Folding Stock Adapter Comparison Pt. 3

1.2. 3. 4.
5. 6. 7. 8.

1. Doublestar Ace FSA, 2. SB Tactical BTFA, 3. Sylvan Arms FSA 4. MDT Carbine|Carbine FSA,
5. UTG/Leapers FSA, 6. XLR FSA 7. Law Tactical FSA (and clones) 8. Hera Arms SFU

MDT Folding Stock Adapter $149

The speed with which the unit arrived is exemplary of my experiences with MDT. Every single time they surprise me by getting my order to my door several days ahead of when I might expect. It was ordered on the 10th and arrived on the 13th. I got order and ship notices via email with all the information I needed.

Installation was trivially easy and fast. It took only 2 minutes to uninstall the XLR unit and install the MDT unit. Getting it timed into position was not as easy as the XLR because the MDT uses a single screw to snug up the receiver block to the FSA and the act of snugging it up can easily cause the FSA to rotate a bit. It was not the unending bitch to get clocked right that the UTG/Leapers unit was. The XLR system uses 2 screws which avoids the whole issue and I think MDT might make a few friends by adopting that design element. Getting the butt stock installed was trivial and the castle nut locked it up just fine.


The single center screw that snugs up the chassis end
made clocking the MDT unit kind of a fraught bitch. It’s lugged on
the other side but the lug has a lot of play in it so it’s not helpful.

Now came the biggest surprise so far. The lockup of the MDT unit was FLAWLESS out of the box and there was no way (or need) to tweak it. It’s just tight as a nun’s cunt right out of the box. That being the case, it occasionally was a little less willing to unlock than the XLR unit. You might notice I’m comparing the XLR and MDT directly a lot. Well, that’s because so far they’re really close and it’s the only comparison so far that seemed remotely fair.

After installation and some snap-open and snap close work, it was outside to bash against a barricade. The MDT unit simply excelled. Pushing, pulling, plopping hard on the ground, high angle where I’m putting my fully body weight down through the stock and into the bipod… all were easily tolerated and no evidence of strain on the unit was evident.

It’s a little longer than the XLR unit, just enough that I had to reset my XLR Tactical butt stock LOP from where it was with the XLR unit. Interestingly, not one has been 100% interchangeable with any other so far though the UTG and XLR units were the closest so far.


The large pin in the lower left side seems to be
what provides for a lot of the insanely perfect lockup
that the MDT unit delivers. If only they’d price it right.

The MDT has no mechanism for adding drag to the open/close and if you want it double locking then it’s another $50. Getting to $200 for what is really nothing but a toy for most civilian uses is starting to get excessive especially when UTG manages two-way locking for $15. If MDT would have included that lock-open at the $149 price point, they’d have OWNED this comparison on value for features, and performance.

Given the testing criteria some points were deducted. The steel locking mechanism added .25pts it might not have otherwise gotten but it lost .5pts because it didn’t come with instructions (you have to go online to get them). The choice for steel lockup parts and aluminum body parts, that’s good material selection. That the lockup was SO tight right out of the box actually got me curious as to how they did it because it’s non-obvious. It’s very difficult to have 2 pieces of anything that don’t actually screw together that lock up that tightly. MDT’s engineering team outdid themselves on that feature. After all was said and done, the MDT unit pulled in 16.75 out of 19 points. That reflects my own personal feelings on the matter pretty well so there’s good inter-observer correlation between my subjective analysis and the objective points-based analysis. There’s a bit about the MDT that’s more admirable from an engineering point of view than with the XLR but, I like the XLR a little more overall right now, not least of which because it comes in 30 bucks cheaper and doesn’t really sacrifice anything over the MDT unit but the XLR does have the ability to add friction to the fold to act as a hold-open which the MDT does not unless you pop the extra $50 for 2-way locking.

Additional Notes on XLR and UTG/Leapers Units

Continuing our testing and evaluation of these folding stock adapters, while we waited for the MDT unit to arrive and almost every other unit to come off back order, the fiddling picked up. So what new do we have to report? Not a lot of news but some refinement of earlier points. It’s surprising really how much you get right on a surface examination and a couple quick function tests. The long testing procedure that’s being done is actually almost unnecessary. Important differences jump out at you and unimportant ones don’t.

XLR Folding Stock Adapter $115

The XLR unit is really fantastic and after stopping worrying about breaking the allen key in my hand, I got a little more twist on the drag screw… which didn’t really help at all. I’ve gotten the lockup tuned to perfectly snug. This XLR unit is fast becoming a favorite. It’s just elegant and smooth in all its design and operation. So far this is looking like the one that I’ll use on all of my buffer-tube equipped bolt action rifles long term but it’s still a bit early to say. The SB Tactical is so small and light that it might have to win… if we could ever get hold of one.

UTG Folding Stock Adapter $15

The UTG/Leapers unit continues to not be my favorite but it also continues to impress me with its strength and surprise me with how good it manages to be for fifteen measly bucks. Then again, thinking back to that install and the fact that it’s actually quite difficult to unlock from either the open or closed position it’s certainly not in first place even if it was free. The question is will it be second to last or not. The jury is still out but I suspect that it will be higher up the ladder than 2nd to last. One thing we can pronounce right here and now: If your budget is insanely tight and you need to fold your rifle stock and it accepts AR-15 buffer tubes, then you could do a shitload worse than the UTG. It is not sexy and sophisticated but it is 100% workable.

part 1.
part 2.
part 3.
part 4.
Mid-Series Check-in.
part 5.
part 6.
Declaring the Winners

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