For which firearm?
Wherever you need to. If you're in a field environment, just don't take out the firing pin or extractor, for the sake of not wanting to lose that tiny extractor pin or the small cotter pin which holds the firing pin in place.
Bolt and bolt carrier group
You need a gunsmith
The bolt carrier, the firing pin, the carrier pin, the extractor, the cam pin, the bolt, the extractor retaining pin.... that's the assembly, but the charging handle is also defined as part of the bolt carrier group.
firing pin , breech block, and extractor and ejector mechanism
Trigger with trigger bar, trigger spring, connector, trigger housing with ejector, locking block, slide stop, magazine catch, magazine catch spring, slide lock, slide lock spring, locking block pin, trigger pin, trigger housing pin, Frame, Magazine tube, magazine floor plate, magazine spring, magazine insert, magazine follower, front sight, extractor, rear sight, firing pin channel liner, extractor depressor plunger, extractor depressor plunger spring, Spring loaded bearing, spring cups (2), Firing pin spring, firing pin, firing pin spacer sleeve, slide cover plate, firing pin safety spring, firing pin safety, barrel, recoil spring assembly, 36 parts unless I missed one.
Rings, extractor/ejector, firing pin. forearm
Primer.
The firing pin and extractor for the M9 are housed within the slide assembly. The slide is the upper part of the pistol that moves back and forth during firing, and it contains the mechanism that strikes the cartridge's primer and extracts spent casings. This assembly is crucial for the functioning of the firearm, ensuring reliable ignition and ejection of spent rounds.
Sometimes. The firing pin and extractor may leave marks on an ejected shell that can be matched to a gun.
Clear the pistol of all ammunition, remove magazine. Remove slide. Press extractor pin out with a pin punch. This will release extractor and extractor spring. Insert extractor spring and new extractor, press into place, hold while reinserting extractor pin. Or replace it- a new one costs what a gunsmith will charge to repair one.