A cousin was discussing having his 6" blue Mod 19 cut down to 3 5/8 ". I asked why this odd length and why not just get a 4 inch? He said he had heard that back in the 60's, before the 10mm and 40 cal, the FBI did a study and concluded that the optimum barrel length for a .357 was 3 5/8 inches because that was the absolute minimum length required for the .357 to perform at its potential. He went on to say the FBI ordered 650 of these revolvers in 6 inch and had them cut down. ( Why didn't they just order them straight from the factory at 3 5/8 inches? After all we're talking about Mr. Hoover here) I think he may be confusing this with a run of RB 3 or 4 inchers made for the ONI and NIS and later transferred to the FBI. Anyway, I told him I'd ask. Anyone know anything about this 3 5/8 inch thing?
No offense, but your cousin has been listening to far too many "gun shop commandos." Either that, or the LGS (local gun shop has a butcher with too much time on his hands and more tools than brains) and he needs a "custom project."
The FBI always issued 4 inch guns as basic duty guns. Typically, they were Model 10s or Colt Police Positives or later, the Colt Official Police.
They issued some Model 19s along the way with adjustable sights, the most famous being the ONI guns, which were 4 inch round butt Model 19s transferred to the FBI from the Navy ONI (Office of Naval Intelligence).
When they started looking at shorter guns, they had S&W make some 2 1/2 inch Model 10s with round butt, and then later they finally settled on the 3 inch Model 13. The 2 1/2 inch guns were made in 1974, two years after J. Edgar Hoover died.
It should be remembered that all this time, the primary issue ammo for the FBI was the Winchester "FBI Load," which is a 158 grain Lead Hollow Point +P.
The Model 13s were adopted in 1982, long after J. Edgar Hoover's death (he passed away in May 1972, if I recall). Pursuant to J. Edgar Hoover's long standing policy adopted when the Bureau ordered Registered Magnums, .357s were normally loaded with .38 Special ammo and the Magnum rounds were authorized for carry in special cases or by special arrangements with the Special Agent in Charge (SAC) or some other supervisor. The official Magnum load adopted by the FBI was the Winchester 145 grain Silver Tip in order that the FBI could avoid the flame cutting issues of the 125 grain Magnums.
In any event, there are all sorts of stuff that the Gun Vault people have done at Quantico in terms of experimentation, but I have absolutely never heard of long barreled S&Ws modified to 3 5/8 inch by the FBI.
One plausible explanation for the genesis of this "gun shop garbage," is the fact that Registered Magnums (all of them) made by S&W started with 8 3/4 inch barrels and the factory shortened them to the length ordered by the customer, with the minimum being 3 1/2 inch. That, however, was a factory thing, not an FBI thing.
I have never heard of this little story promoted by your cousin. I will be quite curious to follow this to see if any other reliable source has any real information on this apart from "my cousin heard."
No offense to your cousin, but he needs to leave his fine 6 inch revolver stock. That revolver is discontinued as are replacement barrels.
If he insists, tell him his revolver will be worth about $50 after it is butchered. Save him the trouble, pay him the $50 and buy the revolver from him without him having to use his labor and tools to saw off the barrel. I mean, if he is willing to destroy its value, save him the cost and trouble of modification and just buy it for the reduced value now.
Have your cousin read the book "Magnum - The S&W .357 Magnum Phenomenon" by T.J. Mullin, and have him also read, or at least look at the pictures with this article:
http://www.americanrifleman.org/articles/history-of-fbi-handguns/