Old Glory Gunsmith Shoppe: Drop-In Aftermarket Parts and Kits for Semiauto Pistols

Oct 20, 2014

Drop-In Aftermarket Parts and Kits for Semiauto Pistols

Drop-in custom parts for firearms has become popular, as one can see browsing the collection of YouTube videos concerning the subject.

The majority of the custom parts available are easy to fit, while some require fitting, which reputable dealers will say so in their literature.

For the most part, handguns like the M1911 and the Beretta 92, one can customize them without the use of a drill press and/or a lathe – the latter not readily available to the hobbyist and casual gunsmith.

IraqVeteran produced a video that shows what he considers the five most customizable guns …

The most common drop-in part for handguns is the barrel, replaced because of wear or the desire for increased performance and accuracy, especially for those who own original GI M1911s.

Excellent results can be obtained purchasing aftermarket drop-in parts for the Browning Hi-Power, Beretta 92, and the Glock.

A good aftermarket barrel available is the Clark Custom barrel used for a .460 Rowland conversion. The barrel is quality high precision. The second good example is the Sarco Roto barrel available for the M1911. It improves accuracy for the old .45 caliber war wagon handgun.

Most of the time drop-in barrels are a convenient and simple operation, but be aware that sometimes a gunsmith is required to get the job done correctly.

European pistols are generally easy to drop-in parts, like the SIG .357 caliber barrel for replacement of the .40 caliber Glock. Bar Sto makes such a barrel that just drops in with outstanding results. Add Novak sights and the Glock becomes accurate at fifty yards instead of only 25 yards.

Oversize match grade pistol barrels are made oversize for a reason, but is more difficult to slide into the locking lugs. The reason why they are sought after is because of their superior accuracy. Drop-in units of this type has provided excellent results.

Threaded Aftermarket Barrel for attaching suppressor

If drop-in barrels do not quite fit properly as they should, tight but operating smoothly, it is usually the fault of the barrel hood. It is fitted by carefully polishing away material until it provides smooth working mechanics and does fit more properly. Checking this, I recommend check-fitting it with a slide stop, Remove the slide stop, seat the barrel properly in the frame, complete with a link. Insert a slide stop into the slide stop opening and through the link. If the barrel moves upward, some fitting is required.

When purchasing a drop-in barrel, it is best to order a complete barrel and bushing set. It is the same ideology that auto mechanics live by – if you are going to replace old worn parts with new – replace the whole working assembly to prevent future problems with old parts remaining that does not wear evenly with the assembly as a whole unit.

If you decide to build a pistol, it is always best to check with the manufacturer of the frame and slide for compatibility of parts.

The slide lock safety is one part that you cannot drop in. This part has to be fitted for proper function and clearance against the sear.

The most popular handgun for drop-in part customization is the M911, but the Browning High-Power is also another handgun for fitting.

Another part to pay attention to is the extractor, important to the M1911 and other such firearms like the M9 Beretta. Wilson Combat extractors will provide years of service with few problems. In most cases if the extractor gives you a problem, a bit of polish on it on the extractor's 'bump' behind the claw will cure the problem.

When adding a trigger, hammer, and sear, I advise to purchase the complete kit, or at least purchase the separate parts from the same manufacturer.

Most of my parts and supplies are purchased from Brownells, but Wilson Combat, Ed Brown, and Nowlin are other good options.

A lot of folks do not understand the action of the sear spring and its importance – this is one part you do not want to be cheap on. Also, adjustment is often required which requires some knowledge about gunsmithing. The left rear long leaf of the sear spring contacts the sear. A lighter tension produces a lighter action; however, too light of tension will cause problems – like the hammer following the slide down in recoil.

The middle leaf resets the trigger. This means if it is now working properly, the firearm will fire once and then will not reset until you re-rack the slide, sometimes more than once.

The far right or short leaf maintains tension on the grip safety, an important function of the M1911.

The M1911 is famous for its ruggedness, but still has some rules of thumb. One of them is that when a light trigger action is desired, an aluminum equally light trigger must be installed. If not, the weight will make the trigger bounce the sear in recoil and make the pistol fire when you do not want it to. All triggers, drop-in or not, must be fitted or they will not glide smoothly in the frame. Only GI triggers do not require fitting, seldom used anymore.