Fixed the last of my Bushmaster Brls.
Have a 14.5" 1:7 that was very tempermental. Stuck cases with M193, blown primers with M193, blown primers with Hornady 5.56mm TAP T2.
6-months ago I used Ned Christiansens neck & throat reamer in an attempt to solve or reduce the over pressure induced stoppages. Since then I have used Win 1999 Q3131, Tula 55Gn JHP, Steel cased Hornady 75Gn, Wolf WPA 55Gn FMJ, XM193, Fed LE223T3 and Hornady 5.56mm TAP T2 75 Gn. Switching between brass cased and steel cased without cleaning and during the same range sessions. No stoppages of any kind. Stuck cases and blown primers have been completely resolved. Plus its runs reliably on everything from wimpy Tula to "you'll blow up your gun" 5.56mm TAP T2.
Sucks that such drastic corrective action was necessary on a factory new Brl from a name brand manufacturer. But at least it works correctly now.
Thanks for posting this, I've got an unfired Bushmaster sitting here so it's good to know about this, although I've had several other Bushmaster rifles in the past and never had any problems with them.
Glad you got it corrected.