What other brand brace will fit the stock side-folder tube that comes on the MPX? I like the side folder but the Sig brace makes it to thick when folded, more than twice as thick. Anyone replaced theirs and what with? Thanks for any help.

Its a pistol tube. Any of the non-adjustable braces - SB, shockwave, etc. its a smooth tube tho - doesnt have the little dents for the Shockwave blade set screw. And the SB braces are a butch to get on and off. But work well.

Briefly thought about using the KAK Shockwave myself but couldn't resolve in my mind how the blade style braces looks so weird in my mind, not that any brace design is close to traditional. But the KAKs are relatively affordable and popular, and do cut a narrower beam than any of the SB Tactical rubber styles.

I went with the SB adjustable instead. Looks more 'subgun'. Feels more "proper" in use, too. Downside with this type is the added length created when the brace is collapsed rather than with the folded OEM brace; a backpack-style case carry/range bag solution become taller (a generally bigger overall) if that's your transport method.

A blow dryer helps to soften the brace some when removing the old one and installing a new brace. As long as the brace isn't superheated it will more or less return to its original shape and dimensions.

SBTactical has a new brace coming soon. It appears to be more compact when folded than the original and the sliding version.

https://www.sb-tactical.com/product/fs1913/

Thanks for the help.