LWRC Upper Receiver Swap Question

[dgleavitt]

Hello,

This is my first time posting on this forum but I have an project coming up and thought I would ask before I start drilling holes.

I have a Frankford Arsenal M16 and unfortunately it will not accept mil-spec upper receivers without a little egging of the rear takedown hole towards the bottom. And I mean a little, but it is enough to create wobble in the upper if I go to put it back on a mil spec lower.

So I picked up a 12.5" LWRC m6 upper and really want to run it on the machine gun but I don't want to "ruin" the factory upper in case I decide to sell it. So that brings me to my project. LWRC doesn't sell stripped uppers to customers for what ever reason so I need to modify a standard upper to fit a steel bushing in the gas tube hole.

To do this I need to either get the "X" cut out drilled and reamed on center so it still lines up properly OR Adams Arms makes an upper receiver with no "X" just a hole. Now the adams arms receiver should be easier but it cost more than double a regular upper does.

So the questions I have are; has anyone ever done this for a LWRC system and does anyone have a machinist drawing showing the "X,Y" position of the center of the gas tube hole?

Thanks,
Andrew

 

[TommyGun]

This is a great forum but I think there are more Mac10/11 guys than M16. You could try the M16 Armory over at AR15.com for more people shooting that platform

 

[attherange]

This is a great forum but I think there are more Mac10/11 guys than M16. You could try the M16 Armory over at AR15.com for more people shooting that platform

There are plenty of experienced and knowledgeable M16 shooters here, don't be fooled. The NFA dictates the popular forums by nature.

 

[attherange]

Hello,

This is my first time posting on this forum but I have an project coming up and thought I would ask before I start drilling holes.

I have a Frankford Arsenal M16 and unfortunately it will not accept mil-spec upper receivers without a little egging of the rear takedown hole towards the bottom. And I mean a little, but it is enough to create wobble in the upper if I go to put it back on a mil spec lower.

So I picked up a 12.5" LWRC m6 upper and really want to run it on the machine gun but I don't want to "ruin" the factory upper in case I decide to sell it. So that brings me to my project. LWRC doesn't sell stripped uppers to customers for what ever reason so I need to modify a standard upper to fit a steel bushing in the gas tube hole.

To do this I need to either get the "X" cut out drilled and reamed on center so it still lines up properly OR Adams Arms makes an upper receiver with no "X" just a hole. Now the adams arms receiver should be easier but it cost more than double a regular upper does.

So the questions I have are; has anyone ever done this for a LWRC system and does anyone have a machinist drawing showing the "X,Y" position of the center of the gas tube hole?

Thanks,
Andrew

I have had to make mods to my Frankford RR as well. The difference on the pin holes is most likely a thou or two, not a big deal. If you are comfortable, and have the correct tools, you can fit the upper to the lower yourself. I would consider dedicating the upper to the lower and forget the resale factor. As for drilling out the "X" this is not a hard operation. If you have a drill press and the correct bit, the set up for the job will take longer than drilling the hole. I would recommend checking out M60joe if you feel you want to have any mods done professionally.

 

[DINK]

FWIW, if it was my set-up, I would send the lower to M60joe and have it corrected to GI spec, then send it to U. S. Anodizing for a coating of real Type III hard anodizing. Then ANY upper will slap right on and the value of the lower will be enhanced if and when you go to sell it. Given the number of potential uppers you might want to experiment with, I think it makes sense to correct the problem once and for all rather than having to alter every upper you buy.

YMMV

 

[TommyGun]

There are plenty of experienced and knowledgeable M16 shooters here, don't be fooled

I know that there are a lot of expert M16 owners here and one day in the Far Future I hope to count myself among them. That is if my Form4 ever clears.
I was just trying to give the OP another option just as a member here did for me by referring over there when I was trying to get my Shrike running.

I think y'all got him going in the right direction. I think I got my M27 linker from M60 Joe.

 

[nuge]

FWIW, if it was my set-up, I would send the lower to M60joe and have it corrected to GI spec, then send it to U. S. Anodizing for a coating of real Type III hard anodizing. Then ANY upper will slap right on and the value of the lower will be enhanced if and when you go to sell it. Given the number of potential uppers you might want to experiment with, I think it makes sense to correct the problem once and for all rather than having to alter every upper you buy.

Solid advice this ^^

 

[MarkV]

best advice so far... fix the issue, don't bandaid it. balls of bandaids suck.

FWIW, if it was my set-up, I would send the lower to M60joe and have it corrected to GI spec, then send it to U. S. Anodizing for a coating of real Type III hard anodizing. Then ANY upper will slap right on and the value of the lower will be enhanced if and when you go to sell it. Given the number of potential uppers you might want to experiment with, I think it makes sense to correct the problem once and for all rather than having to alter every upper you buy.

YMMV

 

[dprice3844444]

won't hurt anything if it wobbles