M4 question, mag tube

[Somerset Bar]

I have a used M4 here, with an extended mag tube that someone's installed, however they also installed a spring-fit plug in the tube and I believe left in the original spring (which is weird).

So what are the regs on mag size for semi shotguns? I'm just scratching my head at why there would be an extended mag tube, but a restrictor (and I don't think it's just for hunting, but I'm not up on the hunting regs, I thought it was 3 rounds max).

So I guess I'm wondering if the new mag tube is strictly for aesthetics, and if not...does anyone know where to get the longer mag spring, or what the stock spring size is? The shotty is for 3 gun competition, so trying to figure out what I can and can't do...while staying legal.

 

[Butcherbill]

Semi's are five of whatever largest shell it’s chambered for, it’s irrelevant how many shells it can hold of a shorter length, if you’re hunting with it then 2 in the tube plus one in the chamber.

 

[Grain]

Some Benelli M4 tube extensions were open on the end, so when you removed the screw cap the spring was not captive and flew into the kitchen, down the stairs and into your hockey bag. Some people put a plug of one sort or the other in to prevent just that. The factory magazine spring in Benelli M4's is quite long, and many have left the original in when adding an extension. I've not had an issue in doing just that, they work fine. Some extension manufacturers recommend doing just that. If your hunting waterfowl, max shells you can hold is 3, including the chamber. If your doing that you will need to cut a dowel to work. For 3 gun you can go to what Butcherbill says, 5x 3" shells in the mag, which often equates to 6x 2 3/4" shells, which is legal. Ghost loading will get you another.

 

[Somerset Bar]

Excellent, thanks guys, I'm definitely not hunting with an M4, I'd be worried about every raindrop or blob of mud. I've got an 1100 for that work

The mag extension is sealed on the end, so spring is totally captive, and this plug was set quite a ways up in the tube, I believe it was set for 4-2 3/4 shells, that's why I was asking. I'll set it to 5 3" shells and call it a day.