Author Topic: HDD - Some questions  (Read 1773 times)

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Offline 0351_Vet

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HDD - Some questions
« on: December 25, 2011, 06:07:24 PM »
I read the below posts, but I am still puzzled. 
Where do you purchase a HDD,
Is there a video of the install?
Where can I get the Teflon washers?

Thanks


1
Crosman air pistol - General discussion / Re: GIGX mod recommendations
« Message by quickster47 on December 14, 2011, 02:13:59 PM »
Quote from: gigx on December 14, 2011, 01:48:19 PM

    Sounds like solid advice. Now I have to show my ignorance. What is an HDD? Sounds like new tech I will have to buy  just so I can watch tv.  ??? Can you point to a link where I can buy such a part. Once I see it and disassemble the gun I should be able to figure it out. If it saves gas great. If it gives me a reason to teardown my gun all the better.  :-*


HDD = Hammer Debounce Device

So why is a HDD necessary?  Well, glad you asked that.  The problem with the Crosman 22xx CO2 guns is hammer bounce (repeatedly hitting the exhaust valve, releasing small burps of CO2) and that wastes gas.  So anything you can do to keep the hammer from repeatedly striking the valve will improve (lessen) the CO2 usage.  Therefore, less CO2 gets wasted when the hammer isn't bouncing into the valve multiple times per trigger pull.  The design of the HDD for Crosman pistols allows the hammer to fly forward without any drag, but as soon as it starts snapping backward the HDD expands against the walls of the bolt bore and brakes it.  This stops the hammer from opening the valve multiple times as it bounces back and forth between the hammer spring and valve spring tension, which obviously just wastes gas.

The HDD fits over the hammer's cocking pin, with the slot/opening facing backward.  The opening/slot is what makes the device expand; the hammer snapping backwards makes the pin attempt to back out of that opening/slot and makes the body expand in the bolt bore, creating friction to slow the hammer.  Forward motion isn't restricted though, so your shot velocity remains unaffected.  You just get way more shots per fill since it isn't re-opening the valve after the pellet's already gone.

It's also worth mentioning that the gun is a lot quieter with the HDD installed.  I actually shot a string with the HDD installed first, and then took it out to shoot "without HDD" string.  The gun sounded like a cannon after I'd gotten used to the quiet volume of the gun with the HDD.

Carl

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Crosman air pistol - General discussion / Re: GIGX mod recommendations
« Message by gigx on December 14, 2011, 01:48:19 PM »
Quote from: Smaug on December 14, 2011, 07:54:48 AM

    Firstly, loosen up the trigger spring by squishing it down or cutting off a couple of coils.

    Install Teflon washers at the sides to smooth up the pull.

    Install a HDD. (hammer denounce device) this will save CO2. Or should, at least.

    That's about it. The gun is pretty solid, I think. We like ours. (I bought it mostly for my wife)


Sounds like solid advice. Now I have to show my ignorance. What is an HDD? Sounds like new tech I will have to buy  just so I can watch tv.  ??? Can you point to a link where I can buy such a part. Once I see it and disassemble the gun I should be able to figure it out. If it saves gas great. If it gives me a reason to teardown my gun all the better.  :-*

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Crosman air pistol - General discussion / GIGX mod recommendations
« Message by Smaug on December 14, 2011, 07:54:48 AM »
Firstly, loosen up the trigger spring by squishing it down or cutting off a couple of coils.

Install Teflon washers at the sides to smooth up the pull.

Install a HDD. (hammer denounce device) this will save CO2. Or should, at least.

That's about it. The gun is pretty solid, I think. We like ours. (I bought it mostly for my wife)
Marauder  .25 / CP 4-16x56mm AO Mil-Dot & Marauder P-Rod
Disco .22 / Leapers 3-12x44mm AO  Mil-Dot / Disco Sleeper Carbine
Katana .22 / CP 4-16x56mm AO Mil-Dot
2260 / CCS 2400KT / 2300KT / 1701 / 1377 / 1322 / EB22 / Benji 132 / Benji 422


<'((((><      ΜΟΛΩΝ ΛΑΒΕ


Offline 0351_Vet

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Re: HDD - Some questions
« Reply #1 on: December 25, 2011, 11:24:20 PM »
Actually I just found a 7 page summary on this forum.....I will hold off on questions until I finish the read. Sorry, but my first search of HDD only showed the 3 previous post.   :-*
Marauder  .25 / CP 4-16x56mm AO Mil-Dot & Marauder P-Rod
Disco .22 / Leapers 3-12x44mm AO  Mil-Dot / Disco Sleeper Carbine
Katana .22 / CP 4-16x56mm AO Mil-Dot
2260 / CCS 2400KT / 2300KT / 1701 / 1377 / 1322 / EB22 / Benji 132 / Benji 422


<'((((><      ΜΟΛΩΝ ΛΑΒΕ


Offline breakfastchef

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Re: HDD - Some questions
« Reply #2 on: December 26, 2011, 03:28:10 AM »
The only commercially available HDD I know of is offered by Airguns of Arizona (AOA). I believe they have a link to installation instructions on the website.
Larry

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Re: HDD - Some questions
« Reply #3 on: December 26, 2011, 03:11:33 PM »
The one made by Airguns of Arizona is plastic, only thing I read about it is it brakes fast.
http://www.network54.com/Forum/275684/message/1320787519/My+HDD+design+test+results
push Steven McCann and see if he still makes his HDD
When you have to kill a man,
it costs nothing to be polite.
- Winston Churchill