Tech Line & Tips (FAQs)
Cartridge Denting
One of the most common reloading problems that initiates a call to our customer service technicians, is the denting of cartridge cases shoulders and bodies during the sizing process. There are several different causes of these dents and each has its own unique cure.

When shipped from the factory, all  reloading dies are protected with a moisture displacing oil for shipment and storage. During prolonged storage, this shipping oil may migrate to one side of the die and harden. Before using your new dies, they should be cleaned to remove all traces of the shipping oil. Using a quality bore solvent and a brass bristle brush, scrub the interior of the dies out and then carefully dry them. Be sure no solvent remains in the threaded area at the top of the die that may later run down and cause sizing difficulties. An air compressor will greatly assist in drying the dies after cleaning.

A common and obvious cause of shoulder denting is the application of excessive lubricant before the case is run into the sizing die. When using a high-grade case lubricant, such as our "Imperial Sizing Die Wax" or "Original Formula", a light, even coat applied to the body of the cartridge case is all that is necessary. The lubricant can be applied using your fingers or our lubricant pad. Be sure to wipe the excess lubricant off the case shoulder and neck area, leaving only a thin film remaining.

Lubricant can also build up over time in the sizing die body. Each time the die is used, a new layer of lubricant is added. The lubricant then hardens during storage and gradually builds up until the accumulation starts denting the cartridge cases. Clean the die using the above recommended procedure to restore the interior of the die.

Another common cause of cartridge case denting is excessively sizing the case. In this case, the "dent" is actually a "kink." When the sizing die dimensions aren't closely matched to the chamber dimensions, the case buckles away from the die during sizing. This can be caused by an oversize chamber, an undersize die, excessively bumping the case shoulder or any combination of the three.

A properly adjusted full length sizing or body die should be set up to bump the case shoulder 0.002" for most rifles. When sizing cases for an autoloader, bump the shoulder .004" to .006". This figure can be verified with the Redding Instant Indicator Headspace and Bullet Comparator. Using a Redding's Competition Shellholder Set will make achieving precise shoulder bump a snap. See the Redding catalog or website for more information.

To check for excessive case sizing, compare the dimensions of a fired case and one that has been resized. The diameter of the fired case at any point should not be reduced more than 0.005". If you find that your cases are being sized more than this, an oversize chamber or undersize die may be the problem. Sometimes, it may be possible to polish or hone the die to better match the chamber. Check with the factory if you suspect this problem.

A popular misconception is that sizing dies need a "vent hole" to release air or excessive lubricant. It can be easily demonstrated that a vented die will also dent cases if excessive lubricant is applied to the cases, case dimensions are not compatible with the sizing die or the case shoulder is being bumped excessively.