This old revived thread reminds me of an opposite thread that I briefly participated in on another forum. The OP of that thread had killed or two whitetails with his .223 with heavy bullets and then claimed that a .223 would be a good choice for any big game animal in the lower 48 states.
I simply replied that "there are better choices", and got royally flamed by the .223 cult, including claims of 500+ yard one shot kills on moose with .223 bullets. I have two .223 rifles, and shoot one of them almost every week at steel on our range out to 430 yards. I have killed deer and pronghorn antelope with my .22-250, and have killed at least a dozen deer with a .22 LR, and had several friends that killed elk and even American buffalo with their .22-250s, but again, I say there are better choices.
My first centerfire rifle was a .30-06 that I bought when I was in college. For about 10 years I used that rifle for everything from prairie dogs to elk, because that was the only rifle that I had. I then bought a .22-250 for mainly varmints, a .257 Ackley for deer size animals, and rechambered my .30-06 to .30 Gibbs for elk size animals.
About 30 years ago I bought a Remington Classic Model 700 .375 H&H rifle, thinking that I would use it in Africa someday. In 2000 I went through a two year, nasty divorce and my ex-wife wanted that rifle because I had bought it while we were married, and she said she could use it deer hunting. To my knowledge, she has never shot a deer, either before or after we got divorced.
She did not get awarded that rifle, and I never fired it, and later traded it for a Rem Model 541-T .22 LR rifle, which is a great, inexpensive, and literally no recoil practice rifle.
In 2005 I did go on an African Cape Bufffalo hunt, and I bought a .375 RUM for that hunt. Along with my buffalo, I shot a Chobe bushbuck, a common reedbok, and a couple of other Plains Game with that rifle. And on my next South African hunt I only took my .375 RUM and shot a variety of other PG animals, including a Vaal Rhebok, a Jackal, and a couple of 20 pound Steenboks with that rifle. Not that I thought my .375 RUM was the best choice for those animals, but because it was the only rifle that I had brought for that hunt.
There are also hunters that use their .375s for deer hunting here at home because they say that it's good practice for them with that rifle. Probably a valid reason for them getting used to the heavier recoil of the .375 vs. using "normal" and "better deer cartridges" like a .308 Win, .243, or (gulp) a 6.5 Creedmoor.
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