T----My benelli jammed alot last year,got so pissed I went back to my 25 year old 870. I don't have thousands of rounds through my benelli maybe 1500 in ten years, cause i don't use it that much, What was happenning to me was it would not cycle on a straight over head shot and cheaper 3" shells, I believe the enertia system was getting weak and spring was not strong enough to slam the bolt back forward. I was using estate shells at the time that I know don't have quite the powder as some of the more expensive shells, but I didn't figure to have to shoot the expensive stuff all the time..Wolf springs manufactures a replacement that is supposed to be 10-15 % stronger, for like 15 bucks shipped. I looked into the same system that you bought but could not swallow paying $175 bucks to fix a $1000 shotgun, when I could buy and perfectly functional 870 at a pawn shop for the price of the fix alone. Long story short I took a piece of a.410 shell and put it in the bottom of the recoil cylinder, effectivly "shortening" the spring by about an inch and a half. It cycled all year this year when I used it, which was not very often, but i am a little worried that it might not shoot low base 2 3/4 anymore,we will see..... anyway good luck.
P.S If you want to part with a couple dozen of those G&H let me know
c.j.