Rimfire Accuracy Expectations: 10 shots at 100 yards

grauhanen said:
It's necessary to put this in some perspective. It's said that at 100 yards the Eley Force was so good that it shot a ten-shot group somewhere between .750" and .875" (or 3/4" - 7/8") -- based on the grid on the target being 1" apart. It's hard to imagine .22LR ammo being less accurate at a shorter distance, therefore the Eley must have shot awfully tight groups at 50 yards. Nevertheless, at 50 yards, the SK (Standard Plus? Rifle Match?) shot even better than the Eley Force. The SK must have shot almost uniquely remarkable groups at 50 yards to do better than the ammo that shot the .875" ten-shot group at 100.

A 50 yard group would be more than twice as small as a 100-yard group. In other words, to use an example, if a group was .500" at 50 yards, it can be expected to be more than doubled in size at 100 yards. A loose rule of thumb for .22LR shooting holds that as distance doubles group size triples. In reverse, as distance is halved, group size would be a third of what it is at the greater distance. As a result, a .500" group shot at 50 yards can be expected to be closer to 1.5" rather than 1" at 100. The corollary is that a 1" group at 100 yards will be closer to .33" at 50. To be sure, this is not necessarily a physical law that applies accurately each and every time, but it is a general rule of thumb that is a very reasonable approximation.

The Eley Force ten-shot-group at 100 yards is ostensibly very close to .875" would have to be at least .4375" at 50 yards -- and by all reason even less. To apply the rule of thumb, that Eley Force ten-shot-group at 50 yards would be .292" (or 7.42mm). But even simply halving the group size allegedly achieved at 100 yards, a ten-shot-group at 50 yards that measured .4375" (or 11.1mm) is still very good indeed.

In fact it is good enough to be considered quite a good factory test target achieved with the barreled action in a specially-made testing vise. To give some perspective, Anschutz tests its rifles in an indoor range with the barreled action in a vise. The minimum standard for accuracy is a ten-shot group at 50 yards that measures no more than 18mm (.709"). Anschutz 54 action single shot match rifles do much better than meet that standard. Keep in mind, of course, that these tests are done indoors with no wind whatsoever and with the barreled action in a vise.

To sum up, the Eley Force is alleged to have produced a ten-shot-group at 100 yards that is about .875" -- a size which would still be quite remarkable for a five-shot-group at that distance. At 50 yards this ammo would shoot a ten-shot-group no more than .4375" but very likely even better, perhaps as small as .292". Furthermore, the SK ammo shot so well at 50 yards that it was even better than the Eley Force, which itself is quite extraordinary considering how well the Eley had to shoot. Unfortunately the SK did not hold much accuracy at 100, but that in itself is not surprising as not all ammo remains consistent as distance increases.

If the results claimed above are genuine, then it suggests one or more of several possibilities. First, it's a one-off, hardly ever to be reproduced with that rifle again, sort of like picking the right lotto numbers for next Saturday night. Second, the rifle is very unusual in that it is a one-of-a-kind factory barreled Savage Mark II capable of extraordinary accuracy. Third, there is a force at work here that engendered a confluence of incredible fortune in shooter, rifle, and ammo. Fourth, there is a mistake made somewhere. Unfortunately, the alternative is that it didn't happen as described.
Click to expand...

Great post! I love it! Yes, its SK rifle match I was shooting, but for the most part, I've switched over to Force as my main ammo.

I agree with you 100%; this rifle has been a bit of a mind-bender that I can't quite wrap my head around, at 50 I would say on average it will group 10 shots right around 1/2" for both. Where I judge the group difference is the Lapua SK is much more centralized in a nice cluster, where are Eley has more noticeable dispersion, and it seems flyer tendency as well, although that could be me. When I finally moved this past 50, I was decided on the SK rifle match being my ammo. I did this test at 100, and I figured those two left groupings were good enough, and I'd try the force just to see what happened. When this initially happened I was shocked and confused about how it grouped; at that time, it was the last ten rounds I had.

My next range session I grabbed another box of 50 from a friend and repeated the same test, shot the SK Rifle Match and Eley at 50 and then repeated at 100 again with very similar results, it was a bit windy that day and the windage grew a bit but still at 1" for the Eley force. This group is likely an outlier of excellence, but the ammo holds up the same at that distance. If I do my part and the wind is on my side, it maintains that 1" mark. I haven't figured out why maybe its the barrel harmonics. It such a weird behavior that I've never seen in a rimfire gun. My discipline is about making hits rather than shot placement, but this rifle hammers for me. My last match of the year with it last week netted me my best finish. This rifle has been confusing and awesome for me. I concur if anyone can ever truly explain to me why this rifle shoots like this, I'd love to know. Anyways, thank you for your dedicated response, it was a great read, the mystery of this MK II will live on, if you are ever out in BC let me know and we will hit the range!
 
No worries guys... Once upon a time, I was called a liar for this 300 yard group shot with my CZ452.

Problem is this group, typical of the day, defies the non linear 1.5:1 rule of thumb above.

Sometimes a rifle just gets into a groove like this.

JVOzuAO.jpg
 
Last edited:
22forever said:
Here's a 50 metre 10 shot group
Click to expand...

Awesome! That is one wonderfully small ten-shot-group. The seven-year-old target gives some details on the high end ammo and the tuner that were used. It doesn't show any other details or how many other groups were similar. What was the rifle? Was it a once-in-a-lifetime happy coincidence of everything coming together at one time or is it a regularly occurring result?
 
Last edited:
grauhanen said:
Awesome! That is one wonderfully small ten-shot-group. The seven-year-old target gives some details on the high end ammo and the tuner that were used. It doesn't show any other details or how many other groups were similar. What was the rifle? Was it a once-in-a-lifetime happy coincidence of everything coming together at one time or is it a regularly occurring result?
Click to expand...

The rifle was an Anschutz 54 with a Lilja 4 groove 1 in 16" barrel, Harrel tuner and a Leupold Competition 45X scope. Rifle was given to my son 4 years ago. This was the only 10 shot group fired all the other testing was 5 shot groups measuring as small as .076 up to .2. 12 different lot #'s were tested to find this lot, my son has one brick left.
 
Maple57 said:
No worries guys... Once upon a time, I was called a liar for this 300 yard group shot with my CZ452.

Problem is this group, typical of the day, defies the non linear 1.5:1 rule of thumb above.

Sometimes a rifle just gets into a groove like this.

JVOzuAO.jpg
Click to expand...

You're saying the results suggested in the lone picture are "typical" of that rifle (a CZ 452 Varmint?) at 300 yards? And the picture proves that as distance increases out to 300 yards this rifle shoots in a geometric ratio closer to 1:1 rather than 1.5:1?

That's quite impressive.
 
You must log in or register to reply here.
Back
Top Bottom