Home Forums Hunting & Shooting Ask The Gunwriters Hornet load: Is my chrnograph lying?

With 13 gr. of L'il Gun and a 35 gr. Ballistic Tip bullet, I'm graphing 3190 fps. This seems a bit high? I'd figured about 3100.

Pretty accurate, as well, but not a "half-inch" rifle.

I doubt it. I can't remember how many times I used "published" loads with velocity quotes and found 100 fps more and often time less than they say. I have had people TELL(argue) me I can't possibly get 2700 fps in my 35-284 with 225 gr bullets. I don't know if you know or remember him, but Gary Sitton was a friend of mine and he chronoed that load for me on his Oehler 3 screen. Also, some barrels are just "faster" than others.

With a 40 gr bullet and 13.5 grs of Lil Gun I get close to 3,000 fps from my No 1 B. I would expect that your load and is what your chronograph is showing. My rifle seems slow to me. I am sure others will have data to inform both of us.
Ernie

After a little tinkering on my calculator: from an 8 pound rifle with 13 grains of L'il Gun, a 24" barrel is capable of sending a bullet exactly 3190 fps if the bullet weighs 34.13 gr.

I'd say the chrono is probably working just fine.

Yup. I recorded 3296 fps with 13.0 LG and the new 30-gr Barnes VG bullet recently. Average.

What kind/make is it?

Li'l Gun seems to do amazing things in the .357 with 158 grain Hornady bullets.

It's a Brno Fox (now know as a CZ). Love that gun.

With my Ruger #1. 13.0 grains of lil'gun under 40 gr VMax's gets me a 40 shot average of 3072 fps with a spread from 2996 to 3110 so you don't seem out of line.

A lot of the speed differences come from the barrel length, free bore and etc. I use a 20" Handi rifle and 13.5 gr of Lil'Gun (this load doesn't fit well in WW brass) with a 40 gr V-Max, R-P brass, CCI400 and 1.93" OAL (that's a little long for most guns) that produces 2790 fps instrumental. That converts to 2815 fps MV.

I look at my Chrony as being +- about 1%. I think +- 1% is pretty close for shot to shot variability. If you allow a per cent for barrel variability and a per cent for day to day temperature variation you can get quite a departure from expected velocity without stacking all the variables in the same direction, and without having any one variable all that far from the norm.