The responses and instructions for finding the OAL are very good. But there is another concern here: You say a bullet cannot be inserted in the mouth of a fired case. Once it is fired the case mouth opens just slightly to release the bullet. You should then be able to insert a bullet into that case mouth easily, assuming this is a factory chamber. If it does not, you will need to reduce the diameter of the case neck slightly either by outside neck turning or inside reaming. Forester makes inside neck reamers, but I do not like them. Outside neck turning is a better option. There are many good neck turners on the market. Get one that will adjust to remove about .0002" from the neck brass with each pass. Just lightly skim the necks, load and fire in your rifle again. If the fired case mouth is still too tight, adjust the turner down another .0002" and keep doing this until a bullet will easily slide into a fired mouth. Accuracy will improve.