77gr OTM or 62gr Bonded

[GLOCK10MM]

I am waiting on my Modern Materials SBF to come in. It is an AR w/ a 11.75 inch barrel & I am unsure w/ this shorter length what gr I should be looking towards for social purposes. My other AR's are 16inch on up. Does anyone have any thoughts or experience they can share on this?

[Diamondback]

I am waiting on my Modern Materials SBF to come in. It is an AR w/ a 11.75 inch barrel & I am unsure w/ this shorter length what gr I should be looking towards for social purposes. My other AR's are 16inch on up. Does anyone have any thoughts or experience they can share on this?

From Doc Roberts, over at that *cough*other*cough* site...
https://www.ar15.com/ammo/project/Se...mozTocId803443

Barrier Blind Loads

There has been a shift away from fragmenting ammunition and toward barrier-blind/bonded loads. Doctor Roberts' latest take on this: "For LE and other individuals not restricted by the Hague convention, because of their good terminal performance across a wide spectrum of potential engagement scenarios, the bonded barrier blind projectiles have moved ahead of the fragmenting OTM loads we previously recommended, as the best general purpose loads available."

Also: "If you are, then why are you concerned about properly engineered blind to barrier 5.56 mm loads, since ALL of the current effective barrier blind ammunition penetrates NO more than service caliber handgun ammunition in the event of a miss. For that matter, the recommended 7.62 x 51mm loads for 16" rifle use, like the Rem 150 gr Core Locked Ultra Bonded, penetrate the same depth as handgun rounds...

The better bonded loads like TBBC, are definitely MORE effective than the TSX style all copper bullets, as they expand better, retain more mass, and offer a larger surface area, especially through intermediate barriers.

The current generation of LE barrier blind loads like 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, are at 5.56 mm pressures using appropriate crimped & sealed primers, sealed case neck, same trajectory as M855 so it matches many common ACOG BDC's, etc... The new Black Hills 5.56 mm 50 gr TSX loading is another 5.56 mm offering which offers many of these same features--it matches closely with 5.56 mm 55 gr M193 practice ammo..."

To summarize: Fragmenting loads are still fine if you can anticipate unobstructed shots, but even a home owner may have to deal with barriers and could potentially benefit from barrier blind loads. Should you panic and throw out all your heavy OTM stuff? Not at all - you might simply want to keep the above paragraphs in mind.

If using a short-barreled weapon: The same guidelines apply as for barrier penetration loads. SBRs usually have insufficient velocity to achieve fragmentation velocity.

As per Doctor Roberts: "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."

If barrier penetration IS an important factor:

62gr Federal Trophy Bonded Bear Claw (TBBC) bonded JSP (XM556FBIT3)*
64gr Winchester solid base bonded JSP (Q3313/RA556B)*
50gr TSX loaded by Black Hills*
Speer 55 & 64gr Gold Dot JSP (5.56)*
Federal 62gr Mk318 Mod0 (T556TNB1)*
62gr Federal bonded JSP Tactical (LE223T3)
55gr Federal bonded JSP load (Tactical––LE223T1 or identical Premium Rifle––P223T2)
Swift 75gr Scirocco (usually requires 1:7 twist)
60gr Nosler Partition JSP
Remington 62gr bonded JSP
Federal 55gr TSX (T223S)
Speer 55 & 64gr Gold Dot JSP (.223)
Federal 62gr Fusion JSP (Same construction as the Gold Dot)
Loads marked with * are 5.56 loads and indicate preferred loadings.

[indianalex01]

From Doc Roberts, over at that *cough*other*cough* site...
https://www.ar15.com/ammo/project/Se...mozTocId803443

I agree all the way. For some reason some people think these 77gn Match loads are as good as some of the 62gn bonded loads. They aren’t.

[Diamondback]

I agree all the way. For some reason some people think these 77gn Match loads are as good as some of the 62gn bonded loads. They aren’t.

Main thing I can see Mk 262 shining for in a CQB platform is possibly as a vest-buster since more BG's are starting to armor up. Still trying to settle on one of these as a "stack it deep" standard load for my 10.3 myself... and find a suitable "ballistic twin" for training.

[Ironman8]

I agree all the way. For some reason some people think these 77gn Match loads are as good as some of the 62gn bonded loads. They aren’t.

And some people think these 77gr loads turn into pixie dust after the slightest barrier. They don’t.

[Ironman8]

Main thing I can see Mk 262 shining for in a CQB platform is possibly as a vest-buster since more BG's are starting to armor up. Still trying to settle on one of these as a "stack it deep" standard load for my 10.3 myself... and find a suitable "ballistic twin" for training.

After splitting hairs and chasing data on “the best” barrier blind load, I’ve decided that my “stack it deep” standardized load will be 77gr OTM. If you reload it’s even more realistic to work up a nice stash.

Ballistics tests only show one round through intact barriers. What happens on the 2nd, or 3rd, or 4th round through that same barrier? Personally, I want the best accuracy I can get and if I need to shoot multiple rounds to defeat a barrier, well I’ll be shooting multiple rounds anyway, so it’s a moot point to me. Unobstructed shots are a wash between the two. The BG won’t care what round you used when you put 2 or 3 center mass.

[indianalex01]

How does 223T3 differ from the FBI round? Is it the same projectile but SAAMI spec?

I find the velocities similar. When T3 556 came out there were accuracy issues. Now itÂ’s fine.

And some people think these 77gr loads turn into pixie dust after the slightest barrier. They donÂ’t.

IÂ’ve not heard that. 77gn MK gives you better range but less performance then a bonded load.

Has anyone done a head to head with 223T3 vs Fusion 62gr?

Yes I have. Fusion isnÂ’t as tough through barriers and does not penetrate as deep. It does open up a little better at lower velocities. They both are amazing though. I use both.

Main thing I can see Mk 262 shining for in a CQB platform is possibly as a vest-buster since more BG's are starting to armor up. Still trying to settle on one of these as a "stack it deep" standard load for my 10.3 myself... and find a suitable "ballistic twin" for training.

Where did you hear this from???? IÂ’ve never heard that MK262 is good at defeating armor. A new one and a little bit of Fake News.

[Wake27]

Where did you hear this from???? I’ve never heard that MK262 is good at defeating armor. A new one and a little bit of Fake News.

Yeah I’m not sure how that conclusion was reached. If 262 worked well against armor, I doubt we would’ve developed 855A1.


Sent from my iPhone using Tapatalk

[Diamondback]

Where did you hear this from???? I’ve never heard that MK262 is good at defeating armor. A new one and a little bit of Fake News.

Wish I remembered... now that I hear this, if I did I'd Burn the source. The ol' memory is sadly not what it used to be...

[scooter22]

After splitting hairs and chasing data on “the best” barrier blind load, I’ve decided that my “stack it deep” standardized load will be 77gr OTM. If you reload it’s even more realistic to work up a nice stash.

Ballistics tests only show one round through intact barriers. What happens on the 2nd, or 3rd, or 4th round through that same barrier? Personally, I want the best accuracy I can get and if I need to shoot multiple rounds to defeat a barrier, well I’ll be shooting multiple rounds anyway, so it’s a moot point to me. Unobstructed shots are a wash between the two. The BG won’t care what round you used when you put 2 or 3 center mass.

I guess that’s all fine and dandy when the target isn’t moving, and all rounds are touching where they impact the barrier...