To add a bit more thread drift, helice venues are growing and it is a great game w/present loads limited to 28 grams and no shot larger than #7.5's here, but FITASC says 2.7mm or .106" maximum which would be #7.
You can find a partial listing of US venues here:
https://www.ushelice.com/On another note, the World Cup is being held in Rome this year. The US will be well represented and I believe there will be 12 persons representing us who will be headed that way in the next few days. An interesting aside is that if you think you are good enough or even if you don't and have not qualified for a spot on the US team, you may show up at a World Cup & shoot anyway. Same apples for any of the open USHA shoots held here; some are qualification matches from which team members are selected and some are just races, but they are all always good fun.
Also, there have been huge improvements in both machines & targets over the past several years and there are machines now that can and do load automatically from magazine of targets allowing larger shoots to go smoothly & w/o the tedium of having to manually reload them after each shooter. Where single target traps are in use, they usually limit the number of shooters so the races can be completed in a reasonable amount of time.