GTA
Airguns by Make and Model => Diana Airguns => Topic started by: prosportfan on November 07, 2020, 11:19:55 AM
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My question/concern is, what is the purpose of the metal sleeve? Also if it (the sleeve) has some barely perceptible up/down-left/right movement, can or will it affect accuracy? The barrel is solid as can be and it has a custom made muzzle brake put on it after a chop, choke and recrown by a professional AGsmith. Just want to know should I be concerned. Thanks
Cross Posted
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I think I know what you mean, that little protrusion of a sleeve from the base of the barrel that juts about half an inch around the barrel?
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I think I know what you mean, that little protrusion of a sleeve from the base of the barrel that juts about half an inch around the barrel?
John no not that. It actually covers the whole barrel.
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To make It pretty. Pull it off and look at the barrel. Polishing and bluing the actual barrels is additional steps that increase labor. The barrels are also a different kind of steel that would take blue differently.
The little fin assembly at the action end mates with the action to help keep things aligned and junk out the mobile action.
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Dave I was just wondering if the sleeve is a little loose will it affect accuracy.
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Sorry, I was trying to be a bit funny...
Short answer: The sleeve being tight or loose doesn't seem to have a significant impact on accuracy.
I have two 54s.
My .20 caliber was built up by Hector-Medina and has his Harmonic tuner that holds the sleeve firmly attached to the barrel. It's accuracy is excellent. Best group 0.05" CTC. Typical 0.2"CTC
My 0.177 D54 is more or less OEM with the sleeve resting against the plastic front sight base. Its accuracy is also excellent with its favorite pellet, 0.177 Kodiak Match 10.6gr group sizes at 20yds less than 0..22" CTC .fairly common. The sleeve wasn't particularly rigid but not rattly. I've shot this one for about 10years and consistently get single hole groups at 20yds of about .22" CTC. Best group I can remember was about 0.15" CTC. I haven't paid much attention to the sleeve being a bit loose or not.
I just put on the Diana HTM based on Hector-Medina's design harmonic tuner that holds it the sleeve pretty firmly. Group about 0.3" CTC. Not enough shooting to get firm statistics but plan will be doing more tests this coming week to see.
Iill be doing more testing soon.
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My question/concern is, what is the purpose of the metal sleeve? Also if it (the sleeve) has some barely perceptible up/down-left/right movement, can or will it affect accuracy? The barrel is solid as can be and it has a custom made muzzle brake put on it after a chop, choke and recrown by a professional AGsmith. Just want to know should I be concerned. Thanks
Cross Posted
Aesthetics...
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I understand that you can use them to sleeve HW barrels. ;)
-Y
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Hmmmm, lots of ideas, but few facts.
The barrel of the 48 family is 15.2 mm's OD
Sleeve is 16 mm's X 18 mm's (nominal).
Shim is spring steel @ 0.33 mm's
And yet the shim and the sleeve fit tightly on the barrel.
Few people notice, but the shim is belled on one end and, in the case of the 54, keyed at the other.
The sleeve is also keyed in the case of the 54, but not in the 48/52.
In terms of cost, the assembly is much more expensive than the polished and blued single element barrel.
In terms of time to assemble, it is MUCH more complicated to put in all the components, and then add the sight base; than just adding the sight base.
Aesthetics? DIANA had used sleeves in their Match guns for 300 years before. And those sleeves, with different missions are radically different than the sleeve/shim assembly of the 48 family.
This is Mid-XX Century technology, when CF was not even a substance of scientific study, let alone nano-tubes and nano-fibers. Graphene was just a mathematical model possibility way back then.
So, why go to the trouble?
Vibrations.
Now, what was good for 16-18 ft-lbs (an 0.177" pellet at the limit of stability velocity) THEN, is barely sufficient at 22-24 ft-lbs. NOW, and so the HPM.
Are there better methods now? Yes, and we are looking at them, IF this CoViD thing is ever over and life can go back to its normal pace, there's a bunch of things to happen.
As it stands, we are hostages to those nano-sized, semi-live, things we call "Virus"
On an individual level, some users have already sleeved their barrels in CF tubes with more or less good results, getting the right material is the tricky part. Then preparing the surfaces and using the correct adhesives is the next challenge.
It IS doable. The incorporation of it to the mainstream of the industry is going to take some time.
Keep well and shoot straight!
HM
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Thanks everyone for your help.
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“ Aesthetics? DIANA had used sleeves in their Match guns for 300 years before.”
Hector,
You should re-set your sun dial.
Diana has only been in business since 1890.
Nice try..
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“ Aesthetics? DIANA had used sleeves in their Match guns for 300 years before.”
Hector,
You should re-set your sun dial.
Diana has only been in business since 1890.
Nice try..
ROFL!
Sorry!, one zero too many.
Thanks for the observation, I stand corrected.
;-)
HM
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Ha ha! I'm following this kind of speechless! But, I have yet to get my own D54 off to Hector for some adjustments and now I think I better get off my butt and send it today or tomorrow....
Anyway, I never noticed the barrel was sleeved for some reason obviously and got lost into what you all were talking about!
:D
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Hey just being curious but how or what is the configuration of the metal and rubber washers that are on where the stock screws go in to? Like the front or forward one is? And the rearward one is? Much appreciated.
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Hey just being curious but how or what is the configuration of the metal and rubber washers that are on where the stock screws go in to? Like the front or forward one is? And the rearward one is? Much appreciated.
Josh, If you scroll back through old posts, I think I have some pictures of the positioning of the rubber/metal washers. Should be in my 56TH post.
Steve
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thanks steve