Reliability issues about the AR-15 and AK-47 seem to concern many. My take is that any successful, long-serving issue service rifle will be very, but not perfectly, reliable.
Here’s a report from a range offering rental services of fully automatic firearms that shoots approximately 400,000 rounds each month and their experience with extremely high round counts.
Some of our M4’s have well over 200,000 rounds down range. Barrels have been replaced, gas tubes have been replaced, BCG’s have been replaced but what sets it apart from the AK47’s is that upper and lower receivers continue to function. AK’s get to about the 100,000+ round count and rails on the receiver will start to crack. It’s an easy fix with tig welding but they crack. We have yet to lose an upper or lower AR-15 receiver from cracking
We no longer use ANY piston conversions or factory pistons guns with the exception of the HK-416 “knock-off” TDI upper. I purchased a FACTORY brand-new MR556 and it started keyholing after only 10,000 rounds. The only piston system to last on the range so far is the HK416 and TD415 system. Every other systems we have tried has failed in one way or another.
– USGI mags have outlasted all of the other brands. We use UGSI (Brownell’s with tan follower) and on a mag for mag basis, they have outlasted Pmags and a few of the other mags that we get from mfg’s with new weapons. We don’t have to worry about various generations with different weapons like the MR556, SCAR, F2000, Tavor or a couple of others that use AR15/M4 magazines.
Every single stamped AK receiver has suffered from a cracked trunion. This includes Saiga, Arsenal (Bulgarian), Norinco (Chinese), Arsenal (Russian stamped), WASR, Hungarian, Polish (vintage kits), Yugo (vintage and PAP-series) and new Polish (from Royal Tiger imports).
– We have every type of AK available to shoot except for Cuban, Vietnamese or North Korean.
– US (Century), Bulgarian and Chinese milled receivers have yet to fail.
– Stamped receivers split at the angle of the upper rail and the side wall. N-PAP’s have literally cracked in half perpendicular to the length of the rifle. The receivers cracked just posterior of the front trunion (between center bushing and the trunion).
This may sound crazy but it’s fair to say that they finally suffer a catastrophic failure (cracked trunion) at 80,000-100,000 rounds. Also, we have WASR’s that have suffered a catastrophic failure and we just pull out the old trunion and barrel, grab one from a parts kit, re-rivet, re-barrel and get them up and running.
– The AK is the most reliable but after seeing how many have broken over the last two and half years on the range, it’s not the indestructible weapon everybody talks about (and I always thought it was).