Looking for opinions on collapsible stock for MPX (with ATF Form 1 of course) VS pistol brace from somebody who actually has experience with one/other/both.

I own a carbine length mpx gen 2. It has the collapsible stock. I am taking it down to an 8 inch trilug barrel from In Lead we trust.

https://www.inleadwetrust.com/...x-barrels-w-gasblock

Of course that will be Form 1 sbr. Others will tell you a brace is just fine. I have a a b&t ghm 45 with tail hook brace. it functions as a stock would. It is not nearly as nice as a stock though.

Do you intend to use the brace as a stock, or as a brace? If you intend to use the brace as a stock, the kind you strap around your forearm are pretty uncomfortable and impractical. About the only comfortable brace for using as designed is the tailhook, which cradles under your forearm. As far as shouldering a brace goes, they aren’t as comfortable as a stock IMHO. LOP is generally shorter, and the ones with the rubber flaps that go around your forearm tend to give and move around a little under recoil. For shouldering comfort, a real stock is the best.

That said, there are some advantages of braces. First is not having to deal with NFA hassles and expense. This includes issues with travelling between states with an SBR, which don’t exist with “pistols”.

The advantage of going SBR, other than the ability to use a real stock, is that it’s not subject to arbitrary changes in decisions on whether shouldering is legal or not, or questions on things like whether you can install a VFG or not.

Personally, I’ve got four braced “pistols” and have SBR paperwork in on all four, as I prefer the comfort of stocks, plus the certainty of knowing what the rules are and that they’ll stay that way.

I'm satisfied using the 3-position telescoping SB Tactical brace on my MPX. The folding brace that originally came with the gun was no slouch in use, either. No the 3P is not the nicest piece of hardware to cheek, but the unit is not anywhere near the horrible end of the quality scale. As for shouldering (inadvertently, of course) all of the braces that I own will do that chore just fine. As of now, I see little need to go through the hassle of getting a stamp for an SBR when what I've got now with my pistols functions very well as they are. For these kinds of CQ guns all a true stock would do for me is offer the possibility of some storage cubbies and an additional spot or two to hang the end of a 2-pt sling to, something I can make do without.

Ive used a few braces and the 2 different original stocks, collapsible and folding.

I like the folding to keep the overall length and width as small as possible. I dont really feel a difference between the folding stock and, say, even the shockwayve blade. Recoil is low, so the braces dont hurt to shoot, whether theres a lot or a little stock/brace contacting the shoulder.

Since the one i own now is a pistol, ive kept the shockwave blade on the original folder and love it. Its small enough in folded lenth to fit in my backpack and still comfortable to shoot, with a length of pull longer than the two Sig stocks and other braces. I do give up a little in the thickness of the buffer tube folded against the gun over the “kate moss” original folding Sig stock, but saves me the SBR hassles -both initial and when i travel, has longer LOP, and its super comfortable to shoot on the cheek and/or shoulder.