GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: ODhunter on May 16, 2014, 10:25:30 PM
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I'm about to buy a qb78 and I need the most power I can get but I'm on a budget right know I will be converting it to HPA soon but not in the budget now the reason I need the power is I'm hunting with it so if I can get it to at least 12fpe cheap that would be enough for now if you can awnser that would be great
OD
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Get rid of the cheezy breech seal, you can use one from a Crosman 13XX / 22XX / Disco in it's place.... If that isn't enough power there are other mods to consider.... Are you staying with CO2 ?
Bob
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Try here >> http://www.gatewaytoairguns.org/GTA/library/Charlie_QB-78_Tune.htm (http://www.gatewaytoairguns.org/GTA/library/Charlie_QB-78_Tune.htm)
Can get you way over 12 FPE
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I'm about to buy a qb78 and I need the most power I can get but I'm on a budget right know I will be converting it to HPA soon but not in the budget now the reason I need the power is I'm hunting with it so if I can get it to at least 12fpe cheap that would be enough for now if you can awnser that would be great
OD
if its .22 ya will get a bunch of power easily
1. Icemaker tube to replace factory transfer port seal to barrel
2. Extended bolt probe
will get ya to 720 FPS with a 14.3 grain pellet
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Get rid of the cheezy breech seal, you can use one from a Crosman 13XX / 22XX / Disco in it's place.... If that isn't enough power there are other mods to consider.... Are you staying with CO2 ?
Bob
yes until I get enough money for HPA
Also will this work? http://www.ebay.com/itm/Crosman-2240-2250-2260-2289-1377-1322-2289-Backpacker-Transfer-Port-Breech-Seal-/171189993385?pt=LH_DefaultDomain_0&hash=item27dbb7ffa9 (http://www.ebay.com/itm/Crosman-2240-2250-2260-2289-1377-1322-2289-Backpacker-Transfer-Port-Breech-Seal-/171189993385?pt=LH_DefaultDomain_0&hash=item27dbb7ffa9)
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you can get them from crosman for .90 a piece. they don't distort and can be reused each time you reassemble a break down.
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Icemaker tubing is pennies a foot at hardware store
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pm'd you, I have an extra breech seal.
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pm'd you, I have an extra breech seal.
ok thanks I replied
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I'm about to buy a qb78 and I need the most power I can get but I'm on a budget right know I will be converting it to HPA soon but not in the budget now the reason I need the power is I'm hunting with it so if I can get it to at least 12fpe cheap that would be enough for now if you can awnser that would be great
OD
if its .22 ya will get a bunch of power easily
1. Icemaker tube to replace factory transfer port seal to barrel
2. Extended bolt probe
will get ya to 720 FPS with a 14.3 grain pellet
Like this? http://www.eabco.com/store/airguns/air-rifles/@=S+S%^$#-qb78-velocity-upgrade-xp-tune-kit-increases-velocity/ (http://www.eabco.com/store/airguns/air-rifles/@=S+S%^$#-qb78-velocity-upgrade-xp-tune-kit-increases-velocity/)Xp tune kit also yeah it's .22
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Transport seal will only give you gains if it is crushed, otherwise nope. Bolt probe mod will help boost fps, but nowhere near 720.
The easiest way to boost power is put stiffer hammer spring. (washers)
Remember speed needs more gas.
Have fun...I modded both QB78 & QB79 years ago and the 79 is still my fav.
Good luck
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Increasing hammer spring tension will make you THINK your gun is more powerful (because it will be louder), but you will only be wasting CO2.... The exception is if you are shooting at maybe 100*F when the higher pressures may be able to use more hammer strike....
Bob
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Had to go look up some of my notes from co2 QBs.
Your original post was looking for 12 foot pounds and I just assumed it was a .22. May be a wrong assumption, have reread your posts and don’t see caliber mentioned (at least by you).
Didn’t find 12 foot pounds in a .22 QB needed many mods, Are only talking about 615fps with standard 14.3gr. pellets. Ice maker tubing transfer port should get you there. Can certainly do all the mods and end up going faster.
IF you are thinking .177, 12 foot pounds gets harder to reach. Co2 “likes” larger bores and you’ll need some of the valve and bolt probe mods to get there. Esp. the bolt probe as gas passage in .177 is pretty small.
At least some of the mods (the smoothing/polishing/deburring) go a long way towards making the rifle easier to work on (as it will stop chewing up o-rings during your take downs and reassemblies) and are worth doing even if power is not on your mind.
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At least some of the mods (the smoothing/polishing/deburring) go a long way towards making the rifle easier to work on (as it will stop chewing up o-rings during your take downs and reassemblies) and are worth doing even if power is not on your mind.
The CO2 tuning guide on Charlie da tunas web site (pretty sure it is in the download library here as well) helped walk me through tearing down my .177 ar2079 the first time. Polishing and straightening the bolt and the other polishing and deburring projects really made a big difference and made it feel like a much nicer rifle.
I don't have a chrono, so I can't speak to hard numbers on power. Based on a totally unscientific observations on penetration in the duct seal of my trap, taking the fiber filter out of the valve, opening up the front of the valve, changing the transfer port to an ice maker port and a conservative enlarging of the holes in the bolt gave me a pretty solid increase in velocity.
The increase in velocity is nice, but from a personal satisfaction/shooting enjoyment standpoint polishing and straightening the bolt was the best mod. It made the bolt glassy smooth and makes me happy every time I open or close it.
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Had to go look up some of my notes from co2 QBs.
Your original post was looking for 12 foot pounds and I just assumed it was a .22. May be a wrong assumption, have reread your posts and don’t see caliber mentioned (at least by you).
Didn’t find 12 foot pounds in a .22 QB needed many mods, Are only talking about 615fps with standard 14.3gr. pellets. Ice maker tubing transfer port should get you there. Can certainly do all the mods and end up going faster.
IF you are thinking .177, 12 foot pounds gets harder to reach. Co2 “likes” larger bores and you’ll need some of the valve and bolt probe mods to get there. Esp. the bolt probe as gas passage in .177 is pretty small.
At least some of the mods (the smoothing/polishing/deburring) go a long way towards making the rifle easier to work on (as it will stop chewing up o-rings during your take downs and reassemblies) and are worth doing even if power is not on your mind.
yes it's .22 I'm looking for 12fpe or more until I get some more $$ from what ive heard they have 9.5-10 fpe out of box I would like mine to end up being like nervoustrigger's shooting at like 32 fpe I've talked to him a lot over the past couple weeks and he said he can help me with it I have a crosman breech seal thanks to daveb50 which should get me to the 12 I'm wanting until I convert to HPA
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my 22 caliber qb79 is getting about 28-30 fpe with all the mods i had done to it by him that will not be named
first and foremost you want a xp valve and bolt
stronger hammer spring
expansion of transfer ports helped a bit too...
going from bulk fill or 12g co2 will add at least 100-150 fps if you goto larger 12 oz co2 tank (mostly due to the ability to bounce back quicker after a shot)
going to hpa will make it even stronger
i started by buying the rifle with spring , valve and bolt mod....i did the rest later as cash permitted
i suggest a qb79 over the 79 if you plan on going to hpa becuase choice for hpa with the 78 is basicly just the hipac air cylinders while for the same price for the 79 you can get a ninja regulated bottle that keeps the gun extremly consistant with almost 100-120 full power regulated shots
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eabco is an alternate source for HWSNBN goods referenced above.
http://www.eabco.com/store/airguns/air-rifles/archer-qb78-velocity-upgrade-xp-tune-kit-increases-velocity/ (http://www.eabco.com/store/airguns/air-rifles/archer-qb78-velocity-upgrade-xp-tune-kit-increases-velocity/)
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Transport seal will only give you gains if it is crushed, otherwise nope. Bolt probe mod will help boost fps, but nowhere near 720.
The easiest way to boost power is put stiffer hammer spring. (washers)
Remember speed needs more gas.
Have fun...I modded both QB78 & QB79 years ago and the 79 is still my fav.
Good luck
tell that to Mike melick and my Chrony on a Co2 powered QB78D .22 from his first ever shipment of D models ...I am speaking from hands on experience ...720 fps is easy
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Yeah, not without a lot of work. I tuned my 78 / 79 myself and I know what it takes.
Post a string of your 78 deluxe ::)
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I have modded my qb78 and now probably the most powerful one on the planet. Ported polished parts, pcp valve, my oven seals, 10 shot mag, resolvoir extension... Heaps... All doable at home
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Do a search on this forum for “$200 PCP”, follow the first few pages and you can get very good power levels without spending a dime.
DO NOT increase spring tension, as stated by others that will only waste gas.
In my opinion (my QB78s .22 shoots 16 grain pellets at 630-650 FPS for over 14 ftlbs) the breech seal is first, I use the Crosman one others have suggested, then enlarge the holes the gas flows through on its way to the barrel, try to make them all the same, about .177 or .118, I used a hand drill and Drexel tool. Greatest thing about the QBs is doubling the power with out spending a dime.
One suggestion though, if you plan to convert to HPA later, think seriously about a QB79, it will make the conversion MUCH MUCH easier. If you get a 12 gram adapter for the QB79, you’ll be able to able to use the same CO2 capsules the QB78 uses until you are ready for HPA.
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Cheapest?...likely just changing the transfer port to a bit of icemeaker tubing, spacing the striker spring forward for a bit more tension, and keeping the co2 rifle warm would likely do 12 foot pounds.
Cheap...wouldn't cost anything at all if there is enough slack in the icemaker tubing likely already on the 'fridge.
It is winter (at least on this side of the Equator), and keeping co2 warm and up to normal pressure while out hunting.
Are a whole lot of things you could do...that require tooling, new parts,lots of patience/skill/time to really get them up to high power...can get all into that as the need and the urge hits you,but to get to 12 foot pounds right now,doesn't really have to cost anything.
I reversed a lot of the stuff done in the past to one I converted to 5mm. Basically reverse evolved it back into a standard 12gr. rifle using a standard valve. Ended up at 12-13 foot pounds (depending on the pellet).
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Cheap...wouldn't cost anything at all if there is enough slack in the icemaker tubing likely already on the 'fridge.
I am going to file this one next to "You can boil your toothpicks, they are reusable!" J/K ;D
I can just see my wife rolling her eyes as I try to explain to her why I'm cutting the icemaker line. ;D
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Most installers go on the long side of thing...not wanting to end up short, and time is moneys....so usually end up with a loop of "extra" ice maker tubing taped to the back. rather than haul my butt to the hardware store,I just disconnected it...cut off 4-5 inches...reconnected it...and had enough tubing for something like 30-50 ports.
I just ram thesmooth end of an appropriate drill bit into the tubing and rotate-cut it even with a box cutter.
For a striker spring shim...normally use washers.
For 12 foot pounds,it's a lot easier in .22 than in .177...but the same two simple things can get you there in something like normal room temperature (lets say 70-74F).
have converted a few to HPA, tow to PCP, some to tanker co2, etc. But ended up with the most use for one (that 5mm) as a plain-Jane 12gr.QB78 running at about 12-13 foot pounds.....basically Sheridan "C" power without the pumping.
LAST thing I want to do is to discourage a new shooter. If 12 foot pounds is the goal (which isn't a bad goal for a co2 rifle) can do it with minimal changes.