The jet funnel is for full size USP 9mm and .40 caliber only.
You can put one on a compact, I did, but you run into two things.
First, you have to modify it extensively and it takes a lot of work and refinishing to make it fit and look half-way decent. Second, there are no mags that will work with it when you put it on the pistol. Standard mags will no longer lock in and there are no extended body mags, like the full size white mags, that will work with the Compact.
I have a JF on my CT clone .45 and the mag I am using it the one I made out of two 8 round mags cut and welded together. I have hopes of the soon to be released 10 round HK45 mags working with the JF on it but there are no guarantees. I may have to have some more mags welded.
So, short answer, there are no JF available for the Compacts of any caliber.
It is more of an enlarged opening for the mag well. It helps speed reloads and with it, you do need longer mag bodies. Normal sized mags do not work and that is why it is only available for the USP 9mm and .40 because only those two calibers come in the longer bodied white mags made for use with the JF.
You can do anything if you want to take the time and spend the money, but normally it is not a feasible option for adding the JF to the USP .45 or any Compact, but it can be done if you are in for a challenge.
HERE'S MY "EVERYDAY CARRY" GUN. IT HAS A JET FUNNEL KIT. I USED THE 9MM EURO P2000 16RD MAGS. I CUT AND RE-BENT THE BOTTOM SO I COULD FIT A JET FUNNEL BASE PLATE ON IT. IT'S NOT VERY COST EFFECTIVE BUT WHEN YOU HAVE TO HAVE IT.... YOU HAVE TO HAVE IT OR WANT IT. EITHER WAY I'VE DONE THIS WITH A COMPACT 9/ COMPACT 40/ COMPACT 45. SO, THERE IS A NICH WHEN MONEY IS NO OBJECT AND PLUS IT'S JUST COOL.
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