Thread: 3 vs 5 shot groups

I was looking over some of my old targets for load development (seating depth specifically) comparing 3 and 5 shot groups. And from what I could see I would have reached the same conclusions with 3 shot groups.

Has anyone found the same?
Has there been cases where 3 shots have lead you astray?
What were you testing; seating depth, charge, etc?

I would like to hear from people who have actually tested this. Not; I know someone..., the internet says..., statistics state...

Thanks

Not an expert, but waiting for the barrel to cool does make a difference. More waiting around with 5 shots. Would love to hear from people that have properly tested it too.

Only every check sights with 3 rounds

RUMPY bought new rifle...I did up 4 diferent lots of reloads for it..plus he had some factory

factory 3 shot group,tiny...as in half inch.
reload groups 5 shots...all around 1-1 1/2"
interesting bit when I got calipers out...the AIMING POINT was 1 1/2" so all groups were within aiming mark....
when took 1 shot out of groups they shrunk to under inch ,when took 2 worst shots out...all were under 3/4"

I normally only fire three for a group to sight in....

The more shots in a group, the more sure you can be in your results.

10 shot groups are where it is at for REPEATABLE, consistent results

To be honest, the biggest variable in most group shooting to test stuff like seating depth, charge etc, is actually the shooter himself...

Originally Posted by Micky Duck

RUMPY bought new rifle...I did up 4 diferent lots of reloads for it..plus he had some factory

Would you have ended up with the same 4 loads using 3 shot groups? Removing them in the reverse order of fire (not just excluding the worst 2)?

Originally Posted by ebf

10 shot groups are where it is at for REPEATABLE, consistent results

I completely agree. If I’m proving a load, testing a process, comparing loads/bullets I use 10. However for load development this would be completely impractical.

I’ve always tested with four shot groups and once I’ve settled on a load I’ll test it again and then a third time to to make sure it’s consistent… as the Irish say ‘to be sure to be sure’

I find the best use of a 3 shot group is to identify loads during development that aren't any good.

Tight 3 shot groups may ( probably will) expand when turned into statistically useful 10 shot groups, but a big 3 shot group is never going to shrink by putting more into the target.

Originally Posted by Magnetite

I completely agree. If I’m proving a load, testing a process, comparing loads/bullets I use 10. However for load development this would be completely impractical.

That is why when I do initial load development, I focus on techniques that minimize shooter variability. I trust a Magnetospeed or Labradar enough to fire smaller sample sizes to identify nodes.

Once I get past that point, and want to look at seating depth or other variables, I tend to fire larger number of shots per group, or preferably, multiple groups over multiple days to mitigate that.

But then again the variability may be because of poor charge weights...

And the hamster keeps going round and round

Originally Posted by ebf

That is why when I do initial load development, I focus on techniques that minimize shooter variability. I trust a Magnetospeed or Labradar enough to fire smaller sample sizes to identify nodes.

Once I get past that point, and want to look at seating depth or other variables, I tend to fire larger number of shots per group, or preferably, multiple groups over multiple days to mitigate that.

But then again the variability may be because of poor charge weights...

And the hamster keeps going round and round

BINGO - Thats the way to do it. ...

Originally Posted by Ross Nolan

I find the best use of a 3 shot group is to identify loads during development that aren't any good.

Tight 3 shot groups may ( probably will) expand when turned into statistically useful 10 shot groups, but a big 3 shot group is never going to shrink by putting more into the target.

This. No point wasting ammo on something that a three shot group can tell you is a lost cause. Then when something looks good either do multiple three shot groups to get more data or do bigger groups in one hit to confirm.

The one issue with this ^ though is that one bad shot in a three shot group can make you think it’s no good when it may have been the shooter. Gotta be on your game.

Originally Posted by Micky Duck

RUMPY bought new rifle...I did up 4 diferent lots of reloads for it..plus he had some factory

factory 3 shot group,tiny...as in half inch.
reload groups 5 shots...all around 1-1 1/2"
interesting bit when I got calipers out...the AIMING POINT was 1 1/2" so all groups were within aiming mark....
when took 1 shot out of groups they shrunk to under inch ,when took 2 worst shots out...all were under 3/4"

I normally only fire three for a group to sight in....

What you talking about a 1/2" group @Micky Duck?
IT WAS A 7MM GROUP!!!

Have to say, I'll often shoot a beautiful three shot group, then decide to put another two down the range to prove the point and they're all over the place!

Originally Posted by RUMPY

What you talking about a 1/2" group @Micky Duck?
IT WAS A 7MM GROUP!!!

nah it was a group of 5.56mm holes LMFAO.....