Hello N/a, and welcome! I wish you a very merry Christmas, And a Blessed New Year. If you add your name and location to your profile, we will be able to help you much easier. I haven't seen them, but if you check the furrow, or collar, and see if there is anything but the double tapered barrel. most are changed by removing the nut, and inserting, or transferring the furrows. Some are held in, so i am guessing. You should have instructions telling you how to change them. Thanks for joining.
John 3:16 Please fill out your profile, It helps us to know you better