Moses...
Here's a post made by master gunsmith Charlie Sisk a few years ago showing velocity losses in varous calibers as he cut off the barrels, an inch at a time.
BTW... the barrel length on a Ruger #1 International (aka "RSI") is 20 inches, not 18 inches.
I hope this helps to answer your question. (See below)
Strength & Honor...
Ron T.
Charlie_Sisk
Campfire Ranger
Reged: 02/21/02
Posts: 1321
Loc: Dayton, Texas Been doing a little more experimenting.........
#88566 - 09/14/02 03:15 PM Edit Reply Quote
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.
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.
22-250 Hodgdon 380 34 grains Federal GM210M Remington brass 55 grain Ballistic Tip
27 inches 3469 fps
26 3451
25 3425
24 3407
56 fps from highest to lowest
270 Winchester Hodgdon 4350 54 grains Federal GM210M Winchester brass 130 grain Sierra
27 inches 3115 fps
26 3093
25 3071
24 3054
23 3035
22 3027
21 3001
114 fps from highest to lowest
300 Winchester mag Federal GM215M Winchester brass 74 grains of Reloder 22 180 grain Partition
27 inches 3055 fps
26 3031
25 3024
24 3003
23 2984
22 2960
95 fps from highest to lowest
340 Weatherby Federal GM215M 250 grain Sierra
81 grains Reloder 22 Wby brass
27 inches 2837 fps
26 2817
25 2809
24 2791
23 2777
22 2755
21 2731
106 fps from highest to lowest
I think I will do a little more thinking before I recommend a barrel length in the future. What do you folks think ?
Charlie
.338 Winchester & .257 Roberts
Here is the info about the 338 Win and the 257 Roberts.
338 Win mag
Winchester brass
Federal GM215M primers
Reloder 19....73 grains
250 grain Partitions
27 inches.....2806 fps
26 inches.....2787 fps
25 inches.....2761 fps
24 inches.....2743 fps
23 inches.....2716 fps
22 inches.....2697 fps
21 inches.....2676 fps
20 inches.....2656 fps
150 fps from 27 inches to 21 inches
257 Roberts
Federal GM210M primers
Remington brass
H-4350....45 grains
120 grain Partitions
27 inches.....2860 fps
26 inches.....2834 fps
26 inches.....2815 fps
25 inches.....2815 fps
24 inches.....2798 fps
23 inches.....2775 fps
22 inches.....2760 fps
21 inches.....2739 fps
20 inches.....2717 fps
143 fps from 27 inches to 20 inches
I want to test this on the next 450 Marlin I build and on a 222 Remington. If I get the same results with those, in my mind the test is over. I think this will be enough data to support the findings. Are there any folks out there who have a degree in this sort of thing ? Maybe explain how many data points would be needed to be able to say this would work with the majority of calibers ? Someone with experience in statistical (spell check) quality control?
Charlie
--------------------
Sisk Rifles
400 County Road 2340
Dayton, Tx 77535
www.siskguns.com
[email protected]
1-936-258-4984
The data and opinions contained in these posts are the results of experiences with my equipment, componentry, and testing methodology ONLY. As your equipment, componentry, and methodology is different, NO CONCLUSIONS SHOULD BE DRAWN FROM ANY DATA PRESENTED, nor should any data presented form the basis for any load development. DO NOT, UNDER ANY CIRCUMSTANCES, ATTEMPT TO REPLICATE THESE RESULTS, as doing so could be extremely dangerous.
