I've been slowly trying to catch up on the .223, 6mm/.243, etc threads and the maximizing-smaller-caliber-terminal-performance trend here, and the mountain of evidence there has me too going through this same "downsizing" process, converting from .308 to .243 for my primary hunting rifle (.243 min for big game in Washington). I've been going around and around about bullet selection (will handload for this), looking at both external and terminal ballistics. The aforementioned threads suggest that at the lower end of the caliber range, we want to optimize for maximum tissue damage, which I think points to more frangible cup and core type bullets being most appropriate for deer and elk-sized game (of which I think we'd consider tipped match bullets a subset of). I compiled some ballistics to help organize my thinking on this, and was somewhat surprised at some of the offerings. The following table is compiled from data produced using shooterscalculator online, assuming a conservative MV of 2900 for all projectiles between 90gr and 100gr (note that factory loads with 90-100gr projectiles almost all exceed this and obviously you can push the lighter ones upwards of 3100 FPS, so this is just a baseline point of comparison, and may be less useful for you, but my priorities are achieving the needed terminal velocity for expansion while minimizing recoil to allow more easily spotting impacts), sea level conditions, and a 10 MPH crosswind:
Projectile | BC | Speed @ 500 yd | Drift @ 500 yd |
90gr ELD-x | 0.409 | 1874 | 22.39 |
90gr TGK | 0.4 | 1854 | 23 |
95gr NBT | 0.379 | 1804 | 24.6 |
95gr TMK | 0.49 | 2026 | 18 |
100gr SGK | 0.409 | 1874 | 22.39 |
100gr BTSP | 0.405 | 1865 | 22.66 |
I'm showing speed and wind drift at 500 yds because I *aspire* to be 500 yd capable. I've only included the projectiles that I'm pretty sure will stabilize in my factory Rem twist barrel (would love to be able to include the 108 ELD-M here but fat chance). Some things that stood out to me about this. Even with the conservative MV, all of these maintain that minimum 1800 FPS impact speed at 500 yds. The TMK, with the highest BC by a long shot, obviously has significantly less wind drift downrange, and seems like the obvious choice both from a wound channel and external ballistics perspective (see the .223 thread for the devastation caused with the 77gr TMK), but I haven't been able to find them anywhere. The 95gr NBT gets recommended a lot, but with the caveat that the BC leaves a lot to be desired, but running the numbers even with a really conservative 2900 FPS MV this only results in at most about 2" more wind drift at 500 yards compared with all the options *except* the TMK, which is unobtainium. I was also really surprised to see the soft point projectiles have BCs over 0.4, while everyone seems to assume that those ugly exposed lead tips ought to just tank BC. That actually leads me to some questions: we all seem to regard the tipped match-type bullets over the old fashioned soft points, but I have not really seen a good evidence-based argument for that other than BC, which based on factory published numbers are actually comparable to some of the tipped offerings. How does terminal performance compare between, e.g., the 100gr SGK or 100gr Interlock BTSP against the ELD-X, NBT, TMK, etc? What about BC *variance*? It's commonly assumed that dented points will just tank BC, but you know what they say about assuming.