In 2005 I bought an AR-B from Armalite. It was my first AR and I didn't know much about AR's. It has been a wonderful rifle. I have hunted with it, shot dear with it and run three-gun matches with it. However in the beginning the recoil was so nasty that I got a recoil reducing stock from fab defense. I put it in and everything worked fine, until recently that is. I now have cycling problems. My first attempt to fix it was to install a cryptic coatings bolt carrier group. There was no difference. I cleaned and lubricated it thoroughly of course and also took the gas tube apart and make sure that was okay and it was. Still no improvement. I took it to a gunsmith and he ran 40 rounds of 150 grain ammo through it with no problems. I told him I was shooting 180 grain and he said that might be the problem but it's always shot 180 gr well before. So I started to look into other things and I started with the buffer tube and buffer weight. I found I had an H buffer and a spring that looked like it was in good shape but it has only 33 coils and is 13 5/8 in long. This doesn't seem like any kind of a standard spring that I have read about. At this point I am confused as that spring doesn't seem to match any spring I know about. I don't remember much about what I did when I put in the fab defense stock but I think the spring and the buffer tube are the original Armalite buffer weight and spring. At this point I am lost as to what could be causing this problem to occur after working so well for so long. Any advice/help would be appreciated.

Rangeman7130