AR Sponsor
Posted: 4/21/2015 6:53:36 AM EDT
|
I'm trying to source a new endplate so I can fit a mil-spec buffer tube to my AR.
On my CMMG the endplate has a semi-circular indent to fit the lower. Like so: 
However my 9mm lower has a round cut out. 
|
|
Quoted: It wouldn't fit when I tried the buffer from the CMMG. Quoted: Quoted: Why can't you use the one you have that matches your lower? There is no difference in end plate sizes, end plates don't come in mil-spec or commercial sizes. It wouldn't fit when I tried the buffer from the CMMG. As far as I know the threads on buffer tubes, the castle nut and the end plate are are the same size. The only difference between a commercial and mil-spec tube is the outside diameter where the stock rides. So the end plate that was on the gun should work with a mil-spec tube. |
|
Quoted:
What lower is that? Normally that is a pocket on the lower and not a boss sticking out. It's a billet lower from one of our UK manufacturers. I'll have a word with my machinist buddy as it's not bonded on place as others suggested. Thanks for the replies. |
|
Quoted:
It's a billet lower from one of our UK manufacturers. I'll have a word with my machinist buddy as it's not bonded on place as others suggested. Thanks for the replies. Quoted:
Quoted:
What lower is that? Normally that is a pocket on the lower and not a boss sticking out. It's a billet lower from one of our UK manufacturers. I'll have a word with my machinist buddy as it's not bonded on place as others suggested. Thanks for the replies. Why not open up the interior diameter of the original endplate to be a little larger than the outer diameter of the buffer tube? It would take just a little bit of grinding with a rotary tool and maybe a little filing to do this. |
|
Quoted:
If the new tube will thread into the lower, why won't the old plate work? The threads must be the same diameter. The plate goes over the threads. As said right above, a little fitting might be needed. Take a look at the receiver, particularly under the hole for the receiver extension. |
|
Quoted: Take a look at the receiver, particularly under the hole for the receiver extension. Quoted: Quoted: If the new tube will thread into the lower, why won't the old plate work? The threads must be the same diameter. The plate goes over the threads. As said right above, a little fitting might be needed. Take a look at the receiver, particularly under the hole for the receiver extension. I looked. The plate was on there before, the only difference now is the tube. The threads are the same. Explain what you are saying. |
|
Quoted: A proper receiver has an oval depression under the hole for the receiver extension. It was originally so the nub on a fixed stock fits in there to prevent stock rotation, The OPs lower has a nub coming off the receiver instead of the proper depression. need an AR receiver extension. the ub is probably there for anti rotation, like you said. of course this makes it easier for them but not for the end user who wants to change it. i would modify a standard end plate. edit- does a milspec tube fit in the receiver by itself? |
|
Quoted: A proper receiver has an oval depression under the hole for the receiver extension. It was originally so the nub on a fixed stock fits in there to prevent stock rotation, The OPs lower has a nub coming off the receiver instead of the proper depression. Forest, I didn't notice it was you last evening, haven't noticed you around for a while. I know and understand what you are saying but I still don't understand why the old plate and the new tube wouldn't work. The old plate might need a little fitting. The old plate made for that lower will work easier than a new plate that doesn't match the lower. |
|
Quoted:
i'd bet its different bc its a 9mm lower- blowback action so it doesnt need an AR receiver extension. Quoted:
Quoted:
A proper receiver has an oval depression under the hole for the receiver extension. It was originally so the nub on a fixed stock fits in there to prevent stock rotation, The OPs lower has a nub coming off the receiver instead of the proper depression. No just no. ALL receivers, 9mm, 5.56, 6.8 etc are supposed to be the same. I can take a 5.56 receiver drop in a 9mm hammer, buffer, and magazine well insert and viola it's a 9mm lower. Consequently you can take a 9mm lower and pull out the magazine well insert and now it's a 5.56/6.8 lower. Also blowback actions still require the SAME receiver extension . Blowbacks just don't require the gas tube. The buffer and spring are still needed, and the 9mm carbines use the same stocks both fixed and telescoping. |
|
Quoted:
I still don't understand why the old plate and the new tube wouldn't work. The old plate might need a little fitting. The old plate made for that lower will work easier than a new plate that doesn't match the lower. That IS an interesting question as it should if the new receiver extension fits in the lower receiver. I was going on the using the new end plate. It could be this (just a WAG). Our commercial receiver extensions were based on commonly available tubing (instead if milling to blue prints as the military version is) because it's cheaper. What if that UK made lower did the same thing? Only their commercial tubes are touch smaller (as ours are a touch larger) due to the imperial vs metric system)? For example a 1" tube in the US might be a 2.5 cm tube in the UK (where if they were the exact same it would be a 2.54cm tube - but specifying to the hundredths is more costly). So if my WAG is correct the receiver extensions might interchange (US vs UK) but the UK made endplate is a touch too small. Though that should be an easy fix with a dremel, sanding drum, and 5 minutes. |
|
Quoted: No just no. ALL receivers, 9mm, 5.56, 6.8 etc are supposed to be the same. I can take a 5.56 receiver drop in a 9mm hammer, buffer, and magazine well insert and viola it's a 9mm lower. Consequently you can take a 9mm lower and pull out the magazine well insert and now it's a 5.56/6.8 lower. Also blowback actions still require the SAME receiver extension . Blowbacks just don't require the gas tube. The buffer and spring are still needed, and the 9mm carbines use the same stocks both fixed and telescoping. Quoted: Quoted: Quoted: A proper receiver has an oval depression under the hole for the receiver extension. It was originally so the nub on a fixed stock fits in there to prevent stock rotation, The OPs lower has a nub coming off the receiver instead of the proper depression. No just no. ALL receivers, 9mm, 5.56, 6.8 etc are supposed to be the same. I can take a 5.56 receiver drop in a 9mm hammer, buffer, and magazine well insert and viola it's a 9mm lower. Consequently you can take a 9mm lower and pull out the magazine well insert and now it's a 5.56/6.8 lower. Also blowback actions still require the SAME receiver extension . Blowbacks just don't require the gas tube. The buffer and spring are still needed, and the 9mm carbines use the same stocks both fixed and telescoping. |
|
Quoted:
Proprietary receiver extension? I'd say it's more of an oddball lower with matching oddball endplate. No offense, OP. Receiver threading needs to be identified.... If 1-3/16"-16, then normal receiver extensions (commercial or mil-spec) should fit. And why not re-use the oddball endplate ? |
|
Quoted:
Why not open up the interior diameter of the original endplate to be a little larger than the outer diameter of the buffer tube? It would take just a little bit of grinding with a rotary tool and maybe a little filing to do this. Quoted:
Quoted:
Quoted:
What lower is that? Normally that is a pocket on the lower and not a boss sticking out. It's a billet lower from one of our UK manufacturers. I'll have a word with my machinist buddy as it's not bonded on place as others suggested. Thanks for the replies. Why not open up the interior diameter of the original endplate to be a little larger than the outer diameter of the buffer tube? It would take just a little bit of grinding with a rotary tool and maybe a little filing to do this. ^^ Exactly what I was going to suggest... |
|
Quoted:
^^ Exactly what I was going to suggest... Quoted:
Quoted:
Quoted:
Quoted:
What lower is that? Normally that is a pocket on the lower and not a boss sticking out. It's a billet lower from one of our UK manufacturers. I'll have a word with my machinist buddy as it's not bonded on place as others suggested. Thanks for the replies. Why not open up the interior diameter of the original endplate to be a little larger than the outer diameter of the buffer tube? It would take just a little bit of grinding with a rotary tool and maybe a little filing to do this. ^^ Exactly what I was going to suggest... Got a new mil spec buffer tube today. As suggested I removed a bit of metal from the interior diameter and it fits nicely. Not limited to my stock options now, thanks guys 
|
AR Sponsor