GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Oldblades on June 29, 2014, 05:34:36 PM
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Been really busy with a new Challenger CH2009 that I got from Norm at DiscosRUS. I now have the receiver locked solidly into the stock inletting. Had to go a tape bedding route given the engineered foam stock vs. wood, and am now turning to the forend section.
The barrel itself free floats above the tube, but was wondering if the airtube itself should be fixed to the forend, or floated as well?
I would love to be able to use the tube to add rigidity to the forend by tieing it into it, but not sure if I would be going backwards on this.
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It shouldn't matter, I would prefer to have the reservoir fairly solid in the tube.... Having the barrel restrained by (ie mounted to) the air reservoir is problematic, and sometimes causes POI shifts as the reservoir pressure changes....
Bob
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Thanks. I was getting mixed opinions in my research on this. With the foam stock I thought that it might not be as much of an issue, as it may be with wood.
The way that Crosman integrated the accessory rail into the forend (vs. screws), it seems that they were also attempting to use that to stiffen the forend.
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Give a choice, would want the air tube to be well fitted to the stock from the valve on back. Figure that’s the non-pressurized section, so changes in tube pressure wouldn’t make any difference. Fore end can be floated or soft pressure bedded (basically a pad of softer material). With the free floated barrel, the front end of the air tube’s bedding didn’t seem to help or hurt accuracy (but if the gun “pings” having a free floating air tube lets it resonate…so it’s more like “pingggggggg"
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With the free floated barrel, the front end of the air tube’s bedding didn’t seem to help or hurt accuracy (but if the gun “pings” having a free floating air tube lets it resonate…so it’s more like “pingggggggg"
Ahhhh, you just hit on a 'biggie' there Ribbonstone. The gun does ping a bit and was just getting educated on that aspect of air rifles.
The way I understand it is that it is actually a sound wave ringing the tube? Would a rubber damper in the forend at the corect harmonic be able to 'kill' the wave, or is going inside the tube with a depinger the only way?
I'm going to follow your lead on the exploring the soft bedding. (Really have no choice on that anyway since epoxy aint going to work.)
The rear barrel band also looks like it might make a excellent anchor in the valve area by tapping it and adding a screw from underneath.
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I don't have the huming sound in my right ear anymore, when I go to sleep at night. No more ping is good!! Hill de-pinger
Shooting my action targets (tennis ball) at 100 yards with consistency ( I need to change out the tennis ball ) (scope set on 8 - using 3rd mil-dot - JSB 18.13 at around 910 FPS) . Barrel band has a O-ring that is a tight fit.
(http://i1365.photobucket.com/albums/r750/marauderrifle/IMG_1143_zps7f3d406f.jpg) (http://s1365.photobucket.com/user/marauderrifle/media/IMG_1143_zps7f3d406f.jpg.html)
(http://i1365.photobucket.com/albums/r750/marauderrifle/IMG_1146_zps4759a84b.jpg) (http://s1365.photobucket.com/user/marauderrifle/media/IMG_1146_zps4759a84b.jpg.html)
(http://i1365.photobucket.com/albums/r750/marauderrifle/IMG_1145_zps6eebcc5a.jpg) (http://s1365.photobucket.com/user/marauderrifle/media/IMG_1145_zps6eebcc5a.jpg.html)
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The Crosman platform with its full length mono tube design should be the least affected of all by pressure variations within. Funny, they have the most stable tube on which to mount a barrel band then they use the sloppiest floating barrel and shroud system. ???
Tom
BTW, nice barrel band. Looks a lot like this one :)
(http://i1147.photobucket.com/albums/o553/QVTOM/RainStorm/RS30barrel009_zpse4935530.jpg~original) (http://s1147.photobucket.com/user/QVTOM/media/RainStorm/RS30barrel009_zpse4935530.jpg.html)
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Not really sure why, but changing the geometery of the tune can at lessen it (or make it worse, but at least you’d know what direction to take). Given the variables of spring tension/fill pressure/stroke there is more than one way to get to 12 foot pounds (and a lot more if you add in transfer ports and striker weight). Am guessing that that air pressure induced impuse that powers “ping” would be loudest at some resonate frequency that matches the tube’s length.
Who know? maybe it’s still there but outside our hearing range (let me know if the dogs in the neighborhood start barking).
Other people have used external wraps/pressure points/deadening material acting on the ouside of the tube to deaden the noise. Can always do a quick experiment and grab the tube with your hand to see if it dampens the noise.
Most just make or buy a depinger and put it inside of the tube to break up that pressure pulse, taking away what powers the ping.
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I slid 2 orings between the barrel band and shroud on both my Marauders
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Tom
BTW, nice barrel band. Looks a lot like this one :)
That's cute, I like the smiley face :)
BTW - Anyone who has been on the forums for a while knows that Tim Hill invented the barrel band with picatinny/weaver style mount - sorry :-[
(http://i1298.photobucket.com/albums/ag60/hillairguncom/IMG_2956_zpst3ukgyxw.jpg)
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Not sure I go as far as calling it an invention :) Some folks will stick a picatinny on anything ::)
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Not really sure why, but changing the geometery of the tune can at lessen it (or make it worse, but at least you’d know what direction to take).
I spend a lot of time with blue painters tape, business cards, and rubber binders and blocks, doing temporary stuff to see if it will work.
I'm still in my comfort zone with exploring bedding and blocking of the action, and action harmonics.
That all goes away real quick right now when it comes to following you guys' leads on the internals of a pcp. So I need to keep the back door open. ;)
ie: Heres my 'receiver bedding' to this point. Turned out to be extremely stable and will likely stay as is.
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Not sure I go as far as calling it an invention :) Some folks will stick a picatinny on anything ::)
Said the copy cat…. :) :) :)
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Just funning with you ;D
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Wow, any of you guys that are having issues with horizontal/diagonal stringing, you should really take a look at tape bedding the trigger group to the inletting. (if you only have a single forward action screw and if your TG would be conducive to this).
Its really the only flat spots on the action in this case for the opportunity to try this.
I had some pretty extreme horizontal and found .050 'slop' between the TG and the inletted walls.
Realized the torque applied from cocking had to be doing something to the action in the stock with that kind of free play.
It took 5 layers of tape to snug it up and the difference was amazing. Went from about a 10/1 horizontal (no exaggeration there) to vertical dispersion ratio, to actually a fuzz more vertical now.
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FWIW.....I float my air tubes. The only place my action contacts the stock is a 4 inch section where the single 10-32 bolt fastens it to the stock. It is relieved both ahead and behind this. This is on an aluminum stock. This is where the barrel block and scope mount, also. Prior to doing this, POI changes could be seen at 25y indoors after barrel cleaning and refilling the tube between cards.
Mike
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Just funning with you ;D
As was I ;) More importantly, I noticed your band is installed backwards ???
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FWIW.....I float my air tubes. The only place my action contacts the stock is a 4 inch section where the single 10-32 bolt fastens it to the stock. It is relieved both ahead and behind this. This is on an aluminum stock. This is where the barrel block and scope mount, also. Prior to doing this, POI changes could be seen at 25y indoors after barrel cleaning and refilling the tube between cards.
Mike
FWIW Mike, with the results that you get, I'm all eyeballs on anything that you have to offer. Thanks
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Got me wondering. Do like to find things out for myself.
Short test, so its at least indicative if not proof-positive.
Bedded the Challenger PCP as shown. Black Epoxy bedding doesn’t show up worth a hoot on a black stock, so for the photo cut out some construction paper just to show where the bedding is.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/d52092c8-1f8f-4ea3-b509-3eb97e4b0e30.jpg)
BTW: they do sell release agents for epoxy bedding. But you can use good old Johnson’s Past Floor Wax. Has a “carp load” of uses around the shop, and as long as you keep the tin sealed, last for years.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/b2751c70-ae25-4f32-8f0b-a8a248043ab4.jpg)
Which set the rear section of the barreled action solidly in the stock without any wiggle/rotation, or see-saw movement.
Also left room for a dollar bill to easily slide between the stock and the air tube.
Thicker target paper took a bit more effort to slide between the tube and the stock.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/4972084e-6463-4e2b-aa90-25c1c025fd69.jpg)
So I tried 15 shots ( 3 5-shot groups) at 20 yards with 3 settings:
Free floating (top 3 groups)
Middle set of 3 used 2 target papers, which required me to loosen the stock screw in order to get two layers of target paper in place. GUESSTIMATING by the effort needed to lift the air tube until the paper slides out, would say something like 5-8 pounds of “up” force to the air tube.
Bottom set of 3 targets used one 1 target paper thickness could be slid in without loosening the stock screw. Probably something like 1-2 pounds of “up” force.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/d962c265-f5b1-42c2-8060-b469279f8f66.jpg)
Don’t reallyneed to measure the groups. The quick test indicates this rifle wants to have the air tube free floated.
Will have to test over a few days to see if the POI stays stable to the POA. So long as it does, am going to stick with free floating the tube.
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Teriffic info and nice shooting to boot!
I was also suspecting the tube should be floated now after today. I had used the blue painters tape test last night on the tube and shot it this morning before work. Dead calm and getting some shifting. Then came home this afternoon, pulled the tape and opened up the barrel channel and give that a try per Mikes post.
Pretty windy by then, but the 4 (5) shot groups were non-directional and all in the low .300's ctc at 30 yds. using flags.
So I suspected that to be in the right direction.
That was just confirmation Ribbonstone. Thanks.
Did you have any issues with the epoxy sticking? I have some Devon epoxy that I use on wood stocks, but wasnt quite sure if it would work or not on the foam. Didnt want to start carving up the inletting for the bedding relief, and then discover the answer was 'Not'. ;D
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If you want to try, then get the following together first.
It’s the PARANOID’S way (for those of us freaked out about gluing the stock and gun together).
1. Saran wrap (or whatever you use for plastic wrap in the kitchen)
2. little bit of Al. Foil
3. Johnson’s Paste Floor Wax (in the yellow tin as shown..don’t worry, will have lots of uses, including stocks)
4. Epoxy (prefer two-part slow cure black stuff)
5. Coarse steel wool (or fine abrasive paper).
6. Degreaser (Could be mineral spirits, could be Dawn dishwashing liquid and water…whatever you got).
7..Small sharp pen knife
1. Get barreled action out of stock.
2. Plug the stock screw hole (and any other hole) with a tight ball of Al. foil
3. Slightly roughen the stock finish with the coarse steel wool or fine abrasive paper where the bedding is going to go (as in the picture).
4. DEGREASE the roughened area of inletting.
5. Coat the metal work of the action with Johnson’s Past Wax. DO NOT buff, just let it haze over.
($4 and #5 give a clean, slightly rough area for the epoxy to “bite” into.
6. Stretch the Saran Wrap over the metal work of the action. Try to keep it wrinkle free, but countoured to the metal work. Cover MORE AREA than you expect to need as the epoxy will ooze.
7. Lightly coat the Saran Wrap with wax.. Smear it as thin and even as you can on the Saran Wrap.
8. Mix epoxy for a coating in the areas shown. Leave a “test pile” of unused epoxy so you can poke at it and judge it’s state of hardness.
9. Press the barreled (plastic coated and lubed as above) action into place in the stock. Just push it in by hand hard, trying to keep it even as possible in the stock.
10. Can place a sheet of paper between the fore end and air tube if needed to keep alignment.
11. Keep poking the test pile of epoxy. BEFORE it gets rock hard, about when it’s as hard as a dress shoe’s heal, pull the action back out. (this way it is hard enough to really stick, but soft enough that you can get the action back out even if the epoxy oozed into a recess and mechanically locked the metal in place).
12 PROBALY the Saran Wrap stuck to the bedding and pealed off the metal work. That’s OK.
13. Clean any stray epoxy off the metal work while it’s still putty soft.
14. Small sharp knife to cut off any stay epoxy sticking up over the stock’s edge or oozed into the wrong place. Best to do that before it’s fully set up.
15. Remove any Al. foil plugs (from #2).
16. Let it sit over night to fully cure.
17. Peel the Saran Wrap (if it stuck to the bedding) off the now cured epoxy.
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It’s the PARANOID’S way (for those of us freaked out about gluing the stock and gun together).
Ribbonstone, great writeup and how to.
I've actually done about 10 stocks in rimfire and centfire rifles with Devcon steel epoxy and am always paranoid of glueing the action to the stock. ;)
The twist in your approach for airguns, that I really like in this application, is the saran wrap. In addition to the concern of the epoxy adhering well (or at all) to that foam stock, was getting the action out after the bedding is cured. The way that I do it is to whack the bottom of the barrel sharply with a rubber mallet. That usually breaks the bond and gets the action started on its way out. Then its just a matter of wiggling it on out the rest of the way.
Problem with the air gun is that the 'whacking point' is the air tube. Probably not a good idea. ;)
The other things that you do, that I havent, is the use of aluminum foil (which I gotta try now) instead of big ole blobs of plumbers putty.
Anyone thats ever used the stuff (plumbers putty) will know that its really a pain in the butt to clear out and also leaves a good coating of the linseed oil behind on the stock.
And foremost on the list is the little blob of epoxy off to the side to monitor curing status. That one was a 'duh' moment for me as I had never considered such a simple step in the process.
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Don't have any recoil lugs (or real concern about recoil) to deal with, which makes the process easier. Will take a long time with slow cure epoxy, but the stuff seems stronger than the fast cure types, which gives you time for trimming and clean up.
Probably shoots no better than it did before, although it would take a whole lot of shooting to be sure of that as would be a pretty tiny difference. Does stay stable day to day (or month to month for that matter).
Not real pleased with the small foot print at the rear, which is actually contacting the rear "foot" of the trigger housing, but the only other choice is the end cap..and that's too "wiggly" to use.
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Not real pleased with the small foot print at the rear, which is actually contacting the rear "foot" of the trigger housing,
I noticed that also when I was taping up the trigger. The trigger cutout almost appears that it was preexisting from the 2000 Challenger trigger? I'm not familiar with those and was trying to find a pic in google images to try and find out. Inconclusive on that though.
If they had a full platform back there, it would have been very simple to have a rear action screw into the rear trigger group screw hole.
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Co2 Challenger 2000:
(http://i157.photobucket.com/albums/t50/ribbonstone/co2/0cd81324-366d-4750-b07b-38c5bdeb041f_zpsc22098f8.jpg)
(http://i157.photobucket.com/albums/t50/ribbonstone/co2/8b1bf70b-ab90-4efb-acef-eac711dc02d2_zps0588bfc8.jpg)
(http://i157.photobucket.com/albums/t50/ribbonstone/co2/DSCF1984_zpsbdfec72f.jpg)
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The Marauder rifle's design is a little different than your rifle.
The Hill barrel band keeps with the original lines of the factory style B.B. and the picatinny/weaver rail is added "just" to the bottom. This keeps the rail as high up or close to the rifle as possible (see 1st pic).
If I had turned the rail to the rear, the rail would have to extend downward or lower - in order to clear the pressure tube. I felt this extra distance away from the rifle (though not much) was not necessary and could possibly add to the chances of bumping the rifle against something. Since the rail works fine offset to the front, there's no need to chance it.
Also, by keeping the rail close to the rifle, this allows for any other accessories that may be added, to also stay close to the rifle (inline with the pressure tube) (see 2nd pic).
(http://i1365.photobucket.com/albums/r750/marauderrifle/IMG_2489_zps9400327c.jpg) (http://s1365.photobucket.com/user/marauderrifle/media/IMG_2489_zps9400327c.jpg.html)
(http://i1365.photobucket.com/albums/r750/marauderrifle/Marauderfully_zps6826b5e7.jpg) (http://s1365.photobucket.com/user/marauderrifle/media/Marauderfully_zps6826b5e7.jpg.html)
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(http://i157.photobucket.com/albums/t50/ribbonstone/co2/8b1bf70b-ab90-4efb-acef-eac711dc02d2_zps0588bfc8.jpg)
Well that looks like it tanks my suspicions. Still dont really understand the reason for that void though? Just looks like a corner was cut or a mistake somewhere. Thanks.
Went out this morning, and explored the free floating the tube thing. Broke out the prussian blue, 220g paper, a deep well socket, and started sanding in the barrel (tube) channel.
There was a whole lot of material at the end creating end support for the tube. However by the time I had all that removed the action screw was bottoming out. So I added a thin washer and commenced some quick testing.
Started with the tube completely free floated and had some nice little groups but they were shifting within the set. So I tried some business cards under the end of the tube, to pretty much mimick the original configuration. Same results as before I had started this endeavor, not good not bad, but noticed some stress on the tube. But I really didnt like that pressure point at the end of the tube.
Last experiment was 2 business cards fit loosely right in front of the rear band. All they really were doing was centering and taking up any slack without any real pressure on the tube.
That turned out to be the winner of the morning, and if this holds true then simply bedding the barrel band would seem like the logical permanant procedure.
So at this point my thought is that the tube should be free floated..........kinda. :P
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Challenger 2000 CO2 stock and Challenger 2009 PCP stock are pretty close externally, so I suppose that Crosman made use of existing stock molds, just changing the inletting.
The Challenger co2 wasn’t(isn’t) much of a match gun. They did do a whole lot to strangle out a lot of shots from a single 12gr. (like 80-85 shots in summer, more like 70-80 shots in cooler weather) but the soldiered-on-the-tube “Benjamin” type barrel and the Benjamin 397 type trigger make it into a “7 ring” shooter. With enough work, can make one into an 9-ring shooter.
Set up right, the PCP Challenger has the 10 ring. Trigger is WAY better and the LW barrel certainly doesn’t hurt.
Sooner or later, will find a local kid with aspirations of 10 meter shooting and the Co2 Challenger will get donated.
(http://i157.photobucket.com/albums/t50/ribbonstone/2009PCP/a071fcdd-5531-42d2-8f87-6398816266f4.jpg)
(http://i157.photobucket.com/albums/t50/ribbonstone/co2/ce95aca8-6c8b-4aca-b6c9-66734be78a59_zps043d972c.jpg)
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The kinda sad part is that the more time that goes by, the less chance you will have in finding that kid with an interest in 10M shooting.
Ufda, I went in the wrong direction whatever it was on my forend experiment. Whatever I thought I had earlier, was just a pleasant dream. Gotta back the truck up who knows how far into the previous steps.
Got some Brown Box 10.5's in a package this afternoon and thought that I would give them a try.
Just quickly put out a 30 yd. target and boxed single targets with the scopes windage and elevation, instead of going from target to target.
What a mess. The rifle would generally put 2 or 3 next to, or on top of each other, and then shift 3/8-1/2" in an unpredictable direction.
I wish that I could say that the 2 distinct groups above the target in the lower right were in order. The fact is that the POA was the target below them, but I had no idea which hole that the POI was going to be in on any given shot.
The things I can do to make a perfectly good 9-10 ring shooter into a solid 6-7 ring shooter. ;D
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Really like the challenger stock.. anyone know the cost the stock off the top of their heads?.... would look sexy on my disco double....
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Really like the challenger stock.. anyone know the cost the stock off the top of their heads?.... would look sexy on my disco double....
Michael, get ahold of Norm on his Discosrus forum and ask him.
His prices are about as good as it gets and I think he can set you up with a turnkey Challenger stock for your double.
http://www.gatewaytoairguns.org/GTA/index.php?board=150.0 (http://www.gatewaytoairguns.org/GTA/index.php?board=150.0)
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It's a bit tricky to get a Double Tube into a Challenger stock but can be done. The depth of the forend is just enough to be able to do it.
It also requires drilling the hole for the gauge as the Challenger has a side mounted gauge. On the two I have done the hole in the bottom for the gauge was no issue and I took it one step further by filling in the side hole and they came out very nice.
Norm
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is there any bedding material that would be soft waterproof and help silent the ping?
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is there any bedding material that would be soft waterproof and help silent the ping?
Probably best to keep the two separate, e.g.; bed the stock is a specific manner/way, de-ping the rifle with a de-pinger sized specifically for your rifles caliber;
(http://i783.photobucket.com/albums/yy118/tlka1/IMG_2681_zps7575a5ac.jpg)