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Plus One Magazine Extensions That Work?

I've already tried the S&J Hardware +1 for the 590 and it did not actually let me get an extra round in the tube.

The Suarez unit is supposed too have been specifically made for the Shockwave and actually add a round. But it's no longer p\on their website. They seem to be heavily invested in the Tac-14, so they may have stopped making the Mossberg +1.

So has anyone added a +1 to your Shockwave that works? Which one?
Possible options:

S&J Hardware (didn't work) - $57
Vang Comp (590 & 590A1) - $75
HFD2 w/standoff spike (claims to be for 590, 590A1 and Shockwave) - $62
Nordic Components (universal) - $85
Taccom w/standoff pasta fork (590 & shockwave) - $53
Choate (590A1) - $45


I am using the S&J +1 and can just get nine 1 3/4" minishells in the tube, using the stock spring and the Derlin follower that came with the S&J. It will also accommodate a fifth 3" shell but it's not long enough for a sixth 2 3/4" shell - needs to be at least 3/4" longer. Perhaps the +2?


Did they give you a replacement spring to install? It may be too long and "stacking" up inside the tube. See how the +1 works with the factory spring--maybe that is all you need?


WESCOG Wile E. Coyote School of Gunsmithing
Elite Member
20210225_162304.jpg Here is my 590 Shockwave with the S&J Hardware plus one. But found that I can load 8 Federal mini-shotshells in the tube. May need to revert to the OEM spring.

Now I have swapped out the S&J Hardware for one from taccom3g on the bay. This one will allow me to load 9 rounds in the magazine tube plus 1 in the chamber.


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