Thanks to all of those who recently posted info on different brands of ammo.  After reviewing many of the posts, and thinking of my own experience with the AR-15 (10+ years, several rifles, and many kinds of ammo), I was left wondering exactly HOW reliable your 5.56 mm semi-auto should be.

In particular, perhaps some of you who have served in the infantry/Spec Ops/etc. could could comment.  I.e., using a mil-spec M16, with military ammo, properly cleaned & maintained, and a properly trained soldier/individual, how often will the rifle fail to fire, on average?

One reason I ask is that many of the ammo threads say something like "1 failure to extract in 500 rds." or, worse, "failed to cycle once in 100 rds.".  Contemplating any type of SHTF scenario (or just plain self-defense), I'm not sure I like those odds, if I can do better.  Any comments?  .........Thanks.

I think a regularly cleaned and maintained AR should go "BANG" every time you pull the trigger.  I have only had two "non-fire situations".  One was with the crappy 10 round mag that came with my gun.  The other was because I shot some ammo that a friend gave me.  This crap looked about 20 years old, cases not shiney, and generally was crap.  Well, crap in, crap out.  It was then and there that I decided: only USGI mags and XM193 spec ammo for me.  Never had a problem then.  

Ghost

Never had a problem with Q3131A.  I'm still new to the AR thing though and have only gone through about 2000 rounds.

Another way of asking the question is "What is the MTBF of the mature M16/AR15 weapon system?".  I'm sure that this topic has made the rounds on this board, just can't find it.

I did see one Web site that claimed the M4 had an MTBF of only 200 rds.!  This seems a little low to me, but lack more thorough data.

My goal with all this is simply to find a "Gold Standard" ammo that my rifles work well with, then evaluate every other ammo against this performance (Wolf, surplus, whatever).

As far as ammo goes, there are only three producers of 5.56 ammo I would be willing to bet the farm on.  LC M193, XM193 and IMI M193 (Yes I know Win Q3131A is the same thing as IMI M193, so I guess maybe that makes 4).

An AR15-M16 should fire every time you pull the trigger.  Products from most major reputable companies meet that standard if you do your part to keep the weapon clean and well maintained.  That being said, in 1967-68 I spent a lovely 1 year, 2 days, 4 hours, 47 minutes in that tropical paradise known as Viet Nam.  I never picked up my M16 without having a length of cleaning rod taped to it. Yes reliability has improved greatly and I do own a Pre-Ban AR15, but now days my favorite is a Robinson's Armament M-96 Recon Carbine. It eats everything it's fed, everytime without fail.

Failure to fire more than ONCE every 4000-5000 rounds should not be tolerated if you are using quality ammo in a quality rifle. I would not bet my life an anything of lesser realiability.

Here's some info. Hope it formats ok.

Excerpted from MIL-C-71186(AR) 3.4.7:

Endurance. Carbines shall be capable of withstanding the firing of 6,000 rounds for endurance with not more than the number of malfunctions and unserviceable parts allowed for both single carbine and four carbines combined as allowed in TABLE I. The cyclic rate of fire of not more than one reading on a single carbine or not more than two readings on four carbines combined, shall fall outside of 700 to 1025 rounds per minute. Ammunition used shall be Government standard M855, 5.56mm ball cartridges conforming to Drawing 9342868.

TABLE I. Malfunctions and unserviceable parts permitted in 6,000 rounds.
Malfunctions                             Single Carbine         Four Carbines

Failure of bolt to lock                          2                             4
Failure to fire                                       2                             4
Failure to feed (from magazine)          4                             9
Failure to eject                                     2                             4
Failure to chamber                               3                             7
Failure to extract                                  1                             2
Bolts fails/hold rear                              3                            8
All other malfunctions                         0                             0

Total – Above malfunctions combined 9                            22

Unserviceable Parts                      Minimum Life                    Four Carbines
                                                         Rounds                              Combined

Ejector spring                                   3,000                                       2
Extractor spring                                2,000                                       1
Other parts                                        3,000                                       1

Total unserviceable parts -                                                                -
(above unserviceable parts combined)                                              3