Home Forums Hunting & Shooting Hunting Rifles Measuring Group Size?

1. Are you supposed to shoot a 3 shot or 5 shot group then measure, what is the standard number of shots?

2. When you measure a group are you supposed to measure out side to out side or center to center? What do most people do?

3. When a gun manufacterer guarentees sub moa, Is it 3 or 5 shot group and do you measure center to center or outside to outside of the bullet holes.

Thank You, Just some stuff I wanted to get cleared up.

The 3 shot Vs. 5 shot thing has gone on forever. No correct answer.

To measure a group you measure outside to outside and subtract 1 caliber from the measurement (-.308" of you're using a .30-06)

I believe that most mfg's use a 3 shot group.

Thats the way I do it. I nice digital caliper can help if you haven't done this before.

3 shot groups normal as hunting rifle test. Bench rest shooters are used to 5 shot as the norm. No wrong way, just 5 shot group is a better test of equipment and shooter vs conditions.

As a lark, my BIL and I shot 2 50 shot groups with a 22rf BRNO #4 on a two bull target which resulted in a 3/4" composite group at 50 yds. Didn't prove anything other than two BILs could have a bunch of fun together with a brick of federal red box rimfires.

nsaqam has the formula for group size. To be fair measure the widest spread where ever it aligns. A three shot group is easier to determine as less variables.
Randy

For the method to be accurate the holes or marks on the paper must be full size, and often they aren't.

Accurate enough unless you're in a competition.

Somehow I think LifexIsxHunting is a hunter and for a hunter there isn't a meaningful difference between a .516" and a .545" group.

No sweat. For "practical purposes" just lay the target flat and directly measure c-t-c with a little metal ruler graduated in 32nds of an inch.

Exactly. No need in getting all complicated for most any non-competitive purposes.

Wait, there's another important step.

Take your results, and divide by two, before posting them on the internet.

Way too much humour for me. I am a confessed nutbag and use a magnifier to allign the caliper on the smudges. I forgot all about the divide by two rule, but promise to use it in future. I expect I will be posting some acceptable groups shortly.

Randy

I use digital calipers to measure outside-to-outside and subtract the caliber resulting in the actual size of the group.

For my hunting rifles, I use a 3-shot group since it would be RARE if you ever get more than 3 shots at a game animal.

For my varmint and target rifles, I use 5-shot groups due to the high accuracy capability of such rifles with heavy barrels and, in some cases, single-set triggers.

Each shot you fire at a target increases the chances of enlarging the group size due to the wind, a "flyer" or shooter error like mis-alignment of the sight(s).


Strength & Honor...

Ron T.

As a general standard for testing accuracy in sporting rifles, I like to use 5-shot groups at 200 yards and take measurements of the group vertical height x the group horizontal width in addition to the group extreme spread (measured center to center). I'm of the opinion this gives a better indication as to the rifle accuracy than using only a 3-shot group at 100 yards measured in extreme spread.

Very few production rifle manufacturers guarantee accuracy. Sako guarantees all of their rifles to shoot 5-shots within a 1" circle at 100 yards. Weatherby guarantees both their Vanguard and Mark V line to shoot 3-shot 1.5" group at 100 yards with their Sub-Moa branded Vanguards to shoot 3-shot 1" group at 100 yards. Production rifles such as Tikka have no guarantees but are only tested to shoot 3-shot 1" group at 100 yards. Some are tested with no regard to size of group and some are tested without any regard to shooting groups.

Best:)