Looking for an answer maybe.

Rbeckett

Rbeckett

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I have been tinkering with the idea of building a 1000+ FPS .25 Caliber air rifle. My question concerns how to bore a barrel to the appropriate diameter along it's full length (18-20 inches), and how deep I should make the rifling to spin the pellet to improve accuracy.

Bob
 
This looks like another instance where a D-bit may be the best solution for creating the bore. As for creating the rifling, I have no idea.

Alternatively, what about purchasing a barrel liner? You could make the outer portion of the barrel, then bore for a liner. Brownell's carries a wide assortment of liners, but they are not chambered, so might work well for your purposes. Looking at their catalog I see a liner for .25-20, .257 groove diameter, .435 OD, 1:14 twist, 25" long. Using a liner would still give you your own creation, but with the quality of a commercially produced barrel bore.

As for a D-bit, you might want to see this thread on deep hole drilling: http://www.hobby-machinist.com/showthread.php/20208-Deep-Hole-Drilling

Just some thoughts!
 
There may be a further problem with getting a barrel with the correct spin for an air gun. I am GUESSING the spin needs to be faster than for a .22 short. And,a .22 short spins faster than a long rifle. I can't recall the spin offhand,but if it isn't right,accuracy will be miserable.

I used to have an old "Apache" air rifle from the 50's that had a .25 caliber barrel on it.It belonged to a friend of mine who is several years older than I am(74). I don't know if I still have the gun or not. It did not work since the seals on the piston long ago gave up the ghost. I'll look around and see if it is here.

It's barrel looked more like a barrel liner looks than like a thicker normal barrel. It was an old pump up design. A friend of his told me that the old gun shot "like the hammers of Hades" when it was in use.

Anyhow,getting a .25 caliber projectile to nearly exceed the sound barrier is not going to be the easiest thing to do. I have a big,heavy duty "Kodiak" sir rifle in .22 caliber that does 800 FPS. It would do a lot more in .117 cal..

How are you going to propel the projectile?

Aren't there some kind of super air rifles made in the Phillipines that are large caliber? I have seen pictures and read about them. Rather gaudy looking,but powerful. I can't recall particulars.
 
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You can buy the barrels for high precision air rifles to low quality, depending on how much you want to spend, but they are relatively cheap. We made a few at work in the 90's and they were better than anything that you could buy.
 
It is good to know you can buy barrels. Can you tell me where? I have a Webley service air rifle from 1927(I think). They used to come with interchangeable barrels. I need to make a .22 barrel for mine. If I could buy a heavy barrel,or at least a thin but properly rifled one,I could make a barrel around it.
 
Hello George, you can buy air rifle barrels from Weihrauch, FX, Webley and any other reputable air rifle manufacturer.

There are a couple things to keep in mind. Air rifle barrels are generally a little fussy based on their crown and rifling and therefore like specific brands and or weights of pellets. Also, the longer the barrel, the higher the velocity you achieve (to a point). The highest velocity barrels tend to be 23 - 24 inches.

There has been some development in barrels over the years such as smooth twist and just rifling the last several inches of the barrel. I have attached a link to the smooth twist barrel from FX below:

http://www.airgunsource.com/store/index.php?product=FX-19218&c=275

this one is .30 so if you want one for .25, check out these guys:

http://www.airgunsofarizona.com/

I shoot airguns a lot and believe that the accuracy of the air rifle is hard to beat. At 50 yards on a calm day, I can put pellet on pellet with my Theoben MFR in .22.

Paul.
 
Thanks,Sam. I have a Walther match rifle that is in new condition. I bought it used. A very expensive rifle. It came with the factory test target with 1 .117 caliber hole dead center. BUT,10 pellets went through that hole!!
 
:)) yep!! But if you tell people about it they usually won't believe you about the accuracy. Lothar Walther also sell barrels in .25. Are you looking at making the rifle a pre-charged pneumatic or a break barrel? I have a Weihrauch HW80 (or a Beeman R1 in the USA) in .25 which is a beast. It won't do 1000 FPS, but it will send a 20 grain pellet at 20 ftlb which is enough to kill crows and other varmin without blasting holes through everything. If I use hollow points then body shots will end most vermin up to cats (only ever did this in Australis as hunting in Norway with an air rifle is illegal - regardless of how powerful it is).

The problem if making a springer that powerful is that it has to have a great deal of mass, and the more you squeeze from it, the harsher it is on scopes.

Paul.
 
My most accurate air pistol is a Walther. The same air gun in the James Bond poster(WHY is he holding an air gun?) This gun shoots more accurately than I can hold it,and is just as accurate as a .22 target pistol at the intended range. It has a real hair trigger. I'd never want to sell that pistol. My best Webley is a Webley Premier I got recently. It has an adjustable trigger. A better gun than the Webley Senior which does not,and has the reputation of being hard to hit anything with. I had a Webley Mk.II which also had an adjustable trigger,and would also out shoot the Senior. I have others as well.
 
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Looks like you have the same addiction as I do George. I already ordered the .25 gas piston from hatsan to arrive Saturday and I have a .177 Nitro Venom that is around 1200 FPS with PBA and 1000 with lead. I am having a ton of fun so far and I can keep the per shot cost around 4 cents so far. The .25's will probably drive that up some, but not too much anyway. Good luck and happy hunting to all the airgunners out there with us..

Bob
 
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