Shoulder Bump question from a new reloader

[Jason277]

Hello all, I read through a couple of related threads and I think I see my issue but looking to clarify, So I have only reloaded new brass as Im very new to hand loading. Im shooting a 6.5cm. I have 150 pieces of Once fired brass, some Peterson and Hornady . I have tumbled and deprimed my brass and now started to check my head space with a comparator . I noticed Im getting a range of numbers with in .002. Is this because the brass has only been fired once? Or becuase I was trying different powder charges? If so Im guessing I dont want to " shoulder bump" . Sorry Im a little confused on the resizing step. Thank you in advance Jason

 

[ColPenguin]

What are you comparing them to that they are within 2 thousandths, each other? You don't need to compare the pieces to each other. Compare measurements of the same piece before sizing and after sizing.

Do the resized cases chamber easy enough that you don't have to force the bolt? It either fits easily in your chamber, or it doesn't. The cases are probably not fully formed to the max dimension after the first firing. As long as you're not dramatically overworking the brass then you might be overthinking this.

If the case doesn't quite fit, or the brass is getting longer, then screw the die down a hair more and size another piece again until cases fit your chamber.

 

[Axlrod]

Without knowing how your brass fits in your particular chamber, you can't determine how much to bump your shoulder, if at all. A lot of people will say to bump .002. Saying that is like cutting a board, without measuring the spot you want to put the board.
If you are comfortable with stripping your bolt- removing the firing pin and ejector. There is a simple way to adjust your dies.

If not, the best method for a hunting gun, is to set your size die for camover, following your die directions. And full length resize all cases.

 

[MTSLW]

It's not unusual to have brass measure a thou or two different, especially after the first firing.

What matters when shoulder bumping is that you can close your bolt without feeling an increase in resistance. Should be no difference between a loaded round and sized brass.

Try the short and long fired cases in your rifle and see if the bolt feels tight when you close it, then bump the shoulder back accordingly. Generally you want to size the shoulder back on fired brass that feels tight .002-.003". You shouldn't have any issues unless you are bumping more than .005" back.

If you want to see if the die is contacting the shoulder, use a lighter to smoke it and then slowly screw the die in. You will probably see the shoulder actually get longer as you size it down and before it contacts the shoulder.

Good luck with the journey!

 

[hunterjrg]

You will see some discrepancy between shoulder measurements on fired rounds like that at first. Get an average and adjust die to bump shoulder back .002 thousandths. If you can strip your bolt - do that also checking for a smooth bolt closing. Eric Cortina has a great YouTube video demonstrating this.
I would not adjust my die for cam over. You might see that won’t be enough.
Good luck and enjoy

 

[mtnbound]

Hello all, I read through a couple of related threads and I think I see my issue but looking to clarify, So I have only reloaded new brass as Im very new to hand loading. Im shooting a 6.5cm. I have 150 pieces of Once fired brass, some Peterson and Hornady . I have tumbled and deprimed my brass and now started to check my head space with a comparator . I noticed Im getting a range of numbers with in .002. Is this because the brass has only been fired once? Or becuase I was trying different powder charges? If so Im guessing I dont want to " shoulder bump" . Sorry Im a little confused on the resizing step. Thank you in advance Jason

Do yourself a favor and don't worry about those numbers. Set your full-length sizing die per the manufacturer's spec, resize the brass, prime it, load it, and shoot it.

 

[JGRaider]

If your brass chambers easily, don't resize anything until it doesn't.

 

[Ramem7mm]

There is a youtube video from Erik Cortina that may provide some visual aid on what the process is.
LINK -

Also suggestion is to only use one brand of brass that was fired from your rifle. Dont start with brass from someone else or different lots. Get enough components ie powder, primers, bullets to test what you want to try and have enough left over to shoot for awhile. This method prevents lots of wasted time later on. Look into annealing as well and if you plan on doing this for awhile and reloading the same brass then you might want to invest in one.

 

[streamerfish]

Also suggestion is to only use one brand of brass that was fired from your rifle.

This is pretty important. Don't mix your Hornady and Peterson brass. Each brand of brass needs its own "recipe". Pick one brand and just load with it, keep it simple.

The above video pretty well explains setting up a die for trying to optimize shoulder bump so to speak.

I would also say that the whole two thousand should bump is all about trying to maximize brass life. That 4.5 thousandths bump he had on his original die setup would have worked absolutely fine.

The whole general idea is to resize enough to function properly, but to not resize too much, as that reduces brass life.

This can be one of those getting lost in the weeds types of conversations. I would setup to factory recommendations first and do some reloading. As long as your resizing your brass, and they fit and function properly in your rifle, your good to go. Make sure you get all of that squared away first, then tinker with things later.

And again, don't mix brass.