Took my new mod 48-2 to the range today and it shot dead on. Then when I tried to eject the brass, it wouldn't. I bumped the ejector rod and it ejected, but tightly. The rounds go in smoothly. I only have Federal and Winchester fmj ammo. I thought that it may be dirty or rusty so I cleaned the chambers well. The spent brass will hardly go back in, and not all the way with cleaned chambers. Any ideas?