A lot of people ask if the JF can be fitted to their compacts and while some of us have done it, the problem remains of what magazines to use. Making your own was the only solution by cutting and welding mags together or other tricks (such as using Euro P2K mags in 9mm and .40 with modified floor plates), but with the coming of the HK 45 and HK45 Compact 10 round mags, mags are no longer an issue, at least with the USPC.45. The hard part is making the Jet Funnel fit the Compact. No modifications are needed on the lanyard loop insert that comes with the JF. Just pop it in the Compact.
Below is the standard USP Jet Funnel
And the standard JF on the full size USP 9mm/40
Below is what the JF looks like installed on the Compact, in this case a .45, IF you did it unaltered.
The way I made the JF fit without altering the USPC frame any was to cut and file down the front and top, then shave the sides and back on a belt sander. Finish was done with Brownell's Aluma-Hyde II matte black.
Here are some before and after comparisons.
Below is how the modified JF looks installed on the USPC .45
Now you need to modify the floor plate of the HK45C magazine which is very easy and takes only a few minutes. Simply cut off the top of the floor plate above the front floor plate notch.
Here is how it looks when done.
So, now this winter when it is just too lousy to go outside, grab your file, Dremmel tool, and belt sander and make yourself a JF for your USPC.