RE: 20ga ultra slug report
It took my NEF20 USH 15 rounds or so before it would group. Now its putting 3 hornady SSTs into a 1 1/2 to 2 inch group. Make sure the latch & shelf are dry, wipe it down real good . & when you close the barrel you kinda gotta almost slam it shut, so the latch & shelf engage the same every time. Good luck,