WeiserBucks
Well-Known Member
- Joined
- Aug 16, 2016
- Messages
- 2,609
I've got a box of each and my barrel should be done any day now . After break in , I'm sure I'll find a winner. Thanks for the replies guys.
230 Hybrids vs OTM's , any difference on Game?
- Thread starter WeiserBucks
- Start date
Help Support Long Range Hunting Forum
CONatureBoy
Well-Known Member
This weekend I shot a nine-year-old black bear at 120 yards with a .30-caliber Berger 230-grain OTM (300 RUM, 3,000 fps at the muzzle). Broadside, "middle of the middle" exactly (which was a bit farther aft than I intended). The entrance wound and exit wound both were bullet-diameter holes. The guide found the back third or so of the jacket just inside the skin at the exit wound. Some or all of the lead core must have created the exit wound, and the rest of the jacket must have fragmented between entrance and exit. The guide did gutless field dressing, and we didn't post-mortem after skinning the carcass, so I can't say what the effects were in the boiler room. The bear fell when shot, rolled downhill about 30 yards, and wobbled away over the crest of a sidehill. It was near dusk (and cold) in high-altitude grizzly country (NW Wyoming), so we left the bear 'till the next morning. I found it about 50 yards from where it stood after rolling downhill. I conclude the bullet performed well enough. It was likely too much bullet for a spring black bear at close range (spring bears have no fat left under the skin to help a bullet open up before reaching the vitals). And better bullet placement (or a more frangible bullet) might have made a difference. I would have hunted a lighter bullet, had I not been in grizzly country. Tonight I trimmed the meplats on the rest of my box of 230 OTMs, and drilled them to 0.0465". When I get around to hunting them, I'll report my experience to this forum. I've had great luck with similarly trimmed/drilled SMK 220s, killing two nilgai at 200 yards and a cow elk at 600 yards, all three DRT. Hopefully I'll see the same efficacy with the trimmed/drilled 230 OTMs.
Last edited:
CONatureBoy
Well-Known Member
BTW, I load a bit over 99 grains of Ramshot LRT behind the 230 OTM for my 300 RUM, muzzle velocity just over 3,000 fps (28" barrel, COAL a few thousandths short of the lands). Terrific accuracy.
Opening the OTM Tactical up to that diameter will make its performance quite emphatic, especially at RUM initial velocity. You'll give away a little BC, but if it tickles your fancy then light it up.
CONatureBoy
Well-Known Member
That's my hope. I experimented with exactly the same treatment on the Berger 190-grain target bullet, shooting it into 10% gel block at 100 yards (same muzzle velocity). The gel block showed 1.5" of penetration followed by the sort of wound channel you'd normally get from a VLD Hunting Berger. Barbour Creek did a gel test of the 156 EOL 6.5mm Berger; it didn't open up for inches. I did the same drilling, same test, and got the same improvement in terminal ballistics. So my rule of thumb is to expect VLD Hunting type terminal ballistics from a Berger target bullet drilled to 0.0465" and trimmed (about 0.010 off the meplat). I learned from a paper Bryan L. wrote to expect about a 4% drop in BC. That translates to about a half-inch of extra drop at 500 yards. I'd rather have the more explosive terminal ballistics, at least if I can retain accuracy. I'll be testing accuracy soon, and will report results here when I do. . . .
Here's what the bullet looks like, trimmed and drilled:
I do a very little bit of polishing of the ogive with 0000 steel wool while spinning the bullet, to deburr the outer edge of the trimmed meplat. I have measured bullet OALs before and after my trim/drill procedure, and determined that I get statistically significantly higher uniformity of length. The meplat looks more uniform as well, as you see here. So if I manage not to deform the concentricity when I spin the bullet in my hand drill (I'm very careful about that!), I have reasons to hope that the procedure may even improve accuracy a smidge. We'll see. In my testing with the 156 EOLs, I maintained accuracy.
Here's what the bullet looks like, trimmed and drilled:
I do a very little bit of polishing of the ogive with 0000 steel wool while spinning the bullet, to deburr the outer edge of the trimmed meplat. I have measured bullet OALs before and after my trim/drill procedure, and determined that I get statistically significantly higher uniformity of length. The meplat looks more uniform as well, as you see here. So if I manage not to deform the concentricity when I spin the bullet in my hand drill (I'm very careful about that!), I have reasons to hope that the procedure may even improve accuracy a smidge. We'll see. In my testing with the 156 EOLs, I maintained accuracy.
Last edited:
CONatureBoy
Well-Known Member
(You can see in the photo that it's a very modest increase in interior meplat diameter.)
I'll be interested to follow your findings. I've had similar results using just a 0.040" drill to make sure the tip is completely open and clear. I've been using a G7 BC of 0.363 with an initial velocity of 2740 f/s with that modification and found it to be valid. The modified bullet typically penetrates about four inches and then fragments the nose section with the remained continuing on and exhibiting nominal additional expansion. I haven't been able to recover the shank section, but on white tail deer it normally leaves about a 1-1/2" diameter permanent exit wound.
CONatureBoy
Well-Known Member
That sounds like good terminal performance to me, at a reasonable BC. I got to the 0.0465" number starting from a paper by a military terminal-ballistics expert advising law-enforcement sharpshooters about the use of SMKs for antipersonnel purposes. He experimented with drilling a .308" SMK (which has less space inside the tip than the Bergers) 0.050", and found it performed about like I describe above. I figured a little more space behind the meplat, a little less drilling. Sounds like a little little less for you moderates the terminal ballistics to your taste.
