In search of rifle accuracy

Handloading is essentially a search for perfection. Rifle owners in particular are always searching for that combination of components that will land all their bullets close together on the target. They are never entirely satisfied with the accuracy of their gun, and for some reloaders it’s a never ending crusade to gain the best possible accuracy. For many who reload, the search for accuracy is often a frustrating process that seldom bears fruit. Often a load starts to look promising, with groups beginning to tighten up, then suddenly everything goes haywire. But unbeknownst to the reloader, the failure of his latest combination of components to produce the desired results may not be a load problem at all, but may stem from a fault with his firearm.

In order to avoid wasting a good deal of time with load development, it is wise to carry out some firearm tuning beforehand. Without checking how the gun is put together, and making sure the scope and mounts have no movement, the accuracy of your reloads cannot be truly evaluated if the firearm is faulty. Confirm the basics first, ensure your rifle has a totally inert, crisp trigger pull, a clean-cut barrel crown and that the guard screws are tight. All too often, poor accuracy can be traced to a badly fouled bore. Many bore cleaners do not do a sufficiently thorough job of removing copper fouling. It takes a good bore solvent to get all the fouling out of a barrel. And depending upon the number of rounds that have been fired and how soft the bullet jackets are, it could take several applications of solvent to get rid of blue stained patches and be left with a truly clean bore. If, when looking through the barrel at a slight angle, copper-coloured streaks are visible, the barrel has simply not been properly cleaned.

A common cause of bad accuracy is a poorly bedded action and barrel. Today, many rifles have barrels that are free-floating and make no contact with the stock from receiver ring to forend tip. Most custom stockmakers have long since dropped pressure-point bedding techniques in favour of free-floating, and the majority of factory rifles are bedded that way. Very few factory firearms are being made which exert forearm pressure against the barrel. Gunmakers have come to realize that free-floating a sporter barrel will not only improve accuracy, but keep the point of impact consistent almost indefinitely regardless of climatic conditions.

Sometimes free-floating a barrel will reveal an action that doesn’t sit squarely in its stock mortise. Used correctly, an epoxy bedding compound can usually correct any misalignment problems.

Groups of three shots are not nearly as statistically indicative of accuracy as groups of five or ten shots. But as a rule, good solid data can be derived from 5-shot groups. Four 5- shot groups are normally enough to show whether a load is accurate, but with longer strings, it is essential to allow ample time between shots for the barrel to cool.

After you’ve expended a lot of energy ensure your bore is absolutely clean, many rifles may require one or two fouling shots before groups will settle down. This is necessary because the first shot through a clean bore may have a different impact point from the following shots. It may seem wasteful to fire fouling shots, but you can’t avoid doing so if you want to properly evaluate the accuracy of your reloads.

When carrying out accuracy tests, be aware of any disposition of your groups that might indicate some kind of a problem. Shots that string up and down may be an indication of changing shot-to-shot forend pressure. Horizontal stringing could be caused by the barrel contacting one side of the forearm. Elongated bullet holes may indicate an improper match of bullet weight (length) to twist, or a bullet that’s too thinly jacketed to withstand the velocity being generated.

Needless to say, no amount of tuning will correct a worn barrel and a poorly made one simply won’t shoot well with any load.

Only when tuning up has been completed, will the shooter be able to carry out a serious evaluation of ammunition accuracy, but reloads must be carefully assembled using components and propellant of known suitability and performance. The first step is to select a bullet that is known to provide a high level of accuracy. The brand of case and primer is pretty well pre- determined by your current components inventory. There may be two or three powders which will deliver optimum accuracy, and with each powder, one particular charge weight is likely to shoot the tightest groups. Several reloading manuals indicate which are the most accurate recipes. Of course, it may be possible to get equally good accuracy with other powders, but the propellants they list will give the reloader a better chance of finding the best load a lot quicker. If the propellants shown do not give good results, there may be none that will.

A good load in one accurate rifle is very likely to be no better-than-average in another accurate rifle, and may not be the ultimate combination. It’s worth juggling charge weights and even trying a different powder when attempting to perfect your load.

It’s also likely that your barrel will show a distinct preference for one particular bullet. This is something that cannot be predicted, and can only be sorted out by using the same powder and charge weight with different bullets of the same weight and style. Almost every rifle will reveal a strong preference for certain components.

Varying bullet seating depth, dependent on calibre, may ideally require bullet jump from zero to perhaps 0.50”. Begin testing your load in 0.010” increments. When the best depth is arrived at, additional testing should be carried out at plus and minus 0.005” from the last, best performing load, to refine accuracy.

Whenever possible, initial accuracy testing in varmint rifles should be done with match-grade bullets to gain optimum results. Then, when your load is to be used for hunting, you can readily compare the accuracy of hunting-style bullets against the accuracy levels of match-grade bullets. The same applies to big- game rifles; compare your most accurate load with premium controlled-expansion bullets by loading standard cup-and-core hunting bullets which are cheaper to use on feral animals. Seldom will conventional bullets equal the accuracy or performance of premium bullets, but they’ll be effective enough to get the job done.

When developing loads for serious stretch-out varmint hunting I often use match-grade (benchrest) primers, but for big game loads I have never gained any real advantage from using any other than standard large rifle primers. However, I try to avoid using magnum primers for all calibres except the big belted magnums, including the Winchester Short Magnums. Some manuals recommend using magnum primers with ball powder in the .308 Win., but I limit their use to cartridges where charges are heavier than 50 grains.

Do not underestimate the importance of using better than standard die sets for reloading varmint cartridges. Special benchrest sizing and seating dies make it easier to increase the accuracy of your loads. But I’ve never realized any value to weighing individual powder charges, the better volumetric powder measures like the Redding, will easily meter within one-tenth of a grain.

The trick to developing the perfect combination is in varying one component at a time, while keeping everything else as close to the same as possible. If you fire handloads with a couple of different bullets, two or three powders, and a number of different charge weights of each powder, you will never know when you produce a real improvement in accuracy which of the components was responsible.

The necessity of separating an accurate rifle from ammunition related problems is paramount, but with a carefully tuned rifle and equally carefully assembled ammunition, most modern bolt- action sporters will provide one-minute-of-angle accuracy. With heavy varminters, groups half that size are the goal you should strive for.

This article was first published in Sporting Shooter Magazine May 2013




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