Q: I’ve always strived to achieve shot-to-shot velocity uniformity when developing a handload.
I’ve been chronographing my favourite loads to see just how uniform their velocity is.
To my surprise, I found some of my most accurate loads are not at all uniform in terms of velocity.
I set to and developed some new handloads that produce very uniform shot-to-shot velocities, but poor accuracy.
Now I’m wondering whether shot-to-shot uniformity has any effect on accuracy at all. What’s your opinion about this?
Ken Leather
A: Nothing is carved in stone when it comes to reloading.
My experience has convinced me that uniform charge weights do tend to produce more uniform velocities, at least most of the time.
Even if all charges are carefully weighed, however, some load combinations do produce larger shot-to-shot variations (extreme spreads and standard deviations) than other loads.
While uniform shot-to-shot consistency can indicate a well-balanced load, it may not have much effect on accuracy.
The final proof can only come from shooting a series of groups, not from uniform velocities.
Over the years I’ve found that large shot-to-shot variations are more common with over-bore cartridges than with cartridges having a large bore and relatively small case capacity. But this doesn’t necessarily indicate that the latter is going to be more accurate.
Other factors such as the primer may influence velocity uniformity, but not affect accuracy. Often the rifle’s barrel may not do best with a given bullet, and a change might increase accuracy.
In the end, it is all a matter of trial and error to discover what works best in your particular gun.
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