Thanks for the feedback, fellas. Sounds like more opinions than experience in this case. The only reason I'm going down this road is because 300 blk with modern solid copper 120gr bullets retain 100% of their weight and penetrate the same as 30-30 Win with 170gr CoreLokt (which has killed a pile of elk in the timber).
I'm hunting with a suppressor that is 8.4" long, so barrel length is the main concern here. My 300 blk has a 16" barrel and my 308 has an 18" barrel. Plus 308 seems overkill at 25 yards, considering I've killed elk at 500 yards with similar cartridge.
How is 300 blk any different than elk guides who carry a 243 Win and 100gr Partitions that only have 60% weight retention? The 120gr TAC-TX gets 20-25" penetration in gel at ranges that I will be shooting at.
Not to mention this 300 blk load meets the CPW regs just like the 243 Win ("you must use a rifle that fires expanding bullets with a minimum caliber of .24 cal. or 6mm, a minimum weight of 85 grains that delivers at least 1,000 ft. lbs. of energy at 100 yards")
The reason very few people have experience shooting elk with 300 BLK is fairly obvious. Even on deer and pigs it's an acceptable, but marginal cartridge, especially out of an 8" barrel. My 9" AAC barely gets 2100 fps with a 110 TTSX. Wounding is narrow. The 110 gr V-max is a much better killer, though it usually won't exit. Between myself and my hunting crew down here we've dropped 100+ does and pigs with that caliber (though if you want split hairs, none with the 120 TTSX, only the 110gr version) and most of us drifted back into larger calibers.
I've run 30 cal 180 grain bonded bullets into elk at 2100 fps (600+ yards). The bullet barely made it through the near side shoulder. If you think there's a magic difference between a 120 TTSX and a 180gr bonded nosler at the same speed, you're going to be disappointed.
A 243 partition of any weight blows a huge frag cloud ahead of it *as long as it's going fast enough*. All bullets are dependent on speed for disproportionate to caliber wounding, but mono bullets are really dependent.
Both are poor choices for your intended purpose.
