To much shoulder bump?

cmor_15 · Nov 10, 2023

Wondering how much is to much shoulder bump? Starting with fired brass and didn't have die set properly and some brass has .005 bump. I know i should only be bumping .002. My question is how much bump would be to much and cause case head separation or damage ? Cases are winchester brand in 243 win.

My thoughts are a .005 bump should be ok and anymore could cause issues but I want some advice from someone with more experience.

cajun · Nov 10, 2023

It should be fine.

anotherreloader123 · Nov 10, 2023

cmor_15 said:
Wondering how much is to much shoulder bump? Starting with fired brass and didn't have die set properly and some brass has .005 bump. I know i should only be bumping .002. My question is how much bump would be to much and cause case head separation or damage ? Cases are winchester brand in 243 win.

My thoughts are a .005 bump should be ok and anymore could cause issues but I want some advice from someone with more experience.

A .005 bump is no problem. Factory ammo often has a lot more than that depending on the gun.
I know a guy that bumped a 7stw .020 for multiple firings and the brass was still just fine.

cmor_15 · Nov 10, 2023

Thanks! How much would be to much?

anotherreloader123 · Nov 10, 2023

cmor_15 said:
Thanks! How much would be to much?

I would be hesitant to shoot anything over .030 but even .05 would probably would be fine. Definitely wouldn't continue to bump it that much though.

cajun · Nov 10, 2023

cmor_15 said:
Thanks! How much would be to much?

I had a lee die in a belted mag that was bumping .014. Brass lasted 3 firings. This was when I figured out I should be measuring and not sizing blind lol.

QuietTexan · Nov 10, 2023

There's no way to say whether it's too much or not until you let it grow to where it doesn't rechamber without pressure.

If you're resizing 0.005" on once-fired brass then yes that could be entirely too much. ANY resizing on once-fired brass could be too much. I usually set FL dies to resize 1/2-3/4 of the neck only until the case doesn't rechamber easily, then move downwards from there.

243winxb · Nov 10, 2023

223/5.56 .014" to much. Shell plate defect found.
I would worry starting @ .010" 1 firing maybe ok. More, not good.

cmor_15 · Nov 10, 2023

243winxb said:
223/5.56 .014" to much. Shell plate defect found.
I would worry starting @ .010" 1 firing maybe ok. More, not good.

I agree. I don't even think factory offerings have as much as .01. I could be wrong tho. I want as little bit of case expansion as possible but still have reliable easy feeding.

PddPdd · Nov 10, 2023

I would anneal brass that's been bumped too far to allow the brass in the neck to deform easily to increase the headspace instead of stretching the case head portion of the brass.

MagnumManiac · Nov 11, 2023

A ONE TIME firing at .005" is acceptable, doing this regularly will separate a case in 3 firings easily.
Too much headspace is ANYTHING beyond .002" for good case life…

Cheers.

richhymas · Nov 11, 2023

cmor_15 said:
Wondering how much is to much shoulder bump? Starting with fired brass and didn't have die set properly and some brass has .005 bump. I know i should only be bumping .002. My question is how much bump would be to much and cause case head separation or damage ? Cases are winchester brand in 243 win.

My thoughts are a .005 bump should be ok and anymore could cause issues but I want some advice from someone with more experience.

New brass and factory brass have significantly more than .005 headspace. Try measuring your new brsss or factory brass before and after firing. I agree that it is a case life thing.

KNOTFERSAIL · Nov 11, 2023

Most all my rifles will chamber with .002 bump except one, she needs .004

3 firings on the brass and so .003 bump is snug but .004 Is money. I also do the paper clip trick for head separation before each load. No sign of it yet.

nksmfamjp · Nov 11, 2023

cajun said:
It should be fine.

Here is your answer.

i wonder how people get CBTD shorter than 0.01??

To much shoulder bump?

cmor_15

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