SpudFiles

i bought SDR21 from a supply shop. i checked it and it said... 1 1/2" crestline SDR21. i dropped a golfball in it and it rolled down the barrel. is it supposted to do that? or does it have a firm fit?

a golfball is pretty solid (not soft & squishy), so it probably shouldn't be too tight. Also, I'm pretty sure it is supposed to fit just lose enough to roll down the barrel (@ least with sdr 21). The most important thing is that it doesn't have lots of space around it when it's in the barrel.

Its not supposed to fit tight....

The majority of golf balls will roll in loosely but with very little slop. However, I've found a few balls (5 or 6 out of dozens) that were too large and thus too tight to use.

Therefore the SDR21 is such a good fit that the high end of golf ball size tolerance isn't usable.

About a month ago, I found two golf balls in my backyard, and they differ in diameter by about 1/8". I won't be able to test their fit in SDR-21 until next week, but I'm assuming that one of them will fit very poorly. I suppose that different manufacturers produce balls of slightly different size. This isn't the first time I've heard of golf balls not fitting properly in SDR-21. Try some different ones and see what you get.

I made a golfball launcher a few months ago and I remember taking a golfball to a local plumbing shop. I tried the ball in a piece of sdr 21 and it seemed a bit loose, but still fit well enough for me to decide to buy it. When I got home, I started to sleeve the sdr 21 inside a piece of schedule 80 2 inch (took A LOT of effort and lube). after I finished that process I put a golfball in my newly made barrel and it seemed to fit a lot more snug. Just to a point where I can push it down the pipe with a slight amount of effort.

As a side note, it seems to shoot better when the ball is tighter and tougher to push down the barrel. I am not sure if this is due to the fact that it is a combustion or not, but I am guessing that it is.

jook13 wrote: As a side note, it seems to shoot better when the ball is tighter and tougher to push down the barrel. I am not sure if this is due to the fact that it is a combustion or not, but I am guessing that it is.

If the projectile is tighter, the cannon builds up more pressure behind the projectile, more pressure = more force = more power.

Regardless if it was combustion or pneumatic, it would improve performance slightly.