Velocity change with barrel length.

[Forpest]

While searching for a reamer print today, I ran across the data from a barrel cutoff study done by By Smalley (I helped - running the hacksaw and doing some shooting. This was done using a 5/35 SMc , br-4 primers, moly coated bullets, 32 and 40 grain bullets. 32 grain bullets on top of 31.5 grains of H 322, and 40 grain bullets over 32 gr benchmark. Hacksaw cuts, not attempt at crowning. 45 fps per inch, pretty linear throughout! Accuracy was better than 1 inch with all groups. . Enjoy!

 

[GLShooter]

I've found 25-50 depending on the chambering.

 

[K22]

It depends on the cartridge, powder, powder charge, and barrel length.

For example, shooting a 300 Win Mag with the appropriate large charges of slow burning powder requires a barrel length of at least 24 - 26" to achieve the desire velocity touted for this caliber. When one uses a rifle with a shorter barrel you start to obtain 308 and 30 06 velocities.