by Bmt85 » Sun Jul 01, 2018 10:25 am
Depends on the upper. I just measured the ejection ports on some of my uppers and found that some of them are big enough to fit a 450B case, and some are not. I have 2 uppers purchased from the same manufacturer, but at different times. One that I used in my Tromix build is .5030-.5040" on the unground section, the other is .4990 at one spot and .5005" for most of the opening. So that one will not eject a cartridge without being opened a bit. The one used on my Tromix build probably didn't need to be opened up, but why not do it? It will allow more room for the cartridge to get out of there, and it only takes a few minutes with a dremel. I went the route of only opening the front half of the port, because I figure if the front of the case can get out without an issue, the rest should follow with out much of a problem. Haven't had a problem, so far. Also, when your opening the port, your putting a slight "ramp" to help guide the case out, so as to reduce the chance of it hitting the upper and not ejecting.
So I guess, if you want to try a build without opening up the port, find one with a port at least .5020". You still might run into problems, though.