I looked back through my notes, and I had 0 issues with my form 1 can operating with my MK23. However, with all my pistol cans, two things can generally cause it to fail to cycle.
The first is that you lack a functioning Nielson device. This could be because you have it directly threaded on or have a fixed barrel spacer in it.
Second, your Nielson device is carbon fouled to the extreme. I've done this with my Form 1. As it is primarily an SBR'd PCC can, it can have thousands of rounds through it between services. That Nielson device with its o-rings, springs, and pistons can glue together pretty well.
So if you have a direct thread mount or the equivalent, get a Nielson device specific to your can and gun. Usually, that is a mount, piston, and spring. Lube it appropriately and give that a go.
If you already have a Nielson device, make sure it is adequately lubed. Make sure it is timed to at least one of the teeth properly. If it is out of time, you might be putting just enough preload on the spring to cause issues.
Third, and the least common cause of your problem: is crap ammo. If the ammo can barely cycle without a can, there is a good chance that the can and its extra weight might keep the gun from cycling. Hubba bubba's home reloads won't cut it. It would be best if you had quality ammo that is of a known velocity. For instance, my MK23 does all my load testing for me. It's got a crap ton of rounds down range. When looking back through my load data it has cycled everything above 700 fps.
I've shot slower stuff; with the can, 700 fps with 185-grain bullets is the slowest it has reliably functioned without a can. The can I typically use on it is my 8x1.5 inch, 16 oz, form 1 can. I have mounts for Ghost M's also, and it shoots fine with all 4 of my ghost-m
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