Shoulder bump question....

[MarikinaMan]

I just fired the first 50 rounds off my 6.5CM bolt gun.

Im saving the brass from factory Hornady ammo to reload.

So I'm taking measurements of the once fired brass, and the base to the shoulder is 1.550" using the Hornady headspace measuring tool.

To get a baseline reference, I measured a brand new unfired Hornady case.

Its 1.550".

I'm puzzled. Shouldnt once fired cases be bigger than a sized case?

[ar15barrels]

Are you actually calling guffey with that thread title?

The length can be the same IF your rifle is right at minimum shoulder length and the ammo is right at maximum shoulder length or if the shoulder did not stretch forward during firing.

This is a GOOD thing.
Just make sure that after you size them, you don't reshape the shoulders any shorter than they are now.
Also make sure they don't get any longer during sizing!

[MarikinaMan]

Are you actually calling guffey with that thread title?

The length can be the same IF your rifle is right at minimum shoulder length and the ammo is right at maximum shoulder length or if the shoulder did not stretch forward during firing.

This is a GOOD thing.
Just make sure that after you size them, you don't reshape the shoulders any shorter than they are now.
Also make sure they don't get any longer during sizing!

Cool. Im going to hope that Hornady dies do justice to Hornady brass. I have not heard of checking shoulder length or being concerned about changes in the shoulder shape. My Wylde chambered 223 rifles spits out brass with plump shoulders. New ammo has sharper angled skinny ***** shoulders. I just thought thats how it is. Some much to know.

Thanks for the advice.

[sacrvrrat]

Not a bad thing to have a tight chamber. I am no expert but I think you are going to want bump the whole case back .002 so you have some clearance.


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[dcam49]

Not an expert here either, but isn't that the advantage of a bolt action so as to have the cases form fitted to your chamber?
I have one rifle I reload for and after tumbling I test the fired cases in the chamber and make sure the bolt closes without any extra force over a new unfired round. Then I use the L. E. Wilson case gauge to double check.
If the neck is too long I trim, if all is good I resize the neck and refill.

[divingin]

May also take a couple/few firings for the brass to fully conform to your chamber. On first firing, I usually check the it chambers after sizing, but save full checkout and tweaking for the third or fourth loading and finalize the fine tune/adjustments of everything then.

[ar15barrels]

So I'm taking measurements of the once fired brass, and the base to the shoulder is 1.550" using the Hornady headspace measuring tool.

I have not heard of checking shoulder length or being concerned about changes in the shoulder shape.

The Hornady headspace measuring tool is measuring the length of the datum point on the shoulder to the base of the case.

[BigBronco]

In before Guffey

[SmokeTheClay]

I've had a tough time getting consistent measurements with the Hornady headspace tool out to two thousandths.

What I did do to verify was I used a piece of tape to figure out how much space I was leaving in my chamber. 1 piece of tape (.002) fits. 2 pieces of tape (.004) doesn't fit

This video is great: https://m.youtube.com/watch?v=htvk1UYOXm8

[ar15barrels]

I've had a tough time getting consistent measurements with the Hornady headspace tool out to two thousandths.

What I did do to verify was I used a piece of tape to figure out how much space I was leaving in my chamber. 1 piece of tape (.002) fits. 2 pieces of tape (.004) doesn't fit

This video is great: https://m.youtube.com/watch?v=htvk1UYOXm8

RCBS precision mic does a much better job because it captures the case so there's no way for the case to be crooked while measuring.



They are also calibrated to an actual headspace gauge so you get absolute measurements from them.
If you drop a SAAMI GO gauge into an RCBS precision mic, it should read right on "0".

[sacrvrrat]

Not an expert here either, but isn't that the advantage of a bolt action so as to have the cases form fitted to your chamber?
I have one rifle I reload for and after tumbling I test the fired cases in the chamber and make sure the bolt closes without any extra force over a new unfired round. Then I use the L. E. Wilson case gauge to double check.
If the neck is too long I trim, if all is good I resize the neck and refill.

I think it depends on your intended use. Bench rest probably want as close as possible. Hunting, PRS, F Class where you may have environmental factors you want some clearance.


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[SmokeTheClay]

RCBS precision mic does a much better job because it captures the case so there's no way for the case to be crooked while measuring.



They are also calibrated to an actual headspace gauge so you get absolute measurements from them.
If you drop a SAAMI GO gauge into an RCBS precision mic, it should read right on "0".

Oh man I wish I had seen this before buying the Hornady tool. It always seems to be a little crooked, and when you're talking in .00X inches it really matters.

The Hornady headspace tool is way easier to be off than the ogive tool.

I've set up my current die to shoulder bump somewhere between .002 and .004 so I don't need it for this barrel. When I rebarrel, ill probably buy that RCBS tool or just do the tape thing again to get close if I don't want to spend the $65.

That RCBS tool looks impressive

[ar15barrels]

Oh man I wish I had seen this before buying the Hornady tool. It always seems to be a little crooked, and when you're talking in .00X inches it really matters.

The Hornady headspace tool is way easier to be off than the ogive tool.

I've set up my current die to shoulder bump somewhere between .002 and .004 so I don't need it for this barrel. When I rebarrel, ill probably buy that RCBS tool or just do the tape thing again to get close if I don't want to spend the $65.

That RCBS tool looks impressive

You can also get more accurate measurements than the hornady with a Wilson case checker and a pair of calipers.



There is a strip ground across the face of the gauge that shows the minimum length and the gauge face is the maximum length.
If you are between those two points OR longer, you can measure with calipers.
Since most chambers are longer than minimum length, you want to make your cases fit as snug as possible without binding, that will make your cases stick out the end of a wilson gauge and therefore be easy to measure.

If your cases are too long, you can add a washer to the other end so you don't just measure the case length.

[MarikinaMan]

Since most chambers are longer than minimum length, you want to make your cases fit as snug as possible without binding, that will make your cases stick out the end of a wilson gauge and therefore be easy to measure.

If your cases are too long, you can add a washer to the other end so you don't just measure the case length.

Do you mean to use a caliper to measure the difference between the base of the case and the upper lip of the case gauge?

[FLIGHT762]

If I was buying a bump gauge again, I'd look at the Whidden gauges. $16.00 a pop per size, is reasonable even buying multiple ones for other cartridges.

https://www.whiddengunworks.com/product/shoulder-bump-gauge/

I do have a couple of the RCBS Precision Mics (30/06 & 308). I was able to pick them up at an estate sale for about $15.00 apiece. They are a bit spendy @ $55.00 a pop. They are accurate and are easier to use than the Hornady set. Easy to see the + - from the 0 minimum.