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Ed Harris Friday: Testing .22 Ammunition.

Ed Harris Friday: Testing .22 Ammunition.

Editor’s Note: Here’s Ed again, with some data and procedures on testing .22 LR ammunition for best results. I’ve found that .22 LR is the most finicky of all calibers, both in terms of accuracy and function. I’ve seen numerous cases where a .22 rifle or pistol will shoot horrendous groups with one brand/type of ammo, and turn into a tack driver with a different brand or type – and cost isn’t always a good predictor of success! The same is true for functional reliability; some guns simply won’t run with some ammunition. Even guns of the same make and model will have drastically different preferences for ammunition; I’ve seen identical Ruger 10/22 rifles, for instance, that had different results with different ammunition: what worked in one gun failed in the other, and the same was true for accuracy. Ed has some guidelines for testing your .22 to get the best results for the money you spend!

Inexpensive Doesn’t Mean Inaccurate: test samples and buy a bunch to get the best .22s for the buck!
By Ed Harris (Rev. 5-24-94)

If you don’t live near a well-stocked gunshop, your only source of .22 LR ammunition may be the local hardware or discount store. Old stock in small stores may have been around a long time, but if the bullets are not oxidized, buy it if the price is right. It’s probably OK. Chain stores always have “fresh” ammo, but seldom carry anything but “High Velocity” .22’s. Standard velocity is generally more accurate, but is difficult to find except at gunshops catering to competitive shooters.

Most .22s sold are fired in semi-automatic rifles and pistols by casual shooters. Mass marketers gear their pitch to the shooter who is not technically sophisticated, but simply wants the most “bang for the buck”. “High Velocity” long rifle “solids” outsell all other rimfires combined.

There is little difference in manufacturers’ suggested retail price between “High Velocity” and “Standard Velocity” .22’s, but considering availability and discount pricing, “High Velocity” ammo is generally cheaper, unless you order standard velocity in case lots from a major distributor.

The average user has no control over ammunition manufacturing variables, except to test batches and to buy the most promising lots. Therefore you should pay attention to “lot numbers.” and shoot an entire box of ammunition “for group” in your own rifle before stockpiling a large quantity.

“Lot numbers” are used on almost every manufactured item you purchase. An ammunition “lot” usually indicates a day’s production, and indicates to the manufacturer such things as the year and day of manufacture, the shift during which it was produced, and the loading or packing machine used. Lot numbers are used to identify process control data, and can facilitate a recall if a problem is discovered after the product is shipped.

Most .22 rimfire ammunition is far more accurate than we give it credit. Ammunition manufacturers operate heavily automated production lines which can produce huge quantities. This has kept prices low, so .22 rimfire ammunition is still a bargain.

The manufacture of .22 rimfire ammunition involves dozens of machine operations. These include progressive die stamping of the brass cartridge case, stress relief, annealing, then cleaning and priming; swaging bullets from lead wire; and assembling completed rounds, by metering the powder charge, inserting, crimping, knurling and lubricating the bullets. There are also numerous quality checks of weights and dimensions, and firing of functional and ballistic tests prior to packaging.

Given its inherent complexity, even low-priced “promotional” ammunition must still be subjected to the same basic operations and inspections as “regular” ammunition. Bargain ammunition is so only partly from lower-cost packaging, and long production runs which permit economies of scale. Omitting non-essential operations, such as plating of the bullet, reduce cost only very modestly.

The most important factors affecting accuracy of .22 rimfire ammunition are bullet quality and uniformity of the cartridge case. The bullet must be round, as close to permissible maximum diameter as possible, have its base square to its axis, and not be damaged in handling or in the loading machines, particularly the crimper. The web thickness of the brass through the rim section affects the distribution of primer mix, controls primer sensitivity, reliability of ignition, and uniformity of the dimensions governing headspace, all crucial to accuracy.

Bullet weight and powder charge variation, within normal manufacturing tolerances, is of only minor significance, if the above factors are controlled. Standard velocity and sub-sonic ammunition have somewhat less wind deflection, but in terms of pure accuracy, whether the ammunition is “Standard Velocity” or “High Velocity” doesn’t matter, if “all other factors are equal”.

Industry standards require .22 Long Rifle ammunition average 3″ or less extreme spread at 100 yards for 10-shot groups. US ammo producers easily maintain 2″ as a product average. The best lots will average 1-1/2″ or better at 100 yards from the test barrel, and these are the ones you are seeking! Some US producers test rimfire ammunition at 50 yards rather than 100, but indoor rimfire test groups are usually proportional to the range.

“Average” Standard or High Velocity .22 LR ammunition should average an inch for a series of 10-shot groups at 50 yards. The best .22 ammunition should do 3/4″ or better from a SAAMI dimensioned “Match” chamber, in a target rifle with telescopic sight, fired by a skilled shooter from bench-rest, or by a Master competitor prone with a sling.

“Sporting” rather than “Match” chambers (in which the bearing surface of the bullet is engraved as the cartridge is chambered) usually produce groups up to about 1.3 times larger than the test barrel, though some individual rifles will give surprising results. US production .22 Long Rifle ammunition will usually average an inch or better for a series of 10-shot groups at 50 yards from an accurate sporter. Specialty ammunition such as CCI Green Tag will often do better, frequently under 3/4″ at 50 yards, from heavy target rifles, or high grade sporters with “match” chambers.

When testing, shoot a full box in five consecutive 10-shot groups, without excluding any data. It is common for even poor ammunition to shoot occasional “good” groups, as normal random variation. Results which appear meaningful to casual observation very often are not. You cannot arbitrarily discount individual bad shots or groups, because these are part of the random dispersion and you must look at the entire body of data as a representative sample.

Age is not critical if the bullets haven’t oxidized or the lubricant dried out. I have used 20 year old .22 rimfire match ammo that still produced 1/2″ ten-shot groups at 50 yards. The limiting factor is evaporation of the volatiles from “grease” bullet lubricants, and oxidation of the lead bullet itself. Minor oxidation may affect accuracy for serious competition, but it is insignificant for other uses if it doesn’t cause leading.

High grade match ammunition with oxidized bullets can be salvaged if carefully re-lubed with EP lithium grease, and the excess wiped off with a patch.

In my experience a freshly-chambered rimfire match barrel doesn’t “settle down” into its best grouping for several hundred rounds. Consistency of firing technique is VERY important. Firing several hundred groups from the bench with a .22 rimfire will teach you a great deal about “bag” technique, more cheaply than burning out a Hart barrel on your heavy varmint IBS bench gun!

Some inexpensive ammunition may shoot very well indeed, but high price is no guarantee of accuracy. So, it pays to test lots of any ammunition before purchasing in quantity, to find the most accurate ones!


  • Posted by Grant Cunningham
  • On June 1, 2012
Tags: Ed Harris

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