P220 not moving into battery when suppressed

[STFU]

ALCON, I have a Sig P220R that previously never failed to chamber a round properly.
Now that I have a Silencerco Osprey on the front, it fails to chamber properly about every fourth round.

The slide fails to move the last 2mm into full battery (left pic).
If I push the back of the slide with my thumb...it seats properly (right pic).
View attachment 60082

I have tried several different types of ammo at different pressures, etc. All with the same results.

Could this be an issue with a weak recoil spring?
Thoughts?

 

[M67]

Did you have to get a new threaded barrel for it or have you always used that barrel?

Is your piston and booster spring smooth? No burns and moves freely?

 

[ROLEXrifleman]

Believe it or not, I would start by lubing the rails 1st... you'd be surprised. If you still have the issue then yes, recoil springs need to be addressed.

 

[STFU]

It is a new EFK Firedragon barrel. It was initially sent back because of rounds getting stuck on the feed ramp. They fixed that issue.
Now it seems that the rounds get stuck at the top of the mag, before hitting the ramp or when they do feed, they get stuck in that last 2mm of slide movement.

ROLEX, I always keep this weapon lubed fairly well. Are you saying that because of the silencer, it may need more than usual?

 

[M67]

Why didn't you go factory threaded barrel?

The classic Sig lineup usually run like champs suppressed, my 229 has been flawless

 

[STFU]

They do not OEM a threaded P220-R3 Carry (3.9") barrel.
I did not want the silencer sticking out another .5" on the end of the standard (4.4") barrel.

Sig Custom Shop work to shorten and re-thread a standard barrel would have been a good bit more than the EFK.

 

[M67]

They do not OEM a threaded P220-R3 Carry (3.9") barrel.
I did not want the silencer sticking out another .5" on the end of the standard (4.4") barrel.

Sig Custom Shop work to shorten and re-thread a standard barrel would have been a good bit more than the EFK.

Check the booster spring and piston then, possibly add some quality lube to it.

Maybe polish the breech face, check the extractor and maybe bevel the underside a touch.

Or contact EFK to see if you can send the pistol in to see if they can get it to run suppressed, might be a barrel fit issue. When you hang a can off a pistol you add weight to the barrel and change the characteristics of cycling

 

[STFU]

Problem solved: New recoil spring did the trick.
Thank you all for the suggestions.

 

[KJQ6945]

Problem solved: New recoil spring did the trick.
Thank you all for the suggestions.

Thanks for the update, glad you got it straightened out.
I have a similar issue with a CZ. It will run 115gr fine suppressed, but the 147's aren't reliable.

 

[STFU]

I should have suspected the recoil spring earlier, but I bought my P220 used and it has never choked on a round until now.
My best guess when I bought the weapon was that it had a couple thousand rounds down the pipe. I have easily run another 2000 or so through it. So, the spring is probably close to the P-series replacement interval of 5K rounds.

Not sure what the CZ replacement interval is, but you should check to be sure.
Let us know what you find out!