I started hunting "varmints" (groundhogs & crows) 'way back in the early-1960s using a heavy-barreled,
13-pound Sako in .222 and still have the rifle... and it still shoots less than a half-minute of angle.
The smallest 5-shot group I've ever shot (while developing a varmint hunting load with VihaVouri N-130 rifle powder) was LESS than 1/10th of an inch (.091"). But that was the best 5-shot group I ever shot. It will normally shoot ¼-inch to ½-inch , 5-shot groups @ 100 yards with my handloads if I do my part.
I have fired this rifle & load at 25 yard intervals from 100 yards to 250 yards using the same sight picture (holding directly on the center of the bullseye) and found a 50 grain, .224" Sierra "Blitz" bullet @ a chronographed 3200 fps (using 21.8 grains of V-V N-130) shoots pretty darned "flat" from 100 yards out to 225 yards, then drops rapidly beyond that making the .222 Remington an honest 225 yard varmint cartridge.
Yes, with "hold-over" and some luck, you can get a "hit" further out, but for precision varmint shooting, 225 yards is the limit. However, the Sako with my hunting hand-loads is so accurate that I won't take a shot under 150 yards because it's not a "challenge".
By the same token, a .22 Hornet shooting a handloaded 40 grain bullet @ 2750-2785 fps is a good 150 yard varmint cartridge for groundhogs and smaller varmints. I believe shooting at groundhogs at 200 yards with a Hornet is a bit of a stretch just as shooting at varmints at 250-300 yards with a .222 is also a bit of a "stretch". It's just too easy to make a "wounding shot" rather than a "killing shot" once the cartridge's realistic range is exceeded.
As hunters, we have a "responsibility" to make
clean,
SURE one-shot kills on
ANY type of game at which we shoot. Once you start shooting at any animal beyond the cartridge's "point-blank" range and have to "guess" about how much "hold over" to use to hit the point you wish the bullet to strike, you're taking a chance of only wounding the animal at which you're shooting.
Of course, if a hunter/shooter has had considerable practice at the longer range and can consistently make killing shots at those extended ranges, then that's a totally different situation. But I'm talking about the average (but very good marksman) varmint hunter, not the average big game hunter who generally is
NOT a precision shooter like his varmint-hunting counterpart.
While I've never shot varmints with the .17 HMR and .17 HM2's lighter bullets and lower muzzle velocities, I'd question their use beyond 100 yards on usually tough varmints like ol' Mr. Groundhog... and I'd certainly question even the more powerful .17 HMR's use on groundhogs at 200 yards! There's a
HUGE difference in "toughness" & "survivability" between a prairie dog and a groundhog.
As Ironglow wrote, 200 yards is really a "
centerfire neighborhood".
At least, that's my 2¢.............
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Strength & Honor...
Ron T.