shoulder bumping angle change

[rockwind1]

as the shoulder stretches when it is fired in the chamber, does everything stretch so that the angle stays the same, (in other words, if you superimposed unfired brass over fire brass, would the shoulders be parallel? i am just trying to get a conceptual understanding of what happens when you bump a shoulder. i guess my real question is once you trim all your new brass so that it is the same size, then you fire it, when you bump the shoulder back, does it go back to being the length?

i am trying to figure out how the head space comparetors work, how do i know it winds up on the perfect datum on the shoulder.

back story. i have 100 new hornady 6.5 saum gap 4s brass, and 120 once fire hornady gap 4s. i wanted to work up a new load with the 100 new brass but i was going to trim it first. i want to then start combining the two sets of once fired brass but obviously want them to be uniform, should i wait until i fire the new brass before trimming it so i can match it up to the once fired brass. thanks for any help.

maybe i am over thinking this, how do i make these uniform. both sets are gen 2 brass but i don't know what the first set was trimmed at when new.

 

[Richard Coody]

wouldn't trim until the cases are fully fireformed. even then when i trim i never trim all the way back to trim length. i use half way between max and trim length. consistent length is more important than actual length. don't trim till you have to.

i also would not set my die up to bump shoulders until fully fireformed. usually about 3 firings. just set the die to size the neck and not bump the shoulder. to check if they need the shoulder bumped size a fired case and if it chambers easily no need to bump shoulder. if it chambers with resistance then you can set the die up for your shoulder bump. measure fired brass with the comparator and set the die for a .001 to .002 bump. easy to overdo it. just a slight turn of the die makes a huge difference. .001 of an inch is mighty small.

yes the shoulder of your brass should be very consistent for your new brass, fired brass and sized brass. the hornady headspace gauges work very well.

and actually the shoulder doesn't stretch when fired. Just remember we are talking about 1 or 2 thousands of an inch here. a little piece of the shoulder becomes case body and a little piece of the neck becomes shoulder. When you size and bump the shoulder a little piece of case body becomes shoulder and a little piece of shoulder becomes neck. this process is why your neck grows and needs trimming. it is also part of what causes donuts as the thicker shoulder brass migrates into the neck. Some cartridges need trimming often. some never require trimming. Shoulder angle is a big part of that.

 

[mikeeg02]

I can't add anything useful to that post. So in the words of Taggart from the movie blazing saddles.

Ditto

 

[243winxb]

i want to then start combining the two sets of once fired brass

Is the brass from the same lot? If not, i would not combine.

 

[rockwind1]

Good morning Sir'
I for one would not mix the brass it is important to me to count the times they are loaded, excess trimming is something I try to avoid as well constant FL sizing that causes to much stress. IMO just ensure your cases are say .005 under max and your fine.

hi jim, i possibly left out some info. the already fireformed brass was use one time, my plan was to shoot the 100 of new brass so it also becomes once fired, then i have about 220 brass that i would assume is the same (other than having been shot with different bullets) does that make sense? it seems a waste to just abandon 120 once fire pieces of brass that have been fired from the same gun i am using a load for?

as far as being from the same lot, i am going to confirm. it is the second generation hornady 6.5 gaps 4s brass that george gardner asked hornady to make, i was making an assumption they made a large amount at one time. when a place like hornady makes a run of brass, do they do it in different lots?

should new brass from the same lot and fireformed brass from same lot weigh the same?

 

[fguffey]

i am just trying to get a conceptual understanding of what happens when you bump a shoulder

Good luck with that because it is impossible to bump the shoulder back with a die that has full case body support. And then no one on this form understands the shoulder does not move and there is another word that should be used instead of 'stretch'.

F. Guffey

 

[fguffey]

Is the brass from the same lot? If not, i would not combine.

What difference would it make if it is impossible to move the shoulder back; If you can move the shoulder back and you have figured a way, explain.

F. Guffey

 

[dkhunt14]

Goof luck with that because it is impossible to bump the shoulder back with a die that has full case body support. And then no one on this form understands the shoulder does not move and there is another word that should be used instead of 'stretch'.

F. Guffey

Mr Guffey, you should of wrote the reloading books for the companies. Seeing they are all wrong and say you can. Matt

 

[Richard Coody]

hi jim, i possibly left out some info. the already fireformed brass was use one time, my plan was to shoot the 100 of new brass so it also becomes once fired, then i have about 220 brass that i would assume is the same (other than having been shot with different bullets) does that make sense? it seems a waste to just abandon 120 once fire pieces of brass that have been fired from the same gun i am using a load for?

as far as being from the same lot, i am going to confirm. it is the second generation hornady 6.5 gaps 4s brass that george gardner asked hornady to make, i was making an assumption they made a large amount at one time. when a place like hornady makes a run of brass, do they do it in different lots?

should new brass from the same lot and fireformed brass from same lot weigh the same?

brass in the same lot won't all weigh the same. let your target tell you what is working. only change one thing at a time.

don't listen to guffey. the man is confused.

 

[Richard Coody]

Lastly 220 cases at a time is a lot of prep work for a lazy dumbass like me. Am I thinking wrong?

with a SAUM i believe 100 cases would last me a lifetime. in fact when i get a new rifle i get 100 pieces of lapua brass and that usually does it for me.

 

[6MMsteve]

What difference would it make if it is impossible to move the shoulder back; If you can move the shoulder back and you have figured a way, explain.

F. Guffey

 

[6MMsteve]

What difference would it make if it is impossible to move the shoulder back; If you can move the shoulder back and you have figured a way, explain.

F. Guffey

 

[ireload2]

Tens of thousands of do just exactly that every day. I don't understand your persistence telling this fib. Goof luck yourself.

Goof luck with that because it is impossible to bump the shoulder back with a die that has full case body support. And then no one on this form understands the shoulder does not move and there is another word that should be used instead of 'stretch'.

F. Guffey

 

[Intheshop]

Golf has a Mulligan,handloader's have a Guffy.Which is much more complex,it's when things "are" & "aren't",at the same time,or......