Understanding .327 Federal Mag. Ballistics

posted on April 29, 2010
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
201042915453-327_f.jpg

From the moment Federal announced the .327 Federal Mag., Internet experts and gun goobers discounted it as another pip-squeak cartridge. Some folks just don’t understand external and terminal ballistics. The performance of any cartridge is dictated by physics, not by perception, prejudice or pontification. The laws of physics apply equally to all bullets while in flight, while penetrating a magnificent buck or while punching through a homicidal maniac.

Penetration is dictated by bullet weight, impact velocity and expanded diameter. All things equal; faster, heavier and smaller (in diameter) bullets penetrate deeper. Tissue destruction is more difficult to predict. Velocity, expansion and energy transfer are the best indicators. Generally, with bullets that penetrate to the same depth, those moving the fastest and exhibiting the largest expansion factor will damage the most tissue.

A .327 Federal Mag. bullet is initially 0.045” smaller in diameter than a 9 mm or .357 Mag. bullet—that’s about the thickness of a potato chip. The .327 Federal Mag. also uses lighter bullets launched at higher velocities. Bullets currently available in factory ammunition retain their weight well and expand at a higher ratio than many .357 Mag. projectiles. (This is the advanced bullet technology touted in advertising and often scoffed at by armchair ballisticians.) This means the .327 Federal Mag.’s projectiles will penetrate similar to 125- and 158-gr. hollow-point bullets from .357 Mag. loads. It also means they are very likely going to damage more tissue because of the higher impact velocities and greater expansion factor. The 115-gr. Gold Dot .312 bullet expands to more than twice its original diameter.

I tested the terminal ballistics of three .327 Federal factory loads and one handload in 10 percent ordnance gelatin, and when compared to hundreds of other handgun and rifle loads I’ve also tested, it’s clear the cartridge has the right stuff for coyotes, deer and even felonious fiends. High velocity combined with some of the best expansion factors you will find, matched with ruggedly constructed bullets are what makes this possible. With regard to external ballistics, all .327 Federal Mag. factory loads drop less than 6” at 100 yds. if sighted in at 25 yds.

One downside to the .327 Federal Mag. is that there are only three factory loads available. Another disadvantage is that most 0.312”-diameter component bullets won’t hold up to the high impact velocities. Currently, Federal and Speer are the only companies offering loaded ammunition, and Hornady’s 100-gr. XTP is about the only component bullet that will not disintegrate or over-expand when impacting at violent speeds. But that is changing. New for 2010, Federal has an 85-gr. jacketed soft point load and Speer a new 100-gr. Gold Dot load. Both the 100- and 115-gr. Gold Dot bullets should be available for handloaders very soon.

The .327 Federal Mag. is not a better approach to achieving terminal performance; it’s just a different approach. Some like big bullets that lumber along and some like medium size bullets that move a bit faster. If like me, you believe in the attributes of lighter bullets that radically expand and impact at lightning-like speeds, the .327 Federal Mag. might soon become your favorite revolver cartridge, too.

Latest

David Keene Obituary F
David Keene Obituary F

Remembering Past NRA President David A. Keene

David A. Keene, a prominent conservative leader and NRA President from 2011 to 2013, died on March 8, 2026, at 80 years old, from pancreatic cancer.

Semi-Automatic Bans Are Unconstitutional

If the logical application of the rule of law means anything in this constitutional republic, bans on massively popular semi-automatic firearms will be found unconstitutional.

New Handloading Helpers: The Latest Reloading Gear From RCBS

When Hodgdon Powder Company took over RCBS in 2024, company leaders said positive change was coming. By looking at the new products RCBS introduced in 2026, it’s clear they were right.

North-South Skirmish Association to Hold 153rd National Competition in May

At the North-South Skirmish Association's 153rd National Competition, members will compete in live-fire matches with original and reproduction muskets, carbines, revolvers, mortars and cannons.

Review: Heckler & Koch G36 .22 LR

What was once a service rifle for a brave new world all those wasted years ago is now running free as a rimfire option for armed citizens.

Steyr's At Series Handguns: All-Metal & Modular

Designed as a collaboration between Steyr Arms and Arex Defense, the At series of handguns are built on metal frames and have several user-customizable features not seen in other offerings.

Interests



Get the best of American Rifleman delivered to your inbox.