One of the test beds I use when trying out new versions of of breech plugs is an old CVA Optima Pro. I noticed that the standard breech plug in this rifle is only supported by threads in the barrel; the 209 primers just barely contact the receiver. Looking at it, I decided that I could modify it to take a quick release breech plug. Using a hacksaw, some files and a couple of grinders I removed about 10mm (400 thousandths of an inch) at the back of the barrel behind the barrel threads, and enough of the piece to which the barrel is welded to allow the new breech plug to clear. I then built a new QRBP to fit the modification and accept a primed 32 H&R Magnum case. I chose to remove this much material from the barrel because the head of the bolt from which I make my breech plugs is about .450" thick. I tested the modification and it performed with no apparent problems. I will make some more QRBP's and do more testing.