Bigbull Posted May 19, 2019 Author Report Share Posted May 19, 2019 Pretty sure mil spec gas tubes are 304 not 303. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted May 19, 2019 Report Share Posted May 19, 2019 2 hours ago, Bigbull said: Pretty sure mil spec gas tubes are 304 not 303. Nope, 303 stainless. It's the only thing that's ever been spec'd for the gas tube, once they came up with that. Quote Link to comment Share on other sites More sharing options...
Bigbull Posted May 19, 2019 Author Report Share Posted May 19, 2019 Gotta disagree on that , quick google search from multiple manufacturers say 304 , here is a clip from spikes themselves. Spike's Tactical has produced what we believe is the best gas tube out on the market for the AR-15 rifle. Our gas tubes are made out of Mil-Spec 304 stainless steel and then are Melonite coated for greater heat resistance, corrosion resistance, and lower reflection. These gas tubes are not only great for .223/5.56 uppers, but are perfect for the 5.45 uppers when you shoot cheap, corrosive, surplus ammunition. These are the same gas tubes that we install on our ST-15 rifles and all of Spike's complete upper receivers. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted May 20, 2019 Report Share Posted May 20, 2019 You'll be able to find a copy of the TDP out there somewhere - it's still up in a few places. It's the actual document with all the specs, and it clearly lists 303 stainless for gas tube material. 6 hours ago, Bigbull said: Gotta disagree on that , quick google search from multiple manufacturers say 304 , here is a clip from spikes themselves. Spike's Tactical has produced what we believe is the best gas tube out on the market for the AR-15 rifle. Our gas tubes are made out of Mil-Spec 304 stainless steel and then are Melonite coated for greater heat resistance, corrosion resistance, and lower reflection. These gas tubes are not only great for .223/5.56 uppers, but are perfect for the 5.45 uppers when you shoot cheap, corrosive, surplus ammunition. These are the same gas tubes that we install on our ST-15 rifles and all of Spike's complete upper receivers. Quote Link to comment Share on other sites More sharing options...
Bigbull Posted May 20, 2019 Author Report Share Posted May 20, 2019 I would love to see this data as I can’t find anywhere ? I buy my blanks from a company who makes these by the ton for many companies and they call out for 304 milepec? On top of that I haven’t been able to find a single gas tube in 303 ? So please find me this spec sheet ! Quote Link to comment Share on other sites More sharing options...
98Z5V Posted May 21, 2019 Report Share Posted May 21, 2019 17 hours ago, Bigbull said: I would love to see this data as I can’t find anywhere ? I buy my blanks from a company who makes these by the ton for many companies and they call out for 304 milepec? On top of that I haven’t been able to find a single gas tube in 303 ? So please find me this spec sheet ! It's in MIL-C-70559, and you're right - it IS gonna be hard to find a copy of that. You'll have to dig long and deep for it. Inside it, it will state 303 stainless for gas tubes, because 303 will never work-harden with heat. You can't heat-treat it. That's the exact reason it's the specified material. You see lots of manufacturers making 304 gas tubes - it's a hell of alot cheaper than 303. Ask a company "what's mil-spec about your gas tube?" Is it the shape, the bends? The OD or ID? If it's 304, it's not because it's made from the material that was specified in MIL-C-70559. Quote Link to comment Share on other sites More sharing options...
willbird Posted May 21, 2019 Report Share Posted May 21, 2019 Interesting that the 304 is actually more corrosion resistant. HOW TO CHOSE BETWEEN 303 AND 304 STAINLESS STEEL ALLOYS? 303 stainless steel is a free-machining grade of 304 that has sulfur added to increase its machinability. It is particularly desired for automatic machining operations for this reason. It also maintains the mechanical and corrosion resistance common to stainless steel. While the sulfur content does decrease its corrosion resistance and toughness when compared to 304, the increased machineability is worth it for certain applications. 304 stainless steel, among the most popular stainless steel alloys, has a minimum of 18% chromium and 8% nickel. Clinton Aluminum keeps a grade known as 304L #4 finish stainless steel sheet in stock. Its low carbon content makes it suitable for most welding operations that are common in construction and other industries. 304L also provides for excellent rust resistance and low intergranular corrosion. 304, like all austenitic steels, is non-magnetic in nature, and it also features low electrical and thermal conductivity. It also is recognized for its higher corrosion resistance than most other stainless steel alloys. Choosing between the two most often comes down to whether machining is a prominent part of your application. 303 stainless steel is specifically made for machining applications, whereas many 304 grades can be difficult to machine. This increased machinability will often make up for the increased cost, and the lowered toughness and corrosion resistance of 303. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted May 21, 2019 Report Share Posted May 21, 2019 I had always been told the gas tube was designed as the weak point in the system. When it fails it's an easy fix.?... @98Z5V explanation of not work hardening with heat makes the most sense though. Quote Link to comment Share on other sites More sharing options...
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