How many rounds to determine MOA???

[cslinger]

How many rounds should be fired to determine a rifle and ammo's MOA.

For example I put a three shot group today at 100 yards through almost the same hole, call it about 1/4 inch or so.

I then put about 15 rounds through a hole about silver dollar sized.

I also flubbed quite a few rounds in the process of learning the new stock and getting used to scoped shooting.

I was using Black Hills 168 grain ammo for the accuracy test and UMC cheap stuff to site in. The UMC was very very inaccurate compared to the Black Hills match ammo. I am sure I did my fair share of screwing up but I was pretty consistent with the Black Hills and I played hell with the UMC.

Anyway so what would the guns MOA be considered. Is a larger group of rounds better than a smaller group? Does it matter that I didn't start shooting the match stuff until the gun was reasonably heated up, about 15 rounds of UMC, through it?

I am kind of new to bolt action, scoped precision shooting so I am just looking for some pointers.

Thanks
Chris

 

[Dave R]

There's some discussion on this topic...

The generally accepted standard is 3. Theory is, if you're hunting, you should never need more than 3.

Unless you're shooting Prairie Dogs, of course.

Also a lotta folks think 5 is a better meaure. They're right, of course.

And the Speer reloading manual says that, from a statistical standpoint, 7-round groups give the most statistically valid info from the least number of rounds fired.

So if you want to brag, use 3 shot groups. If you want to make your rifle shoot better, use 5-7 shot groups.

 

[curt]

I disagree with dave r, i think the generally accepted standard is 5. Even more importantly is that they be 5 consecutive shots not the best 5 out of 20. I've often seen a group open up with a 4th or 5th round flyer...but then again i'm not a HP shooter or anything. I'd say that a 15 rd group the size of a silver dollar is pretty impressive depending on rate of fire and wind conditions.

Course some folks (present company excepted) seem to get their best groups with one shot

 

[uglygun]

If it is the capability of the rifle/load that I am trying to determine, I'll shoot enough rounds or average together several groups until I feel I have something that is statistically significant.

A single 3 shot group is fine in my mind for testing to see if you have a rifle/load combination accurate enough for the purposes of hunting.

For the anal retentive folks though, finding out precisely what the rifle's boundaries for precision are, it usually means shooting enough rounds for a decent sample size inorder to achieve some kind of normal distribution.

From the most stable position for shooting, 3 groups of 5 shots each might be enough to give a decent portrayal of the rifle's true abilities. Or just one or two 10 shot groups could go far in doing similar.

Whatever it takes to find a point which about 95% of your fired rounds fall within, that would probably be the point at which you've fired enough rounds.

Long time ago when I first tried to evaluate my accurized AR15 I found that I would have quite a good percentage of my 5 shot groups hovering right around 1/2 inch. But for some reason I'd get a 5 shot group that would open up to 3/4 inch or right at 1 inch. If I had been recording all my 5 shot groups I would likely have found pretty strong evidence of what percentage of rounds fall within 1/2 inch, inside of 3/4 inch, and inside of 1 inch. Instead, I wound up shooting 10 shot groups more often when evaluating loads, I found that my better loads were putting 6-7 shots inside of 1/2 inch and then 3-4 shots would be responsible for pushing it to 3/4 inch or 1 inch.

My best handload to date after averaging several 10 shot groups is right at 3/4 inch.


Why the long process? My accurized AR15 is primarily a varmint rifle and it does get a lot of long distance shooting at little critters. What's more, my groups are typically fired in rapid succession to determine if the rifle is consistent while hot as well as when cold.

 

[Cosmoline]

I've always found best results with one shot.

 

[cslinger]

I'd say that a 15 rd group the size of a silver dollar is pretty impressive depending on rate of fire and wind conditions.

It ain't that impressive. No wind, bipod, 10x scope and a very slow and deliberate one round at a time firing. Probably took me 45 minutes to an hour to go through 20 rounds but that is with range clears etc.

I am just trying to get used to the rifle and trying to find out what round shoots best. I would like to be able to consistently get 3-5 shot groups of less than an inch but that will come with practice I guess.

Thanks for the info.

Chris

 

[cslinger]

I've always found best results with one shot.
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Yeah me too.......................................................if I can get that one shot into the shoot and see that is?