Target velocities

[tcoz]

Is there such a thing as a target velocity to try and attain with a specific weight bullet in a certain caliber?  I’ve never seen target velocities listed in any kind of reference so I usually shoot for the same velocity as a good commercial ammo with the same bullet weight.

[jkrispies]

It depends on your load and purpose.  

 

For pistol I try to keep it just under the speed of sound to avoid cavitation through the sound barrier as well as keeping the noise level down while maintaining as high of a subsonic velocity as I can get away with.  

 

For rifle, I try to pick a bullet (or several) that looks good, get its ballistic coefficient, and plug it into a ballistic calculator to figure a good velocity that will give me the zero and point blank combo I want. If it’s a long range round then other drop points might come into play as well.  I then go from there picking from the various powder choices that will give me the velocity I want to match my chosen zero and point blank.  When choosing powder, I’ll also try to go with one that is consistent through temperature variations such as Varget and RE-15, but ultimately I’ll real life test a bunch and go with whichever gives me the most consistent velocity and accuracy on paper.  I’m not a bench rest shooter, though, so I’ll usually quit when I find one that works good enough in my mind rather than testing ad nauseum.  

 

So, to answer your question, yes, I do refer to off-the-shelf manufacturer load data to a certain extent, but that’s pretty early in the research, usually when I’m plugging in initial ballistic calculations before I get into the more individualized powder data.  

Edited June 3, 2018 by jkrispies

[jwhittin]

Many shooting sports have a minimum power factor you must meet.  The power factor is simply the Bullet weight*velocity/1000. You need to load to a higher velocity which ensures you don't fall below the required minimum velocity to make power factor for your bullet weight. That's your desired velocity.  

 

The rule books for the different shooting disciplines explain everything. Or just do a web search.  

 

 

[jkrispies]

1 hour ago, jwhittin said:

Many shooting sports have a minimum power factor you must meet.  The power factor is simply the Bullet weight*velocity/1000. You need to load to a higher velocity which ensures you don't fall below the required minimum velocity to make power factor for your bullet weight. That's your desired velocity.  

 

The rule books for the different shooting disciplines explain everything. Or just do a web search.  

 

 

Yeah, that too!!!  If that’s the benchmark, try to give yourself about 5 pf in wiggle room to account for variances.  You don’t want to measure too low on match day.  

Edited June 3, 2018 by jkrispies

[Hi-Power Jack]

10 hours ago, tcoz said:

 I’ve never seen target velocities listed so I "shoot for" the velocity of commercial ammo with the same bullet weight.

 

That's usually a good reference point.

 

I frequently like loading lower than factory loads for a nice soft shooting load.  I load 

9mm rounds around PF 110 for my KelTec P11 (very light gun).

 

I also play with the velocity to see if accuracy will be affected - I like accurate loads,

so I might go higher or lower in velocity to attain a more accurate load.

 

For shooting 9mm Major, of course, I go way above commercial rounds - but follow

the "target velocity" needed to attain Major PF (165+).

 

If you're shooting .40 or .45 Major, you can get by with much lower velocities than

factory ammo, and still make Major.

 

For .223 and close range shooting, you can go MUCH lower than factory ammo and

still have a very nice, accurate soft shooting load     

 

 

[jwhittin]

Here is how to do it.