Technical Newsletter From Your Ballistic TechniciansVolume 3, Issue 2
|Cartridge Length and Semi-Auto Handguns
by Dave Brown
The following relates the proper method of determining the correct cartridge length for any specific bullet. Maximum cartridge length varies with each bullet specifically by manufacturer, model, and each individual gun for which it is going to be loaded. Normally, the dies are setup to hold the bullet securely while allowing the cartridge to be as long as the guns magazine and chambering will allow for that specific brand and model of bullet. To do this the procedure is: 1. Take the barrel out of the gun so that it and the magazine can be used as gauges. 2. Hold the barrel muzzle down and drop an empty case of correct length into the chamber making sure it is fully forward in the chamber. 3. Note where the head of the case comes to with respect to the hood, or top rear most portion of the barrel. 4. Without primer or propellant seat the bullet into the previously used case making the cartridge as long as the magazine will allow. Caution: Magazines dont always work well when fully loaded. Still, what fits in the top of the magazine may stick toward the bottom. Its a very good idea to push the dummy cartridge to the bottom of the magazine using a wooden dowel, toothbrush or what have you to check the clearance. 5. Drop this cartridge that has passed the magazine test into the chamber making certain the cartridge is fully forward. Give it a firm push. Again note where the case head extends in relation to the hood. If necessary, the bullet should be seated deeper into the case until the case head is level to where it was in test two. 6. Seat the bullet one quarter turn deeper into the case. This will allow the bullet a .020 run at the rifling which will help maintain safe pressures while allowing for differences between various lots of that specific bullet.This will result in a cartridge length that feeds well, and gives maximum case volume for the propellant. 7. Put the gun back together and strip the dummy cartridge from the magazine with a fully drawn slide. The dummy should feed and extract smoothly.
|Handgun Brass and Coke-Bottle Effect
By Dave Brown
Most handloaders have gone to carbide sizing dies for the fairly straight walled brass handgunners normally encounter. This pretty much eliminates the cases need for lubrication and its later removal. A carbide steel insert die sizes all it passes over to the same dimension. However, cases often have some taper to them. If your case bodies are sunk-in beneath where the bullet is seated, try sizing the case to just slightly past where the base of the bullet will be seated. Make certain you have sized enough of the case that the bullet is being firmly held and the cartridge chambers smoothly without binding. Cartridges sized this way will look professional.They will be without the sunk-in under the bullet look which is termed the coke-bottle effect.
Rick Williamson and son Tyler, with their fine deer taken in Wyoming, October 18, 1995 with a .25-06 Competitor pistol and a Sierra .257, 120 Gr. HP.