Barrel Length and Velocity loss WWB 40 Cal

[xd4zero]

I have been curious about the amount of velocity loss due to barrel length. Conventional wisdom seems to say that you can count on about 50 FPS loss for every inch of barrel length. Thanks to friends I had all 3 barrel lengths of XD's in 40 caliber available, so i decided to chronograph Wally Worlds economy pack of Winchester 165 gr FMJ target ammo in all three barrel lengths. The results were:

5" Tactical velocity was 1065.0 FPS
4' Service velocity was 1022.5 FPS
3' Sub Compact velocity was 966.3 FPS

All results were 10 shot averages with screens 10 feet from the muzzle and temperature was 80 degrees. At least with this load, it seems as if conventional wisdom was right.

[wJAKE19]

thats some good info to have..

[JD McDorce]

I would expect this to vary by type of powder used, with fast burning powders showing less variation and slower burning powders showing more variation. YMMV.

[xd4zero]

Originally Posted by JD McDorce

I would expect this to vary by type of powder used, with fast burning powders showing less variation and slower burning powders showing more variation. YMMV.

You are probabaly right, it will probably vary to some extent even between firearms. However, it probably will not vary a large amount unless you use an extremely slow powder. Winchester Ranger 165 gr SXT, which I would expect to be loaded with a slower powder than WWB did not vary that much:

5" Tactical velocity was 1220.5 FPS
4" Service velocity was 1170.5 FPS

which is exactly 50 FPS. I did not get a chance to check it out of the Sub Compact, I ran out of time. Maybe next time.

[ampleworks]

Talk about a hell of a jump from value packs to Ranger-Ts!