Ok so I am no stranger to pistols or rifle, I've always been around shotguns with multiple time shooting clay and just plain fun blasting things to pieces. I've not shot any competition but would like to plan ahead when purchasing my next shotgun. I would like to eventually shoot 3 gun but currently dont even own a pump shotgun so heres where all my questions come in... I am going to be buying a semi auto 12g for a multitude of uses, including future 3 gun use. I have narrowed it down to stoeger m3k, m3000 or 930JM. I dont plan to use the gun for home defense as I have guns serving that purpose already. I would however like to use it for skeet shooting some when friends go out as well as the very rare trips to go dove hunting(I will plug the mag tube of course). What length barrel would be best for an all around, fun, tactical, 3 gun, hunting shotgun which will likely be my only shotgun over the next few years. I like the idea of one gun that does it all though it doesn't do any of it the best, kinda like my glock 19. Also what chokes would be best for what with the barrel length recommended. I know you can buy spare barrels but for the cost I was seeing on an initial search i would rather just get a cheap pump with a different length barrel, but like i said i would prefer one gun to do all of it. I am really thinking a 24" m3k would be the best rout but am not familiar enought to be comfortable buying it withoug getting some consutation on here first. Also what upgrades, accessories etc do you recommend for this set up. I don't know if i will want to run doubles or quads but what length extension tube is recommended for either?

Hopefully this all makes since, I appreciate all the feedback!

The M3k is a good gun. not the best, but a good gun. MOA precision is the go to place for setting one up (http://moaprecision.com/).

Tube length depends on what division you are shooting.  Divisions with magnified optics, Tac-Ops (Practical), you want a tube that will hold 12 doesn't matter if you are doing load 2 or quads.

Divisions with red dots, Limited (factory) most of the time limit you to eight in the tube at anytime. 

24 inch is a good all around length, but 26 might be better. 

ETA: Stay away from the mossberg. some folks can get them to run, but IMO it's now worth the effort. 

Thanks for that info! I have heard most people enjoy shorter barrels for 3 gun, would 26 put me at a dissadvantage down the road?

if you have a 12 round tube it will still be longer than a 26in BBL

Ok, bare with me... I'm new to this, so at risk of sounding stupid. My thought process was that even with a longer tube the barrel length would be more a matter of the scatter of the pellets at different distances. Are you meaning saying that the barrel length is more about the swing and maneuverability of the rifle over the patterning of the shot?

The barrel length (like in a rifle) is related to velocity, your choke selection will effect your pattern. in 3gun we shoot low velocity shells, I shoot 1145FPS in my versa max, but is if this is going to be an all around gun that you will hunt with also, the longer barrel will be an advantage in that situation, without being a detriment in 3gun. 

Awesome thanks for the response!

Most shotguns in 3 gun are 24-26" barrels. Just about everyone has 12 rd. or more mag tubes. The longer barrel has a better sight radius.

No one uses 18" barrels and while at one time a quite a few used 21" barreled shotguns, the 21" barrels are kind of passé.

One thing about buying a shotgun for 3 gun, is you want a shotgun that runs without going down. I had a couple of shotguns that would just quit working in the middle of a stage.  I then bought a Beretta 1301 when they first came out, the gun just runs with minimal up keep.

to echo what Don commented on.. I have a 21" Benelli, and have recently added a 28" for skeet... unless the match calls for slug shots (I have a 10-22 sight milled into the rib on the 21") I'll just shoot the 28"...the first "big" matches I shot were the North Carolina Tactical matches put on by Kyle Lamb at Fayetteville... courses there were in and around automobiles... most recent matches don't really favor a short barrel

I have a Remington V3 with a 26" barrel.  I'd say it's about perfect for an all around gun.  It's not too short for birds or clay pigeons, and it's not too long for the square range.

Unfortunately, it's too short for some of the really long clays on the sporting clays range, and too long for inside the house.  Trade offs and all.

stoeger