GTA
General Discussion To Gateway To Airguns => The Shop => : RCnMo November 03, 2008, 08:23:22 AM
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I figured I'd try to choke the barrel (or the 10" left of it) on my Quest. I will say to all the naysayers out there that there was an improvement on the groups and I now feel resistance in the last inch of my barrel when pushing a pellet through. I made these after seeing Timmy's NASA blocks and figured what the heck. I used a 12ton press and turned the barrel 90 degrees between squeezes. I was skeptical because I couldn't 'crush' the barrel and figured I wasn't doing anything. Well, when I finished up, the pellet definitely had more resistance at the muzzle than before. The groups shrank too!
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That`s way cool. I think I need to do that on my Sierra Pro. Your group shrunk dramatically..... good job!!!!
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you need to make those for sale I need one for my quest
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hmmm. how much to send you a barrel and have you squish it for me? (Not incl. postage obviously)
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Hey Brandon, I sent you a PM
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What were the before and after velocities?
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It was shooting 950 with cphp's and that was with the chopped barrel. I tamed it down a bit the other night by machining down the first 'step' on the guide and it is shooting 850-860 now. It's a much more tame rifle now. I also tried some superdomes this evening and they are grouping pretty decent. I plan on trying them out tomorrow at 30 yards to see how they group.
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yery nice Ralph,
good looking groups and nice blocks.
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Thanks Craig
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IMO chocked barrels generally work best . I measured the inside of my 3 crosman barrels at the bore not the grove depth and all 3 were .177 . I measured both of my rws barrels and they were .174 . If you go to our library you will see a pellet chart my Straight shooters that give the sizes of many pellets . So far all my rifles have liked the cph but none have liked the cpl . I can see why now . I measured my lights and the heads were .174 . Were as the heavies the head is .178 . With the lights the heavy head of the pellet is never touching the barrel let alone getting into the rifling . All the weight is traveling on the skirt and the pellet is trying to wobble as soon as it leaves the barrel . . Also the length of the cph I believe is helping it to fly true as well . Marvin
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Good info Marvin. I've found that the Superdomes seem to group tighter than the cpl's in this thing too. It's still far from a tackdriver. It probably needs a barrel. I can't think of anything else to do to it.
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When I read about true choked barrels the manufacturers generally build the choke into the barrel with a gradual choke narrowing down to an approximate .005 over a certain determined distance. I have also read that choking a barrel post manufactured barrel works as well. But what I do not understand is how would you know the tonnage to apply with a barrel clamp as you have made? Also you have to remember that an air rifle barrel's do not have the hardness as a powder burner barrel's.
Just my thoughts..:)
Gene
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try a little heavier pellet.
milbro clipper 9.0 grain
beeman kodiak match 10.6
this made all the differance for me.
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IMO that pellet chart in the library is a money saving , stress reducing chart . Marvin
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Gene, it was a shot in the dark. This rifle never has shot well for me and I figured I would give it a squeeze because it couldn't hurt. Like I said in the beginning, it didn't appear to be doing anything when I was squeezing it in my press, but when I ran pellets through the bore I could definitely feel resistance at the muzzle. I shot it afterwards with the same pellets and same distance with better results. I know this whole choke thing was a drawn out ordeal on an earlier thread and I was a skeptic, like many. Somehow, some way, I have a choke at the muzzle of this barrel now.
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I never did well in Vegas Ralph...:) Always lose my money..:) I have also heard that RWS air rifles that have the swedged front site grooves is there barrel choke. I have never run a pellet through any of my RWS air rifles but I have otherspringers that are not choked that shoot as well or better..:).. But that is not to say that a choked barrel does not work. There is allot to be said about that subject and especially all the different post choked barrel tools that are made, like yours. Thanks for sharing..
Gene
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The only heavies that I have on hand are the Crosman Premier heavy dome. They shot better than the cphp's, but the RWS superdomes seem to do best for now. I plan on messing with it some more next week to see what I can do. I did notice when I run a pellet through it's bore, the bore feels loose around the breech, hits a rough spot about 3-4" down, loosens up a bit and then hits the "choke" where it is tighter again. I would venture to say this barrel is a POS and a new one would do me wonders. I just hate to have to machine a new breech all over again. BTW Gene, I have never done well in Vegas either. Now I just walk in to a casino, drop my money on the floor and walk out.
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You might go to the library here and look up barrel lapping and get those high spots out . All so if you are worried about the tapered choke you could work on it a bit . But then again what do I know about consuming time or any thing else for that matter . Marvin