Q: revolver ammo of ISP before 1967?

Dear readers,
I am doing a little research on the history and development of US LEO ammo.
I would like to know what ammo the Illinois Highway Patrol (ISP) did use in their service gun/revolvers BEFORE the adoption of the 9mm Luger S&W M39 ??
They probably used .38 Special or .357 Magnum ammunition, but I would like to know which brand, what type of bullets, etc.
Did the ISP use metal penetrating ammo or the heavy 200-gr. slugs?

You may want to contact ISP directly if you don’t get an answer here ( isp.state.il.us/ ). Major police organizations often have someone who acts as a historian in an official or unofficial capacity who may be able to help if you explain nicely your reason for asking.


If you don’t receive a response please let me know. Friends in “low” places and all that!


Thanks a lot for the usefull info. I will surely e-mail the ISP, I just need some time to figure out the right questions and especially the right English grammar. Writing in decent English ain’t that easy, you know!
I will let you know ISP’s answer.

Although I hadn’t e-mailed the ISP, I found the answer to my question somewhere on the never ending stream of blogs and forums on the internet.
The fact is, prior to the introduction of the 9mmL S&W M39 pistol ISP had no policy of issueing firearms to its police officers. The ISP officers had to provide their own weapons and ammunition. So theoretically they could have used almost any gun/ammo available. But probably they had .38Sp/.357M revolvers because that was the most popular calibre at that time.
The M39 pistol was the first firearms officially issued by ISP to its personel.

Anyway, thanks for your support!