Shoulder bump

[mongo chicago]

Once you have the die set to where you get the shoulder bump that you want, do you recheck it every time you size the same fired cases, or once it is set - that's it?

 

[Clancy]

Every sizing cycle. Brass that’s been fired a few times may need the die screwed in more. Brass that’s freshly annealed may need it backed out.

Forster lock rings with the .001 hash marks are EXCELLENT.

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[Straightshooter1]

Once you have the die set to where you get the shoulder bump that you want, do you recheck it every time you size the same fired cases, or once it is set - that's it?

If one doesn't anneal their cases, the shoulder and neck work harden more each time they're sized. Varying springback due to that, you're not going to get the shoulder bump you want after a couple sizings. That can be mitigated some by having plenty of dwell time, but that only works for a short time.

I anneal after every firing to keep that work hardening under control where I do get the bump I want every time, even after 16 firings. But, I do some spot checking just to be sure at every sizing session. I find I can get burnt when I take things for granted.

 

[J_idaho]

Every sizing cycle. Brass that’s been fired a few times may need the die screwed in more. Brass that’s freshly annealed may need it backed out.

Forster lock rings with the .001 hash marks are EXCELLENT.

Those look fun I can’t believe I’ve never seen those before. I know there’s some benchrest dies that have clicks for loading on the line when they can’t anneal. But for 10 bucks this would be nicer than using a sharpie. Good find thanks.

 

[Clancy]

Those look fun I can’t believe I’ve never seen those before. I know there’s some benchrest dies that have clicks for loading on the line when they can’t anneal. But for 10 bucks this would be nicer than using a sharpie. Good find thanks.

I love them. A little sharpie mark on the die body for “zero” and the marks are true .001 increments.

I’ve also noticed that the lettering on most dies is worth about .001 per character…. If you have a die you don’t want to upgrade.

 

[6.5 forever]

I use Whidden dies. The sizer has the click ring on it. I check the shoulder every sizing.

 

[D-4297]

Since I'm a old man with severe OCD issues , I check it every time . My goal is .001 Bump , and it is what I expect . I do anneal after every firing and I'm pushing forty reloads on the Lapua .308 SRP Brass .
I check 100% , as I am sizing , and make any adjustments , if necessary . Yeah ; I know there's no such thing as "perfect" but I'll push it to the limit .

 

[swd]

If one doesn't anneal their cases, the shoulder and neck work harden more each time they're sized. Varying springback due to that, you're not going to get the shoulder bump you want after a couple sizings. That can be mitigated some by having plenty of dwell time, but that only works for a short time.

I anneal after every firing to keep that work hardening under control where I do get the bump I want every time, even after 16 firings. But, I do some spot checking just to be sure at every sizing session. I find I can get burnt when I take things for granted.

This ^^^^ Shoulder bump and neck tension stay very consistent if you anneal every time.

 

[SKWERLZ]

Yes
A quick check of a few cases per 50 never hurt.

 

[Coyotefurharvester]

I have my 223 rem rcbs sizing die ring locked. It sizes for several AR's and bolt guns. If a range case DOESN'T drop fit a Lyman ammo checker after sizing, I scrap the case. I keep the shell holder with the die, too much variation in SH.

 

[K22]

I check a sample from each batch every time I size a batch of cases. Usually five cases. I measure the fired case then the sized case to verify I am getting the optimum size. It only takes a few minutes* but for me, it is worth it.

This is the one reloading step I am very particular (anal ) about since optimum sizing can affect not only accuracy but functionality.

*My single piece caliber group specific bump gauge is permanently mounted on a dedicated caliper. This gives me very reliable and repeatable measurements since I am not disassembling and re-assembling. The single piece gauge (Whidden) has no inserts.

 

[precision1]

Yes and no
You got to fire brass enough to fire form.
You start bumping shoulders on once fired brass your gonna over size and Chase your tail trying to make all the same

Also in reloading you gotta deal with sample size and use common sense some.everything isn't going to size or seat the exact same gotta use 3-5 as a sample size .

Even annealing and seating off ogive it's never perfect.

But yeah you should always double check everything you do.

 

[Wild Bill IV]

It depends on what type of shooting sport you are into!!!!!!!
I'm a cold barrel shooter!!! I do once and done high pressure fire forming!!! I bump back right at full chamber length or -0.0005" (just enough for slight compression of the case in the chamber with slight heavy bolt drop very near full bolt lock)!!!

I have found out that lubricity is the key to bumping back this tiny bit!!! A thin film lube is essential!!! Lanolin base lubes (animal fats used mainly for skin hydration) don't provide for a thin film!!! The high pressure oil lubes (derived from crude oil) provides that thin film!!! Those tiny molecules (from long term heat and pressure) act like tiny ball bearing!!!! I've also noticed that lube pastes, waxes, and sprays require a little more force on the press handle!!

At my bench, I periodically check (1 out of 10-15 FL sized cases) the bump compared to a set aside full fire formed case (black brass patina)!!! Plus, I periodically check the cases in the rifle itself!!!

 

[JFrank]

Maybe I’m just getting too old but I can’t seem to understand the obsession with setting back a shoulder at such razor thin margins. Has anyone discovered some benefit on paper at any distance ?
I have only seen problems with fired brass cycling freely.

Jim

 

[GetReal]

I check bump every sizing session.

 

[Wild Bill IV]

Maybe I’m just getting too old but I can’t seem to understand the obsession with setting back a shoulder at such razor thin margins. Has anyone discovered some benefit on paper at any distance ?
I have only seen problems with fired brass cycling freely.

Jim

Jim:
I don't worry about cycling rounds!!! One in the chamber and done!!! What I've experienced, with having slight compression of the case in the chamber, I get great bullet alignment with 0.002-0.003 off the lands!!! The proven theory, from long ago, it is a neck size only (minimal body and shoulder squeeze) using FL die concept or a hybrid resizing of the case, maintaining the full chamber length of the fired case! My 25-06 shoots great at 600 with the smaller radius contour secant ogive Sierra 117SBT GameKings, which gain in BC as the velocity decreases!! Good enough for that 3" heart on a deer or rolling Wiley ONE SHOT KILLS!! This old girl hasn't let me down once, in 40 years!!!! Plus, A carry over from those old days, I neck ream 0.0015-0.0020" larger than bullet diameter on the fired, not formed, necks!!!

 

[6.5 forever]

Maybe I’m just getting too old but I can’t seem to understand the obsession with setting back a shoulder at such razor thin margins. Has anyone discovered some benefit on paper at any distance ?
I have only seen problems with fired brass cycling freely.

Jim

I believe the reason for the thin margin is to help brass longevity.

 

[swd]

The last LR Benchrest world record holder I talked to said he like's .002” shoulder bump and no less. I’ve had many years of shooting and zero problems with brass life at .002”-.0025” bump.

 

[JFrank]

The last LR Benchrest world record holder I talked to said he like's .002” shoulder bump and no less. I’ve had many years of shooting and zero problems with brass life at .002”-.0025” bump.

Me too, it’s tough enough to get all my rounds down range before a condition changes , fighting a bolt open and upsetting the rifle in the bags is an absolute killer.

 

[6.5 forever]

Me too, it’s tough enough to get all my rounds down range before a condition changes , fighting a bolt open and upsetting the rifle in the bags is an absolute killer.

Totally agree. Competition requires slick feeding ammo!