"Nobody ever made a group smaller by shooting at it" (not by me, but I love the quote! Not only is it funny as hell, there's a lot of wisdom buried in it too...)
Remember that a group can be lucky-good or lucky-bad, which makes any one single group not particularly meaningful (so carrying around in your wallet the smallest groups you ever shot actually doesn't really mean much at all). Competition Benchrest deals with this by taking the "agg" (average size of five five-shot groups). When testing ammo, a fairer picture can be gotten by considering all groups fired, not just the best groups.
Still, with all that said, it looks like you and your rifle are both doing quite well - fun, eh? ;-)
When you get around to firing 5-shot and 10-shot groups, realize that they will be bigger, and don't be discouraged by this. I'm not a stats guy, but I think I recall reading that the statistical expectation is that:
- 5 shot groups will be about 1.5 times as big as 3-shot groups
- 10 shot groups will be about 2 times as big as 3-shot groups
(Of course these are averages; fluctuations are part of the game too!)
Keep good records (elevations, loads etc), measure your distances, calculate your ballistics (using the best values you can for elevation, air temp, muzzle velocity, bullet BC), aim carefully, and you'll find it to be pretty straightforward.
If you were to place two or three stakes along your line of sight, say every 200 yards or so, and tie a two or three foot strip of surveyor tape on top - these make pretty good field-expedient wind streamers. When you are firing, strive to fire all your shots in your group when the streamers are indicating similar wind conditions.