Gunsmithing Barrel blanks vs cutting a prefit

[jbjh]

All things being equal, isn't buying a prefit/prechambered barrel and cutting it to the length I want the same as ordering to spec from the same maker?

In other words, why wait 15 weeks if the only difference is length? Or am I missing something?

 

[Drifter™]

I've gone that route a few times with AR barrels with no perceivable ill effects.

 

[Wannashootit]

"Pre-fit" barrels, unless you're talking Savage, are threaded and short-chambered, and need final finish reaming to set the headspace. At least, that's what I usually see referred to as a "pre-fit" barrel.

I'm not really sure what you're asking when you're referring to "length" and the fact that you used the word "blank"...

AR barrels are a completely different animal. Is that what you're referring to?

 

[bodywerks]

Yes it's the same, except the cost of cutting and recrowning the barrel.

 

[Guest]

All things being equal, isn't buying a prefit/prechambered barrel and cutting it to the length I want the same as ordering to spec from the same maker?

No it's not. A blank can be machined to fit your receiver perfectly, as a good Smith will not allow the tolerances to stack either way. On top of that he(smith) is able to clock your muzzle to 1200 hrs when torqued correctly to your receiver.

 

[jbjh]

Sorry I didn't give more info in the OP -

A barrel manufacturer is quoting me 12-15 weeks for a pre-fit Savage barrel made to my desired length. When I asked why they couldn't grab one off the shelf and cut it down for me (same profile), they said that once the centerline was determined, altering the barrel would change the harmonics. I believe that to be true, but what I don't believe is that it would degrade the accuracy.

I might just be an impatient ass, but am I going to be throwing money away if I buy a 26" barrel and cut it down?

 

[Guest]

If your going with a pre-fit as a final either way, no it will not matter. Sorry, I thought you were looking at a blank vs a pre-fit, because there is a big difference with the final product with those.

 

[jbjh]

Thanks. That's kind of what I thought. Sorry for the badly thought out 1st post

If your going with a pre-fit as a final either way, no it will not matter. Sorry, I thought you were looking at a blank vs a pre-fit, because there is a big difference with the final product with those.

 

[MarinePMI]

Actually, it can matter, and often does.

When starting with a blank, a gunsmith (or in this case, the vendor) needs to know the finished length. The reason being; every blank tends to have one end that is slightly tighter than the other. This tighter end becomes the muzzle. The loose end gets chopped back to meet the desired length.

If they were to take a pre-made savage barrel and chop of the muzzle to meet spec, well, it'd be a gamble if the bore remained as tight. Hence their requirement to know the length first, and start with a blank rather than chop a pre-made one already completed to a different length. Just my thoughts on the subject...

YMMV...

 

[bodywerks]

Sorry I didn't give more info in the OP -

A barrel manufacturer is quoting me 12-15 weeks for a pre-fit Savage barrel made to my desired length. When I asked why they couldn't grab one off the shelf and cut it down for me (same profile), they said that once the centerline was determined, altering the barrel would change the harmonics. I believe that to be true, but what I don't believe is that it would degrade the accuracy.

I might just be an impatient ass, but am I going to be throwing money away if I buy a 26" barrel and cut it down?

No you won't be throwing money away. The Smith just didn't want to spend the time to indicate the barrel back into the lathe and cut n recrown. That can take as much as 2 hours.
Only money you're gonna be out is two hours shop labor or the cost of diy parts to cut and recrown yourself.

 

[jbjh]

Thanks for the replies. I'm working with the barrel maker on a variation of their manufacturing process. I'm debating getting the barrel shipped full length and then documenting the accuracy difference from the original and the cut down using the same load.