hirty-some years ago we all firmly believed that handloads shot more accurately than factory ammunition. The gun writers of the day said this was because we could "tailor" handloads to our particular rifle, by trying different bullets and powders to see which Old Betsy "liked."
Most of the time our handloads did outshoot factory ammunition--but after looking back on 35 years of handloading and rifles, I don't believe it was because we tailored anything. Instead, handloads shot better because factory ammo was as bad as the Japanese radios then flooding the market. Like those radios, most 1960's factory ammo was cranked out to sell at the lowest price possible, and there wasn't any of the "premium" stuff we can buy today. Brass and, particularly, bullets were not very uniform, and quite often were slopped together.
I know this because I possess quite a bit of old factory ammo, courtesy of a cop friend. Periodically people arrive at his offices with old ammo left behind by their dear departed grandfather, or found in the basement when they rented a house. If it's interesting, my friend sends it on. Believe me, the average ammunition we shot in the 1960's does not compare with the fine ammunition we can buy today. Back then a scoped bolt-action that averaged 3 shots in an inch was an absolute wonder, and this usually couldn't be accomplished without handloading. With factory stuff, 2-inch groups were considered about all you could reasonably hope for.
Today I routinely test factory ammo that averages 3 shots in an inch at 100 yards, and some does better, even in some very old rifles. Which means the ammo "tailoring" tricks of the 1960's didn't have much to do with the superior accuracy of our handloads. Instead most accuracy gains were due to custom bullets made by companies like Hornady, Nosler, Sierra and Speer, seated straighter than in factory ammo.
It takes more effort to beat today's factory ammo. In the last issue of Rifle (No. 202) we looked at the basics of accurate rifles, which mostly come down to proper action and barrel bedding, firmly seated locking lugs, and a well-mounted scope that's parallax-free at whatever range we're shooting.
But we left one part of the rifle out of the equation, because it directly affects handloads: the chamber. Here we're talking about the entire chamber, including the throat. Exactly how the cartridge and bullet fit in the chamber/throat directly affects accuracy--and how we handload can have major consequences on that fit.
Let's look at the body of the chamber first. This directly affects "headspace," a technical term for the tiny gap between bolt-face and cartridge-head after a round's chambered. Headspace is "controlled" by some feature of the case that keeps the cartridge from sliding too far into the chamber. The simplest method is the rim of older cartridges like the .30-30 WCF: the rim's too big to fit into the body of the chamber and so stops the cartridge.
Most rifle cartridges designed for bolt actions are "rimless," which doesn't mean they don't have a rim, just that it's the same size or smaller than the case body. The .30-06 is a typical example. Because the rim is the same diameter as the case, the steeply-tapered portion of the case called the shoulder keeps a .30-06 round from sliding too far into the chamber.
A rimless variation is the "belted" cartridge, typified by popular rounds such as the 7mm Remington and .300 Winchester Magnums. The belt just in front of the rim was designed to control headspace in old British cartridges that had shallow shoulders, such as the .300 and .375 Holland & Holland cases. On modern, steep-shouldered cartridges, however, the belt's pretty much superfluous.
No matter what form the case takes, too much headspace can be dangerous. After we pull the trigger, the spring-driven firing pin slams the case too far forward into the chamber, whereupon expanding powder gases push the case-head back against the bolt-face, stretching the brass. Case separations can result, even on one firing, and almost certainly occur if the case is handloaded and fired again.
But even "normal" headspace can affect accuracy. Here we're not talking about dangerously excessive headspace, but accepted tolerances. Slight variations in case/chamber fit can cause erratic ignition. Some rounds chamber more tightly, others more loosely, which varies how consistently the firing pin ignites the primer. Bullets leave the muzzle at different velocities, ending up at different places on the target, especially at longer ranges.
This slight amount of headspace "slop" is common with typical with factory rifles and brass. Factories tend to ream chambers at the long end of accepted headspace, because the typical bolt-action .30-06 has to chamber dozens of brands of ammo, both American and foreign. Rifles chambered for belted cases often show even more slop. The belt theoretically controls headspace, so chambers are often cut more tolerantly, and ammo varies more widely.
Most rimmed centerfire cartridges are chambered in lever or single-shot actions. By their very design, typical factory lever rifles don't lock up as precisely as an typical bolt. Single-shot rifles tend to be better, but even in such fine falling-block rifles as the Ruger #1 and Browning 1885, there's normally enough manufacturing tolerance to prevent truly precise headspacing.
Which is where the handloader comes in. We can fit bottlenecked cases to our particular chamber, by first firing cases in our rifle, then resizing minimally. The case headspaces partially on the shoulder (even if belted or rimmed), reducing erratic ignition, and centers itself in the chamber, starting the bullet straight down the bore.
Resizing cases "minimally," however, doesn't necessarily mean neck-sizing. I've fooled around with neck-sizing quite a bit over the years, and find the practice normally produces less accurate ammunition.
Why? The body of the typical factory neck-sizing die is much larger than the case body, so there's nothing to hold the case in alignment with the neck-sizing portion of the die. Consequently the neck's often resized out of alignment with the case body, a condition often made worse when the case gets pulled back over the expander ball.
Aligned, straight, concentric: No matter what we call it, making sure our ammunition's centered in the chamber, from case head to bullet tip, is essential to accuracy. Without straight, we can kiss small groups good-by.
The only way to find out if your dies resize cases straight is to buy a concentricity gauge. I have two on my bench, one from RCBS and one from NECO, and use them both for various purposes, as one is generally handier than the other for particular tasks. When fooling around with a new set of dies, one gauge or the other soon appears, because dies are almost as quirky as people.
In making straight ammo, there are better tools and methods than the average neck-sizing die. All the full-length dies I've tried in the past decade size cases straight, but more often than not, the expander ball pulls the neck crooked. Sometimes this is because the "ball" (actually a cylinder of some sort) is mounted crooked on the decapping pin. Expander-ball/decapping-pin straightness can be measured with a concentricity gauge, and corrected with the judicious use of pliers.
Sometimes, however, even a straight expander ball pulls necks crooked. The only solution I've found is to unscrew the expander, fully size the case, then screw the expander assembly back in the die and "push" it into the neck of the sized case. For some reason, this almost always results in straighter necks.
On the joyous occasions when a new set of full-length dies sizes cases quite straightly, with no more than .002" runout at the case mouth, I mark the die box "OK," so I know cases can be resized without pulling the expander ball. Otherwise the expander-ball assembly lies loose in the box, letting me know an extra step must be performed. This is why I prefer dies with easily-unscrewed expander assemblies, such as those made by Redding and RCBS, to those that require two wrenches and some sweat to remove, like those made by Hornady and Lee. (Both the Hornady and Lee dies usually make fine ammo, but if they don't the only real solution is to buy another full-length die and remove the decapping pin. Use this for resizing, the other for expanding necks. Don't laugh. I've got a couple die boxes with extra sizing dies minus their decapping pins.)
You can also buy match-grade dies, which compensate for all of these factors. Normally they're neck-sizers, but with more precise bodies than standard neck dies. I mostly use these for varmint ammo because they save a lot of time when loading several hundred rounds, eliminating lubing, de-lubing, and (usually) case trimming. I am particularly fond of Redding's Competition Bushing Style neck-sizing die, but Lee's Collet Dies also work very well.
When loading big game ammo, however, I use dies just like those you can buy in any sporting-goods store. With the above tricks, standard dies can produce cases just as straight as those sized in match dies, and the extra time doesn't amount to much when making 40 rounds of ammo.
My big game ammo is normally full-length sized in order to chamber smoothly, but that doesn't mean it doesn't fit the chamber precisely. Unless you use a special small-base die, full-length sizing doesn't restore brass to factory dimensions. Instead it sizes just enough for easy chambering.
If you've got a tight chamber, fired brass may not affect accuracy, but most of the time, fired brass headspaces more precisely and has straighter necks. After "fire-forming" brass in your rifle's chamber, set the dies so that the action closes on a sized case with just a slight amount of extra effort. Many methods can be used, including specialized tools such as Redding's "Instant Indicator" headspace comparator, or blacking the shoulder area with match or candle smoke. I usually just run the die into the press, with the ram up, until the die butts against the shell holder. Then I back it off half a turn and resize a fired case. Normally this lightly-sized case takes some effort to chamber, so I keep turning the die in, perhaps 1/20th of a turn at a time, and resizing the same case until the desired slight "crush fit" results.
This firm headspacing helps center the round in the chamber, even it the case body is sized small enough for easy chambering--and not only with typical modern steep-shouldered cases, but also gently tapered rounds. My own modest rifle collection includes a Marlin 336 .30-30 WCF, a C. Sharps Winchester High Wall .30-40 Krag, a Winchester Model 70 Classic rebarreled to .300 H&H by the Wells Gun Shop, and a couple of .375 H&H's, a Mark X Mauser and a Ruger #1. Chambers are both custom and factory, the rounds both rimmed and belted, but all shoot better with fired brass full-length resized just enough to allow easy but firm chambering.