9 mm Revolver Bores

by
posted on June 11, 2014
** 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. **
201089141944-sw_carry_m-1.jpg

A few years ago, I was deeply involved in persuading Smith & Wesson to build a particular model for the concealed-carry handgunners of this country. As many readers are aware, I am a big fan of the internal-hammer Centennial revolvers. I have been carrying them daily since the early ’70s and consider them to be the ideal concealed-carry handgun. Naturally, I was delighted when the company developed a light .357 Mag. Centennial, and I carry one of these every day. But, in a handgun world awash in 9 mm semi-autos, I felt-and still feel-that the company needed to offer a light 9 mm.

Thus began a series of experiments to prove that this might be a good idea. The firm did offer a stainless steel 9 mm Centennial at this point in time, but it was too heavy to expect habitual carry by all but the most dedicated. I ran a series of chronograph tests comparing velocities of the same basic gun in 9 mm Luger and .38 Spl. If you kept bullet weights the same-124 to 125 grs. and 147 to 150 grs. in both cartridges, the results were surprising. The 9 mm gun turned in faster speeds than the .38 Spl. Since the company used the same basic platform for both calibers, the shorter 9 mm round had a lot of freebore in the cylinder. I assumed that the reason for the velocity disparity was the so-called “jump” in front of the cylinder.

It may have been a contributory factor, but I am now convinced that there is another reason. I don’t believe the barrels on those early J-frame 9 mms were really 9 mms. I think they were .38 barrels marked 9 mm. The smaller 9 mm bullet was a looser fit in the larger bore and the velocity was therefore higher. And I also believe that this makes little difference in a short-range defensive handgun. A light 9 mm Centennial is still a good idea.

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.