All I shoot are Hornady 55 gr FMJBT and I'm disappointed with myself if I get anywhere near 2 MOA 5-shot groups at 100 yards. My typical group is in the 1.25 - 1.5" range shooting at a rate of about a shot every 3 seconds. But if I slow myself down I can get them down to 1 MOA or better. I've posted target pics in the reloading thread before so I won't duplicate them here.
I've only used two powders: Ram X-Terminator; and Mil Surp WC844. My best X-Terminator load was 24g with the bullet seated mid-cannelure (I wasn't concerned about OAL back then). For 844 I'm loading 26.5 / 27g depending on the powder lot. With the 844 I did experiment with OAL but didn't shoot well enough at that range session to make any determination.
I've been out of work for the past three months so I haven't gotten to the range lately. But next time I do I'll try to slow myself down and see if I can get any better results.