Can shorter barrels shoot faster? –

Can shorter barrels shoot faster? –

Barrel Speed: 6.5 Creedmoor Bartlein vs. Factory barrel muzzle velocities

In addition to gunsmithing and reloading content, is well known for the barrel length vs muzzle velocity experiments. Over the years I’ve tested all kinds of cartridges and provided empirical data sets for them. I was recently testing factory 6.5 Creedmoor ammunition and ended with muzzle velocity data in the same atmospheric conditions for 7 different types of factory ammunition in two different rifles (I’ll be posting other findings related to these data soon).

I tested a custom and factory rifle. The custom rifle, was a Surgeon action with a 22″ premium cut-rifled Bartlein barrel. The factory rifle was a Ruger Precision rifle with a 26″ hammer forged barrel. When I started looking at the data set I was shocked to see that the Bartlein barrel, despite being 4″ shorter, was always producing a higher muzzle velocity than the factory barrel.

In 6.5 Creedmoor- Effects of Barrel Length on Velocity 2019, test results indicated that (in our test barrel) for most loads an inch of barrel loss would reduce muzzle velocity an average of 14.8 ft/second. If barrel performance was equal, the 22″ Bartlein barrel should be approximately 59 ft/sec slower than the 26″ RPR barrel for a given load.

I tested seven different factory loads (from left to right), Federal American Eagle 120 gr OTM, Hornady 129 gr InterLock American Whitetail, Norma 130 gr OTM, Federal Gold Medal 130 gr OTM, Sellier and Bellot 140 gr FMJ, Winchester 140 gr OTM, Hornady 140 gr ELD Match and Hornady 147 gr ELD Match. While this isn’t an exhaustive list of factory 6.5 Creedmoor ammunition, it is representative of what is available to most shooters.

This is the custom rifle. It has a custom action with a barrel I threaded and chambered at my shop, 782 Custom Gunworks. I seated it in an MDT ACC chassis. The barreled action assembly includes these parts from Brownells:

My RPR is set up with a Nightforce NXS 5.5-22×56 scope in a Spuhr mount and a Harris bipod.

To record muzzle velocities I used a MagnetoSpeed barrel mounted ballistic chronograph. Most of the data represents ten-shot strings for the match loads and five-shot strings for the rest of the ammunition (with the exception of the 147 ELD, which was a 5 round string).

The 22″ Bartlein barrel produced faster muzzle velocities than the 26″ factory RPR barrel with all 7 loads. Despite being 4″ shorter, the Bartlein speeds averaged 8 to 88 ft/sec faster with an average muzzle velocity 39.8 ft/sec faster than the Ruger.

This data set shows that you can’t always predict with certainty how a load will behave in a particular barrel. Both barrels had been used quite a bit. Was the Bartlein faster because it is cut rifled, hand lapped or had a tighter bore? Was the Ruger Precision Barrel slower because it was hammer forged, carbon steel or possibly had a larger diameter bore? I’m not sure we’ll ever know, but speculating is fun!

I’d like to thank Brownells and for supplying the ammunition used in this test.

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