Dustysa4

It seems that you would need to close the loop to me. Closing the loop will make the striker released later, allowing the striker block more time to disengage. You will have more pre-travel, and less over-travel doing this.

Final update for future searchers with the same issue... I called up Mossberg and ordered a pair of their 10-shot JM Pro mag springs. The CS person on the phone indicated that the different models of 930's had different springs, but the shipping invoice I received says SPX, so...??? I installed the spring and now it hand cycles like it should. The spring required no trimming, has a lot of excess past the tube, and is finished nicely at both ends. At $3.50 each, might as well buy a few since it is a wear item.

I found it at McBrides, here in Austin. It appeared to have been used very little. Lately, Joe McBride has had better deals on used stuff than TGT. The GT Dist here in town usually has some police trades for reasonable prices. Last time I was in there they still had a few Atlanta PD M&P's. Might check them out...

LikeToShoot: It only has about 250 rounds through it. The good news is that I was able to compare side-by-side with a Rhythm that functions as it should. Simply swapping the +9 tube and un-trimmed spring on to my 930 made it function properly. I went ahead and pulled them completely apart and everything seems to be identical otherwise, less the blue furniture. I was surprised to see that the shell stops were identical (Mossberg says the Signature Series has an over-sized bolt drop button). The un-trimmed Rhythm spring on the left, my factory 4+1 spring in center, and the Nordic spring on the right. Also note they are arranged from higher gauge (left) to lower gauge (right), and that the Rhythm spring uses an obviously different coil rate. I believe that while Mossberg sources Signature Series extension tubes from Nordic, it seems they use their own spring. Why some people have no issues using the Nordic Components spring, and others have issues, is beyond me. I'm just happy I *think* I found a fix...

wgj3: I can literally rapid fire shells out of the loading port by doing the manual unload you described. There is definitely pressure against the shell stop. I had a chance to look at my friends 930 Rhythm. He has the same dummy rounds I do, so we loaded it up with 13 in the tube (!&$! Awesome!) and it hand cycled rounds 13 through 1 with minimal effort. I walked it back as slowly as possible and once the bolt carrier moved back past the rear shell stop tab, the whole shell stop assembly would pivot, the front stop moved out of the way, and the round popped out of the tube and on to the lifter. I went through his dummy ammo and found the most chewed up examples and they all performed flawlessly. He was kind enough to let me take it down and examine everything. The differences I found (other than the obvious blue furniture and +9 extension tube): His mag spring extended almost 2' past the end of the extension, it was never trimmed. His mag spring is "finished" on the follower end, as most factory springs are. His mag spring uses a thinner gauge. I suspect his rear shell stop spring might be a heavier spring too, but it's hard to tell. This weekend I'm hoping to have time to swap parts and see if his mag spring and/or rear shell stop spring will allow mine to function. Thanks for all the replies and suggestions. I really do appreciate it.

Thanks for the response Nuke. Yes, your assumption is correct that it's not feeding from the magazine when HAND cycling, and only with the extension kit installed. Believe me, I've just about ripped my finger off, really cycling it as quickly and forcefully as I can, with no success. I've been sure not to "short stroke" it as well. Without the extension, rounds move past the shell stop with minimal effort. I also agree with you, if the shotgun was not designed to be loaded using the charging handle and the bolt release button, it no longer serves the purpose I bought it for. Even if it worked 50% of the time, that's not going to cut it for gaming. Edit: I've actually seen that thread via search and have performed the things you mentioned. It seemed to help some. Still not to where I'd use it in a match. Thanks for your help.

I'm somewhat new to this board and to competitive shooting. I've spent about the last week looking at long threads on here and mossbergowners.com, reading about 930's having trouble feeding from extended magazines. I recently attached the Nordic +5 MXT extension to my 28" field model, and began having this issue. I have taken everything down to bolts, polished the shell stop, and still have the issue. I was assuming/hoping that it was a combination of spring pressure against a rough shell stop, so I trimmed the spring as well, one coil at a time, and at this point I'll probably need a new spring. I'm at 5" past the end of the tube and it still won't feed the 1st few rounds from the tube on to the lifter. I'm sure this problem is old news for many of you... My question is whether this issue is actually even an issue? When I refer to my manual it states that the proper way to load the 930 is to drop a round in the side port, drop the bolt, and then fill the magazine tube to capacity. Is the recoil of the round loaded in the chamber a designed & timed element, allowing a momentary shift of pressure off the shell stop, and thus allowing everything to function? I haven't had a chance to test this theory yet, but I'm curious what others with this feeding issue have noticed. If that's the intended design, cruiser ready becomes more tedious. Thoughts?

Just out of curiosity, does anyone know whether the AEK w/Apex trigger has more/less over-travel than the FSS kit? Edit: Just got an email response from Apex. FSS reduces travel before and after the break more than the AEK + trigger. Looks like that's the route. Thanks for the insight.

Hello, I recently found a used 5" Pro 40 and have plans to make a limited gun project out of it. I run a FS 9 with an Apex DCAEK in production, and I'm very pleased with it. I was initially thinking I would put the Apex FSS kit in the Pro 40, but I've noticed quite a few people running the standard AEK's (competition or duty or some other combination of springs) on limited guns. Being pretty new to USPSA, can someone school me on the reasoning as to why the AEK might be preferred to the FSS kit? Other than the fact that I'm already familiarized with the AEK feel, and it cost a bit less... Thanks!

Found this for a steal. I plan to use it for a budget limited gun.

When mounted on the core, is it difficult to access the lock- screw on the rear of the Vortex?