AR15 stock won't fit?

shhh said:
The crests of the threads are truncated on the commercial tube, therefore not as strong. But the pitch is the same, so either will spin on to the lower receiver. True military tubes are machined to profile from 7075 and have rolled threads. Commercial is cheaper to make because they are made from 6061 extrusions, which has to be a larger diameter to cut (not roll) the threads.

Or so I've read.

Side note for the inexperienced: always grease aluminum threads before assembly. Snug it up dry and you're guaranteed thread damage.
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Got it, thanks folks. Much appreciated. Sorry for the noob questions, hope I didn't irritate anyone. cheers.
 
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cr5 said:
Milspec are 7075 compared to 6061 and are manufactured differently. The milspec version is tougher.

http://www.ar15fornoobs.com/mil-spec-vs-commercial-spec-buffer-tubes
http://www.thebangswitch.com/the-infamous-mil-spec-standard/
http://thearguys.com/ar-facts/difference-ar-15-buffer-tubes/

I always buy milspec tubes when building an AR or replacing the buffer tube. Mostly just for parts compatibility across all my AR's but also because most reading says they are slightly better and stronger.
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Fair enough. Looking at the picture they look damn near the same, however Forging, 7075 and Rolled Threads add significant significant machine and material investments. Cheaper in the long run, but certainly a large up front investment.
 
I actually was under the impression my new norinco AR would be all mil-spec, but after pulling the stock off it's most certainly a commercial buffer tube. That diagram really helped me to figure it out quickly.
 
highbeam said:
I actually was under the impression my new norinco AR would be all mil-spec, but after pulling the stock off it's most certainly a commercial buffer tube. That diagram really helped me to figure it out quickly.
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Milspec is kind of a misleading term...very few commercial rifles meet all the criteria.
Keep in mind milspec is not just a parts compatibility standard, but also has to do with the type of material used, the finish applied, and even how to QC the parts afterwards. Norks are about as far from milspec as you can get (along with NEA LOL), but generally pretty close to spec for parts compatibility meaning other AR parts should fit....most of the time.
 
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