Hi guys, I’m new to reloading rifles cartridges, but Iv been loading straight wall pistol cartridges for a long time. Iv got a Remington 700 vls barreled action in .223. I’m reloading on a Dillon 550b, with a Redding full length type s sizing die, and Redding micrometer seating die. Iv been reading a lot, and it’s come up often to bump the shoulder of the case back .0015-.002” for a bolt gun if it’s tight to chamber. So my question is, what if it’s not tight to chamber? Just keep shooting the brass until it gets tight, and then set up my die for .002 from that and let everything else grow to that and trim it for length along the way?
-
Having trouble using the site?
Contact support
Shoulder bump if not tight?
- Thread starter 03machstock
- Start date
If it’s not tight it might not be completely Fireformed to your chamber yet. I don’t set up for shoulder set back until the third firing. Usually by then I can feel a little resistance from the bolt lugs caming over.
Ok, that’s what I was kind of thinking in my head, but I’m new to this so didn’t want to assume that. Thanks!
Pull the firing pin spring out of the bolt, tap out the cross pin and ejector plunger/spring leaving the bare bolt with just the extractor.
Test chamber your pieces of fired brass (clip it under the extractor first) to feel what resistance if any you get, checking shoulder dimension as you go. You can do the same thing when sizing. Goal is to find that exact amount of sizing where the bolt handle drops freely without any resistance, but that is only maybe 0.001 past the point where you can feel resistance between brass and chamber.
You'll be able to feel the chamber/resistance much more clearly without the firing pin spring and ejector springs involved. 223 is a bit trickier compared to larger cases with steeper shoulder angles. You can darn near size 223 brass with the bolt when closing, so waiting until it gets "hard" to close the bolt is quite a bit beyond where I would shoot for sized brass. My goal is to size just barely enough to get that zero resistance bolt handle drops freely amount of shoulder bump.
Test chamber your pieces of fired brass (clip it under the extractor first) to feel what resistance if any you get, checking shoulder dimension as you go. You can do the same thing when sizing. Goal is to find that exact amount of sizing where the bolt handle drops freely without any resistance, but that is only maybe 0.001 past the point where you can feel resistance between brass and chamber.
You'll be able to feel the chamber/resistance much more clearly without the firing pin spring and ejector springs involved. 223 is a bit trickier compared to larger cases with steeper shoulder angles. You can darn near size 223 brass with the bolt when closing, so waiting until it gets "hard" to close the bolt is quite a bit beyond where I would shoot for sized brass. My goal is to size just barely enough to get that zero resistance bolt handle drops freely amount of shoulder bump.
But none of that is necessary for accuracy or case life. Just take the longest case and bump the shoulder .002” and go on with your life.
Some practical considerations:
If you don’t have a neck sizing die, you’ll need to use the sizer you have to get the necks sized so you can reload.
The difference between .001 and .004 of “shoulder bump” is negligible from either a safety or an accuracy standpoint, if it is consistent, unless you are shooting .2” groups and looking for every edge in order to win.
In field conditions, having a case that’s exactly the same as the chamber (.001 shoulder bump) will cause you problems, eventually, if/when things get dirty.
Sizing is one of the more finicky steps in reloading. Even the most consistent and deliberate sizing process can leave .001” difference from case to case. How you lube and with what, annealing, how you operate your press, dwell time in the die, brass brand, lot number, and number of firings, method of tumbling, time in tumbling process…all of these things will effect the outcome of the resizing process.
So what’s a fellow to do? If you have a neck sizer, cool. Size the necks and keep reloading until it’s obvious that the bolt is tight to close then remove your firing pin and ejector and full length size looking for free-drop of the bolt handle, as previously suggested.
Or, if you don’t have a neck sizer, measure a handful of the fired brass and come up with a “largest common size”. Use that number, minus .002 or .003 to set up your die. Even with only one firing on the brass, “fired size” will be awfully close to a size that will cause resistance on bolt closing. This will get you close enough to run, definitely better than factory and probably better than you can shoot the difference between, until you find yourself chasing the perfect cartridge in either Benchrest or F-Class disciplines.
If you don’t have a neck sizing die, you’ll need to use the sizer you have to get the necks sized so you can reload.
The difference between .001 and .004 of “shoulder bump” is negligible from either a safety or an accuracy standpoint, if it is consistent, unless you are shooting .2” groups and looking for every edge in order to win.
In field conditions, having a case that’s exactly the same as the chamber (.001 shoulder bump) will cause you problems, eventually, if/when things get dirty.
Sizing is one of the more finicky steps in reloading. Even the most consistent and deliberate sizing process can leave .001” difference from case to case. How you lube and with what, annealing, how you operate your press, dwell time in the die, brass brand, lot number, and number of firings, method of tumbling, time in tumbling process…all of these things will effect the outcome of the resizing process.
So what’s a fellow to do? If you have a neck sizer, cool. Size the necks and keep reloading until it’s obvious that the bolt is tight to close then remove your firing pin and ejector and full length size looking for free-drop of the bolt handle, as previously suggested.
Or, if you don’t have a neck sizer, measure a handful of the fired brass and come up with a “largest common size”. Use that number, minus .002 or .003 to set up your die. Even with only one firing on the brass, “fired size” will be awfully close to a size that will cause resistance on bolt closing. This will get you close enough to run, definitely better than factory and probably better than you can shoot the difference between, until you find yourself chasing the perfect cartridge in either Benchrest or F-Class disciplines.
Similar threads
