Barrel Velocity

J

JonE

Guest
I am in the process of collecting the parts for another project, this time a long range 308. In looking at all the new advertising and claims from various barrel makers I see at least two make the claim that their style or method of rifleing increases velocity. Is this hype, wishful thinking or fact? I think we all know that for reasons unknown we sometimes get a fast barrel and sometimes a slow one, but can a barrel maker honestly say and prove that his barrel is X number of fps faster than the competition?
 
It is fact not fiction that certain rifling profiles deliver higher velocity. The 5C rifling will normally give significantly higher velocities than conventional rifling.
 
I shoot British match rifle, limited to .308 Winchester calibre at 1000-1200 yards. We use long throats to get maximum velocities out of 190-210 grain projectiles (example 2740 fps from 210 SMK or Berger) using generally double based VV powder.

My friend with the 5R barrel is getting 50-75 fps more velocity with 1½-2 grains less powder than all the rest of us. One swallow doesn't make a spring, but it sure is a compelling story.
 
John Kielly said:
I shoot British match rifle, limited to .308 Winchester calibre at 1000-1200 yards. We use long throats to get maximum velocities out of 190-210 grain projectiles (example 2740 fps from 210 SMK or Berger) using generally double based VV powder.

My friend with the 5R barrel is getting 50-75 fps more velocity with 1½-2 grains less powder than all the rest of us. One swallow doesn't make a spring, but it sure is a compelling story.
Click to expand...


Or his scale is improperly calibrated :)
 
To do a fair test and to take most of the normal variations of individual barrels out of the results I would think you would need 25 barrels from each barrel maker all with the same caliber and twist and contour. Then each of those barrels would have to be fitted, cut to the same length, chambered to the exact same headspace with the same reamer and tested with the same hot load in the same action. 25 shots from each barrel, ignoring accuracy - recording velocity only with a quality system equal to an Oehler 35P.

That should give a fair representation of velocity differences between makers.
 
Dennis Sorensen said:
To do a fair test and to take most of the normal variations of individual barrels out of the results I would think you would need 25 barrels from each barrel maker all with the same caliber and twist and contour. Then each of those barrels would have to be fitted, cut to the same length, chambered to the exact same headspace with the same reamer and tested with the same hot load in the same action. 25 shots from each barrel, ignoring accuracy - recording velocity only with a quality system equal to an Oehler 35P.

That should give a fair representation of velocity differences between makers.
Click to expand...

Thats why I am asking, I have been around this game too long to believe advertising hype. I spent a number of years as a gunsmith (not benchrest). If I had a dollar for every customer that believed a gun writer and doubted me, I could have retired rich
 
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