shaneshot

First off, I'm brand new to AR's period. Never had one til recently. I read about the 556's accuracy and accuracy in general with an AR. However with the platform itself and shorter barrel it would seem not to really be a tack driver. Not that it was designed to be, don't get me wrong, just wondering what one could reasonably expect with accuracy as related to an AR, say 100 yards.

TMB

I don't know much about ARs I've shot them but never owned one. I do know that barrel length affects velocity but short barrel should be just as if not more accurate.

HappilyAddicted

Take away external factors like wind and with the right scope, you can easily shoot 1 inch groups at 100 yards with an AR Carbine (bench rest).

Brewster

This^^^^

Twist rate and bullet weight can have an effect as well.

shaneshot

Hitting m.o.a. would be a bonus with this. From what I understand the 1:9 twist rate on the 556 is better to stabilize the smaller grain, and will have some drop off in accuracy of the heavier grain, correct? Also from reading, shoot brass and try to avoid steel casings?

Do have a scope mounted (only 4x) on this but have just installed it, not even sighted in yet. All shooting to date has been open sight, not exactly conducive to accuracy at that distance.

Rivers2k

People at guns shops like to say effective rage of the ar-15 is 200 yards but consider this the marine corps shoots its last stage of fire at rifle qual with the m-16 at 500 yards.

M-16 is the military equivilant of the ar-15. I personally shot between 8/10 and 10/10 with iron sights at the 500 yard. Imagine what the effective range is with a scope! Targets are man size silhouette. Accuracy is as good as its shooter. I would draw your attention to the comment under 500 yards "gravy points".


USMC Known Distance Course of Fire

STAGE ONE:
Distance Time Rounds Type of Fire Position
200 Yards 20 Min 5 Slow Fire Sitting
5 Slow Fire Kneeling
5 Slow Fire Standing
Notes: During this stage of fire, the Marines are only allowed to load 5 rounds at a time before making a complete safe weapon and changing positions. The total time is 20 minutes for all 15 rounds.
A sling is allowed for all positions except for standing. During the standing position the shooter may either have a tight parade sling, or take it off the weapon.

STAGE TWO:
Distance Time Rounds Type of Fire Position
200 Yards 70 Sec 5/5 Rapid Standing to kneeling
Notes: 5/5= a tactical reload. The Marine is only allowed to load 5 rounds in each magazine. Therefore, the Marine has to reload for the second magazine. Makes for some interesting groups if your not careful to get that natural point of aim back.
A rapid fire means just that; Firing rapidly. (You only have 70 second to get them all out!)
STAGE THREE:
Distance Time Rounds Type of Fire Position
300 yards 5 Min 5 Slow Kneeling

STAGE FOUR:
Distance Time Rounds Type of Fire Position
300 Yards 70 Sec 5/5 Rapid Standing to kneeling
The position change from standing to kneeling is one of the better parts of the range. It really tests the Marines ability to adjust their firing position quickly, just like they might in combat. Drop to the ground and fire.

STAGE FIVE:
Distance Time Rounds Type of Fire Position
500 Yards 10 Min 10 Slow Prone
This yard line is often referred to as "gravy points" because the you really get to take your time here.

Brewster

Awesome information. Thanks for posting!

Rivers2k

Not a problem. The known distance course of fire was actually a lot of fun. It was my favorite part of basic training. Mostly because the shooting but also because the DI's didn't mess with us so much that week LOL.

Brewster

What was the barrel length(s) you all were using?

Brewster

What I've read if the twist rate is too tight for a bullet the bullet will break apart coming out the barrel. As far as accuracy I don't know. One of the seasoned shooters here will chime in I'm sure.

shaneshot

Not sure what you mean by "break apart". From my understanding, the twist rate varies to what is best by grain due to stabilization factors. If it is too far off it can create a tumble which destroys accuracy (but can be more deadly to soft tissue). Am I off or is there something (else) I don't know about?

brimic

Good info.
I have a very large and expensive book on all of the major and minor details needed to progress in NRA Highpower Rifle, in it I remember the author stating that the training he got in the Marine Corps gave him a pretty good skill base for this sport. He went on to mention that the skill level needed to be an Expert rifleman in the Marine Corps is about on par with the lowest qualification in Highpower Rifle (Marksman).
The 10 ring is scaled for distance is is approximately 3MOA across. Many courses used scaled down targets for use at 100 or 200 yards, while National Match courses are shot at 200,300,and 600 yards.

I've pulled targets for a local High Master shooter and witnessed him put 20consecutive shots into a 1MOA X-ring from 200 yards from prone using nothing more than a NM model AR-15 and handloads. In the right hands, they are plenty accurte enough to do the same at 600 yards, though there is probably a small handful of people in the world up to that task.

krwada

With the right:
1. AR platform
2. Shooter
3. Handloads

It should not be very difficult to get 0.5 MOA out to 300 yards.

TMB

Some varmit bullet were designed to be shot in slower twists if twist is to fast you have to slow down bullet or they can fly apart in flight is what he's talking about I think? Would be handloader thing I would think factory ammo would probably state not suitable for what ever twist but I don't know if they do.

bwinters

With iron sights I can hold 6 inches off hand at 200 yards wiht most ars. If the gun is scoped take 2 iches off that. this is with a colt or bushmaster newer gun.