MickB 0 Posted February 19, 2011 Report Share Posted February 19, 2011 I have a converted S12, done myself using parts from CSS. I was having FTE and FTF issues. Checked the gas holes, and found 3 at 0.070". Took the gas block off and opened them up to 0.093" using a 3/32" drill bit. Estate and Walmart Federal seems to be extracting OK (MD arms plug as setting #5) but I am still having failure to feed issues. While test firing at the range today, we figured out that the rim of the shell being fed from the mag is hitting the front trunnions and stopping the bolt from closing. Only way to clear the jam is to bang the stock on the ground while pushing back on the charging handle. Anyone come across a FTF like this? Do I need to work on the extractor? The feed ramp on the barrel? Take some material off the trunnions where it's scraping? Thanks in advance! Mick Quote Link to post Share on other sites
MickB 0 Posted February 20, 2011 Author Report Share Posted February 20, 2011 The op rod is fine. If I use a 3" shell, the feed angle is such that the rim is taken high enough to clear the trunnions. Looks like it is confined to 2 3/4" shells and the feed angle. Mick Quote Link to post Share on other sites
YOT 3,743 Posted February 20, 2011 Report Share Posted February 20, 2011 You probably should have done some polishing/reprofiling first, but you'll be ok. Look in the stickies. All the information is there. BTW the front trunnion is not where the shell enters the chamber. See: http://forum.saiga-12.com/index.php?showtopic=63485&st=0&p=608574&hl=+front%20+trunnion&fromsearch=1entry608574 Quote Link to post Share on other sites
MickB 0 Posted February 20, 2011 Author Report Share Posted February 20, 2011 The rim of the shell is hanging up on the part of the front trunion that projects into the receiver. Specifically the area right above the rear most rivets holding the trunnion to the receiver. This is the part of the front trunnion that is located directly in front of the bolt carrier rails. The binding is such that it will actually cause a gouge in the rim of the shell. I hope that description is more clear. Mick You probably should have done some polishing/reprofiling first, but you'll be ok. Look in the stickies. All the information is there. BTW the front trunnion is not where the shell enters the chamber. See: http://forum.saiga-1...=1 Quote Link to post Share on other sites
YOT 3,743 Posted February 20, 2011 Report Share Posted February 20, 2011 (edited) You may want to seek warranty work on that one, but I see you already converted. Cadiz is one I think. Pictures are really helpful. Edited February 20, 2011 by Yeoldetool 1 Quote Link to post Share on other sites
Paulyski 2,227 Posted February 20, 2011 Report Share Posted February 20, 2011 Pictures are really helpful. +1 A picture of the jam would help. Also, the type of mag would be nice to know. I have a feeling this may be one of the jams where 2 3/4 hits the barrel hood? Quote Link to post Share on other sites
G O B 3,516 Posted February 20, 2011 Report Share Posted February 20, 2011 Is the problem specific to a particular mag or does it do this with all of them? most feeding jams are caused by a poorly fitted mag. Quote Link to post Share on other sites
MickB 0 Posted February 22, 2011 Author Report Share Posted February 22, 2011 I'll try and post pics later. The mag in question is a 10rd AGP. Also happens on an MD Arms drum. I'll also have to try the original 5rd mag as well. However, I'm suspecting it's the feed angle of the shell. Mick Is the problem specific to a particular mag or does it do this with all of them? most feeding jams are caused by a poorly fitted mag. Quote Link to post Share on other sites
TonyRumore 1,332 Posted February 22, 2011 Report Share Posted February 22, 2011 Most likely a problem with the feed foot on the bolt. The case head is not sliding upward and is being driven forward with the rim too low to clear the trunion. Quote Link to post Share on other sites
darthhamtaro 0 Posted February 22, 2011 Report Share Posted February 22, 2011 whats a feed foot? any pics? Quote Link to post Share on other sites
MickB 0 Posted February 24, 2011 Author Report Share Posted February 24, 2011 This is exactly what it sounds like, Tony. What is the fix for a bad feed foot? Mick Most likely a problem with the feed foot on the bolt. The case head is not sliding upward and is being driven forward with the rim too low to clear the trunion. Quote Link to post Share on other sites
MickB 0 Posted February 24, 2011 Author Report Share Posted February 24, 2011 (edited) Here is a pic of the FTF taken from the mag well. Mick This is exactly what it sounds like, Tony. What is the fix for a bad feed foot? Mick Most likely a problem with the feed foot on the bolt. The case head is not sliding upward and is being driven forward with the rim too low to clear the trunion. Edited February 24, 2011 by MickB Quote Link to post Share on other sites
MickB 0 Posted February 24, 2011 Author Report Share Posted February 24, 2011 Another angle Mick Quote Link to post Share on other sites
MickB 0 Posted February 24, 2011 Author Report Share Posted February 24, 2011 Pic from the top Mick Quote Link to post Share on other sites
MickB 0 Posted February 24, 2011 Author Report Share Posted February 24, 2011 Lastly, a pic of the front trunnion. Note the rub marks from the shells passing by the trunnion. Mick Quote Link to post Share on other sites
MickB 0 Posted March 2, 2011 Author Report Share Posted March 2, 2011 UPDATE I got to compare my S12 with that of a friend's that functions 100%. Hand feeding a shell into the chamber, the feed angle was identical on both guns. My S12 also had a much more generous feed ramp cut. What we found was that the angled cut of my left trunnion was a lot shallower than his. This meant on my gun, the rim of the shell was hitting the angled cut on the right trunnion, then was getting pushed hard against the left trunnion where the angled cut stopped. A few passes with a needle file was all it took to increase the cut enough so that the shell stopped getting wedged between the trunnions. Mick Quote Link to post Share on other sites
Torqued 8 Posted March 2, 2011 Report Share Posted March 2, 2011 I had this exact same problem that Tonys repair of my feed foot still has not fixed 100%. Could you circle and describe in a tad more detail, so I can check my s12 to see if mine has same issue. Quote Link to post Share on other sites
MickB 0 Posted March 3, 2011 Author Report Share Posted March 3, 2011 (edited) No problem. Area I worked on is circled in red. Now, I will say this - you're doing this at your own risk! Before you do anything, remove the recoil spring, bolt and carrier. Take a 2 3/4" shell and while pushing down on the rim, push it into the chamber. The rim should ride up and over the angled cuts of the trunnions with perhaps a small amount of drag. If the rim gets wedged up tight against the vertical flat of one on the trunnions, then the angled cut of that trunnion could be too short. You want to extend the angled cut forward a little at a time until the shell feeds smoothly. WARNING - do not go dremel crazy. Use a small, fine gun smith's or jeweller's file and take of a small amount and test with a shell again. Repeat as necessary. It is literally removal of the paint/parkerizing off the surface and taking off the tiniest amount of metal. That is all it takes. I cannot over emphasize this last point. Mick I had this exact same problem that Tonys repair of my feed foot still has not fixed 100%. Could you circle and describe in a tad more detail, so I can check my s12 to see if mine has same issue. Edited March 3, 2011 by MickB Quote Link to post Share on other sites
Torqued 8 Posted March 3, 2011 Report Share Posted March 3, 2011 Ahh, I see, I thought you were working on the right side where you can see some friction has occured. Last night I put some shells in the mag, with the bolt removed and tried to push the shell in manually, and it was catching between the two, pending the shell feed angle. Should the rim of the shell fit between the tight spot no matter what angle? Meaning, should those choke points be wide enough to pass the rim of the shell regardless, or is it meant to be tight if the shell does not come through at the right angle? Quote Link to post Share on other sites
MickB 0 Posted March 4, 2011 Author Report Share Posted March 4, 2011 (edited) Don't feed the shell from the mag. Take it out, as well as carrier and bolt, and feed the shell into the chamber with your hand while simultaneously gently pushing down on top of the rim. The shell should ride up and over the angled cuts on the trunnion. It appears to me that the trunnion acts as a ramp for the rim of the shell to help it rise into the correct position, in conjunction with the feed foot of the bolt. If you take off too much metal, you could make things worse, as you have already found out. In my case, the right trunnion was fine. The shell was getting wedged against the flat of the left trunnion, which is where I slightly relieved it. Mick Ahh, I see, I thought you were working on the right side where you can see some friction has occured. Last night I put some shells in the mag, with the bolt removed and tried to push the shell in manually, and it was catching between the two, pending the shell feed angle. Should the rim of the shell fit between the tight spot no matter what angle? Meaning, should those choke points be wide enough to pass the rim of the shell regardless, or is it meant to be tight if the shell does not come through at the right angle? Edited March 4, 2011 by MickB Quote Link to post Share on other sites
srupp23 2 Posted May 4, 2011 Report Share Posted May 4, 2011 I am having a similar problem. The shell wont feed the last couple inches and fails to chamber all the way. I have to push the charging handle forward real hard to get it to chamber. This happens probably 1/3. Never had and FTE problems just feed problems. I sent my saiga to Cadiz for warranty work hopefully they can solve this issue. Its been 37 days since they recieved my s12 hopefully not too much longer. When I get it back if I still have feed problems I might revisit this thread. Having a hard time seeing what your talking about by your pictures. Quote Link to post Share on other sites
Shadoh 16 Posted May 4, 2011 Report Share Posted May 4, 2011 I had this problem on my gun as well. Whats worse is that the bolt rode low enough to that the rim of the shell would hit it coming out as well. Some careful profiling took care of it. As everyone says, less is more when removing metal. Quote Link to post Share on other sites
Machinist 150 Posted May 4, 2011 Report Share Posted May 4, 2011 I have a converted S12, done myself using parts from CSS. I was having FTE and FTF issues. Checked the gas holes, and found 3 at 0.070". Took the gas block off and opened them up to 0.093" using a 3/32" drill bit. Estate and Walmart Federal seems to be extracting OK (MD arms plug as setting #5) but I am still having failure to feed issues. While test firing at the range today, we figured out that the rim of the shell being fed from the mag is hitting the front trunnions and stopping the bolt from closing. Only way to clear the jam is to bang the stock on the ground while pushing back on the charging handle. Anyone come across a FTF like this? Do I need to work on the extractor? The feed ramp on the barrel? Take some material off the trunnions where it's scraping? Thanks in advance! Mick Check the area around the shell feeding ramp where the lugs lock the bolt closed. I noticed that the brass rubbed the sides of the casting and stopped the bolt from closing completely, i used a file to remove a little material.Second remove your gas block again and chamfer/polish where the carrier rod enter the back of the gas block, this also was a snag point on my gun. after both mods my gun will run anything on the correct gas plug setting. Quote Link to post Share on other sites
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