Yea that's not good.
Mil Spec only requires something like 4MOA from XM193 and some is better than others. It's a 1/7 twist barrel and some of those shoot 55gr bullets OK and others don't shoot it worth a damn. One reason I like 1/9 barrels is because I have so much mil surp 55gr to shoot. If 55gr was all you were testing with I wouldn't be too concerned at first. That said I can't think of any of my 1/7 barrels that only get 6 MOA with anybodies mil surp 55gr.
PRIVI 62 gr has a pretty good rep though and your Sierra HPBT's hand loads certainly should have tightened up those groups to better than 3 MOA. I've heard that the company that makes the barrels for Spikes also makes them for Daniel Defense but I don't remember the company name. I'll try and find out who it is.
Before you give up on it you might also try shooting some 75 gr bullets thru it. They might shoot a lot better. I'd love to hear how it shoots with 75 gr rounds.
Mil Spec only requires something like 4MOA from XM193 and some is better than others. It's a 1/7 twist barrel and some of those shoot 55gr bullets OK and others don't shoot it worth a damn. One reason I like 1/9 barrels is because I have so much mil surp 55gr to shoot. If 55gr was all you were testing with I wouldn't be too concerned at first. That said I can't think of any of my 1/7 barrels that only get 6 MOA with anybodies mil surp 55gr.
PRIVI 62 gr has a pretty good rep though and your Sierra HPBT's hand loads certainly should have tightened up those groups to better than 3 MOA. I've heard that the company that makes the barrels for Spikes also makes them for Daniel Defense but I don't remember the company name. I'll try and find out who it is.
Before you give up on it you might also try shooting some 75 gr bullets thru it. They might shoot a lot better. I'd love to hear how it shoots with 75 gr rounds.