SpudFiles

i was thinking of building a pneumatic gun with a small barrel. what would be better a 1/2 inch or 3/4 inch barrel? Please tell me the pros and cons.

why not have both?personally i would go with half inch for marbles and batteries.

For the same length and assuming you're using a 3/4" valve, the larger barrel will have more power potential.

1/2" is good for batteries and 3/4" steel is good for spent 12 gram Co2's. I'm not really a small bore expert but you should easily be able to use either one at long lengths with a high enough volume. If you do the C:B for the 3/4 then you'll only be wasting a little on the 1/2.

The thing I love about 1/2" barrels is they fit Nerf Darts perfectly. Apparantly 3/4" CPVC fires paintballs. Just put a 3/4" thread on the exhaust, and make a 1/2" barrel with a 1/2" to 3/4: bushing to a 3/4" threaded fitting, so you can screw either on.

My first and second guns were 1/2'' I love it, but my current gun is 3/4'' which shoots empty shotgun shells (fill them with water and freeze them) but I would do interchangeable barrels.

well i have a 3/4" barrel (uk pipe though not sure if that makes a difference) and its a perfect fit for 12g co2s then i have a barrel with an i.d. of ~18mm which is also fun to use, its just personal preference really, i suggest you check out this thread on ammo and see what you want to shoot the most and choose the barrel to suit.

http://www.spudfiles.com/forums/ammo-ideas-t1724.html

k thx for the info guys
I think i will go for the 1/2 inch barrel because it shoots marbles

Just have a reducing coupling for your body diameter to your barrel.

Yes like the others said your best bet is to make an adapter so you can use both barrels rather than just one