Iv'e been frantically searching the web for any help with my issue. I've had some luck finding people with similar problems but after replicating their "fix" I still haven't had any real luck.
Problem: My Sig R716 patrol is having some serious FTF issues. I have FTF with CBC M80 Ball (7.62x51) everytime. I had some luck with PMC Bronze .308 (7.62 NATO) 147 grs. FMJ but after 15 rounds now it FTF everytime too. The first ammo I tried was Hornady Whitetail 150 grs. .308 InterLock it has worked flawlessly and still does but I don't want to be limited to particular brand of ammo. I can get FTF with the other two ammunitions, slap a few Hornady rounds in the mag and it runs fine... The majority of the FTF seems to be the bolt traveling too fast, so fast it doesnt pick up a round or sometimes mis-feeds it. At one point the bolt was sticking about 2cm from fully closing and seating the next round. This would result in a nice jam. This problem has seemed to work itself out through cleanings and use. Now the FTF are fully cycled just without the next round being picked up and chambered.
What I've Tried: I've cleaned the gun several times, re-oiling it, sometimes more than others to see if i can get a different outcome. A simple cleaning of the gun seems to have worked for some, but not for me. I've tried firing the gun on all gas settings and have checked the piston system to make sure everything is working properly. I've heard about a "break-in period" but I imagine at around 200 rounds things would be getting better, not worse. I say worse because the PMC is no longer working in the weapon either, still the Hornady functions perfect. I only have the one Magpul Pmag that came with the rifle and additional mags have proven hard to find. I said :censored: IT! and ordered 2 more Pmags for $60 a pop.... ?!?!! (I know) When they get here I'll be testing them immediately and hoping for some positive results.
First thing I think of, is the magazine. Try the other mags when you get them, that will tell you real quick. Second, inspect your feed ramp. Any misalignment when an empty mag is in? I have heard similar stories with the 516. Has Sig customer service been of help? I am guessing if it gas system related you are probably not alone. Leb, Colt, or anyone have any other thoughts?
I had a similar problem with my Kimber 1911 ... had lots of jamming, cleaned the heck out of it ... still not picking up the next round or jaming. Bought some Wilson Combat mags and it runs like a dream.
Sig customer service suggested putting some more rounds through it, trying different ammo and of course cleaning it. The feed ramp appears fine to me, when I rack a round it always chambers fine, after I got through the "2cm from fully seating issue". I really hope its the Mag, even at their ridiculous prices it would more than likely be the cheapest fix.
I had a similar problem with my Kimber 1911 ... had lots of jamming, cleaned the heck out of it ... still not picking up the next round or jaming. Bought some Wilson Combat mags and it runs like a dream.
First thing I would check is the mags.
I had a similar problem with Les Bear mags through my Kimber TLE II 1911, Wilson mags work flawlessly and they are all I use now.
Problem is It is a new design and not many on this forum have them. Plus a piston design is different from a direct gas impingement like the AR10. I think Lebben has a piston model so Maybe he can offer some insight. I would be a little forceful in a nice way with Sig customer service, as in get this fixed!
Just checked a Sig forum, you are definitely not alone. I would talk to Sig and send it back. Interesting that both rounds you had problems with were NATO standard, 147 gr.. I would think the whitetail Hornady would have been more of a problem. The forum said Sig was polishing the feed ramps, and a lot of forum members felt it was a problem of tight tolerances being worked out. But for a new gun that seems like very questionable reliability. Good luck.
Describe the failure to feed in more detail. Does the bolt simply not pick up a fresh round? Or does it partially pick a fresh round and the nose "hangs" at the feed ramp?
Does the bolt lock back on an empty magazine after the last round has been fired?
There's a possibility it's the mag that was sent with the rifle. Have you disassembled the mag then cleaned and oiled the spring? Checked for any nicks, burrs or anything that would bind the spring inside the mag body?
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