There are numerous modifications that can be had to customize your 1927 Semi-Auto.
Some of the modifications that you might choose:
Replace the factory springs with an Ez-Pull Spring and Buffer Kit
Replacing the grips for ones that are more rounded. Working on wood.
Replace the front grip hanger with a .5" mount.
Installing a non-cross bolt 1921 or 1928 stock so that it can easily be removed and represents the period. (requires an adaptor on frame)
Mill and contour frame to more closely resemble the model 21/28 Thompson.
Pin the compensator, for a more permanent attachment.
Re shape and thin the compensator to resemble earlier models.
Re shape the front blade site to resemble earlier models, or replace the compensator with a ring style site like the 1921 Colt.
Install a set of GI paddle selector switches. (a full auto pivot plate will be needed if the GI rocker and safety are used. The frame will need drilled to accept the rocker switch.)
Link the selective fire switch to act as a bolt hold open device. (Very Nice Feature! Replaces the need for the third hand tool.)
Replace the rear site with an original Lyman ladder site.
Re-shape the actuator handle to look like an earlier model.
Mill the drum magazine slots, to allow easier installation.
Modify the magazine catch to accept GI magazines, preserving the original magazines.
Modify the receiver to allow for easy frame separation. (no longer use a tool to disassemble)
Install a 10.5" barrel. (needs BATF approval, under the NFA (National Firearms Act) Short Barrel Rifle Procedure.
Smooth feed ramps.
Zero the sights for a 0 at 50 yard POI. (point of impact)
Adjust magazines for proper hole alignment as well as feed lips.
Replace ejector with a GI style. Original ejectors will need to be shortened.
Polish bolt for the bright bolt appearance.
The new Kahr L drums have some redly reparable problems.
New L Drum Tuning
Note: If you decide to stock a spare bolt or firing pin, there are differences between the older Auto-Ordnance 1927A1, and the Kahr 1927A1 bolts and firing pins. Firing pins require hand fitting.
Bolt Difference Image
Disassembling the 1927 Semi-Automatic.
The Properties of Oil and Lube
There are other modifications to enhance the appearances and function of your rifle.
Many can be obtained by contacting pkNOSPAM@gwe.net **Remove NOSPAM, at Diamond K Gun Smithing
Diamond K is a top notch service, rendering very high quality workmanship.
Probably the most important part of collecting and shooting Thompson's, is that you enjoy it and have fun.