This seems to be asked just about ever week so I want to make a thread to address it.
What are the differences between a Shocker SFT made in 2003, 2004, 2005, 2006? And later?
The answer is there are many small differences. Nearly every part of the marker was changed at least once between 03-06. Some parts were changed multiple times. However, the overall design of the gun and how it works stayed the same. SP continuously updates their guns with new parts as soon as they become available, they don't wait for the new year to release a different gun with all the new parts combined. This is to encourage players to buy new-in-box model markers since they will always be the top shape in terms of parts.
What year is my gun?
There's no way to tell definitively unless you know when it was purchased. You can use the serial number to get a ballpark on the year it was made, but it's not totally accurate, and furthermore it doesn't really matter (because the gun is essentially the same).
serials 1 to 3900 were assembled in 2003. (1 to 400 are generally considered pre-production due to the low availability at the time, some of the extremely oldest guns used prproduction parts)
serials 3901 to around 8000-9000 were assembled in 2004.
serials around 8000-9000 to 13000-15000 were assembled in 2005.
serials around 13000-15000 and later were assembled in 2006.
NXT Shockers use their own serials so the SH and SHK prefixes ended in 06.
If you have a PL Shocker SFt then your guess is as good as mine
Brief synopsys of production changes between 2003-2006:
- Bolt - originally delrin, changed to aluminum in 2004.
- Aluminum bolt - Updated to allow them to use standard o-rings for bumpers (early 2005).
- Bolt sleeve - Originally aluminum, changed to delrin in later 2003 to cut costs, then chamged back to aluminum in late 2004 since they're a little more reliable.
- Bolt guide - Changed to the "HE" version in Jan 2004 which have come on every Shocker since that time. The HE bolt guides have a depression between the two front o-rings, the older ones didn't. This only matters if you're using a SP HE bolt.
- Solenoid - Originally used Parker solenoids with attached boards. Humphrey solenoids begun shipping in some guns in early 2005 (some shipped with Humphrey, some shipped with Parker) but the humps were ceased in late 2006, and Parker solenoids are used exclusively since then (NXT).
- Solenoid spacer screws - These were added in 2004 to replace the previous "lock" screws which tightened onto the solenoid then had smaller screws attach on top to hold the upper board in place. These were dumped because nobody had the tools to install them corectly, leading to stripped manifolds.
- Solenoid manifold - small changes, nothing too major.
- Vertical adapter - Updated to hold a pressure gauge in May 2005, although it didn't appear in all guns until late05/early06.
- Vertical Max-Flo piston - updated in early 2004 to help prevent piston o-ring breaking problems.
- Regulator housing - went through small changes, nothing too important.
- Powerswitch actuator - updated in 2004 to the current version. The older "cloudy" ones were less bright and made it easier to break the powerswitch.
- Upper board - These changed a half dozen times over the years. I won't go into it but the current ones use brighter LEDs, better powerswitch placement (less breaking), and have small protection to guard against grip screw damage (although they can still be damaged if you try).
- Lower board - The hardware changed a few times but nobody noticed it. Flipped switches started to appear in late 2004. The programming for the boards has changed many times but it's generally not noticed. The only case where it is publically noticeable is the addition of the Nerve programming, which increased the dwell range (Humph solenoids required this) added rebound modes, and started in Vision mode.
- Vision eye - material and design was altered a little bit. Nothing too drastic though.
The newer Shocker NXT models feature many additional changes that are actually of note to how the guns work. Check the NXT FAQ thread for info there.