I hear from a friend in Europe that the European SF soldiers are reporting poor terminal performance in hostage rescue missions (African pirate locations) with 10.5 inch M4s. So I wish to ask:
Are U.S. forces using 10.5 inch 5.56s also experiencing poor terminal performance?
Is there a solution to the performance problem? Or in other words, which 5.56 ammo would be a good choice for a 10.5 in. barrel?
Many thanks!
Yes, everyone knows that the fragmentation range is very limited (usually under 80yds depending on the load). So if they are trying to kill bad people past that, they are of course going to run into a problem. If they are using something like an M855 round, they are going to have an even greater problem.
SF units/SEAL’s use the MK18 and HK416.
Ammo selection can be anything from the M855, MK262 to the Barnes Bullets. I have heard various reports that the MK262 and Barnes loaded ammo is working well. So the solution is to use heavy grain ammo AND understand the range capability of the 10.5" barrel.
I believe one of the Staff guys on here had a kill well over 100yds with an M855 round in the sandbox. Shot placement is everything. 
C4
A big issue is that european ammo in general does not provide the same terminal performance as US ammo, and nowhere close to Mk262.
Another issue is that, frankly, most “European SF” are not on par with US/Canadian/UK/Aussie SF.
And yes, sub-optimal performance with 10.5 guns is well documented, thus the widespread use of alternate ammunition.
IIRC, it was KevinB, and it was >400 yards.
This has been well-documented this since Black Hawk Down. Variety of factors, but proper ammo helps a lot.
Fighting on ships presents an assortment of engagement ranges. It is not like taking down a crack house in LA. A shorty would not be my first choice in 5.56 for a super tanker.
For those of us with no VBSS training or experience, what WOULD you choose, given your druthers?
FN 308 minimum.
AR platforn with a 300 Short mag or 300 Whisper.
D Williams
And in your experience with taking down ships or GOPLATs, an AR10 in a short magnum is a reliable piece?
When I was on a USCG boarding team we used M16A2’s and 14" Remington 870’s. Inside the ship a 14" was handy. Outside (depending on size) the M16A2 worked just fine. I would say that a standard 14.5" M4 with the appropriate ammo would be the better compromise.
Just blue-skying for a minute, if you could have ANY small arm/s you wanted for that application, what would it be?
Back in the 90’s, the MP5 was the primary VBSS weapon used by the SEAL Teams. The M4 was sometimes used depending on the situation. A VBSS team may have mostly MP5s with a few guys using M4s and breachers using 870s.
Now, I believe you would see Mk18s with a few M4s and shotguns.
For me, I would probably be fine with an M4. I think the 10.5s are kinda getting to short. Like Iraq Ninja stated, some ships are freakin’ huge and a 100+ yard shot is something you may need to take.
Even inside of these ships, there are hallways that can stretch more than half the length of the boat.
I’ve done VBSS on some big ships carrying connex boxes stacked 3 high on the deck. We’d fast rope down than have to use the fast rope or a rappel line to get down off the connex boxes. Having guys with M4s holding security was a must. We would have helo snipers on either side providing overwatch as well.
I think I would like something like the HK417 or SCAR-H with a 14.5 barrel, an ACOG or Elcan 1x4.
Let’s keep it on topic.
I think a lot of European nations frown on any ammo that hints at being a hollowpoint in any way, shape or form, which eliminates much of the more effective 5.56mm ammo.
So I am wondering if 55 grain ballistic tips or 62 grain Gold Dot would make a substantial improvement in terminal performance in a 10.5 barrel for under 50 yard shooting, or would those bullets just go through like solids too.
There is actually a thread that discusses optimal 5.56 mm SBR loads: https://www.m4carbine.net/showthread.php?t=19881.
Thank you. I am thinking 55 Gold dots for the added velocity.
While the 55 gr Fed Tac load actually works better in SBR’s than the 62 gr Fed Tac load, conversely the 64 gr Gold Dot is superior to the 55 gr load in SBR’s…
Weird. But I am also confused by the idea that travelling at the sped of light gives on infinite mass, something I have not achieved at any of the buffets in Las Vegas. 
Seriously, thank you for the guidance.