Re: Primer pocket depth
By using a cutter to "square" the bottom of the primer pocket, the main benifit achieved is removal of the small radius that remains at the bottom of the primer pocket after it's formed. Primer pockets aren't machined, rather they are formed or headed. It's difficult to accomplish this and leave a perfectly square bottom. By removing this small amount of material from the bottom of the primer pocket it allows the primer a much more solid surface to seat on. This accomplishes two things. First it assures every primer will be seated to a uniform depth below the back of the case, and second it gives the primer itself a solid surface to seat on preventing it from being driven deeper into the pocket by the firing pin at ignition. By doing this it assures the primer will receive a solid blow from the firing pin with all of the firing pins energy being transfered to the primer itself, and not wasted driving the primer deeper into the pocket. Bill T.