There isn't much to say about this particular modification. In 2014, I made a FROG demo video with some test firing to show how the FROG markers operated, but the video was plagued with shooting problems. Don't get me wrong, these markers are pretty unreliable, so I was expecting some level of trouble. After encountering some barrel breaks I eventually came to realize the markers have a large problem: their chambers have a diameter of 0.690" which is dangerously close to the size of paint being fired through the bore.
Although I don't plan to ever play with these markers on the field, I still want them to at least function correctly. To that end I set out to fix the chamber bore problem. Luckily I happen to keep a 0.701" diameter reamer handy, which I use for body production; this is the perfect size for the FROG breech modification.
The mod went smoothly so I got the markers reassembled and back to their working condition. Now the only thing remaining is to make another test firing video. I'm not sure when that will happen (it's a pretty low priority) but I hope to get it done someday...