AR builds

[Capbyrd]

I was recently helping a buddy put together a MEGA billet receiver set.  The MEGA upper is too big for my receiver block.  I had to send him to a local smith to tighten down the barrel and the flash hider.  


As time nears for me to build out my upper, I am concerned of running into a similar issue with my CMT billet upper.  So my question here is what receiver block are you guys using to build out the CMT uppers?  

 

[RED333]

I picked up this one, fit well.

http://www.ebay.com/itm/271414493499?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

[Ted S.]

What receiver block do you have? Do you know the dimensions of the indents to hold the reciever? I have a cmt upper, I might be able to help a bit... Sent from somewhere in the cosmos using magic...and bacon. Edited March 12, 2014 by Ted S.

[Capbyrd]

I have a two piece block. Like a clamshell but not hinged.

[Garufa]

I was recently helping a buddy put together a MEGA billet receiver set.  The MEGA upper is too big for my receiver block.  I had to send him to a local smith to tighten down the barrel and the flash hider.  


As time nears for me to build out my upper, I am concerned of running into a similar issue with my CMT billet upper.  So my question here is what receiver block are you guys using to build out the CMT uppers?  

 

 

I used two pieces of 3/4" plywood.  One snug piece between the takedown lugs with another across the stop sandwiched in a vise.

 

Disregard any cracking sounds you hear, it's just the plywood compressing.  :lol:

Edited March 12, 2014 by Garufa

[LngRngShtr]

could always get the kind that hold the barrel via the extension then it won't matter what the upper looks like

 

Bill Geissele makes one called a "Reaction Rod"

Claims he saw it used by US Army Marksmanship unit and refined the idea,

 

Brownells makes one also about half the price but no flats but claims will do both ar15/ar10  Midway also offers one  just Google AR15 reaction rod. 

 

http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/barrel-tools/ar-15-m16-308-ar-barrel-extension-torque-tools-ar-15-m16-barrel-extension-torque-tool-sku080-000-637-27452-53686.aspx

 

also handy to hold upper for any other part of your build, hand guard,muzzle device etc.

Edited March 12, 2014 by LngRngShtr

[Dolomite_supafly]

I have done it two ways. I tried it using the two blocks like Red linked. And they work great, especially with uppers that are not forged.

 

I have also clamped the barrel into a vice and tightened down the barrel nut. It works just as good but I am always worried the locator pin on the barrel will mess up the upper receiver at the notch it fits into. So far it hasn't happened but it is a concern of mine.

[Capbyrd]

I found just the upper set of the one that Red posted.  

http://www.amazon.com/dp/B00FCK3BQ8/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=WQPW3LLCLH6C&coliid=I2TC64PRVP1PPN

 

I'm going to give this a shot.  

I've seen these before and they always made me nervous.  But I've never seen them used with a top piece and set sideways in the vise.  Makes me a lot less wary of them.  

 

 

Thanks for y'all's help