John Reno
Below is a good book with a lot of information on reloading by someone with a good bit of experience under his belt. And you asked about “how many reloads do we get from our cases”. Your question covers a lot of ground and one of my pet peeves is reloading dies. I have five different full length .223/5.56 reloading dies to help with what I’m about to say.
We live in a plus and minus manufacturing world and our chamber and dies come in different sizes. My “worst” die is a Lee full length die and I say this because this die sizes the base of the case more than any small base die I own. This same Lee die will push the shoulder back further than any other die I have. The dies I like the best are the RCBS AR series dies because they do not over work the brass.
Now to Mr. Zediker and his book and reloading tips. He tells you to measure a new unfired case at several points from the base to the neck. He then tells you to measure the same case at the same points after firing and after full length sizing. The resized case should be at least .003 smaller than its fired size and .005 smaller is optimum for the AR15 rifle.
Bottom line, chamber pressure, brass quality and “NOT” over working your brass are all factors in case life. Enlarged primer pockets are caused by higher chamber pressures and exceeding the elastic limits of the brass. And neck splits happen early from over working the case neck. So your cases will last longer when you do not shoot at maximum pressures. And if you have resizing dies that do not over work the brass.
And one other note, I keep reading about a “difference” in .223 and 5.56 chamber pressures. So remember this, both the .223 and 5.56 are loaded to the same chamber pressure of 52,000 cup or 55,000 psi. And the actual difference is the throats of these rifles, and “NOTHING” is written in stone. I have two AR15 rifles and a Bolt action Savage .223. And the throat in my Savage is longer than my AR15 rifles.
Below is the milspec for civilian commercial contract 5.56 M885 ammunition made for the military and the max rated pressure is 55,000 psi. In a older version of this milspec both 52,000 cup and 55,000 psi are listed. So don’t do as so many do and confuse the European NATO CIP standard of chamber pressure at 62,000 psi using a different pressure measuring method than we use in the U.S. Meaning 52,000 cup, 55,000 psi and the European CIP 62,000 psi are the exact same pressures measured three different ways.
Now look at the link below and “see” how much longer my Savage throat is than the AR15 rifle. Savage decided the chamber should be big enough for the cartridge and the company lawyer to fit in.
HOLLIGER ON .223/5.56 CHAMBERS
http://www.radomski.us/njhp/cart_tech.htm
Another good read below.
Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_overworking_brass.html
And the best for last, you can buy Forster full length resizing dies and have the neck honed by them to your desired diameter.
“If you purchase a Forster non-bushing, full-length sizing die, Forster will hone the neck dimension to your specs for about $10.00 extra. This way you can have a FL die that provides the right amount of tension for your particular load. Forster dies are relatively inexpensive so you can afford to have a couple of FL dies with necks honed to different diameters”
FL Bushing Dies vs. Honed FL Dies
http://www.accurateshooter.com/technical-articles/reloading/fl-bushing-dies-vs-honed-fl-dies/
Meaning honing the neck diameter of the die to match the neck thickness of the cases you are using, and making your case necks last longer. And forget bushing dies, if the bushing reduces the neck diameter in one step over .005 the bushing die can induce neck runout.
