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Discussion Starter · #1 ·
Hi!

I finally got the replacement piston detent spring. I used a punch to remove the pin, but didn't know that the piston was not symmetrical and thus I did not mark the orientation.

The front of the piston, near the pivot point is angled and there are two possible ways to put the piston in:

#1, in which the slightly longer edge is down. If you hold the slide facing "Heckler & Koch" marking (left side), the angle on the piston close to the pivot point points to 1 o'clock (or to the breech).

The other way (#2) is with the longer edge up, and holding the slide the same as above, the angle would point to something like 11 o'clock or toward the front of the gun.

I installed mine by using #1 orientation, and the piston can drop down some 30 degrees below the horizontal axis, and pivot up until it hits the top of the slide.

Can someone who knows P7s tell me if I did installation of the piston using a correct orientation or not?

Thanks!!!
 

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I have an M8, so mine may be a bit different... but:

My piston can only be installed one way. There is a notch on the port side (left hand side as looking forward) and the piston will only fit that one way.
 

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Forgot to mention, that my piston cannot pivot up to hit the inside of the slide, but it does pivot down to approx 30 degrees below the slide... maybe a hair less.
 

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Discussion Starter · #4 ·
Thanks CZ-75

Hi!

Thanks for a quick reply! I have a P7 PSP (sorry for not clarifying that) with a 12/82 date stamp, and the piston can go in either way.
When I put it in using #1 option, it pivots up to the slide and down to about 30 degrees where it stops.
When I try #2 it rotates as far down as you want it :mad:

My guess is that #1 is correct, but I'm hoping for input from P7 PSP owners ;)

Thanks CZ-75!!!
 

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Just checked my P7 PSP and it is set as your #1 option.

:53:
 

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Did your pistol not have marks on the piston itself and the frame? Both my '83 and '95 have "tic" marks to properly orient. Do early model not have them?
 

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What a good price for a P7M8 these days? I saw one at a local store for $1350.00, I'm not sure if it's new or not, and people on other forums asking $1500.00 for a used one. I know there some out there that are police trade ins. I'm thinking about getting into one of these.
 

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I'm in almost the same boat. My PSP came with the roll pin smashing the detent spring. I called HK but they are closed until Tuesday for inventory. I need to get a replacement spring, when I talk to Travis I'll ask what the recommended installation method is.
 

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Discussion Starter · #9 ·
Thanks HKDave and CZ-75 (again)!!! I'm taking it out to the range in a few minutes ;)
bzinbv: You can get a replacement piston detent spring from Numrich if you (like me) can't wait for HK to reopen on the 14th. There is no science to this and apparently only one way to do it in P7M8, but in P7 PSP that German ingenuity had not kicked in yet.

There is a chevron (arrow) in the slide, but absolutely no markings on the piston. That's the first thing I checked.

You can still find a very small quantity of P7M8 pistols - the most recent ones I've seen had casings collected Oct 15 '07.
 

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I just picked up a used P7M8 (KF date code) w/ 11 mags and a holster for $1200. Slight holster wear, but not bad at all. Gun was very well taken care of.

Good deals are out there, you just have to be patient and check a lot of sources. I actually stumbled across this one while I was looking for a used Anschutz .22lr on another forum.
 

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Talked with Travis about this issue, and we came up with a way to describe how to install it properly. JudgeUSP your #1 method is correct. If you remove the slide and place it on a surface with the sights down, front sight to the left, the sloped angle on the front surface of the piston (the left end of piston) will look like this: \

Travis wanted me to ship my slide back, but he relented and will get me a spring in a few more days. The replacement part has to come from a different person in the organization, but it will get here in a few days. The spring is not required to fire a P7, but it will quiet the cycling down some since it keeps the piston under tension. Thanks for the tip on Numrich, I've bought a lot of parts from them for M1s and Springfield’s.
 

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Does anyone have a technique for getting the roll pin back in without mashing the piston detent spring? Given that the spring is under tension against the pin, this seems like no easy task. I have already come close to mashing it once and don't want to destroy a $5 spring. Any input would be appreciated.

BTW this was a Grade A from CDNN that failed to come with the spring, which I obtained from Numrich.
 
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