Thanks for all the helpful posts , sorry for the delay in responding

I have been busy on other projects.

I tore it down last night, the poly tube was deformed on the lower end, so I shorted it a little more and put it all back together. The poly tube is hard and fits very tight in the lower.

I have not chronied it because it is still early morning here and the lighting is not quite good enough, but I still get the air leak. But after examining my chrony on another project, I noticed that the chrony was not open as far as it should have been because of the tripod mounting, so 900 FPS could be the velectiy it was shooting before at a 2000 PSI fill.

But some more facts about this leak.

It has been there since I got the rifle.

It is felt lightly on the left forearm.

The saftety has been removed from this gun and the threaded hole is open, I don't seem to get air from that hole.

Malan, you said that I should not be confused with air movement thru the side caused by the hammer racing forward on firing, so is this perhaps a natural thing with the Bam 50 series to have some air escape from that slot?

If I replaced the poly with the transfer tube insert with the orings, are they all the same size? If not being as I am not a machinist, where would I get one.

I hesitate to spend a lot more money on the gun, I paid too much already, and I have a Royale 500 carbine that does everything the BAM does but does it a lot better.

But then I guess that is just air gunning.