I'll preface this with saying I've never killed an elk, but I've killed a pile of deer, and many of them with a .243 Win and 100 gr. Partitions. From virtually any angle I KNOW that Partition will penetrate the vitals, I've had more than a couple that were severe quartering towards and either had exits on the opposite ham or bullets on the skin on the off-side ham. I wouldn't hesitate to take the .243 after elk with 100 gr. Partitions, or I suppose a Barnes would work as well. That being said, the last few years I've been breaking in a couple of .260 Remingtons. I'd stoke that thing with 140 gr. Partitions and feel even more confident with slightly more recoil than the .243. The .243 will get it done if you need it to.
Different experience here with deer. I've killed two whitetail bucks here in NE MInnesota with a 6mm Remington, 50 yards, standing still perfectly broadside, both heart shots, hot handloads with a 95 gr partition. Neither bullet exited. Both bullets came apart radically, without the partition holding up. I found the empty cup bases. Maybe I was too close? They were about 230 pounds each. Anyway, I switched to Barnes and killed one buck with an 85 grain x-bullet: it exited. Admittedly, not much experience, and the partitions certainly killed both bucks. The broken-up partitions scrambled their innards well. However, I consider the 6mm marginal for big deer (an unpopular view) and demand an exit wound for better trailing. I've killed about 130 whitetail and feel that my BAR in 30-06 and 180 grain Hornady soft points is the ultimate woods gun for big deer. I like 7mm STW or 270 Win for open country. I would not use a 6mm for elk unless I had a very good reason like I could not handle recoil, had no other gun, or just wanted to try it as an experiment. I've only killed a few elk and all but two were with muzzleloaders. I used a 35 Whelan on the two firearm elk. IT exited both times. I liked it. IMHO
I use my 6mm mostly for pronghorn.
Bill
