SO nice to be seeing gopher content in December. No wonder I'm prowling the WestJet sight daily looking for deals.
I shoot .223 primarily, but, did run a .204 for a season. It was a 1:12" that shot 39gr. SBKs best. However, it took about 10x longer to find a load that would rival the accuracy I'm getting from my .223. I wanted it to shoot 32gr. V-Max best for 100-200 yard groundhog shots~the gun just wouldn't cooperate. the SBKs shot bug holes, but the gun was too pretty to get rained on so I sold it and stuck with my .223.
For a while this year, I was contemplating/pricing the idea of getting a 20 TAC together to keep powder consumption down (vs. .204) but speed kind of up there....but I abandoned the idea as cost was a bit cost prohibitive. In my research though, I discovered a .223 bullet I didn't know existed, the 35gr. NTX. Non-lead bullet that could allow for a boat tail design and still be that light. Last weekend, I tested them on the hotter end of the spectrum using 3 powders, 4 loads of each. Almost all were MOA or better, 2 groups (one H4895, one Varget) had 3 shots cloverleaf @ 100 yards. The POI on the H4895 was simply 1-1/2" high of where my pet load for that gun shoots...so I could run those as is!
I don't own a chronograph but these have to be moving quicker than my lighter-charged 53gr. V-Max pet load is shooting. Whether or not they dismantle a groundhog the same or better~remains to be seen.
I'd still like a .20 and will echo what's been said already. I never found wind drift to be a big issue in practical terms, but, Alberta is a windier place than S. Ontario as a rule. The 39gr. SBKs really over penetrated too, so, better (likely) as a coyote bullet vs. a groundhog one. Don't get me wrong, a hit=instant death...but...I shot some right through LENGTH wise and considering the size/weight of some of these groundhogs, that's an interesting thing to see.