Smith & Wesson 5906, 4506 and 4006: Used Police Trade-In Buyer's Guide
Smith & Wesson Third Generation pistols were a common police sidearm in the 1990s. Many were later sold off as trade-ins. This guide covers three of them: the 5906 (9mm), the 4506 (.45 ACP) and the 4006 (.40 S&W). It also explains what to check before you buy a used one.
What the Third Generation is
S&W first-generation pistols have two-digit model numbers, such as the Model 39. Second-generation pistols have three digits, such as the 459. Third-generation pistols add a fourth digit, such as 5906, 4506 and 4006. A few value-line models are exceptions.
The model number is a code. The first two digits show the caliber. The last digit is 3 for an aluminum alloy frame or 6 for a stainless steel frame. All three guns here end in 6, so they are stainless steel. All three are double-action/single-action pistols with a slide-mounted safety lever that also works as a decocker.
The three models at a glance
| Model | Caliber | Magazine | Weight (listed) | Years made |
|---|---|---|---|---|
| 5906 | 9mm | 15 rounds (10-round also sold) | about 1070 g (38.3 oz) | 1989 to 1999 |
| 4506 | .45 ACP | 8 rounds | about 1.16 kg (2.6 lb) | 1988 to 1999 |
| 4006 | .40 S&W | 11 rounds | about 1058 g (37.3 oz) | 1990 to 2011 |
The figures come from Wikipedia and can differ a little between sources and variants. The 4006 launched in January 1990 together with the .40 S&W cartridge, and has a 4-inch barrel. The 5906 and 4006 use staggered-column magazines.
Which agencies used them
Wikipedia lists these users. Some used close variants, not the exact model.
- 5906: Los Angeles, Colorado Springs and Honolulu police departments, and the Puerto Rico Police Department (1990 to 2010).
- 4006: California Highway Patrol (until 2019), Colorado State Patrol (1998 to 2008), Nevada Highway Patrol, Alaska State Troopers and Iowa State Patrol.
- 4500 series variants: the 4566 was used by New Hampshire State Police, and the double-action-only 4586 was the Idaho State Police sidearm from 1992 to 2002.
A police history does not tell you how a single pistol was treated. Inspect each gun on its own.
Reading the markings
Find the model number on the slide or frame. Look for agency or property markings on the slide, since a trade-in often has them. Check that they match the story you are told.
The 4506-1 is the later version of the 4506. It has a round trigger guard in place of the square one, and later guns have blued hammer and trigger parts and laser-etched markings instead of roll marks. Write down the serial number and compare it to the paperwork. Your dealer will record it on the transfer forms.
What to inspect on a used pistol
Bore and feed ramp
Look down the barrel with a light. You want a clean bore with no heavy pitting or bulges. Check the feed ramp for gouges or rough spots.
Frame and slide
Holster wear on stainless steel is normal. Look for cracks, deep dings, battered slide rails and loose slide-to-frame fit. Work the slide by hand. It should move smoothly with no grit.
Safety and decocker
Test the slide-mounted lever with the pistol unloaded and pointed in a safe direction. It should work firmly and decock the hammer without sticking. Check the trigger in double action and in single action.
Magazine and disconnect
The magazine should seat fully and drop free. These pistols have a magazine disconnect, so they will not fire without a magazine fully in place. Have your dealer check this with you. Look for dented feed lips and weak springs.
Finish wear
Stainless is tough, but check for rust under the grips and inside the slide.
Magazines and parts
Magazines are made for a specific model and caliber. Do not assume a 9mm magazine fits a .40 or .45 pistol. Ask the seller for the exact magazine part and make sure it works in your gun. These pistols are out of production, so check parts availability for your model before you buy. A pistol that comes with two or more good magazines is easier to own.
Buying through a licensed dealer
A licensed dealer (FFL) handles the transfer. You fill out ATF Form 4473, and the dealer runs a NICS background check through the FBI system. NICS was created under the Brady Act and launched in 1998. Under federal law, a gun sold across state lines goes through a licensed dealer. Your state may add other rules, such as waiting periods or permits. Ask your dealer what applies where you live.
FAQ
Are these pistols still in production?
No. Wikipedia lists the 5906 and 4506 as ending in 1999 and the 4006 in 2011. Used guns are the only choice.
Is a police trade-in worse than a private gun?
Not by default. Check the bore, slide fit, springs and magazines on every gun, whoever owned it.
Can I have a used pistol shipped to my house?
Not as a normal rule. Out-of-state sales go through a licensed dealer, where you finish the Form 4473 and background check. Ask your dealer about the steps in your state.
General information, not legal advice. Current as of September 2026. Laws change; check the official source before you act.
