Today trying the same Sig srd9 on two different p226 Legion sao 9mm pistols, both with their own SilencerCo threaded barrels shooting S&b 115 grain. One functioned fine for the dozen or so shots fired while the other would fire once and then not fire. The slide would stop about a 1/4” back and out of lock up. It did this every shot. While the other pistol worked fine. I have no experience with silencers on pistols and very slight experience with silencers in general. I am wondering if I need a heavier recoil spring?
Also for anyone considering this combination, the factory sights will not be usable with the srd9 in place. In spite of being told by sig customer service and the sig master dealer I bought the srd9 from told me.

Any advice anyone has would be greatly appreciated,

Greg

You can use your sights but you have to be able to shoot with both eyes, something I can't do.
Some guns with threaded barrels now come with a standard and a lighter, not heavier, recoil spring. The lighter spring will allow the bolt to go all the way back and allow it to slam forward with more more force and go into battery.
It seems like now two guns are the same when it comes to using with a suppressor. Sometimes changing to certain brand or weight bullet in the subsonic ammo you use.

Thank you very much George. I did the both eyes open thing and it does work some what for me. It’s like shooting an aimpoint sight with the front blacked out and both eyes open. But when my eyes get tired it does not work constantly for me. The lighter recoil spring is something I would not have guessed. Thank you very much for taking the time to help me here George!

Greg

I have had this happen on several guns. Swapping cans often will fix it. I think the issue when swapping cans are the difference in the spring weights of the booster assembly.

When swapping cans does not fix it, often I can attribute it to a much tighter barrel to slide lock up. It just sits in lock a fraction too long under recoil.

Keep in mind that aftermarket barrels, even those that are "drop-in" may need professional gunsmithing to operate propperly. In your case, I am betting the SICo barrel is the issue. I would bet it is a tight fit.

You could have a gunsmith look at it and sort it out. You could do what I did, and run about 500 rounds of 147 grain through it. THat seemed to break everything in for me. I did keep it doused in oil though.

Here is my 226R Elite SAO with a SiCo barrel.

Thanks for the advice DSgrouse. Specially when it’s on such a similar pistol. I will run some more ammo through it and see if anything changes. Thank you again for taking the time to help out,
Greg

I had the same problem. It seems to help if I give the piston and spring a shot of Rem oil.

I tried a heavier spring and definetly not the answer.

I also had to swap out sights. Found a used set for a P220 and went with Dawson Precision for a P226.

Bought a suppressor ready P320 Compact and it runs flawlessly out of the box.

Chris

Thank you for taking the time to help out Chris. That’s good to know and I will give it a try,
Greg