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

Fiocchi’s new Hyperformance SBR Enhanced line of ammunition
Fiocchi’s new Hyperformance SBR Enhanced line of ammunition

Selling Short: Fiocchi's Hyperformance SBR Enhanced Ammunition

Fiocchi’s new Hyperformance SBR Enhanced line of ammunition isn’t a mere marketing gimmick. It’s designed for top performance out of short-barreled rifles, and it delivers.

New For 2026: Yankee Hill Machine Victra-20 Shotgun Suppressor

Yankee Hill Machine introduced its VICTRA-12, a modular 12-ga. shotgun suppressor, last year. This year, the company is bringing out a 20-ga. version with the VICTRA-20.

The Armed Citizen® June 22, 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.

Important Notice To Members: Exercise Your Rights. Assist In The Nomination Of Directors.

The NRA Bylaws provide for the election of one-third of the members of the Board of Directors each year. Those terms of office will expire at the 2027 Annual Meeting of Members in Atlanta, Georgia, on April 24, 2027.

Skills Check: Pistol Standard Xray 2 Drill

Examine and strengthen each part of your presentation and shot in this revealing drill.

Gunsite at 50: Celebrating a Golden Anniversary

It’s no secret Gunsite Academy is celebrating its Golden Anniversary this year. In August, it’s holding a 50th Anniversary Alumni Shoot to celebrate five decades of training excellence, tradition and community.

Interests



Get the best of American Rifleman delivered to your inbox.