Alright, I'll admit, I'm not all that great of a shot. Consequently, I don't necessarily compare my group sizes when testing groups of handloads. For instance, if one group shoots 1.6" at 100 yards while another shoots 1.4", is it really the load being more accurate, or did I happen to shoot a little better that time? That's the question I'm usually asking myself.

While testing loads, I always use a chronograph to record the velocity, as many handloaders do. I also record the standard deviation of the group's velocity to get an idea of how consistent my handloads are. However, I've often wondered how much the standard deviation relates to downrange accuracy. I generally go with the load that gives me the smallest velocity deviation regardless, but sometimes I wonder if that's the best thing to do.

What do you guys think?

I say yes, absolutely. Less variance from shot to shot should translate to less variance on the target. However, I'm not sure how one would quantify net effect of perfectly uniform velocity. As reloaders, we control the things we can, like measuring powder the same way every time, keeping brass in batches and trimming/sizing them the same way, we use the same brand components. Unfortunately, there are a lot of things we cant control, like the consistency of powder and primers from lot to lot, the construction of the bullets, etc. Fortunately, we have a lot of quality components available to us. However, at the end of the day, we do the best we can with what we have.

I'm like you - when I test loads, I'm not going to distinguish between a 1.4" and a 1.6" group. On the other hand, you can really see the difference between that 1.4" group and an 1/2" group.

Looking at the variance in velocity might be a handy bit of information, but it needs to be correlated to other data, like group size, in order to be useful. If you're able to find a relationship between one and the other, you might be on to something. Just keep in mind that you'll need several data points to establish such a relationship. Its hard to say how valuable that information is going to be in the long run, but its interesting stuff nonetheless. Not to mention, if you do start to see some big fluctuations in velocity, it may help you diagnose a problem with components or procedure.

There's alot of factors in accuracy like how consistent is your rest is it exactly the same each and every time ? How many shots in a group ? Is your barrel heating up ? Did you clean between shots ? You have to take out all other possibilities before you can make that call imo.

I agree with muzzlestuffer. There's so much more than minor velocity differences. Even the amount of cheek weld or where the forearm is setting on the bags can cause a change in POI although ever so slightly.

Velocity spread - what most folks refer to in "ES" or Extreme Spread, or "SD" or Standard Deviation" - doesn't tend to make much difference inside 300yrds. The further out you shoot, the more it will matter.

Get your ES under 20 for a hunting load and you're doing better than average. Get it into single digits and you're chasing top level benchrest quality consistency powder charge, neck tension, primer brisance, seating depth, bullet weight...

The easiest "trick" in finding a low velocity spread, low ES, is to find that happy window in your powder charge in which small changes in powder charge don't result in much if any change in velocity. There was a thread on OCW method recently in which I posted a picture, read that thread and you'll get a bit of a picture as to how it's used to find a low ES.