velocity loss
-
twobitokie
- Founding Member
- Posts: 96
- Joined: 24 Feb 2012 22:19
- Location: where arizona and callifornia meet
- Been thanked: 1 time
velocity loss
can onyone give the approx velocity loss between the longer barreled 45-70 and the rio grande 20 inch?
-
Ranch Dog
- Site Admin
- Posts: 9399
- Joined: 23 Jan 2012 07:44
- Location: Inez, TX
- Has thanked: 1838 times
- Been thanked: 2281 times
Re: velocity loss
I could if you gave me a little more information. When you say "longer barreled" what length are you talking about? Also, when it comes to the 45-70 Govt cartridge, you need to talk about what pressure you want to compare as it runs from 28 all the way up to 60 KPSI depending on the firearm.twobitokie wrote:can onyone give the approx velocity loss between the longer barreled 45-70 and the rio grande 20 inch?
As an example, with my Marlin 1895G (Guide Gun) I loaded the 425-grain bullet to 42.0 KPSI and saw 1785 FPS. I'm loading the RG4570 to 35.0K PSI because it is a 336 frame vs. the 1895 frame, but the velocity loss from less pressure is not as great as you might expect. I'm seeing 1730 FPS, a difference of 55 FPS. The RG's barrel is 1.5" longer than that of the Guide Gun.
The everyday 1895, with it's 22" barrel at 42.0K PSI would deliver 1845 FPS. What that 110 FPS difference spells out at 100 yards is 300 foot pounds of additional energy. 2160 FPE for the RG4570 and 2460 FPE for the 1895. There are a number of ways to define terminal performance but that really is not much difference. I doubt that any North American hoofed big game animal is going to be able to tell.
Michael
