Hey Len good morning. I don’t shot much looped tubes but for frameless I like 1636 and 2040 for 1/4 steel works good in fb and short draw . I have 1632 that I have used looped it throws 1/4 ok for cans but I don’t like it much for frameless shooting 1/4
Stuff from gzk and DK seems fine . Believe me or not but I keep my tube out in shop fridge the good stuff will stay flexible when u take it out of crisper the other stuff will hold the coil shape and has no flex and if u pull on it does not retract very well until it warms up . That said a fridge is not -15 lol
I shoot a lot of 1/4" and looped 2040 IMHO is way overkill for that small ball. As it is right now I use 1030 and that ball is really sailing, same for 1636.Once I get to the 275-300fps range I'm shooting super flat to the 25+ yard range and I'm fine.
I very much try to get that speed from 5/16" and 3/8" too ------ so my trajectory is known and it is easier for me to judge there my ball is going to go.