I bought a case of PMC 9mm ammo and am getting multiple failures to fire. I am going to replace the main spring as I've had the gun for years and have shot thousands of rounds through it and figure maybe it's time to get a new spring. Anyone know the weight of the spring Sig puts in the 239? Thanks.

Wolff Gunsprings claims 18# is the factory rate.

Wolff Gunsprings as @Chris Orndorff suggests - good folks.

Also check the firing pin for smooth operation: Hold hammer back with thumb with trigger pulled. Use suitable wood or plastic rod to push firing pin forward for a quick check.

Thanks guys. It’s not all the time. Every 3rd round or so. I’ll get a new spring and see what happens. My 226 was doing the same thing so I suspect it’s the ammo but I need to be sure and figure it’s probably time to change the springs anyway.

Visually inspecting the primer indentation should give you all the information you need to determine if the firing pin is impacting the primer with the proper force. No sense replacing gun parts if they are doing the job and it's the ammo at fault.

Late reply, sorry. Each round that failed to fire had an indentation on the primer which is why I suspect the problem is the PMC ammo. I asked some guys who have used that ammo before ( I have not) if they experienced any problems with PMC but all of them said they have not.

I have purchased and shot a LOT of PMC ammo. I have experienced no problems with it failing to fire in different handguns.

on the other hand i used to buy pmc
ammo because it would have lots of ftf
which was great training.
if you have a good primer strike it’s all on the ammo

Well, I figured this would be a good time to do something I have been thinking about doing for some time. Buy a Super Strut kit form Robert Burke. It should arrive this week. If anything, I will know what the actual problem is.

Does the gun have a short reset trigger?

Unlike every other Sig, the 239 usually requires clipping one coil off the hammer spring. This is from Sig itself when I was struggling years ago shortly after the short reset trigger was introduced. Worked for me.

Update. It turned out to be the gun not the ammo. I installed the Super Strut kit, went to the range and shot 200 rounds of the PMC. Not one failure to fire.

quote:

Originally posted by Bulldog7972:
Update. It turned out to be the gun not the ammo. I installed the Super Strut kit, went to the range and shot 200 rounds of the PMC. Not one failure to fire.

Edited to add. Because the Super Strut ones with a 20 lb spring, I called Robert Burke to find out why. He told me that the Sig standard for the 239 is a 21 lb spring. He feels that a 16-19 lb spring is too light and will not last long hence the compromise with a 20 lb spring which he feels will last the lifetime of the gun. Even with the 20 lb spring the trigger pull feels lighter than that and I’m pretty happy with it.