Reloading TIP — O-Rings can help reduce run-out when sizing

This inexpensive method can help you load straighter ammunition with slightly higher measured concentricity (i.e. There is less run-out on the bullets and case necks. Use a Rubber O-Ring to secure the die locking ring. This allows the die (slightly) self-align to the case being sized. Your die may be slightly off-angle if the flat top of your press isn’t perfectly square with your thread axis. This happens when the bottom end of the locking ring presses against the top. The O-Ring allows for the die to float slightly which may reduce run-out during case sizing. GSArizona, a top prone shooter who unfortunately passed away last year, tried this trick. Place the O-Ring onto the die, and adjust the lock ring to make sure the O-Ring is slightly compressed at the correct height. Measure a few more cases. As the die can now float slightly as the case enters or leaves it, you will likely notice a slight improvement in neck concentration. Although it isn’t going be a significant improvement, it’s a positive one.” While O-Rings can help reloaders size dies, we don’t recommend them as a cure-all. It’s worth a try. If the O-Ring reduces measured ranout, that’s great. You only have to spend a few pennies to test it. Lee Precision manufactures die lock rings with O-Rings. Lee’s unique lock ring design allows for the same type of self-alignment. Lee lock rings won’t secure to the die threads so they can move as you insert or remove dies. This can cause slight adjustments in your die setting. You can still enjoy the benefits of the Lee design by using an O-Ring underneath a conventional die lock rings (that can be locked in position), but without the risk of it moving.