OK guys, no need to be contentious.
A bumping practice in common terms was implied by the OP talking about resizing just far enough that 0.001" of excess headspace for the cases was created (i.e., the shoulder set back 0.001" from its as-ejected size). However, even though that is now commonly called "bumping", I don't believe it is the original meaning of the term. I try to remember to call it "setting the shoulder back" as distinct from "bumping", though others disagree.
The reason for the distinction is my aging memory recalls the term "bumping" first showing up among benchrest shooters writing in Precision Shooting Magazine in the 70's or 80's who had got custom sizing dies for their rifles cut from blanks using the same reamer that chambered their rifle. A sizing die like that can move a shoulder back without making the brass narrower than the chamber, retaining a neck-sized-only case body fit with the exception of the 0.001"-0.002" excess headspace from "bumping" of the shoulder. Lot's of references are written to the contrary, though, and they call partially setting the shoulder back in an FL sizing die or in a Redding Body Die "bumping". I still think it originally meant setting the shoulder back without narrowing the body below chamber diameters by doing it in one of those custom chamber reamer-cut dies, but that is often not how the term is used today. That is unfortunate because it means the original type of "bump" resizing is being forgotten by the collective handloading community memory as a possibility to explore.
I have to say that is a little confusing, but I think you don't mean the case is only as long as a piece of paper is thick. I suspect you mean sized until the case leaves excess headspace in the chamber that is 0.001" to 0.003" to 0.004".
Oh yes. This is not recommended practice unless you decide you want to try it to see what happens with a really tight fit. I don't think I've ever seen a newly made commercial case that was longer than a minimum chamber in .308, and even that was only in some uncommon foreign-made 7.62 cartridges. I am only saying that making the cartridge that long is within the rules of the game. The manufacturers actually know they would get complaints if they made cases that long. The reason it is within the rules is that all SAAMI cartridge length and diameter dimensions are the critical values beyond which operation of the weapon system is prevented due to an oversized cartridge. In the case of the chamber, the dimensions given are critical minimums, with criticality having the same definition but in the opposite directions; too small prevents operation.
A bumping practice in common terms was implied by the OP talking about resizing just far enough that 0.001" of excess headspace for the cases was created (i.e., the shoulder set back 0.001" from its as-ejected size). However, even though that is now commonly called "bumping", I don't believe it is the original meaning of the term. I try to remember to call it "setting the shoulder back" as distinct from "bumping", though others disagree.
The reason for the distinction is my aging memory recalls the term "bumping" first showing up among benchrest shooters writing in Precision Shooting Magazine in the 70's or 80's who had got custom sizing dies for their rifles cut from blanks using the same reamer that chambered their rifle. A sizing die like that can move a shoulder back without making the brass narrower than the chamber, retaining a neck-sized-only case body fit with the exception of the 0.001"-0.002" excess headspace from "bumping" of the shoulder. Lot's of references are written to the contrary, though, and they call partially setting the shoulder back in an FL sizing die or in a Redding Body Die "bumping". I still think it originally meant setting the shoulder back without narrowing the body below chamber diameters by doing it in one of those custom chamber reamer-cut dies, but that is often not how the term is used today. That is unfortunate because it means the original type of "bump" resizing is being forgotten by the collective handloading community memory as a possibility to explore.
cw308 said:
I have to say that is a little confusing, but I think you don't mean the case is only as long as a piece of paper is thick. I suspect you mean sized until the case leaves excess headspace in the chamber that is 0.001" to 0.003" to 0.004".
tangolima said:
Oh yes. This is not recommended practice unless you decide you want to try it to see what happens with a really tight fit. I don't think I've ever seen a newly made commercial case that was longer than a minimum chamber in .308, and even that was only in some uncommon foreign-made 7.62 cartridges. I am only saying that making the cartridge that long is within the rules of the game. The manufacturers actually know they would get complaints if they made cases that long. The reason it is within the rules is that all SAAMI cartridge length and diameter dimensions are the critical values beyond which operation of the weapon system is prevented due to an oversized cartridge. In the case of the chamber, the dimensions given are critical minimums, with criticality having the same definition but in the opposite directions; too small prevents operation.
he went back and started over, he found he could get the same accuracy with rejected cases if he indexed them. No one on this forum read the article; with one exception.