62gr M855 or 55gr M193: Must choose ONE or THE OTHER for 16" bbl 1:7 twist

[Defaultmp3]

Feel better now?

For anyone who isn't a jackass, I'm speaking in general terms, about a typical 16" barrel with a typical 1:7 twist.

I'm asking about comparative ballistic performance and accuracy between those two rounds in general. There are other factors beyond "what the hell my gun likes" such as the steel core and overpenetration.

So generally speaking, which one would YOU buy in light of the "modern concerns" listed above?

There is no "in general", though. If you're keeping it specifically to stash away for duty use, I would very much see what my gun likes, because accuracy is all that really matters in this context, since the terminal ballistics of both are pretty mediocre. The only real difference I can think of is that M855 can penetrate UHMWPE, while M193 out of a 16" is not going to be defeating steel plates very well. However, accuracy out of my gun would easily trump any body armor defeat, given that there's lots of ceramic armor out there.

All things being equal, I would lean toward M855 for pure duty use, I guess, because of its slightly better ballistic co-efficient and UHMWPE defeat, but I would much rather buy M193 if I was simply stockpiling, so that I could use it for training and use it against steel targets with less concern (assuming proper distance to give the bullet enough distance to be safe with a 55 gr bullet). If this is truly an emergency use only stash, I'd much rather have a smaller stash of quality duty ammo with barrier blind bullets than a bunch of M193 and M855; going through 1000 rounds without any kind of resupply or movement is pretty fantastical.

[markm]

Body armor isn't really a factor in so much as the zip of M193 will defeat the same armor that M855 will in the given distances. Any armor that can stop one, can stop the other. The mythical abilities of M855's penetrator are just that.

[498cm3]

Go with the 855. Small detail but I believe 855 ballistics are more compatible with the carbine sight radius. Or that was the intent, anyway. And in my experience at 300m is the 855 disperses slightly less and holds the wind just a touch better.
I am talking standard irons here.

[SearchMe]

Likely to face targets with body armor then M855, but stay away from PMC, low velocity.

I appreciate the warning. I've been reading reviews of the X-TAC saying it's top-notch in all respects... It's tough to know which online opinions to trust these days.

But that's not the worst of it; now you can't be 100% sure if your date for the evening is actually a DUDE. Ha! The whole thing is coming unglued, and leftist dimwits can't understand why thinking people are serious about arming up.

I will dig deeper on the PMC velocity issue. Do you have suggestions for PMC alternatives?

[Defaultmp3]

Body armor isn't really a factor in so much as the zip of M193 will defeat the same armor that M855 will in the given distances. Any armor that can stop one, can stop the other. The mythical abilities of M855's penetrator are just that.

Uh... no. UHMWPE can easily defeat M193 at the same distance that M855 would absolutely penetrate it. This is a well-known issues with pure UHMWPE plates, and why all level 3+ has become a popular marketing label for plates that use UHMWPE, to indicate that a plate can stop M855 (or other steel core penetrator rounds), typically through the use of a ceramic strike plate. M855's steel penetrator is pretty garbage in general at barrier defeat, but presents a unique threat against pure UHMWPE plates.

https://drmorgear.wordpress.com/2022...lates-by-m855/

[SearchMe]

There is no "in general", though. If you're keeping it specifically to stash away for duty use, I would very much see what my gun likes, because accuracy is all that really matters in this context, since the terminal ballistics of both are pretty mediocre.

Heh heh. That last line makes me laugh because until now I've put my faith in .30 cal. Per your comments, and the comments of others, I guess I will "buy a box of both" to see if there's any noticable difference for my particular rifle before jumping in with both feet.

The only real difference I can think of is that M855 can penetrate UHMWPE, while M193 out of a 16" is not going to be defeating steel plates very well.

A) I would lean toward M855 for pure duty use, I guess, because of its slightly better ballistic co-efficient and UHMWPE defeat,

B) but I would much rather buy M193 if I was simply stockpiling, so that I could use it for training and use it against steel targets with less concern (assuming proper distance to give the bullet enough distance to be safe with a 55 gr bullet).

So it's not just me then. In A and B above you spell out exactly my connundrum. What I take away from your remarks and from the helpful comments of others here is this:

I need to expand my budget to include BOTH cartridges in order to accommodate doomsday, training and personal defense.

THAT'S THE ANSWER FOR ME.

If this is truly an emergency use only stash, I'd much rather have a smaller stash of quality duty ammo with barrier blind bullets than a bunch of M193 and M855; going through 1000 rounds without any kind of resupply or movement is pretty fantastical.

What cartridge do you recommend for this? A particular bullet weight and shape? A particular manufacturer? Give me a starting point for further research.

Thanks

[markm]

Uh... no. UHMWPE can easily defeat M193 at the same distance that M855 would absolutely penetrate it.

Interesting. I've never shot UHMWPE with anything so I can't debate that point. Unusual to find a medium that has such a penetration spread between the two projectiles.

[kerplode]

193 for lulz and Bonded JSPs for realz

What cartridge do you recommend for this? A particular bullet weight and shape? A particular manufacturer? Give me a starting point for further research.
Thanks

Gold dots if you can find them. If you want it now, Fusion is a good substitute.
62gr Fusion @ SGAmmo

[Defaultmp3]

What cartridge do you recommend for this? A particular bullet weight and shape? A particular manufacturer? Give me a starting point for further research.

I personally use Speer Gold Dot 75 gr. Federal MSR Fusion used to be a very popular choice as essentially a clone of Speer Gold Dot 62 gr., but with far wider availability and usually much cheaper. I'm of the opinion that any good bonded round, as often used in hunting, is going to be a much better bet than M193 or M855. The monolithic copper rounds are also viable, but seem to usually be more expensive, although you'll get better ballistic coefficient out of them usually for like-weight bonded rounds without ballistic tips.

From DocGKR, with his formatting preserved:

3/1/17

Only after proper foundational and ongoing repetitive refresher training, cultivating warrior mind-set, and ensuring weapon system reliability do you need to worry about ammunition selection. Most folks would be far better off practicing with what they have, rather than worrying about what is "best". As long as you know your what your weapon and ammo can realistically accomplish, it is all just a matter of training and shot placement. I would much rather go into battle with a guy who practices 15,000 rounds a year using generic 55 gr FMJ out of his old M16A1 than with some guy that has the latest state-of-the-art ammo and rifle, but only shoots 500 rounds a year. If you need to delve into the arcane subject of agency duty ammunition selection, below are the state of the art choices in 5.56 mm/.223:

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For LE Patrol use, where there is a high incidence of potential engagements around or involving vehicles, ammunition that is able to effectively penetrate intermediate barriers, particularly vehicle glass is critical. The best LE 5.56 mm/.223 loads for intermediate barrier penetration using 1/9 and faster twist barrels are the 5.56 mm Federal 62 gr Trophy Bonded Bear Claw (TBBC) bonded JSP (XM556FBIT3) and 5.56 mm Winchester 64 gr solid base bonded JSP (Q3313/RA556B) developed for the FBI, along with the outstanding new Black Hills 5.56 mm 50 gr TSX loading. The Hornady 5.56 mm 55 gr GMX is another acceptable option. Note that these are all true 5.56 mm loads that require a real milspec 5.56 mm chamber, not a SAAMI .223 chamber--be sure to check with an appropriate gauge or reamer. Most other acceptable LE barrier blind loadings are at .223 pressures, including the .223 55 & 62 gr Federal bonded JSP Tactical loads (LE223T1 & LE223T3), along with loads using Nosler 60 gr Partition JSP, Remington 62 gr Core-Lokt Ultra Bonded JSP (PRC223R4), .223 Federal 55 gr TSX (T223S), .223 Horn 55 gr GMX, and the .223 Speer 62/64 gr Gold Dot JSP's (and identically constructed Federal 62 gr Fusion JSP and Federal XM223SP1 62gr Bonded JSP). The Speer 75 gr Gold Dot JSP and Swift 75 gr Scirocco bonded PT are also good choices, but usually require a 1/7 twist. Note that the Barnes all copper TSX bullets are great projectiles and offer good penetration through barriers, however, when first hitting a laminated automobile windshield intermediate barrier, most TSX bullets exhibit less expansion than bonded JSP’s, as the Barnes jacket either collapses at the nose, the jacket "petals" fold back against the core, or the "petals" are torn off; this results in a caliber size projectile configured a lot like a full wadcutter, leading to deep penetration. If running 1/12 twist barrels, stick with the BH 50 gr TSX, Fed 55 gr TBBC, Fed 55 gr TSX, Horn 55 gr GMX, or Speer 55 gr Gold Dot. NONE of the fragmenting 5.56 mm OTM bullets, even the heavy 75 - 100 gr loads, offer acceptable performance through automobile windshield glass. Contrary to what many believe, M193 & M855 FMJ are not very good against glass; the best military 5.56 mm load against glass is 52 gr M995 AP, followed by the 62 gr Mk318 Mod0 OTM and 70 gr Optimal "brown tip" OTM.

In those situations where intermediate barrier penetration is not a critical requirement, for example LE urban entries or long range shots in open conditions, then OTM, JHP, and standard JSP loads can offer acceptable performance. For 1/7 twist barrels, the Hornady 75 gr OTM, Nosler 77 gr OTM, and Sierra 77 gr SMK OTM are all good choices. The experimental BH loaded 100 gr OTM exhibits impressive fragmentation, even at relatively low velocities, however while capable of shooting out to 600, it is optimized for 200 and under. If stuck with 1/9 twist barrels, the heavy 70+ gr loads are not universally accurate in all rifles and the 69 gr SMK OTM, the 68 gr Hornady OTM, the Winchester 64 gr JSP (RA223R2), the Federal 64 gr TRU (T223L) JSP, Hornady 60 gr JSP, are likely to run accurately in the majority of 1/9 twist rifles. Again it is critical to keep in mind that the above loads fail to offer adequate penetration through intermediate barriers.

For longer range engagements using precision weapons like the Mk12 SPR or DMR rifles with faster 1/8 or 1/7 twist barrels, one of the combat proven 5.56 mm (ie. 5.56 mm NATO pressure loads, not .223 SAAMI pressure loads which run about 200 f/s slower) heavy OTM loadings are a good choice: the Barnes 70 gr TSX (Optimized "browntip"), Hornady 75 gr TAP (#8126N), Nosler 77 gr, or the Sierra 77 gr Match King (Mk262 Mod1) and 77 gr Tipped Match King.

Short barreled 5.56 mm weapons, such as the Colt Commando, Mk18 CQBR, HK416, HK53, HK G36C, etc… offer advantages in confined spaces. With SBR’s it is best to stick with the barrier blind loads recommended above, although the heavy OTM's suggested for long distance shooting will also work. SBR's can run into rotational velocity issues with some loads, so it is generally best to select faster 1/7 twist barrels whenever possible. Remember, with SBR’s, effective engagement distances are significantly reduced compared to the longer barreled carbines.

Keep in mind, that with non-fragmenting bullet designs, heavier bullet weights are not necessarily better, especially at closer ranges and from shorter barrels. As long as penetration and upset remain adequate, it is possible to use lighter weight non-fragmenting bullets and still have outstanding terminal performance. With fragmenting designs, a heavier bullet is ideal, as it provides more potential fragments and still allows the central core to have enough mass for adequate penetration. In addition, heavier bullets may have an advantage at longer ranges due to better BC and less wind drift.

Whatever projectile is used, it is best with a cannelure to prevent bullet set-back in semi-auto/auto weapons. Also, be cautious with the exposed lead on some JSP designs. Often they will run great for up to 200-300 rounds, but then mysterious feeding failures will begin as a result of lead build-up on the feed ramps. I have personally seen this occur with a variety of JSP's including 55 gr, 60 gr, and 64 gr in LE training courses. As soon as FMJ or OTM was substituted, all the feeding failures ceased.

Be sure to watch your ammo storage conditions. Temperatures above 150 deg F will degrade the powder and cause pressure spikes. Hint: Think locked metal conex containers in the mid-east, car trunks in the southern U.S., and storage areas near heaters in the northern U.S. Also be cautions of leaving a round in a very hot chamber; besides the obvious danger of a cook-off, the powder can also be damaged by the heat, leading to dramatically increased pressures when the round is eventually fired.

A large SWAT team in this area had a failure to fire from an M4 with Hornady TAP ammo during an entry--fortunately no officers were hurt and the suspect immediately threw down his weapon when the carbine went click instead of bang. After the incident was concluded, the team went to the range and expended the rest of their carbine ammo and had one additional failure to fire. This same team had 3 Hornady TAP rounds fail to fire in training a couple of years ago. When Pat Rogers was teaching a class at a nearby agency, there were 5 failures to fire using Hornady TAP ammo. In all 10 cases, there appeared to be good primer strikes, but no rounds fired. On analysis, the ammunition had powder and checked out otherwise.



However, despite what appeared to be good primer strikes, two problems were discovered. First, when accurately measured, some of the primer strikes had insufficient firing pin indentations. The failed round from the potential OIS incident had a primer strike of only .013"—the minimum firing pin indent for ignition is .017". In addition, the primers on the other rounds were discovered to have been damaged from repeated chambering. When the same cartridge is repeatedly chambered in the AR15, the floating firing pin lightly taps the primer; with repeated taps, the primer compound gets crushed, resulting in inadequate ignition characteristics--despite what appears to be a normal firing pin impression. Once a round has been chambered, DO NOT RE-CHAMBER IT for duty use. Do NOT re-chamber it again, except for training. This is CRITICAL!!!

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Many LE agencies around here used the Hornady 75 gr TAP OTM, Winchester 64 gr JSP (it was on the state contract for very low cost), and similar Fed 64 gr JSP TRU load (223L)--all have worked well in actual officer involved shootings against unobstructed targets. However in the wake of the serious terminal performance failures by non-bonded .223 64 gr JSP's due to inadequate penetration into the criminal's Toyota Tundra truck in the July 2010 CHP OIS incident in Oakland, quite a few agencies here switched to general issue of Barrier Blind loads like the 55 & 64 gr Gold Dot loads, along with the 55 & 62 gr TBBC loads that previously saw more limited use.

Do short barrel 5.56 mm carbines have some limitations? Yes, especially beyond 100 yards, but BFD…learn what they are, train, and drive on. Despite the ballistic compromise, for LE urban work with lots of entries, the 10.5-12.5” BCM, Colt, Centurian, LaRue, LMT Mk18/Commando style weapons w/Aimpoint RDS's are the best weapon types for this mission. For GP LE Patrol use, properly built AR15's like the 14.5-16” BCM, Colt, LMT, LaRue, Centurian carbines with Aimpoint RDS's and 3x magnifiers in quick detach flip mounts like the LaRue LT649 are superb choices (quality variable optics like a S&B 1.1-4x Short Dot, NF 1.1-4x, or Trijicon 1-4x are also good options) -- pick the right tool for the job.

Interesting. I've never shot UHMWPE with anything so I can't debate that point. Unusual to find a medium that has such a penetration spread between the two projectiles.

This has been a sore point in the armor business, as unscrupulous salespersons have been known to tout how their Level III pure UHMWPE plates can take hit after hit of M80 and M193, while being very lightweight and positively buoyant (or at least neutral) in water, while neglecting to mention that M855 can easily defeat their plate.

[markm]

I too would like to go all Bonded bullet. But it just is not what we shoot every weekend for longer range stuff, and point of impact can be dramatically different.