Looking at rails for a new project. I’ve not seen either of these rails in person, but have looked at several threads here and elsewhere. I understand that the Troy Alpha mounting is likely an improvement compared to the VTAC/Troy TRX Extreme. And I looks to me that the DD MFR mounts differently than all previous DD rails.
Could those who have handled both discuss the mounting security details compared to one another?
Also I see that the MFR weighs 12.2oz. Am I correct in assuming that includes the DD barrel nut? I cant find a weight listed for the Alpha. Anyone have an accurate weight for the 13"?
I just got the 13" Alpha during Troys Black Friday Sale.
I wanted to weigh it, because like you I couldnt find any info on it, but I dont have a scale that will accurately measure it.
Another strange thing I found is that my rail’s length is 13 1/8" long, 13 1/4" if you count the anti-rotation tab.
Everything I had read said it would be 13.8", im actually glad it is shorter, but still odd.
I will try to get pics later today, I know its hard to visualize.
On to the mounting of the rail.
With the delta ring assembly removed and your low pro gas block installed ect…
You slide the rail onto the stock barrel nut with the top rail at the 1 O’clock position, then you turn it counter clockwise to lock the rail in. There is a groove inside the rail for the barrel nut teeth. This stops the rail from being pulled forward.
There is a small anti rotation tab that stops the rail from rotating too far counter clockwise and lines up the top rails. This is on the outside of the rail and butts up against your receiver.
There are 3 screws with tabs on the inside of the rail. The rear of the tabs lock into a groove in the rail.
When the screws are tightened the front of the tabs tabs push against the barrel nut, and the rear of the tabs are locked into the groove inside the rail.
This prevents the rail from spinning.
On a side note, the front flip sight has a slight bit of side to side movement. It probably equates to about .5 MOA. This is something I had read from other owners as well. Although it moves, it flips up the same each time, it can just be pushed left each time. So unless bumped it will be dead on, and if it is bumped your still only very slightly off. Nonetheless I was a little disappointed by the sight movement.
And the small anti-rotation tab doesnt touch my receiver, I had to back it off just a hair in order to line up the top rails. Its possible its supposed to be that way
OK first, when you are saying clockwise or counter… You are referencing from the muzzle end correct? I usually reference from behind the gun but for consistency I’ll stick with yours.
I can see that rotation one direction is prevented by the external tab. It’s the little inside tabs and how they prevent rotation that I have a hard time visualizing. They just pinch inside the barrel nut right? They are screwed through the rail so I can see how the rail cant rotate in relation to the tabs. But, as they just pinch the nut I cant grasp how they prevent rotation clockwise toward the direction you have it to install if force is applied and they slip on the inside of the nut.
It’s entirely possible that I am being thick and missing it. Help me out here.
You are correct, its just the pressure from the tabs on the barrel nut that prevent clockwise rotation. It seems very sturdy and tight, I dont see it coming loose, but it seems possible if somehow torqued very hard that direction. Even if it was hit hard off something I dont see it moving the rail, It would have to be the perfect directional force
I think its better than the old system for the TRX extreme and better than the Samson ect… that just use the 2 screws on the bottom to pinch the rail together, but none of these rails are bomb proof like some of DD’s quad rails for example.
I have no idea how the DD rail your referring to locks up however.
The DD appears to be well thought out. Looks fairly impossible to rotate without severely damaging it as it looks to overlap the receiver top and bottom on both sides. Keeping it from moving forward (and actually applying back-pressure ) are 4 angled screws that go into a grove in the outer front of the barrel nut.
I have found plenty of pics here and elsewhere of the DD MFR setup. If I could find some of the inside rear of the Troy Alpha maybe I could wrap my mind around how those internal tabs keep it secure.
I also ordered the Troy Alpha 13" no sight during the Black Friday sale. When it arrives I will take pictures. The BCM BFH 16" lightweight upper I ordered will not be here until Monday. It won’t be ready to mount until I send it to ADCO to have the FSB shaved. When it comes back, I will take more pictures.
Not my Picture, but this is the view inside the Alpha.
If you look at the bottom of the picture (3 O’clock on the rail) you can sort of see the first groove where the barrel nut teeth seat. Then the groove behind it are where the tabs lock into the rail.
You can also sort of see the anti-rotation tab at about 2:45 in the picture. Right beside the top rail
