Ok guys could use a little help. I have a 870 Comp. that I've added a adjustable butt plate to help with LOP, gun fit an recoil. It has added enough weight to the back of the gun that the balance is now off. I would like to add a weighted barrel cap to help bring the balance back to the center of the gun. The cap on the gun has a sleeve that is made inside the cap an sets down into the magazine tube. Not sure why it's made that way other then to help vent exhaust gasses from the guns gas system. The add on weighted caps do not have an type of venting. So I'm asking if anyone has dealt with this an could possibly offer some advice. Thanks ahead of time.