A Handloading Pro Dissects Mistakes
He’s Made And Some He Hasn’t
By M.L. McPherson
Historically, metallic cartridge handloaders have believed they have wide latitude in load parameters—bullet type and seating depth, propellant type and charge range, primer type and case type; and in handloading practices, such as crimping or not. While to some extent we do have some latitude in many of these areas, we certainly do not have complete freedom, at least not if we want to produce safe and effective handloads.
Perhaps the best advice for all but the most advanced handloaders is to find and follow a recipe specifying every aspect of the load and loading procedure. Loading tools and practices also matter. Handloaders who do not realize the importance of these facts can and do get into trouble. What saves them from myriad disasters resulting from the use of the dangerous loads we all too often concoct is the incredible safety margin built into the guns we use. However, this fundamental layer of protection sometimes fails to be sufficient because handloaders can be so ingeniously reckless.
At the local range, a handloader was shooting his .44 Magnum Super Redhawk. He was having trouble ejecting the fired cases. He complained about his handload not working well. I asked, “Where did you get the loading data?” He replied, “Internet forum.”
No surprise! Web gurus routinely omit critical load details. In this instance, which primer to use for a safe load with his chosen charge, propellant and bullet. As this handloader had assembled it, the load was dangerous.
Another handloader used an Internet forum recipe to create .45 Colt ammunition. His combination of propellant and charge, primer, bullet seating depth and case should have resulted in a perfectly safe load for use in his custom 5-shot Ruger revolver. However, his expander die excessively enlarged the necks on his resized cases. Hence, the resulting loads had inadequate neck tension.
As he fired the first shot, recoil pulled the cases off the bullets in the unfired chambers. Bullets in several unfired rounds protruded from the cylinder face. This would have been sufficient to warn a well-informed handloader not to continue using this load.
Detonations are real! This handloader learned the hard way what can
happen with the wrong primer. In this instance, the primer was too
mild to properly ignite the charge. Paradoxically, a too-hot primer
can render the same result. This combination should have given a
perfectly mild load. Had the charge burned normally, pressure would
have been far below normal for the chambering.
The Sinclair Chamber Length Tool is a simple device (A), designed to snugly fit
in a modified case neck (B). Insert the tool into the modified case, insert the
modified case with the tool into the gun chamber, close and lock the action, then remove the case
and tool. Chambering drives the tool into the case (C) (middle, lower right)
and therefore gives the actual length of the chamber neck. In the lower right picture,
(left to right) is a standard .221 Fireball case, the modified case with the Sinclair tool
showing the measurement of the chamber neck and a converted .223 Remington case with a
longer neck reaching to within 0.015-inch of the end of the chamber neck. Because the
.221 case has such a short neck, a case that correctly fits the chamber has a 25-percent
longer neck—very beneficial. (D) As with most commercially chambered rifles,
difference between listed maximum case length (left) and actual maximum-feasible case
length is commonly about 0.050 inch. Here is a factory .221 Fireball case (left) and
a converted .223 Rem case (right). In a cartridge with such a short neck, this difference
is particularly important. Furthermore, it makes no sense to continuously trim cases just to
abide by a listed trim-to length. Often, letting cases lengthen to within 0.015-inch of
chamber length is beneficial and safe. The Sinclair tool allows you to accurately assess
actual maximum-feasible case length.
However, this handloader did not realize the insufficient neck tension represented not only a mechanical problem but also a potential hazard. So, he drove the protruding bullets back into the cases, cocked the hammer and pulled the trigger. The cylinder and frame disintegrated. Poof! A very expensive custom revolver sacrificed as a valuable handloading lesson in so many microseconds.
The primer blast moved the bullet into the barrel before propellant ignition occurred, because neck tension was inadequate. Then the compressed chunk of propellant behind the bullet ignited. As the Krupp Commission proved in 1888, ignition of a charge resting entirely at one end of an unfilled chamber always generates a standing pressure wave within the chamber. In this instance, pressure at the peak of this wave progressively increased until it exceeded the strength of the cylinder. For lack of a better term, we erroneously call this process a detonation.
Never assume any die set leaves the case with adequate neck tension. Historically, manufacturers commonly shipped dies with oversized expanders, as in this instance.
Another handloader tested a self-concocted load in his .300 Weatherby Magnum. He believed the relatively mild CCI-BR2 primer might give better accuracy than he had gotten with the recommended, and relatively powerful, Federal 215 in his first version of the load. He tested his BR2 loads when it was 32 degrees F (I happened to be at the range). He was using a hard-to-ignite, single-base propellant. The charge did not come close to filling the case. His was a perfect recipe for a detonation. On his second shot, the charge failed to ignite.
Case dissection showed the primer blast had compressed the charge into the front of the case and fused many granules. Almost certainly, if the propellant mass had subsequently ignited, it would have destroyed the gun through detonation. Follow the recipe and never assume any component substitution is safe.
My testing at the Accurate Arms ballistics laboratory proved even when a detonation is unlikely, primer substitutions often alter pressure widely—and unpredictably. For example, in the .30-06 with a normal charge of A4350 in otherwise identical loads, pressure using various rifle primers varied by 17 percent (54,500 psi to 63,900 psi).
Worse, how primer substitutions will alter pressure is entirely unpredictable. For example, in some handgun loads, use of a standard primer instead of a magnum primer will double pressure. Therefore, when someone tells you they can predict how a primer substitution will alter a load, stop listening: They have just demonstrated they do not know what they are talking about.
Improper primer seating is the most common primer-related problem in handloads. The face of a properly seated primer always rests noticeably below the head of the case. Inadequately seated primers result in misfires and squibs and can lead to a detonation.
Consider bullet substitutions. Bullets of the same weight and basic type vary both in length and in core and jacket toughness—these variations matter—longer bullets tend to generate more pressure (bullet occupies more of the case), harder bullets tend to generate less pressure (reduced obturation results in reduced bullet-to-bore friction). For example, in standard-length .270 Winchester loads using identical charges of A4350 and the CCI-BR2, pressure with various 150-grain hunting bullets varied by 32 percent (54,700 psi to 72,400 psi). The former would be a very mild .270 load, the latter is in the pressure range for a .270 proof load.
Ballistician Bill Falin did similar tests with the .35 Whelen. The charge of A2015 needed to generate maximum pressure with various 250-grain spitzer bullets varied by 8 grains.
To avoid using the wrong propellant or returning unused propellant to the wrong container, never have more than one propellant type within reach during any loading session. To avoid using the wrong charge:
• Always double-check the scale setting to verify you are using the intended charge (as a nascent handloader, circa 1968, I had to pull bullets from 20 .244 Remington loads after discovering I had the scale set 5 grains off what I intended).
• Always verify you are using the intended data (handloaders have destroyed dozens of .300 Winchester Magnum rifles when they inadvertently used .300 Weatherby Magnum data; any similar mistake can be similarly disastrous).
There is no such thing as a “simple mistake!” Here are the remains of
Model-70 Classic .270 Winchester. In this instance, the handloader used
the right charge of the wrong propellant. Double check everything!
These .22 Hornet groups fired with the Savage M25 include (left to right) a
factory load (obviously does not have everything right), a handload shooting
almost as good as this gun will, and a factory load shooting almost as good
as Mic’s best handloads—differences are in the details.
Dropping The Charge
Contrary to intuition, the method and consistency you use when charging the cases is far more critical than precisely consistent charge mass is. For example, consider loading .308 Winchester rounds using a carefully weighed 46-grain charge of Varget. We can easily keep the mass of all charges between about 45.95 and about 46.05 grains.
Conversely, when we dump charges of Varget from a measure adjusted to dump 46-grains, some charges might be as light as 45.5 grains and other charges might be as heavy as 46.5 grains. Nevertheless, unless we practice extreme care in dumping our carefully weighed charges into the cases, our dropped-charge loads will be significantly more accurate, despite having 10 times the variation in mass.
If you must weigh and hand-pour charges, here is how to get the best results: Position the spout of the pan toward the side of the funnel, so the charge swirls down the funnel cone. Pour slowly and minimize variation in the case-to-case charging rate. The resulting loads are always more consistent and more Accurate. And this method eliminates log-jamming.
This handloader assumed a primer substitution would be harmless. He was
very fortunate. Had the charge ignited after the primer blast had driven
it into the front of the case, a dangerous detonation could have occurred.
This primer (left) is seated fully to bottom of pocket without any pellet preload.
The primer seated deeper (right) preloads the pellet (note its flattened face).
Pellet preload sensitizes the primer and ensures proper ignition. This is
particularly critical in guns with limited striker energy (most non-bolt-actions)
and usually improves accuracy with any load in any gun.
Handloaders often mess up perfectly good loads during the crimping operation. Contrary to intuition, if a light crimp is good, a heavy crimp is not necessarily better. Crimping is generally a mistake, but there are mechanical requirements to prevent the bullet from being driven into the case by recoil in a tubular magazine or during chambering in a self-loader, and to provide smooth chambering. Crimping is also necessary to limit bullet pull in revolvers generating significant recoil. Exceptions always exist, too. For example, use of the Lee Factory Crimp Die often improves loads in cases with limited neck tension, such as the .22 Hornet.
The too-common result of excessive or inconsistent crimping is reduced bullet pull, which always reduces accuracy and can render the ammunition useless or, as noted in the report on the custom .45 Colt revolver, dangerous. Crimp quality is critical to ammunition quality.
The safe practice of metallic cartridge handloading requires we follow a recipe, use the right tools and understand the difference between a safe load and a dangerous load. Use data sources specifying every aspect of the load and follow the data and all related advice.
One area where the standard suggestion is often bad advice is case trim-to length. Typically, in a factory chamber the mouth of a so-called maximum-length case rests 0.065-inch short of the end of the chamber neck. Generally, so long as case necks are at least 0.015-inch short of reaching the end of the chamber neck, the longer the case necks are, the better the ammunition will be. Sinclair offers a simple and inexpensive tool to allow you to accurately measure chamber neck length.
A final note: More often than not, brand-to-brand case-weight variation is sufficient to alter a perfectly normal load. A charge weight safe when used in the lighter case can turn into a dangerous overload if used in the heavier case. Details matter.
Resizing The Bottleneck Case
Redding Competition shellholders allow the handloader to adjust full-length
resizing. Doing so can essentially eliminate stretching in bottlenecked cases.
Case sizing in a conventional full-length sizing die is a one-size-fits-none
proposition. Using a conventional shellholder (left) doesn’t take into account
your rifle’s actual chamber and the case will usually be sized too much resulting
in a shorter case life. In this example (right), using Redding +10 Competition
shellholder leaves the case body 0.010-inch longer. Therefore, functional
headspace of the chambered case is 0.010-inch less. Competition shellholders
are available in +2, +4, +6 +8, and +10 sizes for most case families and
Redding has made taller versions. Use the longest Competition shellholder
providing free chambering of the sized case. Note: Failing to adjust the
die so the shellholder solidly abuts the base of the full-length sizing
die will always result in a significant increase in case-to-case headspace
variation, which will reduce accuracy.
When handloading for a bottlenecked case in a factory rifle, use of a standard sizing die and shellholder is practically guaranteed to result in a case with more headspace than is necessary, usually about 0.006-inch. This leads to the need to trim cases, shortens case life and reduces accuracy. The simple expedient of using the correct Redding Competition shellholder solves these problems. Using these shellholders, I have repeatedly reloaded thousands of cases in dozens of chamberings without ever needing to trim a case. But you don’t always want the case to fit the chamber so precisely; when loading for dangerous-game hunting, use the standard shellholder, give up a bit of accuracy and case life for assured easy chambering.
Sinclair International Inc., 200 South Front Street, Montezuma, Iowa 50171