OAL question

[beasler]

I'm just getting started reloading. I've read that when firing cases for the first time, loading to a particular rifle's chamber OAL will produce more concentric formed necks. But, my HS Precision 300wsm has a detachable magazine that is .10 off the lands than the rifle's chamber OAL. My accuracy with max mag length is good, but I want to know if I should fire-form my brass at chamber OAL first before loading at the shorter magazine length. I'd rather not get into neck turning now if I can avoid it . . .

Thanks for the help.

 

[Mag 300]

Re: OAL question

I suggest that you fire form the brass to the chamber prior to making any "target loads in that it removes one variable

 

[beasler]

Re: OAL question

Thanks Bill. You confirmed my suspicion.

Should I be concerned with a difference of .10 off the lands for the magazine length? Seems a bit much, but I'd be interested in opinions.

 

[michaeltx]

Re: OAL question

I'm not quite getting your question. Are you saying that seating a bullet closer to the lands will result in more uniform neck wall thickness after firing?

 

[desertHK]

Re: OAL question

Why waste bullets and powder and load it to chamber OAL if you are going to be restricted by the mag length? If you don't care much for single loading then that would be okay. I am just saying...

 

[beasler]

Re: OAL question

Michael - that's what I read, and that it is important the first time new brass is fired. Then the neck will be fire-formed more uniformly. Not sure I buy it though, because doesn't the brass expand to chamber maximum each time it's fired? That would mean I have to load to the lands every time . . . which I'm not going to do because of the mag length, which I think is HK's point.

If doing it on the first firing will help case neck uniformity through the life of the brass, I'd be willing to do it single load to the lands for the first firing. Otherwise, it wouldn't make sense.

So that's my question: will loading single cartridges with bullets seated to the lands help with case neck uniformity for the life of the brass, or would the uniformity be affected later anyway when I back off .10 for subsequent loadings?

Thanks fellas

 

[michaeltx]

Re: OAL question

I've never heard that, and can't seem to make it work in my brain. The neck is fire formed every shot, then we size them back so the case can hold a bullet. Fire-formed brass is regarded as being more accurate than new or FL sized brass, but it's irrelevent for the neck. As far as 'ironing out' uneven neck wall thickness, I dunno, but I'd have to see it, and I REALLY don't buy that seating to the lands would have any effect at all on this.

I wouldn't worry about it, load to mag length. You may, or may not, find additional accuracy by seating closer to the lands, but rounds in the magazine are awfully nice too. Adjusting freebore with a tangent ogive bullet is more of a final tweak than anything else.

 

[FNuser]

Re: OAL question

I've had rifles that shot their best as far back as .1 jump don't sweat the s.s. if thats where your load is gonna be anyway there is plenty of other stuff you can tweak. I think what your refering to is fireforming brass that has been turned as opossed to brass that hasn't been turned being slightly out of concentric. If we are looking at the hole surrounded by the neck you can see how an uneven wall thickness will put the hole out. But I assume you aren't shooting tightneck chambers and our resizing die is from a quality manufacturer. So it will straighten out our "fireformed" case. and our cartridge wont be in a bind as the headspaced case is cammed in finally. Does that make it clear?

 

[beasler]

Re: OAL question

Thanks fellas. Ran tests today in various loads at magazine max length. Will adjust from there. You've alleviated my concerns. That's what I get for listening too closely to a benchrest reloading manual . . . .

 

[Mag 300]

Re: OAL question

HK has the point well noted, if the magazine cannot handle them why do it .
I thought the question was simpley the best measurement for oal and that is using the fired brass from the rifle itself
Bill