By Bob Farmer:
There are a few different reasons for reloading your own ammunition, reduced cost, improved accuracy, and the enjoyment of the hobby, to name a few. Improved accuracy is the main reason I reload my own ammo. I reliably see marked differences in accuracy between hand loads and factory ammo in most guns, especially center fire rifles.
One way that helps get the most of reloading accuracy is just neck sizing the case instead of the traditional full length resizing. When a rifle case is full length sized it is returned to factory specs over the full case. Neck sizing leaves the body of the case but only returns the neck to factory specs. Using the neck sizing procedure eliminates the flexing of the case body to fit each individual chamber when fired. Eliminating the case flex makes for a more consistent burn of the gas leaving the case and firearm. We all know that consistency is the name of the game in reloading accuracy.
Other advantages of just neck sizing is it will lengthen case life, and the reloading process is sped up because you don’t need to lube the cases for neck sizing only. I know this is a HUGE plus for me. I hate that part of the process.
One disadvantage of neck sizing is you have to keep your ammunition separate if you have multiple guns of the same cartridge. Usually chambers are slightly different for every rifle. A case fired from one particular rifle may not fit into a different rifle if the case is not full length sized. I do have a couple of Savages that the chambers are almost identical and I can use the same neck sized ammo in both guns. Most of the time this will not work however.
If you are reloading for anything other than a bolt action, especially autos such as the AR-15, neck sizing only will seldom work. It will most likely cause feeding problems. Pump and lever actions are others that may or may not work. Be careful when trying to feed a neck sized cartridge into one of these types of firearms. If it doesn’t feed easily don’t force it or you may end up with a stuck cartridge; which means money for your gunsmith.
There are two ways to accomplish neck sizing only. The best way is to use special neck sizing dies. These dies have a special collet that will squeeze in from the sides of the neck case. The other way is to use a standard full length sizing die and set it up higher in your press so it only contacts the neck of the case. You will need to lower your expander ball so that the spent primer will spit out. The use of the collet dies will give you more uniformity, which again, leads to better accuracy.
This is a brief overview of the process. Neck sizing is an easy and economical way to improve accuracy and extend the life of your brass. Give it a try, I’m sure you will like the results!
This picture shows the collet system used in neck sizing reloading dies. Note there is no traditional expander ball. The collet squeezes the case neck onto the properly sized shaft inside the die.
