GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Tgomez82 on November 30, 2016, 10:29:53 PM
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I have 2 QB78 one has a tube extensions and is obviously bulk fill only, the second I have the bulk fill cap for it but it is still capable of using 12g's. I am considering buying the extension and going to bulk fill only with this one as well. But I have read that the shot count is not so great with a QB being bulk fill. They will both be staying co2 only no HPA conversion on these 2. My question is what kind of mods can I do to improve my efficiency with these..??
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In stock form, there is far too much hammer strike which wastes CO2. The simplest modification you can do to improve efficiency is to shorten the hammer spring, one coil at a time, until the velocity just begins to fall.
To take it further, see about making or buying an SSG which is a device that limits the spring travel so as to prevent the hammer from rebounding with sufficient energy to re-open the valve (which wastes gas).
There are certainly other techniques that can be used, like lightening the hammer and installing a bstaley O-ring buffer but the two above are the ones I would recommend.
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Thank you Jason I will try these recomendations and see what I come up with. Unfortunately I don't have a chrono so it kinda limits the modding I can do, what are th benefits of a delrin valve stem such as the ones available through mountain air..??
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There's really no meaningful benefit to a using a Delrin poppet with CO2, and in fact it may be detrimental because it can be difficult to get a good seal at CO2 pressures (800 - 900psi) and because the material is so hard, it is more apt to bounce and waste gas in my experience.
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Thank you again Jason I appreciate all of your help and input I will see what can come up with to get some decent efficiency from these QB's seeing as I won the Chinese barrel lottery with both of them. They are absolute tack drivers. I've inly shot them to 30 yards so far, but they are impressive.
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That's good to hear you got good shooters. I haven't come across one yet that won't shoot ragged holes at 25 yards or more with some flavor of JSB. So I guess at some point we should declare the barrel lottery a thing of the past.
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And what about to check 1500 PSI pressured air too ?
I have done universal CO2-800PSI/PCP-1500PSI plug on my QB78/177 deluxe.
http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=113196.0;attach=169996;image (http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=113196.0;attach=169996;image)
Chinese barrel need to be recrowned for encreasing accuracy.
http://forum.gunshop.cz/download/file.php?id=34486&mode=view (http://forum.gunshop.cz/download/file.php?id=34486&mode=view)
CO2 need stable temperature for accuracy
http://forum.gunshop.cz/download/file.php?id=34812&mode=view (http://forum.gunshop.cz/download/file.php?id=34812&mode=view)
You need to clean barrel after 20-30 shoots too
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And what about to check 1500 PSI pressured air too ?
I have done universal CO2-800PSI/PCP-1500PSI plug on my QB78/177 deluxe.
http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=113196.0;attach=169996;image (http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=113196.0;attach=169996;image)
Chinese barrel need to be recrowned for encreasing accuracy.
http://forum.gunshop.cz/download/file.php?id=34486&mode=view (http://forum.gunshop.cz/download/file.php?id=34486&mode=view)
CO2 need stable temperature for accuracy
http://forum.gunshop.cz/download/file.php?id=34812&mode=view (http://forum.gunshop.cz/download/file.php?id=34812&mode=view)
You need to clean barrel after 20-30 shoots too
1) The OP wants to stick with CO2
2) The barrel doesn't NEED to be recrowned if you already have a tack driver.
3) Constant temperature is without question.
4) If you're talking about cleaning the barrel every 20-30 shots, why? Nobody does that, and I doubt that people will buy that. It often takes a barrel several shots to stabilize after cleaning or a pellet change.
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You can add a couple o rings between the valve and hammer #16 I believe . This should help with the efficiency by eliminating some of the hammer bounce . Search for the Bstaley mod it will go into more detail.
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I agree with you Doug, I have cleaned the barrel on my first QB once that was when I first got it and I have had no accuracy issues in the 1,500 or so pellets I have run through it, well not counting my ldc pellet clipping which I just can't get figured out.
Hobbyman thanks for the info I will search this mod and see about applying it to my QB
Thanks to all who have taken the time to reply
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OK
I had reached sub MOA accuracy only after barrel recrowing and frequent CO2 dirt clearing out.
What is you accuracy ?
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Here are various pellets at 25yrds
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We'll the other pics won't load but they are all pretty similar to that one
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Have co2 bulk filled, and the only way to really keep track of how well they use gco2 is to figure out the gas use per shot.
I'll metion this up-front: co2 is cheap, and to doesn't matter all that much how much co2 you use per shot if it gets the perfromance you want. You just bulk fill more often and spend a few more cents along the way.
Co2 is figured by weight, so if you have a handle on the amount of co2 bulk loaded into the rifle, can figure out the gas used. As much as I am NOT a "metric-head", grams works out better for this kind of figuring.
Co2 gets to be a real "pig" when you puch for higher speeds/energy. Has a lot of things going against it for a hot-rod. "Thick" gas, lower pressures, a self-cooling natuure, and heavy enough to actually count as ejecta.
With a good scale, you might notice is how little co2 you manage to get into a bulk fill under "field" conditions (where both the rifle and the fill tank were are the same temperture). Could figure a max as 1oz of co2 per 43cc's of volume as the same ratio of paintball tanks.
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Ribbonstone, thanks for the reply I guess I am asking for a lot wanting my QB's to be gas sipping hotrods. The only reason I want as much effieciency as possible is because sometimes where I go it's a long hike to get to good shooting and I didn't want to carry a extra air with me if not necessary but I guess I will have to change plans with that. Either way I will try and get as good as I can with both power and efficiency
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I have 2 QB78 one has a tube extensions and is obviously bulk fill only, the second I have the bulk fill cap for it but it is still capable of using 12g's. I am considering buying the extension and going to bulk fill only with this one as well. But I have read that the shot count is not so great with a QB being bulk fill. They will both be staying co2 only no HPA conversion on these 2. My question is what kind of mods can I do to improve my efficiency with these..??
You might want to try a Teflon valve stem in your QB. It will seat easier than Delrin @ co2 pressures, and probably be more reliable than the oem stem. I've found that one of the better ways to improve shot count in a QB78 is to reduce striker weight. Several of the folks have done this in different ways ranging from simply grinding the sides, boring the center, or fabricating a new one from a lighter material.
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Well now that my local paintball shop has CO2 up and running and I was able to get a couple of fills I am going to get a shot count on both rifles with a full fill. Once I've done this I will lighten the hammer and chop the spring and see where I am at. The we shal go from there thank you all who took the time to share your recommendations with me!
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And I am too tired from hand pumping pcp's next years bonus goes to tanks or a compressor, we will see after i meet with local scuba guy next to fleet farm store :)
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Just not a lot of volume in a standard 12gr. co2 tube. Inside it's about 3.5" long and about .75" in diameter. So that works out to something close to 2.9-3 cubic inches...which we'll call 50-55cc's (have to include the inside of the valve for bulk fill).
Tyopical paintball tank will safely accept about 1oz (28grams) for each 43cc's of volume. So lets say a safe fill for a QB tube would be something like 1.2oz. (about 35grams) of co2. Two 12gr. would be 24grams.
But every time I've measured bulk fill vs 12gr. us, bulk fill shoot a bit faster and used a bit more co2 per shot. So you may not get any more shots from bulk filling a QB, may just get faster shots.
And you'd not even get the same number of shots unless you got a full safe fill.
So the solution might be to gain volume. A longer gas tube (or extension) would do that. But I have to say, if you could stand the extra weight, a tanker QB would cure it even easier. Swapping pre-filled tanks is a lot easier.
Getting a full fill:
Get a full safe fill when bulk filling would likely help, but you can't really get a full fill out in the field. Co2 is not like air in this repsect: there's little pressue difference between the co2 in the fill tank and left over co2 in the rifle when they're both at the same temperture.
Basically have to create a temperture difference between the rifle and the fill tank. In the summer, will put the tank on the back porch and the rifle in the house near an AC vent. In the cool months, will reverse that and have the tank near a heater vent and the rifle out on the cool back porch. In no case will I let the fill tank get too hot (not more than 90F).
(In the cold of winter, I just don't usually use co2).
When the fill tank is connected to the rifle, the fill tank is warmner...higher pressure...and the rifle is cooler...lower pressure...and more liquid co2 will flow into the rifle before they equalize in pressure.
As the gas flows, the fill tank decompresses a bit and cools down...the cooler rifle compresses the gas and warms up. IF you start with a temperture difference between the two, more liquid co2 eneters the rifle before they equalize.
Which is why, when the fill tank and the rifle are at the same temperture, they equalize pressure quickly, with less gas flowing into the rifle.
It's hard to over fill a bulk fill rifle. Guess you could do it with the help of a freezer and a really warm fill tank, but I've not had the urge to try.
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Thank you ribbonstone for sharing your knowledge with me now I know that my expectations where a bit high, but I haw also found the direction I want to go. One of my QB's does have an extension and the other does not I believe an extension is in th near future for it and maybe also a bulk fill hpa setup for my QB's
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Idaho....and co2 in the winter...not predicting a great outcome in freezing weather (OK...for today and tomorrow you might get into the 40's).
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Yup I hear ya there, that's why I'm thinking a hpa bottle regulated to 900psi output should be in the near future....
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That can be done. Simplest way is to tether an HPA bottle to the bulk fill nipple and just deal with a coiled hose between you and the bottle (which in winter, can just be stuck in a coat pocket).
But no one seems to care much for tethered bottles while wandering the woods; it's like a bungee cord running your quick shouldering and always seems to find a branch to hang up on. Worked fine when staying in one place.
Won't work with a co2 so well even if the co2 bottle is nice and warm inside your coat...the co2 gets cold sitting around inside the air tube of the rifle.
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I was thinking tether it when I'm on the bench and when I'm walking the woods or te desert I can put it in my pack and just bump the rifles as needed. A good carbon fiber 90/45 bottle should give me a few fills and won't way too much I think..
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Given the standard QB tube's volume, using something like 850psi air (which is often the cheap-defalt setting on paintball tanks....be sure it is NOT one of the ones set for really low pressure (like 450psi) paintball applications) are likely to get 3-5 "good" shots per fill.
(And if your extension doubled the volume, then double the shots to 6-10.)
MAy as well keep it tethered as that's likely to be less of a PIA than hooking it up every 5th shot.
For the really inexpenvise end of things, the Al. 48ci 3K tanks are as cheap as HPA gets..can normally find them (new) on line for about $40-50. Maybe another $25-30 for a coiled remote line.
Filling would be way of a paintball shop, so you'd be screwed out in the woods once you run out of air (but there's a gauge to warn you of that).
Power of the typical 800-850psi air is about the same than normal warm weather co2.
But (assuming no leaking) how many shots could you get from a 48ci tank? Well, it should be proportional to a 3K 13ci tank at 800-850psi, which is depending on the way the rifle's tuned. Worst case, somthing like 250 shots...best case, something like 500...then back to the paintball store. Do have one QB79 13ci HPA (800-850psi) that manages 200 shots at 12 foot pounds, but I've worked the snot out of it to get there....so for that one, if it were a 48CI tank would be up to 800 shots per fill.
The four main down sides to this are:
1. Co2 tends to swell o-rings, which actaully slows any leaks to neary nothing. Air won't do that and kind of looks for ways to leak that co2 won't. Not always a problem, some co2 guns are actually sealed well enough for air...others just disguise their leaking (see bottom text).
2. You're hauling around a 3" wide/ 9" tall metal tank connected by a coiled line to the rifle. Really doesn't bother me to be teathered with I'm bench shooting, or whan set up in one place rather than wandering around.
3. Are linked to the paintball shop for a fill...and they tend to not be open or far away when you need a fill NOW.
4. Best to turn the tank to "OFF" before you are finished for the day. Then shoot the pressure down (good shots at first, just burps as you go along) until you can easily detach the fill line.
Disguised co2 leaking.
Fill it today, and it still shoots next week, so it didn't leak...right?
Well...maybe.
But with co2's self-regulating nature, you could have put 2oz. into on day 1, and 7 days later it has 1/2oz in it...but it will shoot just as fast as it did on day one.
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Wow lots of info to process. I have a remote line and 2 20oz co2 tanks, I will look for a couple of hpa tanksto purchase in the near future. I think for long grounds squirrel shoots from the table being the there's won't b a problem for me but I will probably stick toto point off the air tube when out stalking rabbits and squirrels I want to do some more mods to get more velocity and in turn a higher fpe but that will be a later post thanks again I really do appreciate all your info and you sharing your knowledge with me as I am just getting into co2 and pcp's
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2) The barrel doesn't NEED to be recrowned if you already have a tack driver.
Can you axplain mee please what is it ?
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2) The barrel doesn't NEED to be recrowned if you already have a tack driver.
Can you axplain mee please what is it ?
What he means is if the rifle is already shooting accurately there is no need to modify the barrel. A "tack driver" is a rifle that shoots pellet on top of pellet over and over again.
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Good stuff here except I don't know about cleaning every 30 shots. I just go by rule of thumb it's good until known accuracy starts falling off. Then I clean. But honestly that's like never for me outside initial cleaning.
I didn't see discussion on exactly how you are bulk filling. one thing I'd correct from some of the other posts is you aren't trying to move "gas" from your supply to the rifle. What you are trying to do is move liquid CO2. This may be why you aren't getting many shots per fill. You want less gass and more liquid. The liquid then turns to gas in the rifle to propel your pellet. This is actually what makes CO2 "self regulating" as I believe CO2 vaporizes at 850-900 psi. So as long as you have liquid you have self regulation. Velocity will quickly fall off as soon as you have no liquid.
Anyway, to accomplish this you want supply to be above the rifle so liquid can flow. You also want the rifle to be cooler than the supply. I've gone so far as putting my avanti 888 tubes in the freezer. Since a rifle won't fit in the fridge don't shoot until you are empty. Save some gas and just before filling rapid fire as many shots as you can. This will cool the rifle tube and help in max transfer.
I have a HUGE tank I bulk fill from. I just picked it up and I know that's more than a lifetime supply for me. I swiped it from the bar I used to own. Then took it to the gas supply house and traded for a tank with a siphon tube. This pulls liquid from the bottom of the tank so I don't need to invert tank. If I didn't have siphon tube or invert you can figure out I'd be pushing only gas from the tank to rifle. That sucker is like 30+#s and I didn't want to build a wall mount to hold it upside down.
Hope this helps.
Here's my lifetime supply of CO2 with a glam shot of my Mike Melick hotroded QB deluxe in .22. As I believe Ribbonstone said hot rodded CO2 is a gas hog because your dumping so much volume the liquid doesn't completely turn to gas. Hence each shot you are really inefficient and pushing liquid and gas. As with all CO2 guns giving 10-15 seconds between shots is always the protocol.
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That's a nice looking QB! I got a similar CO2 setup misus the siphon. And yes, it's a pain to invert the tank. In about 20 years when this one is empty I'll exchange it for a siphon tank.
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That's a nice looking QB! I got a similar CO2 setup misus the siphon. And yes, it's a pain to invert the tank. In about 20 years when this one is empty I'll exchange it for a siphon tank.
Yeah Andy, I love having that tank. Although I should shoot more CO2. I really only have a few bulk fill guns so this is actually several lifetimes worth.
That shroud is a coveted Rich In Mi "Q". Never see a RIM Q ever come up for sale. Even with it and the weight this beast has significant muzzle flip. It makes a really cool sound too. It's like a deep thwuuump. Unlike the sound sig of any of my other moderated guns. It's developed a leak so I'll need to rebuild it. Geez it's been like 8 years since I've rebuilt a QB. Used to be like field stripping a 1911, I could do it blindfolded. Now I'd be fumbling through it. Lol. I did break out the QB rebuild kit. Got literally 100's or each oring. Hahah. Ok maybe I'm inspired now to crack this open. Iirc it was shooting 14.6gr at 820 fps? I remember first getting it and shooting my Beeman spinner trap. I was saying to my son that the animals seem smaller than I remember. Then we walked up and saw the QB was blowing the feet off all the animals! Cheap steel!
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If I clean end off barrel ( approximately 2cm ) by cotton buds after every 30 shoots the accuracy normally never fail . Boresnake and Ballistol I use after 100 - 300 shoots only . But it can depend also of CO2 purity ? After I have made universal reservoir cap I use very cheap UMAREX CO2 ( 12g capsules ) only for paper breaking at summer. After each CO2 shooting I clean barrel whit Ballistol before I put QB78 into the box for longer time.
For year-around little range scare starling cases I a have filled my QB78 reservoir whit high pressure air.
8 shoots magazine is enough for approximately 4 days.
SfmBE
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Hey Andrew,
That's the Coolest QB I've ever seen 8).
Kirk
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Hey Andy, is that a RichnMich set up?
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Andrew the stock in your QB 78 is something to be envious about my friend good looking rifle!! Is that something anyone can buy or is it custom?