AR? Commando vs. M-4 pattern

[DonP]

OK, a little help here please.

I have a new Bushy lower coming in and I'm wrestling with the choices for an upper. I already have an A-2 style AR with a 20 inch barrel in the inventory.

I've found and M-4gery upper and a Commando upper for roughly the same price. Both are using DPMS components and are Mil-Spec chormed barrel and chamber.

Can't afford both so I have to make a choice this week.

Any opinions on one or the other?

Don P.

 

[ajacobs]

Between your two you listed I would go with the m4. The commando uppers have to have a long flash suppressor mounted on them to make the minimum 16 in. You might as well have more barrell.

 

[gun-fucious]

the 11.5 inch barrel is weak in the FPS department

As barrel length increases, the bullet is propelled faster by the expanding gasses in the barrel, imparting more velocity on the bullet, resulting in a longer range before a fired bullet drops below 2700 fps._ A shorter barrel imparts less velocity, and therefore the bullet has less range.

Temperature, altitude and humidity are other factors._ As temperature or altitude increases, air becomes less dense and bullets travel faster._ Contrary to common conceptions, as humidity increases air also becomes less dense and helps bullets retain velocity.

It is important, then, to keep in mind that any statistics given can only be approximate and can be affected by a wide range of factors._ But as a baseline, these numbers are what you could expect for 75° F, 25% humidity, at sea level, from various barrel lengths:

Distance to 2700 fps
M193

20" Barrel 190-200m

16" Barrel 140-150m

14.5" Barrel 95-100m

11.5" Barrel 40-45m

http://www.ammo-oracle.com/

 

[Redlg155]

I'd go for the M4 profile.

Unless you are shooting a handgun round the short length is going to work against you rather than for you. The ultra short AR barrels may also be a bit more prone to gas problems.

Good Shooting
Red

 

[capt_happypants]

The Commando upper would be great if you were willing to pay $200 for a tax stamp so that you could make it an SBR.

Otherwise, you get the full length of the 16" bbl, but are stuck with 11.5" muzzle velocities. Your max effective range with M193 is about 45 yards, less than 20 yards with '855.

Go for the M4 upper.

 

[Onslaught]

Ditto -

My bushmaster was originally a "Commando"... It was light weight and handy, but even at 100 yards, there was noticeable bullet drop. And the 62 grain stuff was minute of barn door accurate. I sold the upper and bought a 14.5" upper. Not an M4, but the same length. I'm much happier with it.

But I am considering the SBR route and a second upper, but probably a 10" pistol caliber upper.