Here's what Remington says about the Police guns and how they're different, including about the MIM or machined extractors:
====================================
REMINGTON ARMS COMPANY, LE DIVISION
Important differences between Remington 870 Police and 870 Express shotguns
The 870 Express has been an important part of Remington’s offering to the sporting market.
It was designed to meet a price point in the commercial market while still providing classic 870 functionality.
All of Remington’s 870’s have interchangeable parts, even if they have cosmetic differences.
It is also important to note that many manufacturers use the 870 Express platform for their Police / Combat models.
Without exception, every manufacturer who utilizes our 870 platform serves to upgrade their system to a more efficient, street worthy platform.
While the 870 Express is still an 870, the best pump shotgun on the market, there are some very important cosmetic and functional differences between it and the 870 Police.
To our customers in Law Enforcement, Military, Corrections, and Security, whose lives depend upon the unfailing performance of Remington shotguns, the Police modifications are of paramount importance. Synopses of the variances are provided below.
• 870 Police shotguns go thru a special 23 station check list – ranging from visual inspection, functional testing, test firing, and final inspection.
• All Police shotguns are assembled in a “special build area” at the plant in Ilion, NY. This section is secured and serves only to build LE and Military shotguns, with the same factory personnel working at that assignment each shift.
• All parts that enter the “special build area” are visually inspected by hand to ensure top quality and functionality.
• Due to heavy recoil in buck and slug loads, all 870 Police guns have a longer magazine spring which ensures positive feed and function.
• A heavier sear spring is used to generate a reliable, positive trigger pull between 5 and 8 lbs.
• A heavier carrier dog spring is used to ensure when the carrier elevates the shell, it will be held there until the bolt can push it into the chamber. This ensures positive feeding when using heavier payload rounds.
• Police shotguns do not have an ISS (Integrated Safety System) which is a locking mechanism on the safety of commercial shotguns. This type of locking mechanism can cause delay to an officer who needs the weapon but does not have the appropriate key. LE shotguns have the standard, proven, cross bolt safety.
• The fore-end on the Express model is longer and not compatible with many police shotgun vehicle racks.
• The Police shotguns utilize the heavy duty SPEEDFEED Stocks and Fore-ends.
• The Express model will not allow for the addition of an extension tube without physical modification to the tube and barrel, which can nullify the warranty.
• The Express model has a BEAD BLAST BLUE finish while the Police models utilize either High Luster bluing or Parkerization.
• The Express model utilizes a synthetic trigger housing while the Police models use a compressed metal housing.
• The Police shotgun barrel is locked down with a “ball detent” system in conjunction with the magazine cap vs. a lesser grade “synthetic magazine spring retainer” lock down as used on the Express system.
• The receivers used in Police guns are “vibra honed” to smooth out rough finishes and remove burrs before parkerization or bluing.
• Police shotguns use machined ejectors and extractors, as opposed to powdered metal cast which are utilized on the Express models.
