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Discussion Starter #1
I recently purchased a P7 and so far I've been using the HK piston bore cleaning brush, I wanted to get the scraper also but the prices seem pretty steep so I made one out of brass that is adjustable.
From the looks of the piston bore just using the brass brush I'm not sure a scraper is even necessary but I made one anyway.
Started with
-two pieces of square stock brass
-machined both down to a smaller rectangular size
-slotted one piece thru for M2 socket heads cap screws
-drilled and taped the other piece for M2 x 0.4
-attached pieces together with socket head cap screws
-turned size down to close to desired dimension
-machined down to final size taking a few very light passes with a tool post grinder

Brass does not grind well, with the light passes -0.001" the finish ended up being very very smooth however.
To adjust, loosen the screws and slide slightly apart, tighten screws.
In the pictures it appears the cap screws would contact the piston bore, they however do not.

Takes a little trial and error to set the distance to "clean" the bore.
Above all I don't want to force it in the bore, should just barely contact the bore.







 

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Nice craftsmanship... FWIW, the scraper tool is really designed to clean the very end of the chamber, where the brushing action of the chamber brush bristles cannot get to.
 

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Discussion Starter #3
Ah ha, did not know that,

I'll take a couple thousands off the end on one of the pieces, that should allow cleaning the "back"

Thanks Much
Tom
 

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Ah ha, did not know that,

I'll take a couple thousands off the end on one of the pieces, that should allow cleaning the "back"

Thanks Much
Tom
You saw what the P7 Tool looks like, right? It's end is pointed like a dagger so it can scrape carbon off the very back of the piston tube.
 

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For the life of me I don't get trying to save a little money on something as critical as the scraper for a P7. Its a critical part of the function of a P7.......welcome to the world of P7's. That gas system allows the P7 have many of the unique features that make it different. I would always worry about a homemade tool damaging a part of the system that you can't get fixed.
 

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For the life of me I don't get trying to save a little money on something as critical as the scraper for a P7. Its a critical part of the function of a P7.......welcome to the world of P7's. That gas system allows the P7 have many of the unique features that make it different. I would always worry about a homemade tool damaging a part of the system that you can't get fixed.
+1 for the factory scraper. It costs $40 but it's worth the investment. Or, you can get a U.S. made one fro HKparts.net for $22. I got the HK made scraper to have a peace of mind...
 

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I just bought my p7m8, I have plans to hit the desert with some buddies very soon. Gun did not come with any tools. I cleaned the piston a bit. But not the gas toob. Should I be okay for a day of shooting until I can get a tool?
 

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Everything seems to run smooth. It doesn't seem to like slowly ejecting rounds as much as my Usp. But I figure its normal, for being mainly gas ejected?

The bore didn't seem to be caked as much ad the piston. I hope its good for another few hundred rounds
 

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I have to agree that the factory item is what you need but dam man that is some fine craftsmanship. Let me know how that works out. I like the way it came out nice and clean and from the looks of it it may even work better than the factory tool. Great job. Before you use it I would check with a friend hat may have the tool to fine tune the one you made. To be totally honest, I have never used my scraper yet with my P7 pistols. I use the the foam bore cleaner and leave it to sit for 15 min or so while I clean the rest of the pistol then I use the brush with the solvent and it comes clean. I soak the piston over night and that comes clean with a soft brush. I still get a bit of discoloration which I can deal with. I'm pretty anal with my guns and it bugs the hell out of me but long as it is functioning smoothly than I'm happy.
 

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Discussion Starter #11
Man I really didnt know the HK scraper was just to dig at the back of the bore.
Live and learn.
I should checked pricing more carefully, I was looking on gun broker and the cheapest HK scraper was north of 50 bucks.
Oh well it was fun to make and gave me a reason to use the tool post grinder I made.

Thanks All
 

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Just be careful whatever tool is used. As mentioned, damage to the cylinder is nothing any P7 owner wants. The equipment to properly change a damaged P7 cylinder does not exist in the United States.
 
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