Problems with USPc .40 & AAC EVO 40

[Vew]

I've been having problems with jams, some light primer strikes, and stove pipes. I bought an EFK threaded barrel and have been working with them to try and figure out what the heck is going on. My biggest problem is the gun will jam with the slide in the full back position - jamming on the barrel itself. I would have to hammer the back of the slide to get it to free. This caused damage on the barrel itself. So I sent it back for fitment. After several weeks and a 3rd barrel, I no longer get the horrible jams. However, it still cause some physical damage to the barrel which I have sent back again.

Upon closer inspection of my USP, it seems the stress has cracked the back of the receiver. I have sent it to H&K for repairs (not covered by warranty) and am waiting. It'll be a while since receivers are on back order.

My question is what should my next step be? Do I risk damaging the receiver again when I get the gun and barrel back? EFK is willing to continue to work with me until this is right, so I'm very grateful for their customer service. My assumption of what is going on is the barrel isn't perfectly fitted, with the increased pressure (i can launch brass like 60 feet), it's causing the recoil spring to "bottom out" every time. Since I can't seem to find a company that makes heavier recoil springs for the USPc, should I try and get a full size spring from Wolff and cut it down to fit?

Or should I throw in the towel and save up for a USPT 40? Has anyone heard of this type of problem before on the compacts?

Edit: I apologize if I was supposed to post this in the HK subforum.

[buxom7657]

Not much of a help to your situation, however I will add that at least one factory USP CT .45 works just fine with EVO45. All day, every day.
60' on the brass??? Kinda cool in a crappy way.

[Vew]

After a lengthy talk with one of the repair techs at H&K, it seems that my only solution would to be replacing the recoil spring with a stronger one. However, because I haven't found anyone that makes USPc recoil springs, my only options would be to use a .45 compact recoil spring on my factory rod (but at greater risk since it's a longer spring so compressed it would be longer than the factory .40) OR get a Wolff full size increased power and cut it down.

My may look into reloading custom rounds which I wouldn't mind either. I have a friend that would help me in that regard. Does anyone have experience or know load data for subsonic .40? Most 180 grain factory is subsonic, but the round is still a bit too hot with the EVO on and just tears the crap out of the barrel.

I'd imagine the CT .45 is fine. I was recommended by H&K to get a +10% from Wolff if I do end up investing in a USPT for suppressing.

[Furyataurus2.0]

I would go with a threaded USPC 40 barrel from jarvis custom.