Anyone elses Model 11 .223 prefer heavy ammo?

I bought a used one from 2004 that I suppose has the 1/9 twist. I have shot all kinds of ammo through it on sandbags - remington UMC 45gr JHP, remington FMJ 55 gr, PMC 55gr FMJ, Federal Power Shock 55 GR PSP, Winchester white box 55 gr, Hornady 53 and 55 gr vmax, hornady TAP 55 gr and they all are pretty awful in this gun. 6" groups alot of the time at 200 yards. I got one ok group out of the 45 gr which I think was a fluke - and a 3" group with 55 gr Fed powershock. So one day I put about 25 rounds down the tube of the 55gr variety and then loaded up some Hornady TAP 75 gr. Instant sub-moa at 200 yards. Came back another day - tried 64 grain first, terrible groups, then loaded the 75 gr TAP and another sub MOA group.

I think part of it is the barrel was getting more fouled once I tried the TAP both times, but thats a huge difference. I would expect this 1/9" twist to at least be able to get a decent group with 55 or 64 - the 75 just blows everything else out of the water so far...

Anyone else have this happen with theirs?

May have a really long throat.