GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: KnifeMaker on March 17, 2019, 07:21:23 AM
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I followed Mr. Bob's suggestions on high modulus carbon fiber sleeving and solidly mounting a barrel in the RainStorm. There is virtually no room between the living and the shroud. It is now literally a carbon fiber bull barrel. ;D
the barrel is a Walther, with two carbon twill sleeves bonded to the barrel. New barrel muzzle brace by Neil clague, and the shroud adapter that threads into the breach adapted and machined to be JB steel welded to the barrel and now allows the barrel to be threaded into the breach. Along with 7 Set screws, increased in size to M 1O-6 and set into Heli coils that are bonded to the breach as well. Three on top and two each 10-32 set screws on the side. Will soon add two more.
Here are the results at 50 yards with the Arsenal 257420's cast from the mold I decked to throw them at 50.6-7 grains with a very small rebated BT.
There are 8 shots measuring .203 by .256 inches at 50 yards, 10-12 head wind. So basically 1/4 inch at 50 yards in the wind. Woo-Hoo!!!
Added the Huma Reg back into the mix, and now get 20 good shots. 8)
Gotta love it when something works so well. After so much trial and error.
Knife
Aren't These little bullet cute little buggers. LOL ;D
Click on the pics to get full size.
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The bottom bullet lying horizontal has rifling marks on it. It is sized to .2495 inch. I have shze the bullets in the target at .250 and get better twis definition, and no velocity loss.
Knife
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Excellent group you've got there for 50 yards Michael !!! You've sure come a long way with your RSII indeed. 8)
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Excellent group you've got there for 50 yards Michael !!! You've sure come a long way with your RSII indeed. 8)
She just keeps getting better and better Wayne. 8)
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That’s some fine shooting Knife. Those slugs look very very nice for reaching out past 100 yards. Keep it coming.
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NICE!!!!!!!!
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Beautiful results Knife!! Could we get a picture or two of the rifle?
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Great job.... glad sleeving the barrel contributed to your success.... What is the OD you ended up with?....
Bob
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Now that is slinging some lead in tight groups Knife! Nice shooting!
One Q for you, do you have the barrel & CF sleeved into the breech or just the barrel?
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Wow Michael that is great !!
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Nice shooting and I have to say I am extremely interested in the carbon fiber sleeving.
Do you sleeve all the way from the breech to the muzzle/crown?
I was looking at a couple rifles and wondering if It’s a reasonable thing to sleeve from breech to the barrel band leaving the last few inches of the barrel not sleeved.
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...do you have the barrel & CF sleeved into the breech or just the barrel?
...What is the OD you ended up with?....
Bob
I was wondering the same thing
I may have to pick up a RS!!
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Steve, you need to have the sleeve extend into the receiver as far as possible (at least 2 diameters) for best effect.... If you can't do that, then you will probably benefit from a barrel band part way to the muzzle to prevent the entire barrel from deflecting at the front of the receiver.... The best place for that can only be determined by experimentation.... but if you have to choose a location, I would try 4/7ths of the way from the front of the receiver to the muzzle, with 3/7ths as the next best location.... It is not good to divide the unsupported barrel length by 2, 3 or 4, as those are harmonic nodes.... I suppose you could also use 3/5ths or 2/5ths of the distance from receiver to muzzle if the 4/7th or 3/7th are not choices available to you....
Bob
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The od is now .790 inch in Dia. The sleeving extend to 1/2" from he muzzle, where a support is affixed to the barrel to hold the shroud and ldc in alignment. it was fashioned by Neil clague fo it.
With the threaded insert threaded into the breach and it being 1 inch ong, it is less than the needed two Dia's, but I had no way to bore the breach so it had to do. It is secured to the barrel with steel epoxy to the barrel itself, and release agent was used and the barrel and sleeve threaded into battery while the threaded sleeve was threaded and secured with industrial/ reusable Threadlocker from Fastenal. It was done this way to insure perfect port alignment, and allow removal when needed.
The port in the barrel has been fully blended and mirror polished.
The Huma Reg reinstalled, and set at 165 bar.
I am in contact with Hubb of Huma for a custom plenum and possibly increasing the set pressure.
I still haven't sent the bbl. out for o ring fitting and can't seem to stop enjoying it long enough to let it go for a couple of weeks. GRRRR! ;D
Perhaps I will fit the 26 1/2".257 TJ's barrel from OneShot to enjoy wile she is gone for the fitting. ;D
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would not mid a look at a fired soft caught round to look at the rifling marks... the round looks to be breakin the rules a bit about bearing length... notice no marks on nose past front band...so they may wobble in the barrel just a tiny tiny bit..?
want to see how far up the rifling marks go on a fired round... should be a touch further...
would love to know center of gravity & center of pressure... I think with the drag from the lube groove/ rear band... probably will help recover from any slight wobble very quickly... aero/arrow stability.. ;) ???
do like the looks of the round and am a believer in Bull Barrels one of these days will build one with a 1950's Shultz and Larson .22lr bull barrel and just hang the power plant (think 3000 psi disco)off the barrel...
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Yes, the rifling marks are on the driving bands only. Still trying different sizings. Much more testing to come. ;)
Knife
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While supporting one full caliber in the rifling is ideal, I have seen lots of successful bullets with a bearing length of 2/3-3/4 caliber.... Measuring from that pic it looks like about 70% to me.... I wouldn't want to go much less.... but the proof is in the way it shoots.... 8)
It always pays for us to remember that our guns can't read.... ;)
Bob
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How True! ;D
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" It always pays for us to remember that our guns can't read.... ;) "
you're a preachin to the choir on that one...
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Beautiful results Knife!! Could we get a picture or two of the rifle?
Let me see what I can do. ;)
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The Sun angle was terrible, and I couldn't see the screen on the camera at all GRRR!!
But here goes. LOL
the last pic is my way of being able to test a new barrel before being sent out of an o ring install. Industrial Electrical Shrink Wrap. Red Neck engineering at its finest. LOL! ::) along with a poor boys scope stop. The M10-6 screws are doubled, as one is a locking screw in each of the screw lock down. I used one longer one in the real slot to but the scope ring base against in order to take advantage of the quick release rings. Kinda like not having to re site in every time I pull it. ;D
Next I will mill the breaches top for Picatinny slots. ;)
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don't forget to click on the pic's to upsize. ;)
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Slick set up!!
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thanks tom. The industrial Heat Shrink wrap holds up for at least a thousand rounds without blow by. works much better than I had hoped. Can only use it single shot though.
Making a single shot tray as soon as I can pick up a couple of the proper sized magnets.
Knife