HK USP 45 field pistol

[HCM]

In the HK USP9mm mag I just took apart, the feed lips and the back part and sides of the inside of the mag have metal lining.

I believe this to be the case with the .40 as well.

My understanding is that the translucent white mags do not have as much metal reinforcement and are not recommended for duty.

That may be a change. The last full size USP 40 I had was around the time if the 94 AWB.

If it was a successful design HK wouldn’t have gone all metal in subsequent designs.

[1slow]

I have several full size USP 45s with Lem/Match triggers. All were bought used and are in good shape.

Recently 1 USP 45 has been giving me light primer strikes with some Hungarian Brass case 230gr JHP. As in 10 rounds out of a 100 rounds.
I bought a bunch for practice @ $10.99 a box before the ammo scare. It has been accurate and reliable in 6+ other HK USP 45s.

Other ammo has worked fine in the USP45 that light strikes the Hungarian ammo.

I suspect firing pin, either dirt in the channel , not enough protrusion or mainspring is weak.


To trouble shoot I will swap upper and lower with a USP 45 that does not have problems.

If the light primer strike upper works on a known good pistol lower, I would think the problem is in the light primer strike lower. Weak mainspring maybe.

If the light primer strike lower works on a known good pistol upper, I would think the problem is in the light primer strike upper. Maybe firing pin, either dirt in the channel , not enough protrusion.

Am I missing something ?

Thanks.

[entropy]

Depending on age and serial number, could be fractured firing pin.

Easy enough to remove and check when you clean the channel.

What’s the date code?

[1slow]

AD (2003) is the date code.
Thanks.

[entropy]

Yep. Modified pins around 2005-on. You may want to check it. The slide is straight forward to disassemble. Roll pins. Lots of online vids to guide.

[1slow]

Thanks, will get pins. I may change out all my pre 2005 as a precaution, or is this a good idea ?

[Bergeron]

I broke a firing pin on a pre-2005 USP9F. I'd go ahead and get latest firing pins.

[1slow]

Do I need to change just the firing pin or all of these, redesigned firing pin, firing pin block, and firing pin block spring ?


• 2005 (AF): Redesigned firing pin, firing pin block, and firing pin block spring

Thanks.

--------------------------------------
Changes made to the USP series over the years:
• 1993 (KD): Original USP .40 and 9mm. USP40 came out first
• 1994 (KE): Reduced the slide weight by 1.1 oz
• 1994-95 (KE-KF): Changed to a polygonal rifled barrel (Prior barrels were standard land and groove)
• 1994-95 (KE-KF): Changed trigger transfer bar
• 1994-95 (KE-KF): Changed recoil guide rod to a "captured spring version"
• 1995 (KF): Changed trigger mechanism
• 1995 (KF): Changed frame to allow new-design hammer axle and LEM conversion
• 1995 (KF): Changed hammer strut
• 1995 (KF): Changed one-piece catch to two-piece catch
• 1995-96 (KF-KG): Added rubber spur to hammer
• 1995-96 (KF-KG): Changed angle on slide lock
• 2000 (AA): Added locking feature to hammer strut support (lanyard safety)
• 2001 (AB): Converted captive recoil spring retainer from c-clip to machined end on USP Compacts (not USPf)
• 2005 (AF): Redesigned firing pin, firing pin block, and firing pin block spring
• 2005 (AF): Changed to longer catch and new hammer with the cut-out for the new catch
--------------------------------------------------

[entropy]

I believe it’s the block, the pin, and the spring. The issue was the original firing pin had a machined cutout for the firing pin block that had 90deg angles cut on it. You’d think that superior German engineering brain would have caught that potential fail point...🤷*♂️. New pin has a radius cut and a matching block along with a new spring. Thanks for jogging the memory...

It’s a pretty simple fix. FWIW, I have not had another breakage since 2006 in any USP variant, and I have put thousands and thousands (more like tens of thousands) of rounds thru 3 different guns.

[1slow]

Thanks.

I ordered all 3 parts: FP, FPB, and FPBS.

I also ordered a new style hammer strut. See below reference.
-----------------------------
Some more LEM on pre AF USP data:
FROM HKPRO FORUM
LEM ON PRE 2005 USP PISTOLS

Your hammer strut is different from the 1994 era, get a current version. It can cause some irregular firing issues mixing an up to date LEM kit with the early hammer strut.
Bill