RThoads
Subscriber
23g should be good.I used 23g needle to draw, so I don't think that the needle is the issue. This happens to all 3 vials that I used (Test, NPP, Primo).
I still have some new vials, but if I don't know the cause of the disintegrated rubber, those will end up the same as these vials.
If you've been using 23g and they are good quality, the needle size is not an issue.
Sure 25g is even better (but as you go smaller, the time it takes to draw will start really increasing -- I've even used slin pins for daily tren-a in a past cycle, but I needed to slightly warm the oil to help make it practical).