After experiencing both success and failure with rubber O-rings in the Omega, i headed in a different direction and tried out metal washers like sabotloader discusses in another thread, instead of the rubber O-ring.

My first trial with metal washers was yesterday, using a steel washer; the steel washer worked OK, but there was a very little blow back. The compression was about 0.012" compared to a factory breech plug, and that seemed some tight to me. It took effort to close the breech.

This morning i tried out an aluminum washer that started out as a backer washer for pop-rivet. It was turned down on the lathe, until it seemed it would make a nice fit. It was installed in the breech plug, and it won't fall out any time soon. It ended up being about a 0.008" compression compared to factory. Then i went into the hills to give the aluminum washer a try. Here is a picture of 8 primers fired this morning in the Omega:







One can see that the aluminum washer allows about as much blow back as an O-ring. The breech closed with a nice snug feeling, not like with the steel washer, where it seemed to be too tight. The 0.008 compression of the aluminum washer worked better than the 0.012 compression of the steel washer containing blow back, and it felt more better when put into battery.

Three bullet speeds were timed at 13 yard, and they were 1752 fps, 1756 fps, and 1762 fps. To me, this consistency in speeds indicates a pretty tight breech. It seems i should make more aluminum washers.