Home Forums Hunting & Shooting Ask The Gunwriters Standard Deviation

What number would you consider acceptable in a 22 Hornet small game loading?

FWIW to me velocity SD is more and more important as the range lengthens. For the distances at which I'll use my .22 Hornet - 200 yards maximum on a still day - it is not something I worry about. In still conditions I can group five rounds under 2 inches at 200 consistently with my rifle, and that is about good enough to knock off a rabbit or similar sized critter at that distance from a rested position when conditions favour it. I simply don't shoot anything further away with that rifle, and while I have SD figures written down somewhere, in practice I don't worry about it with this round.

YMMV

Depends on your purpose, doesn't it?

Don’t deviate from the standard

I don't have an answer for that, but I do have a question: How many shots will you fire to generate your estimate of SD?

Exactly--and it has to be tied into the other important factors also mentioned.

It takes more shots to get a good estimate of standard deviation than most people suppose, and when you do get it, it is a lot less important than many suppose.

That said, the commercial ammunition I have tested had an SD around 35 FPS. It's easy to handload to 20 FPS, and with a little effort you can get into the low teens. But it is practically never worth the effort to do that.

9

We’ll I’m at a SD of 32 FPS on a 10 shot string. Must be decent as I’m getting 1/2” to 5/8” for my 5 shot groups at 100 yards consistently off a rest.

41

If I'm getting good accuracy, I never look at these numbers.

I like these responses.

Lol….ok.

Just trying to use all the information my Chronograph gives gives me to my advantage

For a 22 Hornet that the OP is talking about this is acceptable advise, for a longer range cartridge you have to look at the numbers

Can't help myself:

Most handloaders have no clue how many rounds ("samples") are required to come up with a reasonably valid standard deviation number. In fact the ONLY reason they're vaguely aware of SD is because their inexpensive chronograph provides an SD number, even of only three rounds.

The major ammo factories I've visited (including their ballistic test labs) generally consider at least 40 rounds as minimum to provide a meaningful SD number. This doesn't mean their ammo will always result in the finest accuracy, but it does provide a better chance of pretty fair accuracy in a wide variety of rifles.

It's also much more meaningful than the SD number handloaders arrive at after a 3-shot string--which has about as much statistical reliability as betting on an inside straight.

I'd stop thinking about SD. Check it at 200 to see what sort of accuracy and drop you are getting out at the further distance, and then get off the range and go shoot some small game with it.

On the "turn" or the "river?" Big difference!
(Couldn't help myself either... LOL)

I think you're right. I suspect that shooting beyond about 400 - 500 yards will bring real meaning to these numbers that many obsess over needlessly at shorter ranges. My response was in regard to the shorter distances because most shooters, myself included, don't shoot at long range.

The primary use of the 3 shot SD calc is to come on here and brag about it.

I'll add an observation. As others have said, It means virtually nothing in a small data size. But what i have observed over time (decades, in some cases) is that more often than not, a load (even with only 3 shots of data per string) is more likely than not to remain consistent over time (effectively, a larger data size). Looking over the multiple pages on my spreadsheet, low SD/AD loads also show a trend to be more accurate. So when starting out, i use it as an additional indicator of potential.
But, the only real data that matters is consistent accuracy over time. I can't afford to shoot statistically relevant strings when developing a load so have come to rely on these observations.

My hypothesis is that this trend would be true for high SD/AD loads, but honestly, I do not have data over time for "underperforming loads", nor have i plotted all of my data on a graph which would be skewed towards loads that perform.

Again, these are trends based on observations, not rules.