It seems to me that have found in the M16 direct impingement uppers, that gas ring wear seems more associated with how fast rounds go through than the number of rounds shot. I had five different uppers with which I put the bulk of the 12,000 rounds I used in Beta Testing for the Tenko that I personally tested. I would run either four 30 round mags or a Beta-C, pull off that upper, and install another upper. By the time I got to the fifth one, the first one had cooled. All five still have their original gas rigs. Some were brand new at the start of testing. Others were used with several thousand rounds on them.
Vegas wanted to put most of his 10,000 rounds of testing through one upper. So I sent him a PSA with a CHF FN barrel with double chrome lining thickness with a chrome plated bolt group for ease of cleaning. Most of his testing days were, run a thousand rounds using 30 round mags straight ahead, clean the upper, and reload the mags. Then do itagain the next day or a couple of days later, if life got in the way. He partnered with a neighbor. The neighbor did most of the shooting, and Tom loaded mags, until the 1,000 round
case of ammo was gone.
Because Tom was going to put 1,000 rounds per day through one upper, I also installed a single peice gas ring. When brand new, the friction of the single peice gas ring would not hold up the weight of the carrier. The single peice gas ring still runs just fine even after those thousands of rounds of use. The five uppers I used, still run fine.. I used to use the weight of the carrier/friction of the gas rings as my test for gas ring replacement. Now I wait until the upper short strokes to change the rings. Of course, gas rings are cheap and I keep them in stock. I hope this helps those new to the direct impingement system.
Scott
