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.

I would also add that a headspace gauge is a very useful tool.

Whether you're bumping zero or .002, you need to have your FL die set low enough so that it doesn't squeeze the sides of the case and move the shoulder forward...which will cause the aforementioned chambering issue.

Thanks for the info. I brought shell holder up to touch die. Then gave the die a 1/3 twist down, ran case through, it chambered. Then turn dieback about half of last adjustment. Chambered great. Loaded some rounds this way and took rifle outside and chamber rounds, perfect ! I am leaving alone, locked down die.

I find that the chamber of the rifle I'm sizing for is even more useful . . .

Perfect!

Yes, the sized brass still has to fit in the chamber, a headspace gauge lets me know where I'm at for future reference. Also, I've never had brass NOT chamber when the shoulder is bumped 2-3 thou, it saves on brass, and the brass fits the chamber better promoting accuracy, if it's only sized a little bit.

That's true. Once in a while you come across one wildly out of spec. I have a 222 that has a very tight chamber. Not sure how they got it out of the factory, but it is an excercise in wrist strength closing the bolt on factory rounds with it. I imagine that's why it barely looked used when I bought it for a song a couple years ago.

I don't have my notes on hand for the measurement, but shoulder setback is several thousandths short of a dimensional sketch. New cases come up a tad short for trim until they've been fired a couple times, since I'm loading it pretty mild.

*added*

A chamber cast can be very useful too, when you have some weirdness going on. I've got a 303 Savage that has good headspace and is accurate, but has the mostly grossly overdiameter chamber I've ever seen from the shoulder forward to the mouth. A chamber and throat cast explained why it is great with jackets and monos, but won't do much other than keyhole and lead the bore with cast bullets.

Good post and explanation. However, I don't think it will push the shoulder back that much. Maybe .010" in extreme cases. If it did, RCBS and other places would be fighting lawsuits for blowing peoples guns up. I've had some chambers, like on a couple 300WSM's, where I've had to set the die right down on the shell holder and turn it in a little more to get the proverbial "cam over", we always hear about. Otherwise I'd have ammo that did not fit in the chamber. Most chambers are pretty close and should be within SAAMI spec. If they were out or too big, that creates problems (excessive headspace) that could also be detrimental. I'm with you on partial full length sizing (PFL) too. You get exceptional accuracy (as you've shown in many of your posts) and your brass lasts longer than if you were to full length size your brass. No need to neck size anything, unless you are full on shooting competitively and expecting 10 shot groups in the .3's. Something I don't think a lot of guys really get.

Not nearly, he should fine tune his die setting so there is very minimal resistance when he chambers the round in his rifle. Then he will know he is perfect. Its real easy to adjust the die for that. Leave the die set further out, run the brass through the die, check to that chamber. If it does not chamber, run the die down just a bit further. This is what beretzs and I were talking about earlier about PFL sizing your brass. You wouldn't need those neck dies, if you learned this technique..

As long as the case was shot in the gun I just use a neck sizing die. I been doing this for years on numerous guns and have never experienced any chambering issues.

As far as thinking you're just neck sizing with a standard die it's not possible...by backing a full lenght sizing die out what you end up with is a partially sized case with a partially sized neck..

These days the serious competition guys are full length sizing.

I’m just a hunter who likes accurate rifles. My standards are certainly not what a serious competition guy would want. I’ve grown fond of Lee collet dies, occasionally using a Redding body die when warranted by chambering being a bit harder than usual. Almost never need the body die.

That's why I mentioned a headspace gauge. Also springback varies enough that for me I bump the shoulder back so all the shells chamber. Some will have a bit of resistance, others won't, but I know how much they are actually bumped with the gauge.

I used to exclusively PFLR my hunting ammo. Then I started using Redding Nk and Redding body dies. Now I mostly use LCD's and the body dies. I can sand the mandrels to get enough tension to hold the bullet in the case while in the mag, but "tune" the Nk tension. Sometimes changing Nk tension helps, sometimes it makes no diff with hunting rounds. Plus there is no lubing with the LCD's and it's easy and quick to size brass. The LCD's really are the easy button.