The bolt closes, the chamber gets dark, then for most the the light goes out. I check head space at least two different ways without a go, no or beyond head space gage, on some rifles that would be three different ways., for most this is not possible because they are too consumer oriented. I sent a Winchester Model 70 300 Win Mag back to Winchester, long story, we had words, all I wanted was a full length sizer die to fit their chamber OR a chamber that fit my dies, and SAMMY was no where in sight. The chamber was too long, too large in diameter and gouged,, and Winchester said the rifle chamber needed to be polished, or honed, or reamed, then I ask? If the chamber is too long, too large in diameter and gouged how is polishing, honing and or reaming going to remove the ugly from the ugliest chamber I have ever seen...and then I am told that is their policy, and again SAMMY was never mentioned as a standard or reference, and all I wanted was a die to fit their chamber, or a chamber to fit my dies, for the 300 Winchester Mag I have full length sizer dies, a forming/trim die, neck sizer die and a versatile full length sizer die, and they could not understand the difference between my dies and their chamber was time.
The Ackley chamber, there are three different ones, in the perfect world the rifle chamber starts out as an Ackley Improved chamber, next the chamber starts out as a 30/06 chamber and later is chambered to an Ackley chamber, in this configuration not all of the old 30/06 chamber is removed, not a problem unless the shooter/reloader has a set of Ackley full length sizer dies and or thinks the parent case will head space in the Ackley chamber, it will not.
The Ackley Improved neck is longer than the neck of the parent case. meaning when the parent-case is chamber in the perfect Ackley chamber the short neck of the parent case is sized (formed) when chambered, thus resistance to bolt closing, the rest of the shoulder and case body is formed when fired, most have no clue because they do not measure before and after but because time is a factor when fired to form, the case gets shorter, not longer, blow out the case does not mean out the barrel, it means out against the chamber, AND, when this happens the neck is pulled back, part of the shoulder becomes part of the part of the neck and part of the case body becomes part of the shoulder.
Then there is the 30/06? chambered to the Ackley Improved by moving the barrel back, moving the barrel back allows the reamer to remove all of the original chamber, then? if the neck diameter is the same or if the original neck diameter is smaller in diameter, no problem. Unless, someone decides to go from 7mm57 to 280 Remington Ackley Improved, then there are 8mm chambers that will result in necks with two different diameters if research is not done first.
F. Guffey
