Best barrel crown for air guns. .257 cast bullet application
Well I edited my subject a couple of times and now it almost contains my whole question. I am getting ready to fit a TJ’s barrel and customizing a spare reg/spacer/valve assy. to be used to shoot these .257 cast bullets and still looking for information on some of the finer points to keep from making mistakes.
#1: Barrel crown angularity or specs.
#2: How much air is this slug looking for compared to my .25 or .30 Edguns shooting JSB’s
Thanks for any help you can offer.
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Informed information ? :biggrinn: Sounds like something from former USSR : “Information needs to be informed and then kept secret” … 😯
For information on performance with cast bullets in Edguns or at least in theory, Old Goat can give you tons of informed information.
There is really nothing magic that needs to be done to the crown for cast bullets, I usually did mine with hillbilly gunsmithing, spinning the barrels in a makeshift lathe using a drill motor to turn it and a flex shaft dremel to put a uniform crown, just make sure it is uniform on all sides and has no burs. Your crown is protected by your shroud so you don’t have to be worried by recessed crowns to protect the rifling like you would on a PB hunting rifle. But Doug did the best ones with his lathe for me and I also had threads for a flash suppressor to get those blasts of air away from the base of the bullets.
To get a workable velocity your going to have to use a lot of air. I had 36 inch interchangeable barrels on my Haley, one was 1-14 one was 1-10, I shot tethered most of the time and I got around 45 shots with a 44 CF SCBA bottle starting at 4500 and running thru a Mako regulator set at 3500. This gave me right on the verge of supersonic with the Lyman 257420 bullet and 980 to 1000 FPS with the 100 grainers depending on the weather. Question I have is do you have enough air on board to give you enough shots and volume on firing thru your valve to make it work.
Now right now I am enjoying weather in the 80’s here in Vietnam, but your puckering up in the states, temperature affects velocity in PCP’s, so don’t be too forlorn if that velocity is a couple hundred FPS lower than you want, it will come up some come summer, if you ever get another one there. :winkn:
Wow !!! to air consumption…. I bought a complete spare reg./valve assembly to customize for this project so I will play wide open on this deal and see what happens. Good to hear on the crown, I have a good gunsmith quality lathe but am a novice to average user of it so I will do all the work myself but will make a couple of test runs on solid bar stock before cutting the barrel thread on both ends and doing the crown. Sounds like extended air tubes and and shrouds and refilling during a competition will be necessary.
Ridetoeat,
There is really nothing magic that needs to be done to the crown for cast bullets, I usually did mine with hillbilly gunsmithing, spinning the barrels in a makeshift lathe using a drill motor to turn it and a flex shaft dremel to put a uniform crown, just make sure it is uniform on all sides and has no burs. Your crown is protected by your shroud so you don’t have to be worried by recessed crowns to protect the rifling like you would on a PB hunting rifle. But Doug did the best ones with his lathe for me and I also had threads for a flash suppressor to get those blasts of air away from the base of the bullets.
To get a workable velocity your going to have to use a lot of air. I had 36 inch interchangeable barrels on my Haley, one was 1-14 one was 1-10, I shot tethered most of the time and I got around 45 shots with a 44 CF SCBA bottle starting at 4500 and running thru a Mako regulator set at 3500. This gave me right on the verge of supersonic with the Lyman 257420 bullet and 980 to 1000 FPS with the 100 grainers depending on the weather. Question I have is do you have enough air on board to give you enough shots and volume on firing thru your valve to make it work.
Now right now I am enjoying weather in the 80’s here in Vietnam, but your puckering up in the states, temperature affects velocity in PCP’s, so don’t be too forlorn if that velocity is a couple hundred FPS lower than you want, it will come up some come summer, if you ever get another one there. :winkn:
Viewing 5 replies - 1 through 5 (of 5 total)
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I’ve seen VERY good results in the .223 caliber.
Even with an normal BSA .22 barrel.
You can fit such a barrel in a .25 long.
When Shooting 41 grain RWS bullits with 100 joule, 25 to 35 shots for one fill could be possible.
The reg set at 150-155 bar.
This caliber has proofen to be very stable in accuranty.
It is the overal winner for the last 2 years in 100 meter match shooting!
Anyway: I think it is wise to have some spare valves when shooting cast bullits……..
Regards, Robert.