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

Staccato P4x Review 1
Staccato P4x Review 1

First Impressions of the Staccato P4X

Down in Texas, Staccato launched a new pistol to celebrate America's 250th anniversary: the P4X. One can hardly blame them considering that the company's entire product line is based on the 1911, arguably the most American of handguns.

A Big Third Circuit Ruling on America’s Rifle

In an appeal of a case the NRA filed in 2018, the U.S. Court of Appeals for the Third Circuit struck down New Jersey’s ban on “assault weapons” and “large capacity” ammunition magazines as unconstitutional.

Top Cop: How an Armed American Saved President Trump’s Life

An NRA Benefactor Member and NRA Certified Law Enforcement Patrol Rifle Instructor, Sergeant Aaron Zaliponi likely saved the life of President Trump in Butler, Pa. For these reasons, the NRA has selected him as the 2025 Law Enforcement Officer of the Year.

Review: Rock River Arms A1 Carbine SBR

The Rock River Arms A1 SBR is just plain cool, and there’s little justification needed beyond that for picking up a new gun. It’s a mixture of throwback, retro and nostalgia with a bayonet lug, and you just can’t go wrong there.

The Armed Citizen® July 20, 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.

Plinking Perfect: 5 Must-Haves for Your Next Rimfire Shoot

What better way to celebrate 250 years of freedom than to go out plinking this summer? Here are five great products that will make your next rimfire range trip better than ever before.

Interests



Get the best of American Rifleman delivered to your inbox.