Well I bought the non jacket conversion for my disc extreme and when the plug got put in half way and stopped, I had a hell of a time getting it out.When I did get it out, I noticed several threads on the breech plug were rough and sharp.It also damage the first thread on my barrel as well but I being in a hurry didnt inspect the plug before my father in law put it in with a single pass of white tape.
My rifle was new in the box as well old stock though I think the plugs have a few issues now if you have had a problem like I did !!!!!