Canadian Airgun Forum

I did a quick search so forgive me if this has been covered. When you add a hipac, does it up your velocity? Or can you set a hipac to be sub pal?

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fishing, hunting and rap music.

You can definitely tune a hipac to be sub-pal. Lots of people do that for target shooting.

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Mike

FX Streamline .22 - Optisan Mamba Lite 4-16X44
Hammerli Pneuma Elite 10 .22 - Bushnell Elite 4200 4-12X40
Custom Crosman 2240 w/ LW barrel - Vortex Strikefire
Remington AirMaster 77 PAL rated - CenterPoint 3-9X40

Thanks for the info. Would someone without a lathe and such be able to do it? Or does it require making custom parts?

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fishing, hunting and rap music.

You can do it pretty easily just by modifying the parts in the 2240. I'm assuming you're talking about the HiPAC that's meant to fit in there, right? If so, just reducing the hammer spring strength can help adjust velocity.

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Mike

FX Streamline .22 - Optisan Mamba Lite 4-16X44
Hammerli Pneuma Elite 10 .22 - Bushnell Elite 4200 4-12X40
Custom Crosman 2240 w/ LW barrel - Vortex Strikefire
Remington AirMaster 77 PAL rated - CenterPoint 3-9X40

I was thinking about hipac for a qb78. But reducing spring strength would have the same effect right?

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fishing, hunting and rap music.

Yup, definitely should.

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Mike

FX Streamline .22 - Optisan Mamba Lite 4-16X44
Hammerli Pneuma Elite 10 .22 - Bushnell Elite 4200 4-12X40
Custom Crosman 2240 w/ LW barrel - Vortex Strikefire
Remington AirMaster 77 PAL rated - CenterPoint 3-9X40

Reducing the transfer port, and a lighter valve spring will reduce valve lock while reducing velocity. A lighter hammer spring will increase the possibility of valve lock unless you only fill the gun to under 2000 psi. Even then you might still be over. A heavier pellet might compensate for the overage, but in the eyes of the law, they would test it with lighter pellets. The parts for adjusting the transfer port and valve spring and hammer spring are all available on line, but without a chronograph, it would be impossible to know for sure.

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If I had only one wish, it would be to be able to "unsay" things.

Awesome! Just want to convert to air instead of using c02 all the time. But with my limited knowledge, might be biting off more than I can chew at the moment. I do have a chrony though

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fishing, hunting and rap music.

What sort of shot count do you get from a QB78 + Hipac in .22 with an fps in the mid to high 400s?

Do you have a hi pressure pump ?

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If I had only one wish, it would be to be able to "unsay" things.

No sir. I have a scuba bottle that I use for my pcp.

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fishing, hunting and rap music.

I think some of you are confusing hipac with RVA

This is a Hipac http://www.powermaxhipac.com/5--hipac-units.html

This is RVA http://scopesandammo.com/storefront/pro ... ster-p-717


or maybe it's just me?!

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Custom Design by ME PCP/HPA Air Carbine 10-50X60 Scope My 2018 FT Open

I think it's just you sir. We were discussing the hipac for a qb78. A power adjustor for a 2240 won't fit on a qb.

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fishing, hunting and rap music.

no I was just showing what a RVA is, a Hipac will not change speed of your pellet unless you run it at higher pressure.

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Custom Design by ME PCP/HPA Air Carbine 10-50X60 Scope My 2018 FT Open

Well considering that CO2 pushes at below 1,000psi and a HiPAC can run at 2,000psi in the same airgun with no modifications, higher pressure seems inevitable. So to stay sub-500 you can do a few things without fancy tools to keep the velocity down:

- Mimic what's done to keep velocity lower in the Crosman Challenger air rifle; use a brass sleeve as a valve filler to reduce the volume of air inside the valve. In the case of he Challenger this sleeve fills almost half the air space without interfering with the valve operation. Something similar could easily be found if you have a lot of spare parts around, or just take the dismantled valve to a hardware store and see what small parts could be used. Any plastic should work, doesn't have to be brass. Maybe some vinyl thick walled tubing...

- Insert a very small object shaped like an aluminum pop rivet into the transfer port hole to restrict flow. A tiny brass or copper tube with one end flared out using an awl then a small hammer would work. Or again, plastic tube would be fine, just heat and shape until it's flared enough not to push through.

- Reduce the mass of the hammer and shorten the harder spring which comes with every HiPAC. Chopped off by about 1cm this spring will still easily smack open the valve stem at 2,000psi. Even 3,000psi, as I have that setup in mine now. The lighter hammer will reduce wasted air considerably and if there is no RVA your velocity should be helped in staying low.

- Don't do the various high flow valve modifications which make dumping air more efficient. You could even find a sleeve and fit it to the valve dump hole and solder or epoxy it into place, further restricting flow.

I'm sure to have left out a thing or two, but you get the idea. Lots and lots of shots per fill can be yours by doing this sort of thing. Provided your HiPAC doesn't leak like a sieve, like mine did, from pretty much everywhere. Took a lot of my time and skill to make that stop. Works great now, so well that I've got a guy looking at making me a tiny regulator for it. He just needs to find some Belleville washers smaller than the HiPAC's smaller ID of 0.612“ then it seems he can go ahead. I've got fingers crossed, as that'd mean no more constant dialing out of the RVA as I go through a series, battling to maintain constant velocity.