Buffer tube: CMT and LMT

[greentips]

Hello all,

The CMT and LMT tubes are advertised as "mil-spec" which most of the time it is only referred to the dimension.

However, are they actually made out of forging like Colt, or just an extrusion tube of the proper dimension.

thanks!

[VA_Dinger]

I've never really given this much thought to my buffer tube. As long as it's the right size for my buttstock I'm fine with it.

[M4arc]

I'm pretty sure Colt does not manufacture buffer tubes in house. The get them from CMT

I don't know about the LMT tubes but when comparing my LMT buffer tubes to my CMT buffer tubes I'll be damned if I can tell a difference.

[greentips]

The buffer tube is pretty thin walled. I think that's the reason it calls for forging

[M4A2_L073754]

Originally Posted by M4arc

I'm pretty sure Colt does not manufacture buffer tubes in house. The get them from CMT

I don't know about the LMT tubes but when comparing my LMT buffer tubes to my CMT buffer tubes I'll be damned if I can tell a difference.

Only difference I can find, is bleed holes. CMT has traditional and LMT has 3 small holes on last three locking slots.

LMT is also dry lube coated exterior.

MN

[RAM Engineer]

Originally Posted by greentips

The buffer tube is pretty thin walled. I think that's the reason it calls for forging

It's been a long time since I had materials engineering, but I think with thin walled tubing, you are better off with an extrusion. Modern bicycle frames are pretty thin-walled extrusions (commonly thicker at the ends, ie double-butted). Economics, ease of manufacture and processing are some of the reasons to choose extrusion over forging/machining.

I'm not sure what post-machining stress-relief the buffer-tube requires. I think less is required of an extrusion than a machined forging.

I tend to agree with Va_Dinger.

Jason

[UPSguy]

Originally Posted by M4A2_L073754

Only difference I can find, is bleed holes. CMT has traditional and LMT has 3 small holes on last three locking slots.

LMT is also dry lube coated exterior.

MN

Does the CMT also have the protruding lip infront of the threads that the LMT has? I know the Vltor I had didn't. What is the purpose of that protruding lip?

[RAM Engineer]

Originally Posted by UPSguy

Does the CMT also have the protruding lip infront of the threads that the LMT has? I know the Vltor I had didn't. What is the purpose of that protruding lip?

Are you talking about the extended part of the buffer tube that hold the buffer detent in?

[UPSguy]

Originally Posted by RAM Engineer

Are you talking about the extended part of the buffer tube that hold the buffer detent in?

Yes, I think that is what I am talking about. MY Vltor tube did not have that lip, or at best it had a very tiny one. Probably would have never noticed this but when switching from a TD PR4 to a DD rear swivel mount there wasn't enough thread on the Vltor for the castle nut to tighten down on. Putting the LMT on with the lip solved the problem.

[Robb Jensen]

I like the new VLTOR tubes, they're mil-spec and have numbers on the top of them. I drill a hole on top of my CTR stocks so that I can use the numbers. I like the where the 2nd click out on the VLTOR tube is located, it's perfect for me for most of my shooting.

I run the CTR stocks with the optional rubber pad (it adds friction so that it doesn't easily slide around on my shoulder).

[Dport]

Originally Posted by UPSguy

Does the CMT also have the protruding lip infront of the threads that the LMT has? I know the Vltor I had didn't. What is the purpose of that protruding lip?

The LMT tube I had had it. My CMT tube does not. Go figure.

[C4IGrant]

The fit finish award goes to VLTOR. The best value goes to CMT.


C4