups. I always shoot single loads (state law on DNR ranges). My modifications for the gas tube: * trimming the upper handguard retainers to fit the Vepr's handguard. * removing the front upper handguard retainer ring completely for aesthetics (I could not remove the spot welds so I just cut the ring off, and left the base ring). * slight grinding of the gas tube retainer surface so that its flush with the Vepr's retainer. * the spring clip gives it a tight fit I have not tested the tube with all 8 holes enlarged. My previous tests used the tube in stock form, and with 2/8 holes enlarged to 1/4". I believe Lollygagger did this on his Saiga w/o any detrimental side-effects. And the absolute worst you can do is slow down the bolt but I do not think its possible: 1). The gas block and piston seal is where most of the initial pressure is built up. 2). As soon as the piston/carrier picks up speed from the initial pressure buildup, any gases vented out of the tube isn't going to affect the travel. 3). It would serve to clear the gas tube quickly and allow the piston/bolt to travel back to the locking position much faster. The Sako M92/M95 with adjustable gas blocks has a setting to vent out all gas to provide a bolt-action type mode, described as a "sniper" mode. My guess is the Finns felt that the gas system was too slam-bang aggressive and hurts accuracy. And the other benefit is that all of the excess powder residue/carbon/gas does not go back to the shooter's face under the receiver cover or trunion vents. There's also less crap to clean in the action. I welcome constructive comments on this topic. Quote Link to post Share on other sites
Bvamp 604 Posted December 12, 2004 Report Share Posted December 12, 2004 I put a vented Ultimak rail on my SAR1, and I have noticed less buildup, increased noise, and slightly less muzzle flip under rapid fire. Also, although I havent checked the temperature with an actual tool, it does seem to run a little bit cooler as well. Quote Link to post Share on other sites
k_dawg 0 Posted December 12, 2004 Report Share Posted December 12, 2004 Do you have more powder resident on the outside of the rifle? I'ld be afraid to use a cleaner on the exterior paint work.. Quote Link to post Share on other sites
metroplex 0 Posted December 13, 2004 Author Report Share Posted December 13, 2004 Nope, it flies into the air. Worst case scenario is that you use BreakFree CLP to clean off the finish (safe for use on painted surfaces). Quote Link to post Share on other sites
lollygagger 1 Posted December 13, 2004 Report Share Posted December 13, 2004 Nope, it flies into the air. Worst case scenario is that you use BreakFree CLP to clean off the finish (safe for use on painted surfaces). Yeah, that was my experience...pretty much just goes into the atmoshpere! I noticed no remarkable build-up around the gas port area. I too, would use CLP to wipe painted surfaces. I intend to do exactly the same thing on the .308 Saiga I'm acquiring -I'll report back (nobody seems to have done this on a .308???). Lollygagger Quote Link to post Share on other sites
ricardomagana 0 Posted December 13, 2004 Report Share Posted December 13, 2004 Can you post any pics of this or whatever you can to help one out! Quote Link to post Share on other sites
lollygagger 1 Posted December 13, 2004 Report Share Posted December 13, 2004 Can you post any pics of this or whatever you can to help one out! Here... Lollygagger Quote Link to post Share on other sites
Bvamp 604 Posted December 13, 2004 Report Share Posted December 13, 2004 here is what im talking about......4 holes per side, eight total. same modification to saiga should work as lolly says....I like my optic out off my face on a fast gun, so I bought this part. sorry so dark.... 1 Quote Link to post Share on other sites
metroplex 0 Posted December 14, 2004 Author Report Share Posted December 14, 2004 Ah it's the Ultimak gas tube w/ vents!! Quote Link to post Share on other sites
Bvamp 604 Posted December 14, 2004 Report Share Posted December 14, 2004 needless to say, i was quite pleased when it made the gun seem a little bit louder.... Quote Link to post Share on other sites
Wolverine 10,360 Posted December 14, 2004 Report Share Posted December 14, 2004 BVamp, It looks slick. Did the Ultimak slide right in or did you have to make modifications such as moving the gas chamber? I am thinking of venting the forearm like yours or some of the others with four holes and perhaps installing a quick remove or folding grip on a rail on the underside of the forearm. Have you seen any like this on a Saiga and do you know where I can find a rail that will fasten on the forearm without compromising it? I did see on some of the 308 threads that one gent was having problems with the (wood & synthethic) forearm breaking under normal use. Although he was trying to use a 7.62 synthetic forearm on his 308. Many thanks for your experienced input. Wolverine Quote Link to post Share on other sites
Bvamp 604 Posted December 14, 2004 Report Share Posted December 14, 2004 remember, my gun is not a SAIGA. I own a saiga12, not a saiga rifle. The ultimak is on my SAR1, which is a romanian made AK. It fit the gun perfectly, though. The part is made a hair short intentionally, and is mounted with clamps, so there is no need for the regular AK gas tube holding lever. in case you have not seen the gun I put the rail on, i will post it once again for you. its not a saiga, and the foreend mounts in the traditional AK fasion. You would probably be better either calling ULTIMAK or someone like blackjackbuffers and asking them if it will fit a regular siaga rifle without tooling things other than your handguard being cut back to allow the part to be fit to the gun. Also, you would need to find out if you need barrel shims under the ultimak on a saiga barrel clamping, as I do not know if it is the same radius as a regular AK barrel. Quote Link to post Share on other sites
Wolverine 10,360 Posted December 15, 2004 Report Share Posted December 15, 2004 Bvamp: Thanks for the info and picture. I'm glad I waited to hear from you before ordering the part. Cool looking weapons. I bought the same handgrip you have on your SAR1. I have a new Romanian WASR-10 I have done some work on but will likely not invest much more than what I have in it now: RSA retainer plate, magazine release extension, and mojo peep site. I was not impressed with the fit and finish. I had to work on the furniture, magazine well and FCG. Although the rifle functions OK it is not is well made and does not operate as smooth as the Saiga. So now I am looking at doing the conversion on the Saiga. I decided to move the FCG rather than buying all the ACE bolt on stuff and drilling the adaptor. It will be awhile but when i get it done i will post it so everyone can have a good laugh. By the way is that a 20 rd. mag I see on your 12 gauge? Thanks again for helping out those of us less experienced with the AK stuff. Wolverine Quote Link to post Share on other sites
Bvamp 604 Posted December 15, 2004 Report Share Posted December 15, 2004 nope, thats a regular old 5 rounder on the shotgun. big, arent they? there is a 20 rounder in the SAR1... like i said, contact the place you were thinking of buying the part from and see what they say for fit. I would think it should still fit, but you may have to trim down the front handguard is all.... Quote Link to post Share on other sites
TWGLADF 0 Posted December 16, 2004 Report Share Posted December 16, 2004 speaking of regular aks J&G sales has vented gas tubes (like the ones that come on mak90s) for i think $1.99. they are dirt cheap but their shipping is a pain in the ass. i was going to get a new one for my mak90 b/c the one i have has a redish color and the rest of my gun is blued finish. besides, i just like the looks of the vented ones. Quote Link to post Share on other sites
metroplex 0 Posted December 20, 2004 Author Report Share Posted December 20, 2004 I haven't had a chance to hit the range with my modified gas tube (even larger vent holes) because its too damn cold and MI hunters crowd the lanes with their crappy loud bolt guns that can't hit the paper at 100yd. Quote Link to post Share on other sites
metroplex 0 Posted December 29, 2004 Author Report Share Posted December 29, 2004 ttt Quote Link to post Share on other sites
pistonring8 1 Posted January 1, 2005 Report Share Posted January 1, 2005 Lollygager, Did you make 4 holes on each side like the SAR1? And did you also notice a dramatic increase in acuracy? If you guys are noticing an improvement with a ported gas tube and no bad side effects, I think that is a GREAT modification idea! I think I might try this mod on my 7.62x39 Saiga. I am a little worried about filling the foregrip with blowback, but if it works, I can live with that. I am in desperate need of tighter groups! Thank you for sharing this great pearl of wisdom with the rest of us. Quote Link to post Share on other sites
lollygagger 1 Posted January 2, 2005 Report Share Posted January 2, 2005 Lollygager, Did you make 4 holes on each side like the SAR1? And did you also notice a dramatic increase in acuracy? If you guys are noticing an improvement with a ported gas tube and no bad side effects, I think that is a GREAT modification idea! I think I might try this mod on my 7.62x39 Saiga. I am a little worried about filling the foregrip with blowback, but if it works, I can live with that. I am in desperate need of tighter groups! Thank you for sharing this great pearl of wisdom with the rest of us. A Sar, a Romanian, should have the vents in the gas fixture ala AKM's & AK-74's. The 8 holes, 4 on each side, is typical to a AK-47 and the chinese AK's. I copied the chinese AK vent coniguration -four 1/8' holes on each side. I'd recommend it being done...if for no other reason than to keep th weapon cleaner. I feel it enhances performance, but that is just my opinion...I did not test for such. Lollygagger FWIW, This will probably get done to my .308 in a day or two. Quote Link to post Share on other sites
metroplex 0 Posted January 2, 2005 Author Report Share Posted January 2, 2005 I went ahead and enlarged the 8 holes to 1/4" - I haven't had a chance to go to the range yet to try it out. Quote Link to post Share on other sites
IndyArms 10,186 Posted January 2, 2005 Report Share Posted January 2, 2005 QUESTION..... Does it REALLY Matter where on the GAS TUBE the holes go?? I mean as far as top or bottom venting??? I would think that to put them angled UP, would help to REDUCE muzzle climb. However, that may also interfere with your target visualization. If you port them angled down, it wont interefere with your vision, but may increase muzzle climb? Can we make any comments to this effect from trying one or the other or both??? Also... Is this something that the SHOTGUN saiga owners can do to help their 12/20/.410? or is it strictly for the RIFLE calibers??? Quote Link to post Share on other sites
pistonring8 1 Posted January 2, 2005 Report Share Posted January 2, 2005 NICE! Thank you for the advice. I will definately try it and report the results. I have noticed that after 500-1000 rounds that the dirtiest part is the gas tube and piston. I plan on upgrading to a US match grade gas piston from F.A.C. but want to do this mod first as it will keep it cleaner and hopefully increase acuracy. Not to mention, if I can boost the noise level, improve the bolt return rate and flash a little more, it should really add to my "range prowess". Thank you for your facts! Please keep us posted on the performance of the modification to your .308 Thank You! Quote Link to post Share on other sites
pistonring8 1 Posted January 2, 2005 Report Share Posted January 2, 2005 Good question Indy, I would like to see some feedback on that too! Quote Link to post Share on other sites
lollygagger 1 Posted January 2, 2005 Report Share Posted January 2, 2005 (edited) QUESTION..... Does it REALLY Matter where on the GAS TUBE the holes go?? I mean as far as top or bottom venting??? I would think that to put them angled UP, would help to REDUCE muzzle climb. However, that may also interfere with your target visualization. If you port them angled down, it wont interefere with your vision, but may increase muzzle climb? Can we make any comments to this effect from trying one or the other or both??? Also... Is this something that the SHOTGUN saiga owners can do to help their 12/20/.410? or is it strictly for the RIFLE calibers??? I copied the chinese gas tube placement- four holes on each side of 1/8' diameter. The first hole 8mm from the gas tube end, the last 32mm from that point. The chinese tube has these at 2:00 and 10:00. There are 6 raised "flutes" in the gas tube -the holes are placed inline with a flute. Due to the Saiga having this partial hexagonal cover over the upper half of the tube, the placement of the holes is best made at the 8:00 & 4:00 flutes. I don't think that there is significant effect on muzzle climb, braking or compensation associated with which flutes are used. I have no experience with the use of gas vents on the shotgun Kalashnikovs. But, while I doubt if it would be a problem -I'd research it further in such a application due to the shotgun being a relatively low pressure device compared to a rifle caliber...there could be problems. Lollygagger Edited January 2, 2005 by lollygagger Quote Link to post Share on other sites
pistonring8 1 Posted January 2, 2005 Report Share Posted January 2, 2005 (edited) Lollygagger, Thank You for your research, I did notice that the inside of the gas piston is kinda' star shaped and was wondering where inside that star I should be poking through. Your description and measurements were very helpful with this. I think that I will drill through the heat shield AND gas tube at about the 3:00 and 9:00 positions leaving the four holes just above the foregrip on either side. (inside the tube it would be the 2:00-10:00 positions on the flutes) I havent thought of any good reason yet not to put the holes there but if anybody does, PLEASE let me know before I go ahead and do this. Thanks! Edited January 2, 2005 by pistonring8 Quote Link to post Share on other sites
LeadMonkey 0 Posted January 2, 2005 Report Share Posted January 2, 2005 please post pics of these awesome mods> Quote Link to post Share on other sites
lollygagger 1 Posted January 2, 2005 Report Share Posted January 2, 2005 please post pics of these awesome mods> I did on 12/13...look back. I will get likewise done on a .308 Saiga today and tested -I'll get back on results/impressions. Lollygagger Quote Link to post Share on other sites
pistonring8 1 Posted January 2, 2005 Report Share Posted January 2, 2005 I am waiting in nervous anticipation like a schoolgirl under the bleechers! Quote Link to post Share on other sites
IndyArms 10,186 Posted January 2, 2005 Report Share Posted January 2, 2005 OK!!!! HERES THE SCOOP on porting for the Saiga shotguns.... I had MY GAS TUBE ASSEMBLY apart today for routine cleaning and i will admit its the FIRST TIME I have taken that end apart to clean it... DAMN did it NEED IT! OK... there is ZERO point in doing this to a Saiga .410, and probably neither to the other shotgun styles either, if they have the adjustable gas port. The adjustable gas port on the .410 has a gas block in the foremost portion of the gas tube, with a travel of about 1 inch, THATS IT! The gas piston butts up against a gas block inside the tube. That block ( a cylinder, of course) is ISOLATED within the gas tube, in the FRONT portion where the tube is SMOOTH. the tube is then MACHINED smaller, where the flutings start, for the gas piston to go in there. I would say there is NO PLACE nor any REASON to try to put gas port holes in a Saiga shotgun!!! The gas block itself is appx. an inch long, inside a 2 inch long cylinder. The front portion of that cylinder is where the adjustable part threads into it. UNSCREW the gas adjuster, all the way out... and you can see what I am talking about. There are no springs, nothing to go "BOING" its just a solid metal piece threaded in. This is a part that I would RECOMMEND regular cleaning on !! MINE was FULL OF schmutz! Quote Link to post Share on other sites
IndyArms 10,186 Posted January 6, 2005 Report Share Posted January 6, 2005 How do I copy this to the shotgun section????? Cause I think its something important to share! Quote Link to post Share on other sites
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