AR Sponsor
Posted: 11/17/2014 12:04:57 PM EDT
|
anyone have any experience with this company or parts? How about the receiver extension?
http://www.brownells.com/rifle-parts/receiver-parts/buffer-tube-parts/buffer-tubes/ar-15-m16-mil-spec-receiver-extension-prod70713.aspx |
| I've been told it's not what the manufacturers tell you but what they don't. You can have a receiver extension that is mil-spec diameter that's not made from 7000 series aluminum just like the M&P 15 sport, it's 6061. There are those out there who will tell you a 6061 RE is fine but it's your rifle and your butt on the line, spend a few more dollars and get one you know the materials it's made from, BCM, Colt, etc. Remember you get what you pay for! |
|
Quoted:
Mil-Spec receiver extensions are made of aluminum? I always thought they where made of hi-grade steel (4140, 4150, CMV, etc.) Nope, they are aluminum. Original Colt's were 6061 until sometime in the early 1960's when they then switched to 7075. Today, you can get 6061 or 7075 in the aftermarket. |
| The weakest portion of any collapse stock receiver extension tube is the threads. None are known to have broken anywhere else. Unless building a clone the material choice of 6061 or 7075 is of little consequence as it takes the same amount of force to break both as measured during a failure test which is buried somewhere in the archives of this site. |
|
Quoted: The weakest portion of any collapse stock receiver extension tube is the threads. None are known to have broken anywhere else. Unless building a clone the material choice of 6061 or 7075 is of little consequence as it takes the same amount of force to break both as measured during a failure test which is buried somewhere in the archives of this site. I bent my very finest Chinese People's Army factory "mil-spec" diameter receiver extension banging it on the floor @ a gun show. The important thing is my stock didn't break. 
|
|
Mil-Spec in reference to receiver extensions is usually brought up when talking about the diameter of the tube but there is actually more to it that makes a tube 100% Mil-Spec.
Diameter is one but the type of aluminum must be 7075-T6 and the tube must be forged. There are lots of "Mil-Spec" buffer tubes out there that are the Mil-Spec diameter, made from 7075-T6 but are impact extruded. |
|
Quoted:
Mil-Spec in reference to receiver extensions is usually brought up when talking about the diameter of the tube but there is actually more to it that makes a tube 100% Mil-Spec. Diameter is one but the type of aluminum must be 7075-T6 and the tube must be forged. There are lots of "Mil-Spec" buffer tubes out there that are the Mil-Spec diameter, made from 7075-T6 but are impact extruded. THIS. 6061 isn't "mil spec" any more than a cardboard paper towel roll is. Many manufacturers/retailers conveniently "forget" to add "diameter" (only) to the description. They know it's not "mil spec" and it's false advertising. I've emailed many a retailer/manufacturer of their false advertising and some have actually promptly changed their ad. They know that "mil spec" sells, but it's cheaper to do it non mil spec.. so you have to call them out on it. There are basically 3 types (with somewhat of a 4th): Commercial (6061, commercial size and material) "Mil spec Diameter" (mil spec size, 6061 commercial material) "Mil spec" (mil spec size, 7075-T6 mil spec material) ... with the 4th being the TRUE "mil spec" (mil spec size, 7075-T6 mil spec material, mil spec thread rolling (not cut threading)). |
|
Quoted:
I've been told it's not what the manufacturers tell you but what they don't. You can have a receiver extension that is mil-spec diameter that's not made from 7000 series aluminum just like the M&P 15 sport, it's 6061. There are those out there who will tell you a 6061 RE is fine but it's your rifle and your butt on the line, spend a few more dollars and get one you know the materials it's made from, BCM, Colt, etc. Remember you get what you pay for! Please show me a bent M&P Sport extension tube. Thread or link will suffice. This is a nonexistent problem seeking an irrelevant solution. Perhaps some Asian tubes of unknown manufacturer that fail may do so because the wall thickness is substandard, rather than due to the type of aluminum sourced. I want to see a bent Smith tube, please. |
|
Quoted:
anyone have any experience with this company or parts? How about the receiver extension? http://www.brownells.com/rifle-parts/receiver-parts/buffer-tube-parts/buffer-tubes/ar-15-m16-mil-spec-receiver-extension-prod70713.aspx Brownell’s is GTG. Don’t know about your pick. 080-001-046WB may be better. |
|
Quoted: The weakest portion of any collapse stock receiver extension tube is the threads. None are known to have broken anywhere else. Unless building a clone the material choice of 6061 or 7075 is of little consequence as it takes the same amount of force to break both as measured during a failure test which is buried somewhere in the archives of this site. Yield strength difference 6061~40K psi 7075~75K psi |
AR Sponsor