9.8 mm or 9.65 mm?

by
posted on January 22, 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. **
wiley-clapp.jpg

The first decade of the 20th century saw a lot of developmental effort in the handgun field. It’s well known that legendary designer John Browning was involved in both American and European firearms design. In 1910, he had all but completed-with Colt and Army Ordnance-the development of the Government Model .45 pistol. Mr. Browning was also working with FN, the national arms plant of Belgium, and had used essentially the same design as the Colt. There were several different Colt pistols that had an FN counterpart. This was done with the approval of all concerned, because the two companies agreed not to sell arms in the others territories. They had literally divvied up the world and everything was working fine.

But they had omitted a few countries, which were open to competition. Romania, down in the Balkans, was such a place. Colt got wind of a Romanian interest in some kind of medium-bore auto. They developed and produced a scaled-down version of the soon-to-be famous 1911 pistol.  In so doing, they created a collector’s item, the 9.8 mm Colt. Only a few were made, because Colt salesmen were unable to sell the Romanian buyers on the gun.

Aware that this was going on, FN came up with a version of the same pistol. Once again, they were unable to sell anyone on the idea and the guns never went beyond the production prototype stage. They used a cartridge called the 9.65 mm Browning. All of this was well recorded in several respected sources. I once saw one of the Colt pistols at an NRA Convention, but was not allowed to handle it. I have never seen the FN gun or the ammo for it. The whole concept is very interesting to me, but the ammunition is even more so. If Colt and FN made essentially the same gun, why did they use two different cartridges?

It looks like they didn’t. The 9.8 mm Colt and 9.65 mm Browning are (nominally) .15 mm different in size. In English measurement, that is about .0059-fifty-nine ten thousandths-of an inch. That really is not much. As a matter of fact, it’s just about the difference between bore diameter and groove diameter. I would bet serious money that this was the difference between the 9.8 mm Colt and the 9.65 Browning. One company named its round on bore diameter, the other on groove. There is no real difference.

Latest

Aiming
Aiming

The Fire Control Sequence: 3 Steps to Perfect Round Placement

If you want to hit your target, you need three things: a gun, a target and a method by which to hit that target with that gun. Shooting well is the result of a specific process.

Why Does the .44 Special Keep Hanging On?

What is it about the .44 Special cartridge that makes it, well, special?

CAA USA Under New Ownership, Consolidation of Manufacturing

CAA USA has been acquired by Plastimold Products, owners of META Tactical, unifying all three brands and their manufacturing capabilities.

A "Shot Heard 'Round the World" Rings Out in Karnes County

As America celebrates its 250th anniversary, communities across the nation are reflecting on the people and principles that have preserved our freedoms for generations. On Saturday, June 27, the Karnes County Friends of NRA did exactly that.

Behind Winchester's New Supreme Long Range Ammunition

For 2026, Winchester Ammunition took a big step forward in its ammo offerings with Supreme Long Range. Unlike previous offerings from the company, this purpose-built long-range hunting and shooting line required the company to invest in an entirely new projectile design: the BC Max bullet.

New For 2026: Magnum Research Suppressor-Ready Desert Eagle .50

With the growing popularity of suppressors, Magnum Research is bringing its iconic .50-caliber Desert Eagle pistol up to date with a suppressor-ready, threaded-barrel version.

Interests



Get the best of American Rifleman delivered to your inbox.