SpudFiles

I have a general question, but I come bearing gifts!!

First the gift. This is a calculator for determining barrel twist. It works much like ggdt and appears to be a great tool for those who want to take a launcher to the next level of performance.
It even provides the specific gravity of different materials used for ammo.

Now the question (sorry if it seems silly).

I want a rifled barrel. I dont want to buy a pre-made for many reasons (read: sticker shock). I dont feel I can make it myself, as I dont have a machine shop, and im not satisfied with the "big screw head forced down the barrel while twisting" method... I dont think ill be able to achieve the level of accuracy of craftsmanship necessary for high accuracy.

What are my options? Can I buy the material and have it machined?? Hours of internet searching and I Have come up dry. Most all thats out there is cartrage barrels, black powder barrels, and small cal. air rifle replacements. Most all the Korean big-bore air rifle companies seem to want you to ship it to them for repair.... not sell replacements.

Sorry, thought consolidation isn't super easy for me while distracted lol. Just pretend I have a steel barrel I want rifled. Who do I call... where do I go... how much should it cost to get a custom rifling job done??

Im thinking an ~3' barrel @.45 or .38cal. (leaning towards .45)

ThornsofTime wrote:I dont want to buy a pre-made for many reasons (read: sticker shock).

A quick google search turned up this site, I would say 65 bucks is very reasonable for a 0.45" rifled barrel.

ThornsofTime wrote:First the gift.

Well, we've known about the Greenhill equation for quite a long time...

Personally, I prefer a version designed to take all metric units, rather than that version which mixes imperial and metric:
2 * SQRT(V * SG) * D² / L
V = Velocity in m/s; SG = Density in g/cc; D = Diameter in cm or mm; L = Length in cm or mm
Use the same units for D and L, result is the length of one turn in those same units.

As JSR said, just buy a black powder gun barrel. You can get them in .36-.58 cal usually. They aren't too terribly expensive and will get good accuracy.

Some other questions to ask yourself would be:

- will I be firing over the sort of distances and require the level of accuracy that demands a rifled barrel? Have a browse through this testing.

- Will I be able to make the rest of launchers parameters - valve consistency, pressure levels, projectile uniformity, suitable sights etc. - to the same degree that will allow me to take advantage of the rifled barrel?

Or maybe you just want a rifled barrel of the sake of it personally I think you can easily find one for less than $100 and that's a reasonable price to pay for something that will be far better than anything you make yourself and far cheaper than a custom made item.