Just picked up my first AR!

[9mm]

Used from a local shop, a Colt Match Target Lightweight 16" A2.

I'm curious about the proof marks on the bbl and upper receiver. They should say C MB or C MP with a small circle enclosing a crosshair correct?

I'll post pics after I buy some mags and ammo.

["DoubleAction"]

9mm; The Barrel Markings on my Match Target HBAR II Reads :
C MP 5.56 NATO 1/9 HBAR.
Different models will probably have different proof markings.
Don't forget to get you some stripper clips and a couple of loaders.Congradulations ;D

[Mountaineer]

9mm, Congradulations on your first AR15 purchase ;D I got my first AR15 back in March and I really like it, even though I've only had it out one time. Mine is an Armalite/Eagle Arms M15A2 with a 20" heavy barrel. I have a handle mount and a 4x12x42 scope on it now, but haven't been able to try it out yet. Enjoy!!

[9mm]

Hi MT,

What kind of mount did you get for your A2?

I'm realizing that for paper targets a scope is necessary. Most ranges don't allow strung up cans/spinners etc. Sucks. I'm really good at blasting beer cans. ;D

I'm willing to spend ~$600+ for a good set of mounts and a sight.

Also, can anyone educumacate me on the benefits and drawbacks on a 1:7 barrel vs. a 1:9 barrel. My colt has the 1:7 twist.

["DoubleAction"]

9mm; The M-16 from my military duration, had a 1 in 12 inch twist. With my 1 in 9, I have to limit the bore to lighter bullets, as opposed to the 1 in 12, because the tighter twist rate contributes to more friction in the rifling of the bore. This is probably why these barrels get so hot, so fast, which is another reason why I like the free floating forend. The tighter twist rate also contributes to bullet stability, which probably gives reasoning to the 3 shot burst of the 1 in 9 Nato with the fully adjustable rear ( accuracy verses rate of fire ) as opposed to the full auto M-16's with the fixed elevation rear, and the 1 in 12 twist. Tapco sells a see through scope mount for the carry handle for around twenty dollars, or less.

[9mm]

Thanks, I'll try CDNN on Tuesday for a mount.

[Mountaineer]

9mm, I bought my mount and scope from CDNN. The mount that I bought was a see thru mount, and was priced at $9.99. I also bought one of their Target Sports 4x12x42 scopes which are made in the Tasco plant. BTW, the mount that I bought has rings built into the mount and will work with 1" or 30mm scopes.
P.S. I don't know how good I am at shooting beer cans, but in my younger days I was really good at emptying beer cans

[Arclightstrike]

Hey 9mm, regarding the difference between the different twist rates in AR rifling: Originally Colt had started to build all A2s with 1:7 rifling, based on the fact that heavier rounds planned for use in this weapon (such as some early tracer, M-855 ball ["ss-109"], and a few experimental others that never made it into production) are better stabilized with a faster twist. The 1:7 barrels were, to the best of my knowledge, all of the hard-chromed bore and chamber variety, to help keep wear down and to aid in proper functioning (fewer jams or other stoppages). These barrels could accurately propel projectiles of .224 diameter up to 80 grains in weight (a "plain vanilla" 5.56x54mm M-193 Ball projectile weighs 55 grains).

It was later determined that for the ammunition types in actual use by the military (including all modern tracer and M-855 Ball), a 1:9 twist would provide adequate stability for all of them, and the 1:7 barrels are rarely seen on any new AR style rifles, being somewhat more expensive to produce. If I remember correctly, the original M-16s as seen in Nam were of the 1:12 variety, which was adequate for stabilizing M-193 Ball which was pretty much the only ammo used at that time.