On the original question and I'll try to stick to the facts: Why was the 40 S&W invented?
Miami shootout. The FBI were armed with S&W revolvers and firing 38 Spl+P LSWCHP and the S&W model 459 in 9mm JHP with 20 round mags available to it.
At the same time the U.S. Army had just adopted the M9 in 9mm as the standard service sidearm. It replaced the 1911 in 45acp. This was a controversial move.
Law enforcement across the U.S. the transition from wheelguns to pistols and 9mm was in full swing. Overwhelmingly the go to round was the 9mm. It was viewed as an effective round in higher capacity pistols. This was the era of the "Wonder nines". 13, 14, 16 round 9mm handguns were the "smart thing" to have.
The FBI concluded after Miami that they needed a more powerful round and that the 9mm did not cut it for them as it lacked penetration. This sent shockwaves throughout the firearms industry and in law enforcement. Seminars were held, labs went to work, field tests conducted. Over the next couple of years things rolled out.
At first the FBI recommend law enforcement switch to the 147 gr. bullet for the 9mm. Many agencies did that. A problem quickly developed. the 147 gr. bullets and loads had been developed for sub guns and did not always cycle reliably in guns that had been built for the standard velocity 9mm guns with 115 gr. and 124 gr. bullets. The springs and slide weight of the guns were set for the lighter bullets. The hot 147 gr. loads also accelerated wear. Across the country law enforcement agencies were experiencing problems.
The FBI concluded that 12-16" of penetration with expansion, after penetrating some barriers (4 layers of denim, sheetrock, autoglass, etc. each in their turn) was needed for their jhp bullets to be reliable.
This launched a search for the round that could do this.
It also set ammo manufacturers internationally into a unprecedented rush to upgrade the 9mm bullet, the most popular defensive handgun round on earth. Other rounds also benefited but the 9mm got the most attention. They were tasked with developing jhp bullets that met the new FBI criteria. This took some time.
The FBI settled on the 10mm round. This sent a 200 gr. bullet down range at about 1200 fps. A 180 gr. could do more.
The FBI announced they wanted a gun for it in 1987-88 and in 1989 S&W gave them the 1006 with a 5" barrel. Empty the gun weighed 39 oz. It carried 9+1 rounds.
In 1990 S&W produced the 1076 in response to an order from the FBI for 10,000 guns in 10mm. The 1076 weighed empty 39.5 oz. It had a 4 1/4" barrel. It also used 9 round mags with 11 and 15 round mags available to it only to the FBI. The initial order of guns sent to the FBI were rejected and sent back to S&W for rework. The contract stalled. In 1993 about 2400 of the 10,000 guns ordered were delivered. Some were returned for rework. Some sold off. Some went back to S&W or destroyed. The order was cancelled. The 10mm had a short life with the FBI.
There were problems with the guns and the ammo. Many of the guns delivered were not reliable.
Agents were slow to give up the 30oz 459 which held 14 rounds of 9mm or the BHP which some had or their revolvers which they were used to in exchange for a gun that weighed a good deal more and was bigger. The grips were fatter. There were objections to the recoil and slower follow up shots. Accuracy for some dropped off. The FBI tried to develop a load with a 180 gr. bullet at just under 1000 fps to answer some of the problems.
Meanwhile ammo manufacturers were working as was S&W to meet the FBIs penetration requirements.
An IPSC shooter from South Africa, Paul Liebenberg had developed a cartridge based on the 10mm case. He took the idea to S&W. S&W figured that they did not need the case capacity of the 10mm to get a 180 gr. bullet moving at 980 fps. A shorter case could do it and be more efficient. The IPSC shooter's case did the trick. The new case was strong and could withstand high pressures. It could work well with a lighter bullet as well. If a 115 gr. +P or 124 gr. +P 9mm bullet did well than a 135gr., 155gr. or 165gr. pill going faster with a bigger, heavier bullet was even better, they figured. A 135 gr. pill at more than 1300 fps from a 4" barrel was near .357 Magnum territory. A 155 gr bullet at an honest 1200 fps was no slouch. It was 9mm+p velocities without the increased wear on the gun. Without breaking a sweat.
The 40 S&W was introduced to law enforcement in 1990. S&W built the 4003 for it. The gun held 11+1 rounds and weighed 30oz. empty. It held as many rounds as the 10mm but in a gun the same size and weight as a 9mm handgun. Less capacity than a 9mm. More capacity than a 45. With bullets that met the FBIs penetration requirements.
In the history of handgun ammunition no round took off as well and as fast as the 40 S&W. Within a few years it became the dominant police round in the U.S. and remains so today. It was and is the most successful and important handgun round introduced in the last half of the 20th century.
Glock, which had just showed up in the U.S. in the late 1980s, beat S&W to the punch in introducing a gun into the pool. The Glock 22 was essentially the Glock 17 modified for the 40 S&W round. It weighed less than 23 oz. empty. 10, 15 and 17 round mags were available.
Glock did what so many other gunmakers did as well. They just took their 9mms and modified them for the 40S&W. Problems ensured. But after a decade or so were corrected.
The 40S&W remains today the most widely used round in law enforcement in the U.S. and for good reason.
The 357 Sig, based on the 40 was introduced 4 years later in '94, but has not seen the success of the 40 S&W.
Oh the FBI? After swinging back and forth for a bit they ended up with the 40 S&W and the 9mm. Both with much better bullets that met their criteria.
tipoc
