Cut-down barrels and barrel performance?

[BAC]

My last question was an NFA-related one regarding whether or not I can get an N4 barrel cut down to 12.5" for an SBR I'm building. Turns out I have a source in Wes at MSTN. Now I'm wondering how much chopping a barrel down changes its performance. I know velocity decreases with barrel length, but unfortunately that's all I know on the subject. Do barrel profiles also need to change as the barrel length decreases? Is it better to hold out for a factory short barrel, or is, say, a factory 12.5" no different than a 14.5" or 16" cut down to 12.5"?

Thanks in advance,


-B

[SethB]

Well, I'd say that there is no issue with chopping a barrel, but the N4 is Cold Hammer Forged, which introduces a lot of variables that I'e never experienced.

[Robb Jensen]

My chopped down 12.5" M4 barrel runs just fine. I pretty sure MSTN would do an excellent job.

http://img.photobucket.com/albums/v408/gotm4/gunpics/125SBR.jpg

[C4IGrant]

My last question was an NFA-related one regarding whether or not I can get an N4 barrel cut down to 12.5" for an SBR I'm building. Turns out I have a source in Wes at MSTN. Now I'm wondering how much chopping a barrel down changes its performance. I know velocity decreases with barrel length, but unfortunately that's all I know on the subject. Do barrel profiles also need to change as the barrel length decreases? Is it better to hold out for a factory short barrel, or is, say, a factory 12.5" no different than a 14.5" or 16" cut down to 12.5"?

Thanks in advance,


-B


The issue you get into when cutting down a barrel is the chrome flaking off. This is why Noveske will not cuts their N4 barrels down.


C4

[Robb Jensen]

The issue you get into when cutting down a barrel is the chrome flaking off. This is why Noveske will not cuts their N4 barrels down.


C4

That's weird. Does he use a different barrel blank for 7", another for 10", and another for 12", and another for 14", and another for 18", and another still for 20" barrels?

Or are the barrels cut to size and then chrome lined ?

[C4IGrant]

That's weird. Does he use a different barrel blank for 7", another for 10", and another for 12", and another for 14", and another for 18", and another still for 20" barrels?

Or are the barrels cut to size and then chrome lined ?


All the N4 barrels are cut to size and then chromed.


C4

[BAC]

gotm4, Are the sizes you're referring to their stainless barrels or new N4 barrels? I didn't think their stainless barrels were chromed.

Grant, so the issue I'm confronted by isn't a performance one as much as a durability one, then. That's interesting; I'd honestly never considered the chrome flaking off. Not sure how to address that one. Also, Seth brought up a point about the barrel being cold hammer forged. Does that introduce its own complications, or is it mainly the flaking of the chrome lining that I should be worried about?

(I'm this close to just buying the 12.5" Crusader barrel group and sending it to G&R; does anybody reputable make 12.5" barrels?)


-B

[MikeCLeonard]

BAC,

I'd give ADCO a call. They do a lot of barrel services including cutting barrels and have being doing that type of work very well for some time.

If there are any possible issues with chopping a chrome lined barrel....I'm sure they could fill you in.

[C4IGrant]

gotm4, Are the sizes you're referring to their stainless barrels or new N4 barrels? I didn't think their stainless barrels were chromed.

Grant, so the issue I'm confronted by isn't a performance one as much as a durability one, then. That's interesting; I'd honestly never considered the chrome flaking off. Not sure how to address that one. Also, Seth brought up a point about the barrel being cold hammer forged. Does that introduce its own complications, or is it mainly the flaking of the chrome lining that I should be worried about?

(I'm this close to just buying the 12.5" Crusader barrel group and sending it to G&R; does anybody reputable make 12.5" barrels?)


-B

I am not certain what you mean by "performance." The only thing you lose with going from a 16" barrel down to a 10.5 (for instance) is FPS. This only matters if you are trying to kill something out past 100yds and need fragmentation.

My suggestion is if you want an N4 in a 10.5, wait. Noveske is going to be doing some very shortly.


C4

[BAC]

Ah, I shoulda specified what I meant by performance. Performance, to me, is mostly measured in terms of durability/service-life. I know it'll be a while before I'm good enough with rifles to take advantage of the more accurate barrels, but at the same time I don't want to hamstring myself with a questionable one either. Mostly I'm interested in a barrel that's going to last me long enough to get used to the rifle as an SBR and how the 5.56 fares out of a short barrel. My main draw to the N4 barrels was their given durability and accuracy seemed exactly what I was looking for. I've been told to avoid stainless steel for my purposes, but I don't see any other kinds offered in 12.5"*

*12.5" barrel length was selected arbitrarily; I want an SBR, but don't know what sort of velocities to expect out of the shorter barrels and defaulted to the longer length. My heart's not set on a 12.5", just wanted to wait to see chrono'd numbers for the common military loads at the various barrel SBR barrel lengths.

Mike, thanks for mentioning Adco. I'll give 'em a call and see what they can tell me.


-B

[C4IGrant]

Ah, I shoulda specified what I meant by performance. Performance, to me, is mostly measured in terms of durability/service-life. I know it'll be a while before I'm good enough with rifles to take advantage of the more accurate barrels, but at the same time I don't want to hamstring myself with a questionable one either. Mostly I'm interested in a barrel that's going to last me long enough to get used to the rifle as an SBR and how the 5.56 fares out of a short barrel. My main draw to the N4 barrels was their given durability and accuracy seemed exactly what I was looking for. I've been told to avoid stainless steel for my purposes, but I don't see any other kinds offered in 12.5"*

*12.5" barrel length was selected arbitrarily; I want an SBR, but don't know what sort of velocities to expect out of the shorter barrels and defaulted to the longer length. My heart's not set on a 12.5", just wanted to wait to see chrono'd numbers for the common military loads at the various barrel SBR barrel lengths.

Mike, thanks for mentioning Adco. I'll give 'em a call and see what they can tell me.


-B


If your definition of performance is longevity, then stay away from SS barrels.


C4

[BAC]

Understood. Patience or a cut-down N4 barrel it is, then, until I find numbers to shift me from a 12.5" barrel. Thanks!


-B