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PostPosted: Tue Jul 31, 2012 6:55 pm 
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Joined: Sun May 08, 2011 12:25 pm
Posts: 658
Location: Alberta
Well I decided to put a depinger in as the ping is pretty much as loud as the shot itself. So I took a few pictures. I will eventually take it apart as far as possible and take lots of pics since there is nothing like it anywhere else.

I only took it partially apart since I could not find a small enough punch, and I am unsure as how to remove the valve from the air tube since it is in the tube instead of on the end.

If anybody could give me some advise on this I would be very happy. I have included a few pics so you guys can get a bit of a preview.

Rear cap, spring and hammer.
Image

Image

As you can see, the front that actually hits the valve stem is thread and I assume can be moved in and out with the spring guide in the back. Is it possible that power could be fine tuned by adjusting it?
Image

The trigger/sear mechanism is pretty cool. When cocked, a ball bearing fits in to the groove in the front of the hammer. The ball bearing pushes down on one side of the sear? and the trigger latches on the other side. I will get better pics of this when I get a punch tomorrow.
Image

there ball bearing pushes down on the right side and I pushed the sear down so that the contact point with the trigger is brought up for a picture.
Image


And here is the valve. The black ring is part of the tube and the valve pushes against it.
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And here it is from the pressurized portion of the tube.
Image

Now, should the valve just push out? Thanks for any help.


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PostPosted: Tue Jul 31, 2012 6:58 pm 
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Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8979
Location: Coalmont BC
Is that hammer made from Delrin?.... it looks more like plastic than metal.... I woudl think the threaded portion would adjust the hammer travel distance, and hence the power....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
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Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Tue Jul 31, 2012 8:13 pm 
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Joined: Sun May 08, 2011 12:25 pm
Posts: 658
Location: Alberta
The hammer is indeed made of metal. And I might need to do a bit of checking on the threaded portion. I am sure it would just provide enough movement just to fine tune things a little and provide a bit of spring preload.


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PostPosted: Tue Jul 31, 2012 9:34 pm 
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Location: Coalmont BC
If the ball bearing catches in the groove running around the front of the hammer, then changing the screw adjustment will not affect the preload on the spring when the gun is cocked.... It will, however, affect the position of the hammer when it is resting on the valve (uncocked) which has two opposite affects.... Lengthening the screw will add preload to the spring in the uncocked position, but it will reduce the distance the hammer moves when released from the sear.... One increases the potential power, the other reduces it (the hammer has less distance in which to accelerate)....

You will likely find an optimum position, and either side of that the velocity will fall off.... particularly when the adjustment is on the "long" side of optimum, ie the hammer travel is reduced)....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Tue Jul 31, 2012 11:34 pm 
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Joined: Sun May 08, 2011 12:25 pm
Posts: 658
Location: Alberta
Well, this is a non pal gun and I think it is pretty much at the optimum where it is, especially with the 15.9gr JSBs. If you find my other thread I did some velocity and shot count testing with it.


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PostPosted: Wed Aug 08, 2012 3:21 pm 
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Joined: Sun May 08, 2011 12:25 pm
Posts: 658
Location: Alberta
Well due to my small town not having sweet spit all for supplies (2 home hardware stores and I was assured the other had what I wanted but they in fact did not) I had to put the Brocock back together just to keep out the dust and put a bit of air into it.

I thought "What they hey, why not see if it changed velocities". I pumped it up to the 160 bar (the start of the sweet spot), loaded up with 15.9 gr JSBs... 520...518...520...519...517...519... FPS... :shock:

The average for these pellets before take down was about 478 FPS in this pressure range going up to a maximum of 491 FPS in about 30 shots so it is quite a jump considering that I changed nothing with the hammer or valve or transfer port etc.

This just goes to show that having a chrony is very important even if only taking an air gun apart for maintenance.


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PostPosted: Thu May 30, 2013 8:15 am 
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Joined: Mon May 27, 2013 10:46 am
Posts: 1
hello
I just own a Brocock Grand Prix. It was desassembled when i received it.
It seems it is the same mecanics than the Concept.
I'm looking for the number, the positions and dimensions of all the seals.
I know that there are :
* an external seal to maintain the barrel
* a small seal on the valve
* 2 small seals betwin the cylinder/chassis hole part
* probably a seal at the external end of the air cylinder (to close it)
* others?


Can you help a french shooter?

Regards from Paris.

Ben


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PostPosted: Sat Aug 30, 2014 9:44 am 
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Joined: Thu Aug 28, 2014 9:48 am
Posts: 1
the exhaust screws out towards the back of the gun, you need to make a special tool i ve just fitted a regulator in mine from robert lane design it makes a big difference


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PostPosted: Sun Aug 31, 2014 10:28 am 
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Joined: Mon Dec 29, 2008 9:50 pm
Posts: 828
Location: Scotland,Ontario
Which way did you turn to adjust? have you tried the JSB 14.3 or 13.4s?

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