Quantifying accuracy and precision question.

[Bwana John]

How do you measure how well your rifle shoots?
average of all 5 shot groups @ 200 yds?
average of best 5 shot groups @ 100 yds?
average of favorite ammo with 3 shot groups @ 100 yds?
best lucky 3 shot group at local trash pit?


I personally try to use the average of my best 5, 5 shot groups shot off a bench with sandbags @ 200 yds(precision), AND all groups must stay in the same place with same ammo(preferably POA=POI @ 200 yds) from one shooting session to another(accuracy).

I just wonder sometimes when somebody claims "MOA" accuracy with their mass production rifle with commerical ammo, or surplus rifle. If I can get 1.5 MOA groups with a scoped rifle and hand tailored reloads, or 3-4 MOA with a surplus rifle and surplus ammo (using my method of calculating), I am very-very happy.

And just to be really anal while talking about "MOA" and angular measurments, should we be using the angle the group subtends ((radius/radian) X (180/pi)), (not a linear measurment) OR 2 X (arctan of (1/2 the group size/distance))(a linear measurment).

 

[Arc-Lite]

I think most weapons fire great groups, I think most shooters don't. When you get a good working package, of rifle and ammo.... the measurement then, is of the shooter. "Claims" are claims, everyone shoots SMALL groups, and everyone catchs BIG fish !!!

 

[30Cal]

3 twenty round groups, and they all count (if I call a bad shot, I might disregard that one shot). If the load is intended for 100yds, then that's fine, but I generally shoot at 200yds.

 

[kaferhaus]

general concensus on the bench rest scene is 5 5 shot groups. measure them edge to edge, subtract bullet diameter and then average the 5 groups.

That will give you the accuracy of you shooting your rifle with that ammo on that day under those conditions.

shooting one group in the .2s and then claiming you have a quater inch gun is what make us benchrest guys giggle and blow our beer through our noses...

Half the guys on the internet are world class shooters with world class rifles if you believe what you read here and on other boards about accuracy claims..

reality is a stock sporter that shoots 3 shots consistently under an inch with handloads is a good rifle. stock rifles that do better than that are very rare.

Custom rifles that will consistently shoot under half an inch are also not common and very expensive.

shooters that are capable of producing those groups are also few and far between....

unless you're an internet commando.

 

[JohnBT]

For a hunting gun I want to know where it puts the first shot out of a cold barrel.

For target guns, or high-volume hunting guns, a bunch of 5-shot, 10-shot or 50-shot groups will give me a good indication of whether or not I've had too much coffee. I measure edge to edge and subtract the actual size of a single hole in the paper because the hole in the paper is usually smaller than the diameter of a bullet. I understand that baking the targets on low heat will produce cleaner holes, but I've never tried it.

Shooting IR50/50 score targets with a .22 at 50 yards is a humbling experience, even with a Cooper. One of these days I'll get a real rifle... ...or go back to shooting nothing but tin cans and dirt clods.

The common use of MOA is one inch at one hundred yards. I know it really isn't exactly one inch, but I drag enough stuff to the range without taking my Starrett thingy, and a sharp pencil, along for the ride.

John

 

[win71]

JohnBT

Best lucky 3 shot group at the trash dump. That way I know all my rifles are shooting top notch!
Seriously, I really like JohnBT's answer.

 

[Kamicosmos]

When I decide to 'group' my load or rifle, I fire a minimum of 3 5 shot groups at 100 yards, all on the same target in the same string of shooting. I figure for my purposes, I know what I can do over a fair amount of shots. The gun shouldn't heat up enough in 15 rounds to throw its accuracy off (there are exceptions of course). As the saying goes, '3 shots shows what the rifle will do, 5 shots shows what the shooter can do'.

There are some amazing claims of sub MOA work out there. I especially enjoy the various $100 mil surp with WWII ammo doing .3 groups 'all day', rain or shine, hell or high water. I'd love to see some of these shooters at work! I'd be forced to learn something!

 

[Art Eatman]

When I'm checking out a rifle that's new to me, or one on which I've been doing some tweaking, I'll shoot a five-shot group or two.

After that it's three-shot groups. Load testing or sighting in a scope, three tells me all I need to know for a hunting rifle.

I fully agree with JohnBT about the first shot from a cold barrel. That's the only one that's really important.

, Art

 

[Sam]

I'm really only interested in what I can do with the rifle.

For me its offhand at a standard paper plate, not rushing the shot but not getting too comfy either. Paper plate is pretty much 1 minute of Bambi.

For me a good combo does Minute of Paper Plate at 150 yards in x seconds and should do it pretty much on demand. Also like to do port arms to sitting but that takes longer.
Only really into practical accuracy. Slung up and sitting should be a gimme to 300 and if I cannot make me and that rifle do that, we part company no matter whose fault it is. Just not a BR, group shooting kind of guy. 99% of my hunting could be done with a rifle that does 8" at 50 yards.

Sam

 

[Art Eatman]

Sam,. no argument against your ideas, but the use of the benchrest is a way to determine what the rifle itself will do. You work hard at taking yourself out of that equation.

Once you've learned the rifle's capabilities, then it's the time to work up the package deal that is the rifle + the user...

, Art

 

[rockstar.esq]

Sams the man!
Paper plate = 1 minute of Bambi I couldn't agree more. The whole benchrest thing kind of confuses me. The most common comment out of that camp is "It tells you what the rifle will do". To me it's kind of like testing a car by leaving it in park and reving the engine. The rifle is there to work for me, not the other way around. I don't care if it would group better if it was locked in a vise and had the trigger pulled by the best looking of super models. I want to know what it'll do when it gets sucked up against my winter coat,in crappy weather and I do my best. I learn how to "Kentucky windage" my rifle to account for barrel heat, however that's only for when I'm trying to hit a particularly evasive trash can at the dump! Otherwise I spend my time concerning myself with where that first shot goes.

 

[Jon Coppenbarger]

Well I will find out this week. Because I have just had a new Kreiger put on my ar15.
I know what I shoot and how I shoot. So I will sight it in at 200 yards and break it in. Then I will get some zero's on it out to 600 the same day and hope to finish the break in the next day teaching a clinic. Might even let a few of my students shoot it to get a few more rounds down the barrel. It will then get used in a few reduced matches and TRUST me when I say I will know if it shoots or not after I see a group. Then the ammo will get tuned to it over the next month. Man its fun.

 

[JohnBT]

"I want to know what it'll do when it gets sucked up against my winter coat,in crappy weather and I do my best."

Me too, but when it's 90+ outside I like to leave the coat at home and sit in the shade and shoot off a rest. Does the gun shoot better using free recoil, a touch of just shoulder or a two-handed death grip? Which ammo never produces a flyer? How often does the barrel need to be cleaned to maintain pinpoint accuracy. Benchrest, it's another reason to buy more gear. And it's oh so much harder than it looks. Actually, any kind of shooting is harder than it looks if you're trying to become a truly excellent shot.

I'm really just a plinker and sometime hunter at heart and will take almost any opportunity to shoot. When I was growing up we didn't have much ammo. If we didn't see any game we didn't shoot the chambered round just for the heck of it. We saved it for the next day. Heck, I think I was nearly grown before I found out that shotgun shells came in something other than #6 high brass.

I never got into deer hunting. There weren't any deer where we hunted and I understand there weren't many deer anywhere back then. My grandfather and his two brothers had nearly 1500 apple trees in the mountains near Charlottesville and there weren't any deer until after I had left for college in the late '60s or shortly thereafter. They would have known. Now the area, the state for that matter, is crawling with them and my 73-y-o uncle fills his tags every year.

I'd rather eat fried squirrel.

John

 

[wanderinwalker]

Man JC, I'm jealous! A new Kreiger to play with! I've seen what those Pac-Nor, Kreiger and other barrels will do for a good shooter. Amazing things.

I'd say, precision is, can I hit that X-ring on the reduced target, at 300 yards, cold, wet, hungry and tired? With an easy to shoot, accurate rifle, yes, I will. Sure, most rifles will do that on a good day, but what about on a day that isn't so good? And what if I make the trip over to 600 yards and am extra tired by the prone-slow?

So if a rifle is accurate, easy to shoot well and forgiving of the shooter, then I am happy. Right now my happiest shooting moments come from an Armalite National Match AR-15. I haven't been shooting long enough to skin the barrel, but I'll get there eventually!

(JC, would you recommend a Kreiger for a rebarrel for a guy shooting mid-level Master scores XTC? What about something a affordable on an Old Milwauke-sized budget?)

 

[browningguy]

I think you need to understand what you are measuring groups for before you can really talk about how someone needs to do it. For all of my hunting rifles I'm really only interested in the first three shots, so I tend to work on three shot groups.

When I'm working up loads for a gun with new bullet or powder I load three of each variation (could be as many as 8-10 variations), shoot a few fouling shots, then shoot the three shot groups. I then take the two best loads and load ten rounds of each, I measure them in five shot groups to find the best one. After that however I'm back to three shot groups because that's what matters to me most, but I shoot them year round and keep records of them.

I generally shoot all my groups from a sling, sitting at a bench, 100 yards. I like my hunting rifles to shoot under 1.25" from this position. I figure standing, in the field, cold, looking at a good deer, I'm lucky to shoot goups at least twice that size. Although I have to say, I've never taken a shot unsupported in the field, always found something to lean against or lay on.

Custom 7x57 on VZ24 action will shoot my handloads with 154 gr. Hornady's between .8-1" about any day, Factory S&B 173 gr. load about 1.25"
Ruger 77 RSI in .308 will shoot 1.25" or slightly less with my handloads or the Hornady 150 gr. factory load (it hates heavier bullets however)
HK SLB2000 in 30-06 only gets factory loads at present, shoots Hornady 165gr. load at a very consistant 1.1-1.25"
BAR in 30-06 also gets Hornady factory ammo (180 gr.) at present and shoots 1.25-1.5" (this one hates lighter bullets for some reason), gets outside the 1.25" I'd prefer but it's a really nice gr.III and by golly sometimes you just want to look pretty when you're out hunting.
Dumoulin full stocked FN action in .338 will shoot 250 gr. handloads consistantly at 1.1-1.25"

Also have a Vanguard in '06 that I haven't finished working up loads for but it seems to be settling in around 1-1.1" with a couple of 150 and 165 gr. handloads. My 1891 Mauser sporter in 7.65 Argentine is actually one of my most accurate rifles. It was sporterized in the 50's by Williams and had peep sights added, it shoots a handload with 180 gr., .311" Sierra Gamekings into .8-1" every day, it's a slow load at about 2250 FPS but that's good enough for 100 yard shots. Since I can't see good enough to shoot that without a scope, I figure the rifle just has good mojo.

My SKS with a pro point on it and a trigger job shoots around 2.5-3" with commercial Monarch brand ammo, and my FN49 in 8mm is around 3" shooting with a bipod with surplus ammo. My Inglis Hi Power with shoulder stock shoots, well, lets just say you can keep them all on a very large target.

 

[BusMaster007]

Do any of you "accuracy nuts" ever have any FUN? :banghead:
I'll bet you clean your guns, too...

OK, I'm just KIDDING!