Colt Automatic Pistol and Revolver Information - 25 years of Service to Colt Firearms Collectors




Colt Conversion Unit .22 LR-.45 ACP - Disassembly Instructions

Colt .22-.45 Service Model Conversion Unit Parts Identification

1 Slide, complete with Fixed Front Sight, Adjustable Rear Sight, Extractor, Firing Pin, Firing Pin Spring and Firing Pin Stop.
2 Barrel
3 Floating Chamber
4 Ejector
5 Bushing
6 Recoil Spring, Recoil Spring Guide and Plug
7 Magazine
8 Slide Stop

Instructions for Assembling Conversion Unit On
.45 Caliber Colt Automatic Pistol Receiver

Colt .22-.45 Service Model Conversion Unit Sectional View

To Remove .45 Caliber Slide

Remove the magazine by pressing the magazine catch. (After removing magazine, look to see that there is no cartridge left in the chamber.)

Press the recoil spring plug inward with the index finger of the right hand. Turn barrel bushing to the left until the plug is free to go forward; then release tension on the spring gradually to prevent plug from jumping away. Draw slide back until the rear edge of the smaller recess in the lower edge of the slide is even with the rear end of the slide stop; press against end of slide stop which projects from the opposite side of the receiver above the trigger guard, and draw out the stop.

This releases the barrel and slide, which may then together be drawn forward from the receiver, carrying also the barrel bushing, recoil spring, and recoil spring guide.

It is not necessary to remove stocks as all parts of the pistol can be dismounted and assembled with the stocks in place.

In taking the pistol apart, use no hammer, as dismounting and assembling is quick and easy after a little practice.

The hammer should not be snapped when the slide is removed from the receiver.

To Install.22-.45 Conversion Unit Parts

Insert floating chamber in breech of barrel, with ear engaging in slot in barrel lug. Fit ejector into groove in barrel. With slide in inverted position, insert complete unit into slide through front opening. Be sure ejector slides easily into groove above firing pin.

Place recoil spring on recoil spring guide and push spring through opening in front of slide, with guide resting on barrel. Push receiver gently onto slide, engaging corresponding grooves. Insert slide stop through hole in receiver, making certain that it also passes through hole in barrel lug. (Note that special slide stop is provided for use with .22-45 Unit.) Barrel may be forced slightly to front or rear to bring lug opening into line with hole in receiver. Now force slide to rear until small cut in slide is directly above square opening in receiver. Press the slide stop all the way in. Insert barrel bushing in front opening of slide turning as far to left as it will go. Now place the recoil spring plug on end of recoil spring, and turn plug to right to engage spring. Press plug firmly toward rear of pistol and then turn barrel bushing to a downward position, to hold plug in place. Insert magazine and arm is ready to function with caliber. 22 Long Rifle cartridges. We recommend the use of greased type ammunition.


Note: Magazine furnished with Standard Colt Ace Automatic Pistol will not function with this unit.

Reasonable care should be taken to keep the magazines from being dented or otherwise damaged. When placing loaded magazine in the pistol, never push part way in and then strike it with the hand to drive it home as it might spring the bottom plate or the inturned lips at the top of the magazine; it should be inserted in the handle by a quick, continuous movement, but not slammed into place hard enough to cause damage.

Use nothing but thin oil for oiling the arm.

As soon as possible after firing, the inside of the barrel should be cleaned and oiled.

Occasionally a little oil should be put on the friction points, not forgetting ends of the safety lock and slide stop plungers.

Gun of the Month

January 2022

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