Home Forums Reloading Big Game Rifles Having to shoulder bump common ???

I have a 243 that had chambering issues. After chamber gauged, and full length resizing, I shoulder bumped and everything works as it should. Is the of any concern and is it common ??

Nope, Everything gets 2 thousands shoulder bump, every reload.

Are you saying you "full length resized" and it wouldn't chamber and then you "shoulder bumped" and it would chamber? IME full length resizing usually includes at least a minimal shoulder bump. For me is 1 or 2 thou for target rifles, 3 or 4 for hunting/tactical rifles.

I thought reloading dies were made so you couldn't really bump the shoulder....because most rifle cartridges head space on the shoulder.

What do you mean LFC? How would you reload cases over and over if the shoulder wasn't pushed back enough to chamber? Just curious what you mean by that.

Yep, that's about where I like them for reliability and function. Im not understanding the ops question, because if you fl size, you are going to bump the shoulder back. Most times in excess of .003". One of the reasons I just pfl size, or set the fl sizing die to pfl size. Most times there's no need to set the die so it comes into contact with the shell holder. As long as the resized brass fits that chamber when done.

+1

BSA, MANY people that reload do not understand that concept, new reloaders in particular, and therefore do not have the FLS die set up correctly for the chamber in THEIR rifle.

It is also possible for a full length die to lengthen the head to shoulder dimension of the brass, even when the die is flush against the shell holder.

Nope

Could be your FL die isn't turned in quite far enough to start. As the die begins to squeeze the body just below the shoulder it can push the shoulder forward a tad, particularly on cases like the 243 with it's 20 deg. angle, then in a properly adjusted die the shoulder portion of the die will push that shoulder back at the very last.

That's just an educated guess but you can check by chambering a fired case; the bolt should lock up with little or no resistance. Then FL size that case with the die adjusted as you normally would, wipe off the lube and try chambering it again. If it's hard to chamber then there's your proof. Screw the die in about a sixteenth turn at a time or even less and keep trying until the bolt just closes easily. Easy does it here, die threads are coarse so even an eighth turn can move the adjustment several thousandths more than you need.

A Hornady or any other brand of headspace gauge can tell you to the thousandth what's going on but the "try it and feel it" works also. Some folks will blacken the shoulder with a marker and adjust the die down slowly until they see it touch the shoulder.

Be careful not to screw the die in too far so you push the shoulder back several thousandths each time. When I was starting out I'd just screw the FL die down tight against the shellholder each time and cases would only last 3-5 firings before getting that telltale ring showing an incipient head separation

I've never seen that latter part but we're definitely thinking along the same lines here - sizing can push shoulders forward before it pushes them back. My usual verbosity let you get in ahead of me.

If the die could bump the shoulder back then it would create excessive head space.

Nope, not unless the die is adjusted incorrectly

Then explain to me how they get away with brand new brass necks being ~10 thou short and the shoulder is at least ~3-5 thou off. Depending on chamber that all gets blown out on first firing.

Okay, I am tracking what you're saying now. What you're saying is exactly correct. That's usually what happens when you follow the die instructions as laid out by RCBS. They say to touch the shellholder and add an 1/8 or 1/4 turn. In many of my rifles, this will create alot of extra headspace, meaning from 10-20 thou or more in some cases of set back. If you gradually turn the die down to nearly touching you can optimally get 2 thou or maybe a bit more less depending on your rifle which in my rifles is right. You get the slightest resistance upon chambering, but not enough that you need to force anything.

That is what is meant by Partial Length Resizing. I gave up neck sizing long ago since I want to make sure my cartridges feed and chamber the same nearly every time and I don't have an "uh oh" moment.

Yes sir, that's why I will usually create a false shoulder when brass has to grow a bunch to fit my chamber on first firing. Minimizing that initial stretch seems to help all the way around.

Yep, it’s common. And with 243’s generally a guy will have to do it a bit more often—and can vary with the brand and lot of brass—than with some other cartridges.

This^^.
It is not uncommon at all.

Because new brass has a lot of stretch in it still. Most of the initial stretch occurs at the web where it thins to the wall of the brass. This is where we see the expansion ring, and where the walls at the expansion ring will be the most thin at any part of the brass.

If we size the brass too much, and bump the shoulders too much, the next firing the brass stretches there again, creating the dreaded incipient head separation, or actually separating.

I neck size, then bump every 3-5 firings, depending on cartridge, brand/lot of brass, and the chamber of the particular rifle.