For a long time I have wondered about how barrel length affected velocity. I had always been told you need a certain length barrel for certain calibers. I have read when folks compared one gun to another with different lengths but I always thought that was not an apples to apples comparision. So I did a few test myself.
<br>All these were Shilen barrels. I used the same brass through out the whole test. All weighed to with 1 grain. Bullets were tested on the Juenke machine. Powder charges were weighed to .1 grain. The same rest, chronograph, Redding press, primers all from the same lot, bullets for the same box, same lathe, same crowning tool, same cutoff tool, and each rifle done from start to finish on the same day. Ambient temperature was the same because I shoot from inside the shop. I held the rifle the same way on the rest every time. I shot ten rounds first to break in the barrel. Then cleaned with Sweets and fired one fouling shot. Then shot five rounds and took the average. I used a midrange load fron the Nosler book, not too hot but certainly not a reduced load. Here is what I got.
<br>
<br>22-250 Hodgdon 380 34 grains Federal GM210M Remington brass 55 grain Ballistic Tip
<br>27 inches 3469 fps
<br>26 3451
<br>25 3425
<br>24 3407
<br>56 fps from highest to lowest
<br>
<br>270 Winchester Hodgdon 4350 54 grains Federal GM210M Winchester brass 130 grain Sierra
<br>27 inches 3115 fps
<br>26 3093
<br>25 3071
<br>24 3054
<br>23 3035
<br>22 3027
<br>21 3001
<br>114 fps from highest to lowest
<br>
<br>300 Winchester mag Federal GM215M Winchester brass 74 grains of Reloder 22 180 grain Partition
<br>27 inches 3055 fps
<br>26 3031
<br>25 3024
<br>24 3003
<br>23 2984
<br>22 2960
<br>95 fps from highest to lowest
<br>
<br>340 Weatherby Federal GM215M 250 grain Sierra
<br> 81 grains Reloder 22 Wby brass
<br>27 inches 2837 fps
<br>26 2817
<br>25 2809
<br>24 2791
<br>23 2777
<br>22 2755
<br>21 2731
<br>106 fps from highest to lowest
<br>
<br>I think I will do a little more thinking before I recommend a barrel length in the future. What do you folks think ?
<br>Charlie
