With normal maintainence and routine cleaning, (& just a touch of occasional abuse) how many rounds does the average AR 15 - 5.56/.223 digest before accuracy SIGNIFICANTLY degrades?

Here is couple of pics of my 14.5" 1/9" Bushmaster barrel. Lots of shooting, not so much of cleaning Actually this barrel has 10K through when pics were taken...

Shooting distance in all pics is 150m / 164 yds. Diameter of X ring in those target is 2" and 10 ring is 4".

10 shot group of 77gr SMK desperate cleaning session


10 shot group of 69gr SMK after cleaning.


10 shot group of 77gr SMK after cleaning.


Barrel throat / case neck area of chamber. Note chipped hard chrome plating.


Rifling in throat area.



Muzzle.


This barrel still shoots 2- 3 MOA groups to 150 meters without problem.

MN


ETA: question for bigbore, do you happen to know source for the throat erosion gauge? Barrel pictured above is wasted but I´d keep track on my other AR barrels, how soon throat erosion starts to exist.

Quoted: how many rounds does the average AR 15 - 5.56/.223 digest before accuracy SIGNIFICANTLY degrades?

87 rounds!

Research has proven this.

Gentlemen,  

Thank you for your responses, and special cedit to M4a2 and the wonderful pics worth more than several thousand words on the subject.  

I knew that 87 was achievable, just wondered how much further to push it!  

http://i50.photobucket.com/albums/f308/doubleup5150/AR15/qwerqwer.jpg

I had a 20" heavy barrel that was still shooting sub-MOA at 11,000 rounds, but after I checked it again at about 14,000 the bullets were tumbling into the target.  This barrel saw mostly full auto fire with quite a few Beta Mag dumps.

Quoted: Mine came from one of the vendors on Commercial Row at Camp Perry. I dont remember which?  The TE gauges are just a reference and gauge differrently for each barrel. You need to check your barrel when brand new. then mark it for reference later.

I´m aware of that and I´d like to start to check them. I´m waiting for the couple of new Bushmaster barrels.

MN