Home Forums Hunting & Shooting Rimfires Factors in Rimfire Ammo Accuracy...

Couple questions for the educated rimfire masses..... and you fellas.

What, in your opinion, are the critical factors that one can identify and isolate, to improve the overall accuracy of their .22 Long Rifle ammo?

Let’s presume already, that we’ve shot several different brands, and identified the most solid performer or two.... for this instance we’ll use Ahila Super Extra and CCI-SV.

I’m most interested in identifying the most accurate (consistent) rounds from each box, without having to shoot them first... and saving them for KYL matches, or internet group shooting. I figure there are particular traits that can be identified, tested, and some conclusions can be drawn from variables like COAL, rim thickness, weight, etc. I know it’s a gack pursuit.... but y’all know I got nothing better to do with my time.

I used one of my nuts (ogive nut) as a jig to measure rim thickness... and sorted by that first.

Where should I go next... and what should I look for?

PS.... for you Nerds.... here’s what I already came up with on Rim Thickness:

CCI-SV....
52% of the box had a rim thickness of .0400”, with another 30% within +/- .0005” of that. In all, 94% of the rounds were within a .0015” spread.
Avg. = .0400”
82% @ +/- .0005”

Agila Super Extra....
These were much more consistently spread across a .0010” range, with a max delta of only .0020”.
Avg. = .0390”
94% @ +/- .0005”

I would already assert that the smaller variance in rim thickness bears out in the consistency of 50 yard groups.... as the CCIs show occasional flyers that ruin averages. A little testing should confirm/debunk.

For you Perverts already sending me PMs asking for a picture of my Nut.... I sent them....

This is way back in my memory and something that users have no control of, but I believe it was Federal that did a big research program and found besides rim thickness, that the way the primer material was spun into the rim had a big effect on accuracy. Back in the 1994 time frame they cam out with their match grade ammo and the US Olympic team used it along with other countries. At $12/box, I never tried it. Don't beat me up too bad,as I said it is from my memory which I use mostly to forget with

Federal developed some extremely accurate match ammo in the Olympic production. If I remember correctly, the case had a dent in the bottom that supposedly helped distribute the priming compound evenly in the rim.
Aguila advertises they use Eley priming process which contributes to their accuracy.
On the subject of sorting, a trimmed 223 case works well to hold the 22 cartridge for measurement. You drop the cartridge in the 223 and use a dial indicator and surface block or mike over with calipers.

Most of what's been discussed here is largely a waste of time. BTDT.

You pretty much get what you pay for, and you can't make a silk purse out of a sow's ear.

That said, you don't need to shoot the absolute top dollar stuff to get good results. I just got home after winning a 100 yard benchrest match for vintage single shots with my Winchester 1885, in a stiff wind. I shot Eley Match Extra, but I also have had good results with Eley Team, no longer available . My CZ 452 American is also a consistent match winner, using Wolf Match Extra.

Few shooters really know how to test ammo, and most don't want to learn.

Paul

I’m all ears.... seriously... I’d like to know how to test rimfire ammo.

A decade or more ago I did a test on standard velocity Aguila from the same production run five different ways and decided that although sorting and subsorting did improve consistency, reducing fliers, it was excessively time consuming and the results weren't any better than those I was getting with the lower prices ammo from Eley, RWS, and SK.

I decided that for me, .22 LR ammo falls into 3 groups; plinking, accurate, and match grade.

I don't differentiate between brands of plinking ammo. I consider accurate ammo to start with Eley Target, RWS Target Rifle, and SK Standard Plus. I consider match grade to start with Eley Edge, Lapua Midas, and RWS Rifle Match. I shoot a lot of RWS Target Rifle and SK Rifle Match when I'm working with a new to me rifle in .22 LR because they are good enough to give me a clear idea what a particular rifle might be capable of. I also use .22 LR ammo from the "accurate" group to warm up with when I go to the range. If I warm up with an accurate rifle and ammo combo and am not shooting particularly well that day, I pack it up and head home rather than waste more expensive CF ammo.

For the record, I'm not recommending that anyone adopt my process.

It can be chasing ones tail. Rim thickness is one method, supposedly for even headspace. The object is to minimize flyers out of a group. The group may or may not be good, just no obvious flyers. I have always gone with match ammo that the particular rifle likes best. More money.. The groups however speak for themselves. Some times cheap ammo shoots very well, only the rifle knows. Then one can get into different lots of the same ammo.. Which of course is very hard to buy again.. It can be a large dark hole one falls into.

Just keep moving your target closer until you receive personal gratification and desired moa.

OK, here goes. Take it for what it's worth. I'm not inclined to get into a back and forth, "Yes, but...", "Don't you think..." , etc, etc.

Basic scientific testing protocols start with testing just one variable while holding all others constant. Simple concept, but very difficult to do in real life shooting situations, because range conditions change from session to session and even minute to minute, as well as the shooter's physical and mental state. Then, there is this thing called stochasticity, which is a fancy way of saying random variation, which also has to do with how many test samples are used. So, you get posts like "Gee, my rifle shot great groups yesterday, but I went out today and they sucked. What happened?" Maybe something or maybe nothing. It could just be random variation.

Most group testing involves too small a sample size and too few samples to draw reasonably firm conclusions. A few five shot groups probably isn't enough. Then there is the problem of variation between shots. Was that flyer due to wind shift, shooter error, or ammo?

But there is another problem. More shots are better, that makes intuitive sense, but in conventional group measurement, only the two widest shots are measured to determine group size. The rest of the shots aren't included. Two groups with the same outside measurement may look very different. That's where standard deviation comes in, but that's outside this discussion.

So, what to do? What I do to test and compare ammo is shoot a series of two-shot groups. I don't worry about point of impact or POI between groups. I use a 25 bull rimfire benchrest target, two shots on each bull, and shoot not less than 15 pairs for each lot of ammo, and up to 25 is better. Of course that is a box of 50. Then I measure each pair and average the results. Comparing averages for different ammo gives you a basis for comparison. If it's meaningful to you, you can also calculate the standard deviations.

The main advantage to this method is that each shot counts toward the group measurement, not just the widest two of several. Condition changes and random variation affect only two shots at a time. Particularly if you feel you pulled a shot here and there, it's considered statistically kosher to exclude the extremes. This method gives you the most measurement "power" for the ammo expended, thus it's cost effective.

It's not the be all and end all. Just eyeballing a conventional multi-shot group gives you an instant "eyeball" picture. You don't have to calculate anything. You can "see" the variation. You can also see the group center, which is hidden with the two-shot method.

Anyhow, this is how I test and compare .22 ammo. It works for me.

Paul

As I see it, the big problem with weighing .22 ammo is that you can just weigh the entire cartridge, not the components. Because the bullet is by far the heaviest component, a small variation in its weight might not mean much, while the same weight difference in the powder charge might have a significant effect. There is no way to know where the variation is coming from in an individual cartridge, or whether it is significant.

Rim thickness is measurable, but I'm not convinced it's worth measuring and sorting. I'm not made of money, so I invest in ammo depending on what I'm trying to accomplish. Plinking is plinking, offhand doesn't require precise ammo, at least not the way I shoot, and even regular club benchrest matches aren't worth $20 per box ammo, so I shoot mid grade stuff. A major championship is something else, so I might splurge on a few boxes of Eley Tenex. The main thing you're paying for in higher grade ammo is consistency.

Paul

Paul, thanks for the breakdown.... I believe I get the just of what you’re saying. I like the group of 25 two-shot groups concept, and can see how it yields more accurate results regarding consistency.

Another thing that pays dividends with adequate testing of ammo is learning not only which ammo your rifle prefers, but whether small differences in accuracy are worth it to you. I've learned that my CZ 452 American isn't fussy about ammo, and I've found that expensive ammo like RWS R50 might be slightly more accurate than Wolf Match Extra, with the emphasis on "might", but not enough or with enough certainty to cause me to go with the more expensive ammo. To put it another way, the testing I've done has given me a level of comfort with the Wolf ME.

There are formal statistical tests of significance between means (averages), but I don't bother calculating them. Just looking at the means of the pairs for different ammo has been good enough for me.

Paul

Pretty much what Paul has said, but then when you find ammo that works well you buy another brick or two find out it is from a different lot, and it all starts over. The higher end stuff is more consistent, and I guess that is what we pay the money for.

When I did my rim thickness and cartridge weight testing, I split 1,500 rounds from the same production lot five ways:

1. Unsorted
2. Sorted by rim thickness
3. Sorted by rim thickness and then subsorted by weight
4. Sorted by weight
5. Sorted by weight and then subsorted by rim thickness

I shot five sets of fifty rounds from each of the five categories (5x50x5=1,250) over the course of a month. Since I was using an outdoor range, I only shot on days with calm wind conditions, which can be a challenge in frequently windy Nebraska. At each shooting session I shot five, five shot groups, at fifty feet and another five, five shot groups, at seventy-five feet. I shot three sets with the Remington 37 and two sets with the Ruger 10/22. My friend Bob shot the sixth set of two hundred and fifty rounds from his Anschutz on a day when the weather was perfect, but my shooting was "off".

As a control, I also shot fifty rounds of Eley match at the beginning of each set to insure that I was "on" that day.

The unsorted group had regular fliers. The other four groups were more consistent, enough better that they would be worth sorting if accurate ammo wasn't easily available for around $7 per box. Bottom line, the rim thickness gauge went into a box somewhere and I decided to buy a couple cartons of each of several difference brands/styles of ammo that was priced less than $15 per box of fifty rounds so that I could try to match the ammo that shot the best groups in my .22 rifles that are capable of shooting better than plinking grade accuracy.

Ditto... When I used to compete at the .22 event at local turkey shoots I brought the Rem 541T and Eley ammo.. Came home with a bunch of birds.. Yeah, $12/box is a bit steep, but most competitions around here might use two dozen rounds total.. So who cares about price?

YMMV.

I dunno. Some of the affluent retirees who frequent our local range seem to virtually plink with stuff like Tenex or Lapua Midas. Buy it by the case.

OTOH, I once saw a guy shooting Remington Thunderbolts through a brand new Cooper.

After many years of shooting, this has been my first experience as an RSO. You see stuff when you're observing that you don't notice while you're on the line shooting. Some of it is pretty amazing.

Paul

Indeed. I went through a stage where I absolutely had to shoot nothing but Tenex and/or Gold Ultra Match, and I was merely shooting vintage target rifles for fun (and a fair amount of silhouette). I came to my senses, and found that range time spent testing lesser flavors of ammo was just as much fun, not to mention finding accuracy to be virtually as good.

Don't get me wrong, when I need to hedge my bets (such as informal friendly matches to determine who buys the beer) I reach for the top shelf stuff, even though I know in my heart I'm probably wasting my money. On second thought, maybe I shouldn't do that. It's probably cheaper to just buy the beer.

One of the biggest problems with the various sorting methods that try to make Thunderduds into match ammo is that you can't eliminate or test (nondestructively) some of the most important variances: consistent priming and consistent bullet base shape & weight. Nor is it practical for most of us to go through multitudes of ammo seeking performance quirks from a certain lot #.
I just buy and try a box or two of good quality ammo, then go with the best one that accomplishes the goal for the least amount of money.
Sometimes it's just regular old CCI, sometimes it's middle ground RWS or Eley. My skill limits me to the mid level European stuff at best.

I drank the rim thickness gaging KoolAid for a while, in my Winchester M/52 Sporter and my Springfield 1922 M2 Sporter unsorted CCI Std. Vel. gave best accuracy at 50 yds.. I shoot rimfires off the bench for enjoyment and am not in search of gilt edge accuracy. If I do my part both rifles will group 50 shots into one ragged hole, the rifles are both equipped with Lyman Alaskan 2.5x scopes.