So you think you know almost all there is to know about handgun ammunition? Find a deeper, more complex world of ammunition waiting. At your level, it’s no longer about just choosing a caliber — it’s about understanding the history, construction and nuance behind every round. It all starts with deciding to not stick with what you know and get out of your comfort zone.
Team Armscor’s John McClain unpacks the quirks of various caliber options, explores niche options and shares what he’s learned after thousands of rounds at the range.
A bullet’s caliber only tells part of the story. Even rounds that use the same diameter bullet can behave completely differently due to case length, powder charge and design.
“You can have a bullet that is the same caliber, but it’s a different named caliber,” John said. “It’s not about the name — it’s about the casing and what’s behind it.”
Consider the 9mm family:
Some rounds don’t exist to fill a gap — they exist because they’re just plain fun or effective for specific roles.
One standout? .22 TCM, a proprietary cartridge developed by Armscor.
“.22 TCM wasn’t developed to solve a problem — it was born out of curiosity,” said John. “It’s a centerfire round with low recoil and high velocity — and it’s one of my favorite rounds to shoot and show off.”
It uses a .22-caliber bullet in a shortened 9mm case and comes in soft point or jacketed hollow point variants. The .22 TCM 9R version is tailored to fit in standard 9mm-length magazines.
“We made the 9R version to work in Glock-style mags and other compact platforms,” John noted.
Once you start exploring, you’ll encounter rounds like FN 5.7x28, .17 HMR, and .22 Magnum — high-velocity options with lightweight bullets and niche uses.
“They’re fantastic for varmint control and precision shooting,” John said.
Though less common, these rounds offer exceptional accuracy and low recoil, making them appealing to both new and seasoned shooters looking for something different.
The more you explore ammo, the more you’ll realize how many factors are at play: velocity, weight, barrel length, expansion, platform compatibility and, frankly, personal preference.
“You might find calibers that the general population doesn’t care about — but that you personally love,” John said.
Ultimately, being an expert shooter isn’t about knowing everything. It’s about knowing what matters to you and why. Whether it’s obscure wildcats or purpose-built performance loads, advanced shooters often find the greatest satisfaction not in sticking with what they know, but in exploring what they don’t.