I have about 3 cases though my camo 26" stoeger M3000.  So far the gun as been near flawless, but I am having a problem now.
FYI 3 dram is considered standard power for those not familiar with SG loading.  Under that is powder puff loading.

The guns diet and difficulties in order
6 or 8 boxes of 3-3/4 dram high brass though dove season.....never again.. ouch.  I was badly bruised after 3 weekends of doves.
Polished the action, sanded the magazine tube, TTI hammer and trigger spring plus lightly stoned the trigger/hammer surface .
couple boxes of mixed 3 dram at doves, skeets, goofing off
dozen or so mini shells to see what the gun could do.  Of course none ran as expected.
7 boxes of Winchester 2-3/4 dram light target loads, ONE FAILURE TO EJECT.  This is generally regarded as bad ammo.  My pump 870 jammed 3 times in 1.5 boxes on this same stuff.  The rim is not good.  This was not a gun problem.
couple boxes of Federal 3 dram field loads
half dozen hot turkey loads
couple more boxes of mixed 2-3/4 dram light loads. ONE FAILURE.  Pulled the trigger, hammer clicked, but no boom.  Ejected shell had no dent in the primer.  I marked it up to the weak loads.

NOW THE TROUBLE LOAD.  Rio 2-3/4 dram.  The Winchester was hot enough to cycle.  RIO is NOT as hot as the equivalent Winchester or Remington light loads.  I fought through a couple boxes with 2 or 3 or more short stroke type failures per box.  Ran fine in my pump .  Some of the failures were similar to the problem I now have.  THE PROBLEM.  Pull the trigger and nothing happens.  The hammer must have rode the bolt down.  With the RIO's I had this problem and ejected 2 empty hulls, but two other times ejected live rounds.  Every other problem was obviously because the RIO's were too weak, so I marked ALL these failures up to the weak powder charge. Now I am not so sure

Borrowed some hand loaded 3-3/4 dram OR HIGHER dynamite loads from a guy to finish out a 3 gun match.  I had suffered through a jungle run with the RIO failing every other shot and he pitied me...or hated me.  His custom loads were like shooting Turkey loads.  30 bruises later the Stoeger ate all of it but one that was too bulged to fit in the chamber.

NOW THE TROUBLE.  
Switched to Federal 3 dram bulk for a fund raiser.  9 shots no problem for the 3 gun stage.  Went to the SPORTING CLAY, or 5 Stand, or whatever they call it.  Calls for 25 or 30 aerial clays from automated throwers.  It was way more fun than I thought it would be.  I had 4 or 5 FAILURES.  This is with the good Federal bulk ammo that should run no problem. In each case, the gun closed on a live round, but nothing happened when I pulled the trigger.  The hammer must be following the bolt down.  Ejected the empty and the next shell always fired.  Now I have not cleaned the gun in 6 or more boxes.  I will do that, but I am wondering if I should let this go a little longer so I can diagnose it (under the clock no doubt) or if I should just swap back to the factory hammer and trigger spring.  I would like to know whats going on, but if anyone has experienced this I'd love to hear your resolution.

I have/had a similar problem with my Girsan MC312 - a benelli clone - bolt cycles, pull trigger, hammer falls - nothing!  Pull back on cocking handle and live round ejects.  Release handle and new round feeds - pull trigger and shotgun goes bang.
Initially, I thought it was my mistake - possibly knocking the magazine cut off button with my trigger finger.  But that wouldn't account for the live round failing to detonate.
I stripped the bolt down and thoroughly cleaned and polished the firing pin and the firing pin channel.  My logic is that there may be a small burr on the channel or pin that once in a while prevents the firing pin from travelling its full distance when struck by the hammer.  This would account for the failure to fire and the absence of any marks on the back of the primer.
Unfortunately, I haven't had an opportunity to test fire the shotgun since working on the bolt so I can't tell you if this is the answer to the problem.
Good luck - would appreciate you updating progress on this

My first thought is the bolt is not all the way in battery.  Maybe bolt bounce or not chambering fully.

Clean and inspect your bolt, firing pin and barrel extension. Make sure the firing pin is moving freely and is able to extend past the bolt face when in the locked position. Run your bolt wet and lubricate the action bar, spring and mag tube. Once your gun is broken in (at least 500 rounds) you can cut back on bolt lube but untill then run it wet. Run 3 dram federal bulk. This is what worked for me. Or you could just send it to MOA Precision.

I swapped the factory springs back in for dove season.  7 boxes of 3 dram loads.  I had one round not fire.  I had just single loaded a shell into an empty gun and I think the charging handle hit my hand/fingers and stopped the bolt from closing all the way.  I also had 2 FTEjects.  I would say changing back to the factory springs fixed mine.  the FTE might mean I need the Benelli extractor.