Question about OTM rounds vs ball rounds for military use

[MTMilitiaman]

The increased wounding effects of OTM rounds like the Mk 262 Mod 1 and M118LR compared to their ball round rivalries, M855 and M80, are pretty much universally accepted. Because of this increased terminal effect, some have questioned why these rounds aren't standard issue.

My theory is lack of penetration, yet I can't seem to find a source that really shows how much penetration is given up by going with a 69 or 77 gr OTM in the 5.56 or with a 168 or 175 gr OTM in the 7.62. Does anyone know where I can find a good source comparing penetration of these rounds in mediums such as brick and cinder block, wood, steel, and body armor?

The best I got is an ESAPI plate a combat instructor showed me in SOI that had a pair of M118LR rounds in it, in addition to four or five M855s and a couple AK rounds and still kept the rounds from penetrating.

I'd like to see comparative effect of these rounds against different mediums, but the only thing I can find regarding the terminal effect of OTM rounds is gelatin test results, which are pretty well known and leave little round for debate.

 

[Z-Michigan]

My theory is cost and inertia. All the US OTM rounds are precision match bullets that cost multiples of the basic FMJ bullets. They probably could be made more sloppily for less money, but so far no domestic company is making cheapo BTHP rounds for that purpose.

Institutional inertia would be #2. The military has everything in place for the standard issue rounds, and would probably take a decade to really adapt to a new round, even if it could be done in a couple months.

 

[HorseSoldier]

The increased wounding effects of OTM rounds like the Mk 262 Mod 1 and M118LR compared to their ball round rivalries, M855 and M80, are pretty much universally accepted. Because of this increased terminal effect, some have questioned why these rounds aren't standard issue.

But do we all "know" this the same way we "know" 45 ACP is a proven manstopper, even when there's lots of real and empirical evidence proving 45 ACP, like most pistol rounds, is a decidedly poor and unreliable manstopper?

Do we actually know, in a proven by hard numbers on living breathing bad guys and not gelatin sort of way, that Mk 262 is really delivering greater lethality in theater? (And, the bigger question, I think -- is it possible that increased lethality has nothing to do with bullet weight and everything to do with Mk 262 shooting groups about half the size of M855 which may be resulting in more hits with aimed fire?)

I tend to agree with your belief that Mk 262 is a superior round in terms of terminal ballistics, but I don't have any hard evidence it really is. And I know a lot of guys who didn't have problems killing jihadis with green tip.

My theory is lack of penetration, yet I can't seem to find a source that really shows how much penetration is given up by going with a 69 or 77 gr OTM in the 5.56 or with a 168 or 175 gr OTM in the 7.62.

That may be part of it, definitely. It's not statistical data, but my firsthand experience has been that Mk 262 is somewhat less effective about penetrating automobiles than green tip . . . but both are pretty poor, and seem to fail to exit the far side if anything they hit induces much yaw at all. (And tend to zip in odd directions most of the time as well.)

No real comparative data between M80 ball and M118LR -- both will blast right through car doors, etc., without much fuss.

That said, I think the bigger block to their being fielded is simply that lethality with green tip and M80 ball isn't that bad, if the guy shooting actually hits the target. A lot of the failure to stop anecdotes floating around on the internet may or may not have involved the bad guy being hit at all, or being hit as many times as was claimed.

All the US OTM rounds are precision match bullets that cost multiples of the basic FMJ bullets.

Cost to government, if memory serves me correctly, is roughly double for Mk 262 compared to M855, basically $0.50-ish per round versus $0.25. Doubling cost of ammunition for the M4/M16 and SAW across the board simply would not fly, I agree.

They probably could be made more sloppily for less money, but so far no domestic company is making cheapo BTHP rounds for that purpose.

Don't know if JAG would sign off on that. OTM format rounds were adopted for long range accuracy -- no wink, wink, nudge, nudge motives, 118LR simply works much better than 118SB or M80, etc., for long range accuracy. If we adopted another round with OTM format but no increase in accuracy compared to standard service ammo, we're probably treading in a pretty gray area as far as international law is concerned.

Not that that is a show-stopper, regardless. Just issuing a thin-cannelured 77 grain round without the OTM jacket would likely get most or all of the same terminal effects. Dropping the steel core on green tip would tend to tighten up accuracy even without using match grade ammo, as well.

Institutional inertia would be #2. The military has everything in place for the standard issue rounds, and would probably take a decade to really adapt to a new round, even if it could be done in a couple months.

Likely so. Considering things like the ACOGs and MGOs out there with M855 BDC reticles, and other secondary sort of costs, could result in a lot of resistance to the newer round.