Quoted: That's pretty much what I thought, but my curiousity got the better of me, has anyone ever done any empirical tests with match ammo to find out how much it really amounts to. I'd like to see the info, even if it is just to satisfy my idle curiousity. You can never know too much about your rifles hr |
How's this? Hornady 55 grain TAP, lot #020147.
10 rounds fired from a Colt 16.1" light weight barrel with a 1:7" twist chronographed at
2871 fps with an ambient temperature of 79 degrees F.
10 rounds of the same lot of ammo fired from a Colt 16.1" M4 barrel with a 1:9" twist chronograped at
2872 fps with an ambient temperature of 77 degrees F.
Now on two other occaisions using the same lot of ammo fired from the same Colt 16.1" M4 barrel with a 1:9" twist I chronographed 10 shot strings with velocites of
2890 fps at 79 degrees, and
2892 fps at 77 degrees.
As you can see in these examples there is a greater difference in velocity in two different strings of the same ammo fired from the same barrel than there is between two different barrels with different twists with the same ammo.
I've chronographed thousands of .223 and 5.56 rounds and have yet to see a statistically significant difference in velocity in relation to barrel twist. Maybe in extremely controlled conditions you will see a difference, but in a practical setting I have yet to see it.