Ammunition

The 5 Most Common Rifle Reloading Myths

rifle reloading - bullets

Rifle reloading is pretty much like any topic out there in that you can’t believe everything you hear.

It might be a more important topic than others, however, because improper rifle reloading can have a negative impact on the quality of your ammunition, the integrity of your firearms and the safety of yourself and those around you.

In honor of this, let’s take a look at five of the most common rifle reloading myths (and the truth behind them).

Rifle Reloading Myth #1:

Reloading rifle cases is much more complicated than reloading pistol cases.

There can be more complications in reloading for rifles, sure. There are a few belted pistol cases and straight-wall cases that are a bit easier to deal with, after all. (Most pistol rounds).

That being said, loading a bottleneck 5.56 (rifle) round is no more difficult (and arguably easier) than loading a bottleneck .357 SIG round.

The basics are still the same:

  • Load the proper powder in the proper amount
  • Use the correct primer
  • Seat the bullet properly

Admittedly, there is a step of lubrication with any bottleneck case that does not occur with straight-wall cases. Both rifles and pistols use straight-wall cases (9mm or .444 Marlin). The same thing applies to the above-mentioned bottleneck cases.

Rifle Reloading Myth #2:

Being a little over (or under) with the powder measurement can be catastrophic.

The loads that are published by reputable companies like Hornady, Lyman, Hodgdon, Sierra or any other big name in the industry are not absolute limits before a catastrophic event can occur.

If a given rifle cartridge (say 5.56) has a range of 22-26 grains of a particular powder, that does not mean that 26.3 grains will cause a gun to explode. It means the same limit for repeated firing of that round is roughly 26 grains.

Your rifle, ambient temperature and repeated overloading may cause premature wear, however. This premature wear may also cause a catastrophic failure in the future.

Most rifle manufactures build their guns to be able to handle 25-50% excess in pressure at least ONCE. As always, stay within safe limits, but an occasional bump over is not going to cause an explosion of the bolt through your face.

In contrast, some pistol powders have almost no spread between the lowest and highest powder amount—.380 ACP is a great example of this. With a certain powder, the minimum is 4.0 grains and the maximum is 4.4 grains.

Here we are looking at a very small window of what’s acceptable—not to mention many powder measures cannot reliably throw tighter than 0.10 grains.

This means setting the powder measure at 4.0 will get a significant number of powder charges at 3.9 grains. The same thing applies to a measure set at 4.4, producing many loads at 4.5 grains.

Again, neither of these is likely to be catastrophic, but the percentage increase in under/over pressure is much more significant here with 0.10 grain of overage than with the 0.30 overage in the rifle example.

rifle reloading - .458 socom

Rifle Reloading Myth #3:

Loading cartridges at maximum pressure is risky.

In the rifle 5.56 example above, if the statement means to load no higher than 25.6 grains, then the statement is correct.

If, however, the statement is taken to mean loading in the 18-21 grain range is much safer than loading between 22-26 grains, that is completely wrong.

Depending on the powder and percentage of case fill, temperature and angle of the cartridge at discharge, a significant reduction in powder weights can create a very dangerous situation.

When powder does completely cover the primer, there is a chance for delayed ignition/detonation. Normally, powder has a burn rate, which the shooter depends on for proper pressure regulation.

In situations of low powder volume-to-case size, the powder can detonate instead of igniting. This means all the powder burns at once and creates a very strong overpressure situation.

This is much more likely to cause a catastrophic event than a slight excess of powder. This is a common occurrence when people attempt to create their own (from scratch) subsonic recipes.

Rifle Reloading Myth #4:

Loading for maximum pressure provides the most accurate load.

This is almost never true. In most rifle cartridges, there are at least two accuracy nodes. One is approximately three percent below maximum velocity. In a 3,000 fps cartridge, that would be roughly 100 fps slower than max.

There also tends to be a slower node that is around 10 percent lower than peak velocity. In the same cartridge, we would likely see nodes at +/- 50 fps of 2,700 fps and +/- 50 fps of 3,000 fps.

This will vary by powder choice, as well as a percentage of fill for that powder in the given cartridge. In my experience, running an 86-94 percent load density tends to provide the best accuracy with many powders.

Very few rifle cartridges/powders provide the best accuracy/precision, over a compressed load.

rifle reloading - machine

Rifle Reloading Myth #5:

The velocity of a given load never changes.

Many people believe that if you produce your pet load for, say, 6.5 Creedmoor and you do it faithfully and precisely, your velocity will be exactly the same each time you pull the trigger.

I have done some extremely consistent load work, which has resulted in loads with single-digit standard deviations. Essentially meaning each trigger pull the velocity varied by significantly less than 10 fps.

That takes a TON of work and is super awesome when it happens. Even when you are focusing on that, it doesn’t always work.

In comparison, factory rifle ammo is doing really well to vary by no more than 25 fps per trigger pull, and a better assumption would be 50 fps in either direction of the mean velocity.

On top of that, all powders are temperature-sensitive. Some, like the Hodgdon Extreme series, are significantly less affected by changes in temperature. They are still affected.

A load using standard powder developed at 65 degrees hits 2,950 fps and is quite accurate. That same load on a hot day (95 degrees or so) may well hit 3,010 fps and not shoot nearly as tight of groups.

In contrast, on a cold day (24 degrees), the same loaded batch may produce velocities closer to 2,900 fps and also be less accurate

Some competitors load their cartridges based on temperature testing to ensure they are hitting the most precise velocity at all times of year.

Do you have any rifle reloading myths or facts you’d like to share? Let us know in the comments below.

The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (4)

  1. @ Floyd

    Primer brand can have a HUGE effect on the load. Some primers are faster burning, some have a thicker metal skin which provides (a touch) more insurance against blow out. Some are ever so slightly wider and thus more difficult to place (and remove).

    The more important thing is burn rate and temperature of burn and consistency in quantity of primer. These vary slightly between lots of the same brand, but vary HUGELY between brands. In working up loads during the first Ammo shortage about 10 years ago. I started my favorite loads down about 10% when using an alternative primer. Some of those loads were 2-300 fps slower and some were 2-300 fps faster at the same powder amounts.

    This agrees with data some friends figured out. They have precise testing equipment and have determined the pressure curve can go up or down by over 3000 psi, in some bottle neck rifle cases with only a primer change.

  2. In my 56 years of reloading experience I have found there is no industry standard for what constitutes a ” magnum” primer from a standard primer. and different manufacturer’s primers have different burn characteristics. The result is one manufacturer’s standard primer has burn characteristics similar to another manufacturers magnum primer. Due to the small charges pistol cartridges are not significantly affected by primer manufacturer changes but with rifle cartridges it can make a real difference. I have had 100 yard group sizes change from 2.75 inches to 0.625 just by changing primers. Some powders seem to be much more sensitive to this than other powders.

  3. Floyd,

    When I was loading for my handguns, I found the most accurate loads were a combination of: type of powder, amount, bullet and primer. I did most of my extensive testing with the .44 Magnum for hunting, varying loads by .1 grain. I was able to get sub 2″ groups at 50 yards from a bench using several different pistols. While accuracy was decent in each, each liked a different load the best.

    I never did necked cases, but would expect the same would be the case. I retire in two months and will hopefully move back to the country and have my own range again. I will be getting back into reloading and that will include several necked cartridges.

  4. I’ve always thought that the brand of a primer has no significant affect on a load as long as it is the correct size (sr,lr, standard or magnum, bench or match, etc). What say you?

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