Maxi Drop-in Kit  Contents –1 x factory 16j spring, 1 x spring guide (long), 1 x top hat (short), 1 x slip washer, 2 x power washers (15mm hole)


The TbT Maxi Drop-in Kit has custom fitted guides and a genuine Weihrauch 16j spring for optimum performance. Springs are supplied full length, this means with the added efficiency of the guides your gun may be over overpowered. Please ensure you have access to a chronograph before fitting!!


1)  Assemble plastic parts in the piston without the spring prior to fitting. If the rear guide isn’t sitting on the piston skirt the gun won’t cock and the guide needs to be shortened.

2)  Fit the guides to the spring, try both ends and go for the one where the rear guide fits best.

3)  The slip washer is installed into the piston first, if you have made a sleeve the slip washer will hold it in place. Use a small amount of grease on the piston rod and the washer.

4)  The guide fitted spring goes in next with a small amount of grease where the guides are in contact with the spring.

5)  Reassemble the gun and check the power.

If the spring needs shortening, please refer to the video tutorial on our website. The supplied power washers can be used on the rear spring guide to increase power if required.  Tinbum Tuning accept no responsibility for your rifles legality. After any work check your power levels with a chrono!