SBR .308 + 155 A-Max??

[hitman1012]

I have a 14" .308 Noveske AR-10 and was wondering how effective the wound ballistics are with the 155 A-Max's. I have seen the Hornady web site where they test the 155's and 168's but the shortest barrel they do it with is an 18" barrel. Anyway, was curious what the difference would be wound ballistics wise, between a 14" 6.8 SPC and a 14" .308 - using 110 A-Max for the 6.8 and 155 A-Max for the .308. Any info is appreciated. I have not seen any testing using shorter barreled .308's
Thanks

[Spooky130]

I'd be interested to see the changes in effectiveness as the barrel gets shorter on a 7.62N gun. This is addressed many times in 5.56 guns but you don't see as many short 7.62 guns.

The reason I am interested is the future release of the LMT MWS (7.62 version of the MRP). I wonder if they will offer different lengths and how those will effect the 7.62 performance.

Doc - do you have any data on this?

Spooky

[tkoglman]

I have an HK-51 clone (8.3" barrel) and I've done some crude ballastics testing with it.

With standard 7.62 NATO FMJ it will penetrate 1/2" mild steel at 50yds. That's the only range I tested that at. It will also penetrate soft body armor at that range.

I built water tanks out of 40 gallon plastic containers laid end to end and fired various rounds into them. Not quite proper ballistic gelatin, but at least a consistent medium.

.45ACP and 9mm classic Hyrda-Shok would penetrate through 6 feet! of water and bounce off the back wall of the container.

55gr 5.56mm M198 would penetrate on average 22" of water. The bullets would usually split at the cannalluer(sp?).

110gr. .308 Hornady TAP burst the plastic containers (it sure looked cool). The bullets completely fragmented and penetrated about 20" of water.

Now, I know that my "tests" were not really all that scientific, and I know that a lot of things factor into terminal ballistic performance that I was unable to observe or record. BUT - The way those containers of water simply exploded when hit with the .308 was very impressive. I mean, the pistol caliber rounds barely rippled the water, the 5.56 threw up little spurts of water, but the .308 literally exploded the 40gal tanks.

The 110gr. TAP was also amazingly accurate out of the short barrel. With only the iron HK sights (using the MP5 diopter rear) I'm able to shoot about 3moa out to 100m. Very good from such a short barrel, short sight radius, and iron sights. The 110gr round is also very fast so there is little bullet drop over any practical ranges.

BTW muzzle flash is not bad at all with the LE loads due to the flash suppressant powder. The NATO ammo is a different story.

[vicious_cb]

On a side note, how well does the 155gr AMAX perform against intermediate barriers? Does it meet the 12" FBI penetration standard after auto glass?

Also I was wondering what the fragmentation velocity thresholds were.