I've never even heard of a choke tube swelling from shooting small TSS pellets, much less experienced it, and have been shooting TSS exclusively since 2009 with choke tubes a lot tighter than full. Most swelled choke tubes come from shooting large steel shot, eg BBs, BBBs, Ts, etc through tight chokes as the pellets can bridge as they pass through the choke exerting extreme outward pressure on the tube. Small TSS pellets flow through chokes just fine without causing problems IME.