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View Full Version : Can you figure this velocity?



Charlie Two Tracks
03-07-2011, 08:25 PM
I know I need to get a chrony but funds say no for now. I loaded up some LEE 158 gr. RNFP sized to .3585 and put 13 grains of AA #9 under them with TULA mag primers. The Boolist actually weighted 160 grains. In the new Lyman 4th edition, it has a 158 gr. Lyman #358665. It has load data the has 12.4 grains of #9 moving it at 1147 fps up to 13.7 grains at 1326 fps. I then realized that this was shot out of a 4" barrel. I shot them out of a GP-100 with a 6" barrel. They shot great! I was just wondering what the velocity was..... just because I guess

btroj
03-07-2011, 08:35 PM
Book velocities are frequently way different from what I get in my gun. Revolvers can be the worst as the throat and barrel dimensions can make a huge difference in pressure and velocity.

As an example, my SRH struggles to top 1250 with a 240 XTP and 24 gr of H110 even through the manuals say I should be up around 1400. My gun has .432 throats so the bullet doesn't seal in the throats well at all. Go to a Keith type bullet over a max charge of AA9 and I can get over 1400 easily. Those are sized .432.

Long story short, you are most likely between 1100 and 1300 fps. Hard to get much closer than that. Too many variables.

Brad

fecmech
03-07-2011, 08:57 PM
My 6" Gp100 with 13.3/AA9/158 rn is 1260 fps and 1630 FPS out of a 24" Rossi rifle. My 6" gp runs close to Lymans cast bullet handbook 4" velocities.

Charlie Two Tracks
03-07-2011, 09:19 PM
Thanks guys. I was just curious. I knew there would be a lot of variables.