sizing die question

[jb9]

I've recently had a 6.5x47 built and have been working on adjusting the full length sizing die for a minimal shoulder set back. I've simply used the "resize fired case, clean case, attempt to chamber, adjust the die down slightly, resize, etc" method until I achieve no major resistance when closing the bolt.

I thought I had the die set about right however when shooting today I had 3 of 32 cases chamber with noticibly more resistance than the others. The bullets were seated so they won't contact the lands, brass length trimmed to length, and was the 2nd time loaded.

Is this a matter of just lowering the sizing die a touch lower to accomodate brass variability, is there something wrong with my technique, or should I leave it as is? I've used the same approach for other calibers over the last several years without this issue.

Thanks for your assistance.

 

[ChadTRG42]

Re: sizing die question

Basically, you got it. You might add a comparator gauge or an RCBS precision mic to measure just the shoulder when bumping it back slightly. This way you take the chambering out of the equation, and use the gauge. You can measure how far you are bumping it back. About .002" is a good amount.

 

[Mudcat-NC]

Re: sizing die question

Could be a few things. I notice when I size my 6XC brass for in one of my T2ks I get a few that will be tough and usually they are ones that had a little less sizing wax (I use Imperial Sizing wax rather than spray on lube, etc) than the other. I also use is sparingly, like youre supposed to and only hit about one out of a dozen cases. Just that little less wax can make the difference. As a HP shooter, I cant have a tough bolt in the rapids so I check every one of my rapid fire rounds and usually tend to knock them back at least 3 thous, just to make sure, but I still end up checking them. Need that bolt to be slick as sh*t when I am running it during a rapid string.

And, another thing to watch is your die position. I use a Bonanza press and the ring on my Redding die, even if I tighten it, always seems to work lose. If I dont catch it, I will get the ol sticky bolt eventually.

John

 

[Fuzzball]

Re: sizing die question

"I had 3 of 32 cases chamber with noticibly more resistance than the others."

You are experiencing the varying effects of spring back in the brass, that stuff ain't alloyed as thoroughly as we would like. Seems like you have hard places in some of the shoulders so it springs back a little more than you need. Leave the sizer as it is, load and fire tham again and you will likely have 5 or 6 that are difficult to chamber.

So, turn your sized down a little, a very little; no more than 1/32 of a turn. That will move the shoulders another 2.2 thou and should be enough to make up the difference without over doing it.

 

[bigwheeler]

Re: sizing die question

I find the necks in some brass stretching back out with the expander ball. A
shoulder bump die cures the problem.

 

[Winchester 69]

Re: sizing die question

Shimming the dies is an inexpensive means for making very fine adjustments easily.