There is no controversy over the use of DACRON, the controversy is over the use of some other simular products that melt..A wad of DACRON will come out of the barrel in a plug form and land about 10 feet in front of the barrel..
Another option to DACRON are the foam plugs that you can buy from several companies such as Kynoch, they are sized already to caliber and they work very well indeed.
I notice on these threads that the word regulated and sighted in get confused...Regulation is the process needed to get a double rifle to shoot its right and left barrel TOGETHER
