From what I seen with guys at my gun club, they work pretty well. One friend has cleaned the skeet course a number of times using 20 ga ChamberMates in his 12 gauge. I have the Briley fitted tubes, and I think shooting the other gauges is a hoot. The 28 and .410 have no recoil, so it's easy to tell why you missed. (At least as far as your lead being wrong; you still have to figure out WHY your lead was wrong.) I say go for it. You sometimes see the Seminole tubes on eBay, and occasionally the Browning inserts. Looks for inserts that have an extractor that works with the gun's extractor, otherwise getting the expended shells out is a pain.