SJ Hardware Mossberg 590 +1 Extension

[mfan0729]

Recently bought the "new" Mossberg 590, model number 50778. What length should I cut the magazine spring for a +1 extension from SJ hardware? I've heard that those extensions do not actually add an extra shell, even with the springs cut down.

Sent from my SM-G950U using Tapatalk

[strakill]

If it's the 7 shot you bought you gonna want to do the +2 extension. The shotgun comes with Mossbergs +1 on it. When I ordered mine it came with a new spring and follower.

ETA: They do add two extra shells to the tube.

[mfan0729]

If it's the 7 shot you bought you gonna want to do the +2 extension. The shotgun comes with Mossbergs +1 on it. When I ordered mine it came with a new spring and follower.

ETA: The do add two extra shells to the tube.

I don't think the +2 extension would fit flush with the barrel though; that's the only problem I see due to the barrel/magazine tube engagement being moved forward on the new mossbergs.

Sent from my SM-G950U using Tapatalk

[strakill]

It is not moved forward, Mossberg just added a +1 to the standard tube.

I just did this to my brand new 7 shot a month ago. Sits flush with the barrel and runs like a champ.

[mfan0729]

That's weird, the +2 would definitely not fit flush with my 18.5" barrel. I just checked the dimensions.

[Lonestargrizzly]

Havent you heard its cool to have a long mag tube?

[strakill]

That's weird, the +2 would definitely not fit flush with my 18.5" barrel. I just checked the dimensions.

Give me a measurement of the mag tube from the forward part of the receiver to the tip of the mag tube with end cap removed.

ETA: The mag tube should measure somewhere in the 14" - 14 3/4" + or -, the SJ 2+ extension should have an overall length of 4 1/2" + or - and the barrel form the front of the receiver should be a bit less than 18". (I didn't want to pull the mag ext off tonight as I sprained my wrist today and it hurts like heck to torque my wrist but if I must I will put a pair of pliers to it.)

Don't forget in these measurements there is the length of threads that screw over one another will shorten OAL.

I'm willing to help fit this for you. If you don't have the gun in front of you then we are just guessing at this point. I'm giving you my real life experience with the exact gun you have in question.