Bigcountry and folks,

Herman is on the right track describing this.

To add: In my view, the phenomena of 100yd MOA ML for the average shooter would likely be better quantified in average groups versus a single group from a bench.

I would say that many of the rifles, powders and projectiles available are certainly capable of shooting MOA on a regular basis.

Then comes the variables that can can alter MOA capability: Shooter, primer, fouling, fouling deviation, barrel condition and tolerances, projectiles, cleaning proceedures and methods, powder burn deviations, weather and likely more.
The top shooters are the folks that can manage and control the "variables" the best.

I would consider myself about a 2-ish" average ML shooter. Somtimes better than 2" sometimes much worse with a nasty flier now and then that really screws things up.
[&:]

For example I can and have shot 1" groups and even a couple of times sub 1" groups from both an scoped MK-85 and a Rem 700. This said, I've also shot really terrible groups as much as 3-5" with the exact same everything (or so I thought) thanks to a flier or two or sometimes nothings seems to want to group.

The folks that are honestly and on average, regularly shooting MOA or less are logging a great deal of time at the range and possibly not with typical off the shelf approach that most of us average shooters do. These folks are very meticulous managing to the best of thier ability, all of the possible "variables to MOA".

Bigcountry, with an ML and 2.5 MOA average I'd say you are doing pretty well.

My .002...