Shoulder bump

[JMayo]

Resize one just a thou put it in chamber see if it scrapes. If it does resize a little more. If it doesn't then you're there.
Not more than 2 or 3 thou, that's unnecessary for the brass.
Mine are 1 & 2 thou.
If you are kinda new You'll get better with the tools as you go.

 

[Spoonbill]

I am pretty overwhelmed at the amount of ways people accomplish this task, but for me and a lot of others, this is the way.

Dont set them back more than .001 after the first firing, preferably not at all.

Set them back .002 after that.

I can’t see giving advice on how far to screw your die in if I don’t have your press in hand . I’ve seen where touching the shell holder wouldn’t move a shoulder and where touching the shell holder would move a shoulder back 10 thousandths. Don’t take any advice along those lines. Screw it down, back it off a turn and go down from there. (I’ve even seen this bump them a little but only once.)

Forster makes a lock ring with .001 marks on it.

measure, measure, measure.

Inconsistent base to shoulder readings aren’t strange on a first firing, especially when one case might have had 35 grains of powder and another had 39. They’ll even out.

This step (bump check) needs to be done at every loading, whether you anneal or not. They’ll change some as they harden, and they’re real easy to bump once you’ve annealed.

Have fun and shoot!

Thank you for the advice. Please keep an eye out for this thread. Im going to try resizing some cases starting with the die backed off the shellholder like you were saying.

 

[Clancy]

Thank you for the advice. Please keep an eye out for this thread. Im going to try resizing some cases starting with the die backed off the shellholder like you were saying.

If I gathered the info correctly, you’ve got them all around 1.617 now, and that’s fine. You didn’t size anything more than .003.
Redding shell holders is another way to do it, and the wheeler way works too.
I was just giving you a way to do it that didn’t require a lot of extras.

You’re correct that case prep can make a good load into a great one. I really baby my brass, and I do everything by hand. I’ve been doing it that way for a while and it shows in my groups and ES. Little things, like when I see people baring down on motorized chamfer and deburr machines (and especially doing the inside first) just make me shake my head. Almost painful to watch haha.

 

[Ccrider]

If you are getting chamber contact at .620 and none at .619, then I would set my die at .618 and roll. Assuming.001 spring back, the cases will end up at .619. If you go with .617, with spring back you should be around .618 which will still be fine. I would go with .618 because the brass has only been fired once and I would want it to fully expand to .620 and then work the shoulders from there. It could take three firings for some of your brass to fully for to your chamber.

I would not move the shoulder below .002 and so I would be looking for a final shoulder length measurement of .618 or .619.

You may find that some of the cases may have to be sized more than once or left in the press for a few seconds longer to push the shoulder back. I will spin those stubborn cases in the holder sometimes.

Also, inconsistent lube will affect the amount of shoulder movement. If I have a shoulder that will not bump as far as it’s brethren, I add just a little more lube to the shoulder to get that extra .0005 or so.

Last keep some q’tips and alcohol on your bench. Handy way to clean out your dies.

 

[Valkyrie]

I think I have finally found the post/thread I have been searching for. I have been reloading for probably 40 - 50 years but only for quality and cost saving for hunting rifles. With that being said I assembled a precision AR in 224 Valkyrie around 2017 or 18 and jumped into the world of precision reloading. I have been absorbing all I could about shoulder bump, neck tension, seating depth, etc., etc. I also performed a OCW charge weight ladder with a new powder that worked out well also. My problem was that I was having a lot of confusion about shoulder bump because my fired cases, when measured to the datum line, have been very inconsistent in length. I had read about cases taking several firings to normalize in a specific chamber so I felt like I might be on the right track but I don't have the luxury of a bolt gun to verify. Just want to say thanks to the many experts in this thread who have helped me understand how to do this correctly. Spoonbill, thanks for asking the question.

 

[Firearmsunlimited]

Remove the firing pin and spring from your bolt. Take all 4 lengths of cases that you discussed. Start with the shortest one. Chamber each case. When you find your "0" head space piece the bolt handle should fall about 1/2 way closed with no resistance. Set your die to bump the shoulder 2 grand. With your .243 Win. bump shoulders about every 5th firing for standard loads.

 

[okie]

WHERE IS GUFFEY WHEN YOU NEED HIM????

 

[nwmnbowhunter]

Only thing I'll add.

Be sure you are using the comparator consistently. If you measure the and piece of brass ten times, you should get the same measurement.

Other tip is when sizing a piece of brass hold the top of your stroke for 4-5 seconds. I found this to make my "bump" variation much tighter.

Good luck and keep asking questions.