Velocity vs claimed velocity

[FW Conch]

One more thing that the data shows is that the change of 25 fps per inch of barrel length is only rough estimate around a specific barrel length.

It is right on for a .223 bullet at 28 inches but off by 6.5 fps at 24 inches. for this bullet and powder load.

I suspect that estimated change may not be consistent for all bullet types in the same caliber since friction will be different depending upon the amount of bullet body touching the rifling.
I'm not even sure that factor would be accurate for all calibers.
There are probably a couple of other factors that might also complicate the estimated change per inch as well.

CF, Your research, experimentation, and attention to detail are enlightening. I go back to Your posts often for a refresher. Wish I could shoot as much as You do.

Thank You

[Mr.Snerdly]

CF, that is extremely useful information. The 40 degree temperature was about what I was shooting at and it comes reasonably close to what I was getting. Some variation but there are enough other variables that it makes sense it wouldn't be the same.

[CFJunkie]

Mr.Snerdly,

Happy to help.

That's just one less thing to worry about that can distract your concentration.
Now you can concentrate on your consistent set up to achieve more of those really tight groups.

[charlie b]

This thread is drifting away from Mr Snerdly’s original question, but since He seems to appreciate all good information, I hope He won’t mind. I’m guessing the reason for these light loads is for Military or Law Enforcement use. Reduce the muzzle velocity to subsonic, and eliminate the crack, and suppress to minimize the noise. Other than that, I don’t get the purpose of “mouse fa#*” loads.

Yes, it is a bit of drift :)

MF loads are usually for small game, rodents, or just practice when you don't want a loud boom. Before primers became a problem I shot a lot of them, mostly with cast bullets, as a fun 100yd load. Kinda like rimfire but quieter. Some hunters will carry a few to kill small game for the pot at night. Also good for kids and other fun shooting.