I recently had a set of PE Shaft 4 barrel backs modified and I figured I would share the details with anyone who is interested. Normal "Autococker" threaded barrels typically have a thread which requires about 7 full turns to install or remove. On the field this can be quite time consuming and tedious.
Other manufacturers (Tippmann, Smart Parts Impulse/Ion, etc) have used more coarse threading to try to alleviate this. But Autococker threading remains the most popular barrel thread and is used on many (the majority of?) guns to this day.
I noticed that Empire guns (specifically my Empire Sniper) have Autococker threading, but they only have about half as many turns (about three and a half). They still screw in nicely and stay on solidly, but they take much less time to install or remove.
So I sent out a set of PE Shaft 4 barrel backs and had approx half the threads machined off by a local machine shop. The result is exactly as expected. No issues with install or firmness of mounting (still using an o-ring), but it is much quicker to remove/install the barrel. I'm happy with it!
Here are some photos showing what was done (and comparing to other PE barrels and the Empire Sniper barrel):