The Firing Line Forums - View Single Post

Ruger4570 · April 25, 2005, 08:49 AM

I tend to agree with cheygriz on the problem of not getting enough pressure to expand the necks,,, but,, you are within a couple of grains of a max charge of 4064 also. Therefore it does seem strange to some degree, your neck expansion isn't over the top, but is somewhat larger than my 308. I tend to get case mouth blackining mostly when I use boat tail bullets. I have assumed that the bullet releases and some of the gasses slip back past the boat tail before the case mouth has had time to fully expand. It really isnt a problem and will do no harm, just a little unsightly. I have seen many guns do this to some degree with no ill effect.

April 25, 2005, 08:49 AM	#5
Ruger4570 Senior Member Join Date: April 3, 2005 Location: Rochester, New York Posts: 2,136	I tend to agree with cheygriz on the problem of not getting enough pressure to expand the necks,,, but,, you are within a couple of grains of a max charge of 4064 also. Therefore it does seem strange to some degree, your neck expansion isn't over the top, but is somewhat larger than my 308. I tend to get case mouth blackining mostly when I use boat tail bullets. I have assumed that the bullet releases and some of the gasses slip back past the boat tail before the case mouth has had time to fully expand. It really isnt a problem and will do no harm, just a little unsightly. I have seen many guns do this to some degree with no ill effect.