Home Forums Reloading Big Game Rifles Setting your full length die to bump the shoulder.

There are many ways to set a full-length die. All of them are wrong.

It’s incredibly easy to do, nothing is left to speculation or “feel”. I recommend you guys take the time to watch that video I posted.

Laughin' here.....................

MM

marking this thread

I started using the Stony Point/Hornady case gauge 25+ years ago, wouldn't be without it. I have calipers dedicated to my Stony Point case gauge and comparator bodies, and they have been attached to the calipers for going on a couple decades now.

That's the problem with all these fancy tools--a guy finds out just how much things vary, and then drive yourself nuts trying the minimize that variation.........sheesh.

See what I mean?!!!

I often feel that when a person reaches a point where repeatability is nigh onto impossible, he's gone beyond a reasonable point.

Zediker makes a point multiple times in his books: it's up to the individual to decide whether a process is worth the extra effort.

Which means said individual has to know what he's trying to accomplish. Eg. more consistently knocking out "1s and 2s". Or shooting deer and moose out to 200 yds. Or trying to maximize case life. Or not caring. Eieio......

I use the Hornady comparator on my Mitutoyu caliper to measure the bump, and I use the multi-thickness Redding “Competition” Shellholder Set to control the bump. I like that combination because it’s very easy and repeatable.

If you're turning your die in 1/4 or 1/8 turn at a time to achieve easy chambering, you are no doubt pushing your shoulder back a lot more than necessary---unless you happen to luck out with the way your chamber is reamed, the way your sizing die is reamed, and the way your shell holder was machined.

If / when I use a FL die, I adjust it to bump the shoulder back so that I like the way bolt closure feels---slightly firm, but no more than that. I do this using measurements as I go so that I can keep track of the increments of shoulder bump as I am changing the adjustment.

If you do the arithmetic, turning the die body into the press six degrees should bump the shoulder an additional 0.0012" and that is the equivalent of the movement of the second hand of a clock in one second. Mathman has some objection to this concept...I don't recall exactly, but maybe it was press flex or something along those lines. Maybe he'll be so kind as to pipe up and remind us (ME). The concept is still valid, though. To "get it right" by turning your die an additional eighth of a turn is highly unlikely to land you right in the sweet spot.

The brass has spring to it. So when you start it moving it won't necessarily linearly follow the amount the die is turned into the press.

Yes, it's probably a little unpredictable in that way but it still should be a fairly close approximation...but the point is that screwing the die in *just a little bit more* can push the shoulder back much further than what you intend.

I would imagine that annealing reduces the "spring back" effect just as it affects bullet pull (I dislike the term "neck tension").

That can happen even if you're turning the die in by very small amounts. Suppose the little increments you've been using have been working against elastic deformation and then the next increment added on goes into the plastic region. Boing! How did I move the shoulder that much?

Checking fired brass I'll see 1-2 thou variation. Same lot, fired in same chamber. After sizing still about same amount variation.

And that first piece of brass used to incrementally move the die, having been worked a few times, will usually be shorter than the next piece sized at that same setting.

Tedious, but it's about brass life not safety. When I'm trying to keep bump to a minimum will check every piece in the chamber.

That's why I anneal my brass before setting the few FL dies I am using, or my body dies. I measure as I adjust, using a fresh case for each adjustment. Once I find that sweet spot I lock the ring and leave it there.

This is what I do, and love those Redding competition shell holders.

Once you find out which shell holder to use for your load, which only bumps the shoulder between 1 and 2 thousands, you just set up the press normally then on all future loads for that set of dies and that caliber... you are always "bang-on", and don't have to fiddle with resetting the die and testing/measuring incrementally as you lower it more and more.

Saves beaucoup time and is repeatable.

Did you mean .0012, or did you mean .012?

0.0012"