[Originally written 01-10-2010]
Some overlooked advantages of the Mid-Lenght gas system carbine over the carbine-length gas system AR15 for Law Enforcement Officers.
An explination of the mid-length and carbine gas systems can be found in this article: Carbine vs. Mid-Length Gas System on a 16" Barrel
-Mid-Length has a longer iron sight radius, which aids in accuracy. If you have ever shot a 20" AR15 rifle with iron sights and a 16" carbine with iron sights side by side at distance you will notice that it's easier to get more accurate hits with the 20" rifle. This may not and advantage for all LEO's, but there are still many departments out there that don"t allow optics for their patrol rifles.
-Mid-Length has a slightly smoother recoil impulse ( Carbine vs. Mid-Length Gas System on a 16" Barrel )
-The Mid-Length handguard is longer and some taller shooters will find more comfortable. Shooters who use a compention style grip will find more comfortalbe (many competition shooters hold further out on the fore end, and some use techniques like pointing their index finger in the same direction as the muzzle). Many tall shooter or shooters who use a competition type grip find the that Carbine-Length handguards are too short. Here is an example of the grip that I use:
Many guys are starting to figure out what 3 gunners and competition shooters have known for a long time. The further you can get your hand out on the fore end the easier it is to "drive" the gun. The mid-length helps you get your hand further out on the fore end.
-The longer handguard on the Mid-Length aids in resting the barricade on a piece of cover. This is often overlooked by many LEO's.
Many times in a law enforcement setting when a carbine is deployed the Patrol Officer will take up a position of cover on a perimeter or while covering a person or location (ie. barricaded gunman call, drawn out felony stop, alarm call and suspects are still inside the buisness or residence, etc)
While taking up a position of cover we often rest our carbine on a piece of cover (vehicle, fence, concrete wall, tree, post, etc.). The piece of cover often times can serve a dual purpose and can be used as a stable shooting platform.
Think about the shapes of vehicles and other objects you might use as cover as you look at the pic below. If you had a Carbine-Length handguard, would you be able to get your barrel on the piece of cover?
This shows how a Mid-Leght handguard and a 20 round magazine can be an asset in certain situations (the shooter is using a 10.0" rail, but if he wasn't running a Magpul Ranger plate on his 20 round magazine, he could have easily gotten a 9.0 rail onto the barricade in this situation):
Even if it's a brick wall, note how much easier it is to get the Mid-Length handguard on the piece of cover:
As you can see a 2" longer handguard / gas system of the Mid-Length has a lot of advantages over the shorter Carbine-Length gas system. A couple weight comparisons:
LMT 14.5" M4 carbine:
8 lbs 6.0 oz - with light, batteries, VCAS padded sling:
BCM 16" standard Mid-Length w/ Larue 9.0 and Magpul CTR stock:
8 lbs 4.2 oz - with light (Surefire x300 in LaRue mount on the 3 o'clock rail), batteries, VCAS padded sling:
Another resource with a lot of pictures and information about mid-length carbines can be found in the link below:
BCM Complete AR15 Upper and Lower Receivers
