Shoulder bump question
- Thread starter Kejr
- Start date
arlaunch
Active member
Not really,
The more one measures, the more problems we all find. You will find with that exact same die setting, in 3 or 4 firings, the work hardening action of the brass will make the brass "spring back" and it may not size it at all. (at that die setting)
Then you crank your die in a tiny bit, then good to go. Then you forget about it, then run a batch of 1X fired brass through and you end up oversizing it.
LOL.
What is your average?
I usually set up a die with the expander ball out.
If you set up for a solid -3 or -3.5, in as little as a couple firings you may be right where you want to be at -2.
Different brands of brass, even with the same amount of firings will size differently.
Everybody is different.. .
I like to fire 3 firings for absolute accuracy, the 4th with less expectations but generally good results, and the 5th is for plinking.
After that they go in the garbage can.
And i get out a new bag.
Long range shooters use fancier brass and sometimes anneal every time.
The more one measures, the more problems we all find. You will find with that exact same die setting, in 3 or 4 firings, the work hardening action of the brass will make the brass "spring back" and it may not size it at all. (at that die setting)
Then you crank your die in a tiny bit, then good to go. Then you forget about it, then run a batch of 1X fired brass through and you end up oversizing it.
LOL.
What is your average?
I usually set up a die with the expander ball out.
If you set up for a solid -3 or -3.5, in as little as a couple firings you may be right where you want to be at -2.
Different brands of brass, even with the same amount of firings will size differently.
Everybody is different.. .
I like to fire 3 firings for absolute accuracy, the 4th with less expectations but generally good results, and the 5th is for plinking.
After that they go in the garbage can.
And i get out a new bag.
Long range shooters use fancier brass and sometimes anneal every time.
spotstalkshoot
Well-known member
To really know how your brass is fitting the chamber you will need to pull the firing pin and spring. Usually once fired brass doesn't need the shoulders move back, since it has not fully expanded to chamber dimensions. Lube the necks and body of the case, not the shoulder. Keep you die clean and if it has a vent,keep it open. I don't use the expander button on fired cases. I use a depriming die, size without the expander. Then use a mandrel for neck tension. I anneal brass. Poorly lubed case necks will "pull" the shoulders "out" when you drop the ram, especially when using the expander. This will give you inconsistent comparator numbers.
What kind of lube are you suing?...For me using Dillon spray lube vs One Shot or Imperial sizing wax has been much more consistent.....that said I still get some shoulder bump variations just not as much, most are within .0005....sorting by shoulder bump long to short or vice versa will ease the transition, so you aren't firing a .0035 bumped piece of brass behind a .002 piece if utmost accuracy is a concern. Plus it's easy to do.
I appreciate all the replies. I did check the bolt function with the bolt stripped. It has a little resistance for about the last third of the bolt rotation bumped .002. I’m using one shot for the lube. The brass is all the same brand, I’ll do some checking on thickness. I’ll sort these and run a few more through and see how they come out.
Don Fischer
New member
I think the worst thing's a new guy can get, or even old guy like me, are to many measuring devices. The onlyone I have is a dial caliper for measuring case length for trimming. For myself everything else is BS. Started trimming years ago with a plastic RCBS gauge to measure case length. Sort of a go no go deal but it worked. Don't remember what happened to it, I probably felt for some reason a dial caliper would d better, it doesn't! For adjusting the case to fit my chamber, I neck size a couple time's after which the case will no longer chamber. Then turn the FL die down a bit at a time till the case chamber's and I can't feel the shoulder rub. Lock it in and never touch it again. Pretty much the same with bullet seating. I measure the OLL with a cleaning rod and a bullet to start then load one to that length After that keep setting it a bit deeper till no land marks show on the barrel. Maybe not precise but simply works! I set the seating dies up for one rifle and bullet only also. I've never measured to the ogive and see no need to do that other than talking points!
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