Team B2B Precision
Focus: Rifle Dies
Reference: Bryan Litz, Berger Bullets Reloading Manual Edition 1
I will start by sharing two paragraphs from Berger’s Handloading Basics, A “How To” guide by Bryan Litz.
His words, not mine for now:
“The basic approach is to resize the case using a full length resizing die. This will return the casing to its original factory dimensions. The case goes up into the die and has its neck and body squeezed down. In the process, the decapping pin knocks out the spent primer. When the case is extracted from the die, a button will slightly expand the neck to insure it has the proper inside diameter for gripping the bullet. For total full length resizing, the die is screwed into the press until it contacts the shell-holder with the ram in the up position. Backing the die off the shell-holder slightly is a way to partially resize the case.”
More from Bryan:
“For potentially increased precision, many handloaders take deliberate control over how much resizing is done to various parts of the case. For example, you might be able to resize only the neck of the case, and not the body which will create a tighter fit between the cartridge body and the chamber. The tight fit provides the bullet with better alignment to the bore, which may improve precision. Some dies have interchangeable bushings that you can select to control the exact amount of neck sizing. Choosing various diameter bushings allows you to control neck tension, a variable that’s known to affect precision.”
Now I will add to/comment on what Bryan said. In his first paragraph, you’ll note he mentioned the button on the decapping pin. Well, some dies now have incremented expander buttons so you can set neck tension more precisely using a full length die on unturned necks. Also in the first paragraph he mentioned backing the die off the shell-holder, also known as floating the die, to accomplish partial resizing. This is a common technique and Redding dies have now made this a highly repeatable process by using their “Competition” shell-holders that come in sets of five, from .002 to .010 to address partial resizing. I am in the process of altering my personal regiment of neck sizing only, to Redding dies and shell-holders. I will use the Type “S” die with bushings and compare my results to neck sizing only. I have found since I use bushings, I leave out the decapping pin and expander balls entirely and decap with a universal decapping die, followed by the initial cleaning of the brass. I don’t put my brass in my dies until it’s cleaned the first time. After resizing, it’s back in the tank for another bath.
Based on Team B2B Precisions personal testing and the account of our RPR .243 Load Development article at Long Range Hunting on line magazine, we can say without a doubt, we experienced measurable gains in precision by full uniforming of our brass to include neck turning and using bushing dies. When you enter a repeatable factor such as neck tension to your process, you are also affecting velocity and pressure. Knowing that each and every bullet can be released under the same pressure and obtain very similar velocity gives you the confidence that your collected data will give you first shot hits at very extended ranges.
So as you can see, how much you are willing to do will determine your results. Basic dies and hunting bullets will give you good results for hunting. If you are after long range success, whether hunting or shooting sports, the more you do, the better your results will be. The better your equipment, the greater the potential is for repeatable shot to shot performance.
A couple quick pointers that helped us get better results for ES and SD: we ditched the standard chronographs of the 100$+or- variety and now use Magneto Speeds. That and after testing whatever scales we could access, we now use Gem Pro 250s with the future hope of serious German scales.
Next, more on scales and brass.