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

CZ 75 Legend 01
CZ 75 Legend 01

The CZ 75 Legend: Rebirth of an Icon

If you make a short list of the most influential handgun designs of the 20th century, the CZ 75 would make the cut. A half century since its introduction, CZ is honoring that legendary status with the CZ 75 Legend.

39 New Rifles for 2026

Today's new rifles run the gamut from the latest and greatest packed with the most up-to-date features money can buy to retro-inspired models that give us a glimpse of the way things used to be if you wanted to send a bullet "over there somewhere."

The Armed Citizen® June 1, 2026

Read today's "The Armed Citizen" entry for real stories of law-abiding citizens, past and present, who used their firearms to save lives.

Tactical Belts For The Rest Of Us

Most shooters don’t need a "war belt." While enthusiasts like the idea of preparing for every contingency, the vast majority of us need a reliable platform for a range session, a training class or a local club match.

Review: Trijicon Credo 1-10x28 mm Riflescope

With a 10X magnification range, the Trijicon Credo 1-10x28 mm riflescope is ideal for close-range targets, long-range pursuits and everything in between.

Study Shows Widespread Public Approval for Self-Defense, Recreational Shooting

Research conducted by Responsive Management annually for the Council to Advance Hunting and the Shooting Sports (CAHSS) found that, in 2025, 78 percent of adult residents in the United States believe learning self-defense skills with a firearm is completely acceptable.

Interests



Get the best of American Rifleman delivered to your inbox.