question on barrel speeds

[RW]

this is the question; why does the velocity increase from factory to custom and lastly between cut rifled and buttoned rifled my friend has a custom buttoned barrel in 300Win and I have a cut rifled that is not as fast as the button rifled custom? The factory barrels are the slowest and the cut is in the middle, Thank You rw

 

[Stan Taylor]

I think you need to elaborate on barrel length and a couple other things in order to get a good solid answer.

 

[geo.ulrich]

As Stanley said , bore dia., groove dia., twist, throats all come into the equation ......

 

[TAJ45]

Then, some barrels are just faster. Like identical engines in cars. Some just are.

 

[RW]

same length barrel length and the loads are the same 26" one in 10 twist?

 

[Drop Port]

Too many factors come into play to just label factory tubes slower. I've had fast and slow barrels in both factor and custom, to include cut and button. In my experience I've not found what you posted to be consistent. Just my .02

As an added note, one of the slowest barrels i ever worked with was button rifled. And one of the fastest is a current cut.

 

[Ackman]

A very tiny bit of bore dia. variation can make a difference. From my experience cut vs. buttoned has no effect. Here's an example with two of my barrels. Years ago, the 80's, I had a .223 built - Shilen match (buttoned), 26" long 14twist. About 3 months later I had the same riflebuilder do me a fluted H-S (cut rifling), 26" long 12 twist. Both were done with the same minimum spec. 0 freebore reamer. Fired brass would interchange from one gun to another. The kicker is, most accurate load (T-32 powder, 50gr. Blitz)) was exactly the same in both guns, velocity was identical and group size was identical. Didn't think I'd ever see anything like that.
I also have 2 buttoned .223AI barrels same length and twist, different makers, both chambered by the same riflebuilder with the same reamer. Same load, one barrel is 100+fps slower than the other.
You just never know about this stuff.