Articles on various subjects.  The only place where you can find in-depth descriptions of 2100 marks.  For now, my SSC post will be up until I write a true article to replace it.

2100 marks

MK1-This mark has a SMALL SEAM, but it is larger than the mk2. This is the oldest model and the pump cap IS NOT GLUED. The center part of the nozzle is attached to the INTERNALS AND CASING. Mine acted strangely after the mod, as it got between 14 and 17 shots per tank!

MK2-This is really the one with a SMALL SEAM at the back of the reservoir. It has a GLUED PUMP CAP. The pc is slightly SMALLER than other 2100's. The center part of the nozzle is attached to the INTERNALS. This mark is the HARDEST to mod, but is the MOST powerful.

MK3-The newest model, has LARGE, PRONOUNCED RECTANGULAR RIDGES on the back of the reservoir. The PUMP CAP IS NOT GLUED. The pc is slightly LARGER than the mk1. The center part of the nozzle is attached to the INTERNALS AND CASING. This mark is the EASIEST to mod, but is NOT AS POWERFUL as the mk1 or 2.


To easily identify the mark of the 2100 that you are buying in a store:

Twist the pump cap. If it is glued, then the 2100 is MK2. If it moves, then it is not glued and is MK1 or MK3. Then look at the back of the reservoir. If there are ridges, its MK3. If there is a seam, its the hard-to-find and powerful MK1.
Bottom line: If you want the most power and don't mind hacksawing the pump cap, mod a mk1. If you want an easy mod with no complications, but dont mind less power, mod an mk3. Anyway, there is not much difference in power between the 3 marks, so all of them work well for modding.