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View Full Version : UBR not fitting into my lower correctly, Help


Palehorse08
03-20-11, 14:54
I just got my UBR in the mail yesterday and went straight to my workbench to install it on my newest spr build. Everything went great except when I went to slide the main tube into the notch on the back of my lower (not sure of the actual term) to lock it into place it will only go half way in. I gently took a hammer to it, trying coerce it into place but nothing. I wanted to take some sandpaper and sand it down but then I wised up and decided to get some other opinions.

Thanks in advance!
SteadyUp
03-20-11, 15:22
What kind of stock was on the receiver the UBR is going on (did it have a collapsible stock previously)?

I'm looking at the directions on the Magpul's website--what number are you at that is causing a problem?

And good move on not sanding anything-shortbus tragedy averted!
Breadman
03-20-11, 15:32
Are you referring to putting the upper and lower halves of the stock together or seating the upper portion of the stock onto the tube before screwing them together?
HeavyDuty
03-20-11, 15:33
Disregard - misread the OP.

And put that hammer and sandpaper away!
Palehorse08
03-20-11, 16:03
It is a stripped lower so this is the first stock being installed onto it. I am at the step where the buffer tube is already installed and I am putting the main tube into the notched portion of the lower receiver to "click" it into place. The "clicking" part is where I am at, there is a 1/4 inch gap between the stock and the lower.
MistWolf
03-20-11, 16:15
As I understand it, you're talking about the round well in the back of the upper receiver just above the grip. That's where alignment pin (round protrusion) at the front of the stock tube must slide into.

Look and see how deep the well is drilled. The one on my upper is drilled straight, then has a taper. If this hole is shallow, it will prevent the alignment pin from seating all the way.

Other problems could be from the hole diameter being too small, pin diameter being too large or a burr or bit of debris getting in the way. Also, check to see if the pin is mounted correctly on the stock tube. If it's too far back, there will be a gap
Palehorse08
03-20-11, 16:18
As I understand it, you're talking about the round well in the back of the upper receiver just above the grip. That's where alignment pin (round protrusion) at the front of the stock tube must slide into.

Look and see how deep the well is drilled. The one on my upper is drilled straight, then has a taper. If this hole is shallow, it will prevent the alignment pin from seating all the way.

Other problems could be from the hole diameter being too small, pin diameter being too large or a burr or bit of debris getting in the way. Also, check to see if the pin is mounted correctly on the stock tube. If it's too far back, there will be a gap

The pin was too far back, thanks mist wolf!
MistWolf
03-20-11, 16:32
Glad to be a help