My friend has an FN 502 with a suppressor, and it will not run the CCI Quiet at all. We've found that it is just too slow to function. So, I bought a bunch of the Norma Suppressor Ammo and traded him for the Quiet and it shoots great for plinking in my revolver and single shot rifle. Just sayin before you invest in more springs check into ammo marked "suppressor". So far we've had good performance with suppressor ammo from CCI, Norma and Winchester.

 

You may have to lighten the bolt if you want that to work. One of the guys I occasionally see at the range did this. I think there is not enough force to move the full weighted bolt + spring with the quiets.

I've also tried the cci quiet semi-auto and that usually cycles. Might be worth trying.

 

I've also tried the cci quiet semi-auto and that usually cycles. Might be worth trying.

This

Quiet isn't intended to cycle semiautos .

 

I never tried the quiet rounds, but I'll say the standard velocity CCI are just about silent with my SilencerCo Sparrow 22 on the MKIV. After the FRP the only sound is the bolt movement.

 

Same, through my Form 1 can.

 

CCI 40 grain Standard Velocity fired from your Mark IV will remain subsonic, so there's really no point in trying to get your pistol to run with subsonic ammunition; save it for your bolt action rifle.

The above ammo is all I run in my .22 semiauto pistol suppressor hosts; one such being the Mark IV 22/45 shown below...'tis quiet and runs like a sewing machine.

 

There are 3 CCI Quiet loads. The 40 grain @ 710fps, The 40 grain segmented @ 710 fps and the 45 grain @ 835 fps. Which one are you using? The 45 grain was made for use in semi auto and suppressors. There are several 45 grain suppressor loads under 1000 fps available from different manufacturers.