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Discussion Starter · #1 ·
I recently purchased a MAGPUL CTR stock for my 556. It has the same amount of play whether the friction lock is engaged or not. Magpul says the SIG tube is the probable cause. Another member on here had the same issue and bought an aluminum commercial tube and the friction lock worked well after that. I read somewhere (can't remember where) that the mil spec aluminum tube is forged where as the commercial aluminum tube is cast, making the mil spec tube obviously stronger. Are the mil spec tubes that are sold to the public still forged? If so I may sell the commercial CTR and buy a mil spec along with the tube.
 

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Discussion Starter · #2 ·
I guess no one knows the answer to my first question. I even called several distibutors and could not get a clear answer. Be that as it may, I am planning to install a Vltor tube (at least it should be stronger than my stock plastic tube). My question is the Vltor is a 5 position tube whereas my stock tube is a 6 position tube. Am I giving up "extended length" by going with a 5 position? I usually extend my stock at all the way as I have long arms. Thanks.
 

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...rob-ss

...the mil spec buffer tube is produced using 7075 forged aluminum...the commercial buffer tube is "usually" produced from 6061 extruded aluminum...

...aside from the differences in the outside diameter of the tube itself...~1.150 inches for mil spec and ~ 1.170 inches for commercial..the threads on the mil spec tubes are cut to "full height"...ie 1.1875...the threads of the commercial tubes are not...that is... they are cut to ~1.170...the threads of the mil spec tubes more fully engage the threads in the reciever...and have a "slightly" lessor tendency to pull out or loosen......not something i would be overly concerned with though... especially when you stake the castle nut...
 

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rob-ss said:
Are the mil spec tubes that are sold to the public still forged? If so I may sell the commercial CTR and buy a mil spec along with the tube.
...if they are mil-spec...i would just buy a commercial tube...since you already have the commercial CTR...and call it a day...this is not something to be concerned about...really

...if you want a mil spec reciever extension...Bravo Company sells them...
 

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Not sure if you want to go this route (it will sound cheap and shoddy, but experience has proved otherwise to me), but I had the same issue you have....take a 2.5'' strip of electrical tape and put it on the very top of the buffer flush with the back of the tube. This takes up some of the clearance and usually takes half the wiggle out...next step, find the hole where you will have the locking pin engaged, for you I'm taking it's the one furthest to the rear since you need a long length of pull. Cut a small ribbon of tape about 1/16'' wide and 1'' long and stick it above the engaging hole, on both the right and left sides of the tube. The long side should be parallel to the top of the tube (horizontal). If you notice, the friction lock consists of two plastic tabs that "grip" the tube when the friction lock is engaged. Taping both sides takes up more clearance and gives material for the plastic locking tabs to "bite" into. Slide your CTR in place and lock down the friction lock, it should have ZERO movement. Add strips of tape (one on top of the other) to get the exact fit, for me it was no more than 2 strips of tape per side, the tolerances were tight enough. So is it a sexy fix? Nope, but it works, it has not wiggled loose, and cost about a dime...gl whatever you choose!
 

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Discussion Starter · #6 ·
ullie said:
...if they are mil-spec...i would just buy a commercial tube...since you already have the commercial CTR...and call it a day...this is not something to be concerned about...really
Well, you never know when you might run out of ammo and have to butt stroke someone to the head, a forged tube would help hold things together. :wink:
 

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i want to use the VLTOR milspec buffer tube as well since i can grab one at the local gun shop....

other than the buffer tube, what else would i need and where should i get it from? castle nut? some sort of adapter? i want to use a magpul ACS when i do my SBR conversion once i get my stamp.....
 

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rob-ss said:
Well, you never know when you might run out of ammo and have to butt stroke someone to the head, a forged tube would help hold things together. :wink:
... :mrgreen:

...yea...but...the walls of the commercial tube are thicker....073" vs .085"...

... :p
 

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rob, was the original tube the plastic one? Some come with a plastic tube that kinda sucks, may be your problem.
 

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almost same questions...want to get the magpul ctr but i also have the plastic buffer tube and am looking to replace it with an aluminum one.....total noob question but what kind of tool do i need to swap out buffer tubes? from the looks of it some sort of special wrench?? sorry OP not trying to steal your thread....

EDIT: looked it up.....SPANNER WRENCH! wish me luck, hopefully i don't end up breaking my face (or my gun!) on my first amateur gunsmithing adventure! :lol:
 
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