Best Way To Setup Die For .001 Shoulder Bump

[kthomas]

Well - I think you need to differentiate between full FL sizing for hunting rounds, and using a FL die to bump the shoulder slightly for precision target shooting (a la Cortina). I believe this thread refers to the latter, and its fair to say that bumping the shoulder very slightly requires some finesse that is beyond the abilities of many reloaders, particularly newbies. I would suggest neck sizing as a reasonable alternative,if a snug chamber fit is desired. Otherwise, screw down the FL die a quarter turn to give a bigger bump.
I use a Ross for hunting. With its limited camming power, there is no way I would rely upon neck sizing. I would use a FL die with a generous resize, and I would check for fit, one or two brass and all loaded rounds. If I wanted to get fancy, I would use a collet die and a body die to minimize runout.
For my bolt action rifles, I neck size until things get tight - usually 3-4 loads, then bump with a body die (if available), or a FL die. BTW - I dont hot-rod my loads in any of my rifles, so the brass is worked less. The principal reason I do this is to minimize runout, which I've come to realize is a major deterrent to good grouping.
If, for whatever reason, I get stuck with a loaded round that wont chamber, I'll either break it down, or bump the case with the body die.

I guess I've never found it that difficult to put a 1-2 thou bump on a case when FL sizing...

 

[dan belisle]

Checking every round seems like a lot more work than simply bumping the shoulder a thousandth.
Might be okay the first couple times but you’ll end up bumping the shoulder anyways.

Then the ammo may still not chamber in another rifle. That may or may not be an issue.

Depends how tight you want your ammo to be in your chamber I guess. All of this how many angels dance on the head of a pin stuff is usually based on a persons experience with what they have had happen in the past. If a 0.001" bump makes you happy, go with it. Same with neck sizing. They both work until they don't, then you get to figure out why and adjust your procedures accordingly. - dan

 

[dan belisle]

Depends on where and how you shoot.

In some disciplines, neck sizing only is a recipe for disaster. Fine for the square range on a covered concrete pad, but in the actual field is a completely different story.

No, actually if you have debris in your action, you do indeed have other problems. - dan

 

[kthomas]

No, actually if you have debris in your action, you do indeed have other problems. - dan

There are certain types of environments where it's pretty much impossible to avoid.

Use the correct procedure, whether FL sizing or neck sizing, for the job. No one right answer for every situation.

 

[Hitzy]

Can't say I've ever read a thread on here where someone had chambering issues neck sizing.
On the other hand, there are a couple threads a month about someone trying a minimal shoulder bump and having issues.
Spring back of a fired case is already in the neighborhood of 2 thou,

 

[Lead hammer]

Sure but the case body does get smaller when sized, smaller than case spring back.

Easiest way would be neck size, no anneal,( for more springback) and FL size and trim when the brass no longer fits. I would rather do the body size and learn to be consistent, unless you shoot for meat only, and only shoot 10 rounds per year.

 

[Chilly807]

To throw this thread back into perspective, this is what .001" looks like.

The calipers are zeroed at 0.0000, which is better accuracy than they're really capable of. I think Mitutoyo guarantees them for +/- 0.001"

The average human hair, without getting into a discussion of blonde vs. brunette, is 0.003"

 

[*MALICE*]

To throw this thread back into perspective, this is what .001" looks like.

The calipers are zeroed at 0.0000, which is better accuracy than they're really capable of. I think Mitutoyo guarantees them for +/- 0.001"

The average human hair, without getting into a discussion of blonde vs. brunette, is 0.003"

Ya, but how many reloaders actually know how to use calipers properly?

For that matter, I've watched 30-year-experienced 'machinists' squeeze them until they get the size they want or think they can actually trust it to measure a .001" tolerance instead of using a micrometer instead lol

 

[Chilly807]

Ya, but how many reloaders actually know how to use calipers properly?

For that matter, I've watched 30-year-experienced 'machinists' squeeze them until they get the size they want or think they can actually trust it to measure a .001" tolerance instead of using a micrometer instead lol

This is part of what I'm getting at.

Reloading using tools and skills that are acceptable to most people doesn't result in thousands of deaths or serious injuries across Canada every year, if you don't count the animals shot with that ammunition.

On the other hand, I recently watched someone try to chamber what was supposed to be a 270 Winchester round that I suspect was loaded with the wrong size bullet. Thankfully the bolt wouldn't close. A few careful measurements would have been good in that case.

Every time I open a new box of bullets I weigh and measure a couple of samples, just to be sure what's ON the box is also what's IN the box.

I reload using a set of Mitutoyo dial calipers that are nearly as old as I am, and I wasn't born yesterday.

Modern electronics are wonderful, until they aren't. With that statement, you'll have a better idea how old I am.. lol

 

[kthomas]

To throw this thread back into perspective, this is what .001" looks like.

The calipers are zeroed at 0.0000, which is better accuracy than they're really capable of. I think Mitutoyo guarantees them for +/- 0.001"

The average human hair, without getting into a discussion of blonde vs. brunette, is 0.003"

Same calipers I use.

Holding 1 thou of precision for every single piece of brass is a fairly unrealistic expectation. As you point out, the error alone can be 1 thou in either direction. It's more of a guide then anything else.

Ultimately what matters is what the target says, and of course reliability.

 

[cosmic]

Same calipers I use.

Holding 1 thou of precision for every single piece of brass is a fairly unrealistic expectation. As you point out, the error alone can be 1 thou in either direction. It's more of a guide then anything else.

Ultimately what matters is what the target says, and of course reliability.

Well - Therein lies the problem, as any plus side tolerance can give you grief, as the OP has experienced. In your case, you chose a value of shoulder bump that accommodates any natural variance from sizing. If your process is really good (eg good brass, tempered, rigid press, etc.), that variance can be reduced to a minimum, allowing you to aim for a very small shoulder bump and resultant accuracy benefits.
What is odd, and its happened to me - is that the case can actually grow in length at the shoulder under minimal resizing with the FL die. As the case is being compressed past its elastic limit circumferentially by the die, it wants to flow in some direction. If not compressed at the shoulder sufficiently, strain will occur and will result in springback past its original size. Couple that with the expander ball tugging on the neck in an underlubed case and straining the shoulder - more possible trouble (ask me how I know...)

 

[dan belisle]

Sure but the case body does get smaller when sized, smaller than case spring back.

Easiest way would be neck size, no anneal,( for more springback) and FL size and trim when the brass no longer fits. I would rather do the body size and learn to be consistent, unless you shoot for meat only, and only shoot 10 rounds per year.

Agree. This works for most of my rifle shooting. - dan

 

[kthomas]

Well - Therein lies the problem, as any plus side tolerance can give you grief, as the OP has experienced. In your case, you chose a value of shoulder bump that accommodates any natural variance from sizing. If your process is really good (eg good brass, tempered, rigid press, etc.), that variance can be reduced to a minimum, allowing you to aim for a very small shoulder bump and resultant accuracy benefits.
What is odd, and its happened to me - is that the case can actually grow in length at the shoulder under minimal resizing with the FL die. As the case is being compressed past its elastic limit circumferentially by the die, it wants to flow in some direction. If not compressed at the shoulder sufficiently, strain will occur and will result in springback past its original size. Couple that with the expander ball tugging on the neck in an underlubed case and straining the shoulder - more possible trouble (ask me how I know...)

Everything's a tradeoff.

No one solution is perfect or best for every application. That's why we all need to figure out what works for us and the type of shooting we do.

The only thing that's universal across methods is obtain the best components and reloading gear you can afford - this will help avoid unnecessary headaches. But there's always learning curves.

 

[Hitzy]

Well - Therein lies the problem, as any plus side tolerance can give you grief, as the OP has experienced. In your case, you chose a value of shoulder bump that accommodates any natural variance from sizing. If your process is really good (eg good brass, tempered, rigid press, etc.), that variance can be reduced to a minimum, allowing you to aim for a very small shoulder bump and resultant accuracy benefits.
What is odd, and its happened to me - is that the case can actually grow in length at the shoulder under minimal resizing with the FL die. As the case is being compressed past its elastic limit circumferentially by the die, it wants to flow in some direction. If not compressed at the shoulder sufficiently, strain will occur and will result in springback past its original size. Couple that with the expander ball tugging on the neck in an underlubed case and straining the shoulder - more possible trouble (ask me how I know...)

The "ideal" way to be able to FL size every time with no issues is to own a reamer, have a custom barrel made, and custom dies made with the ideal tolerances you want...that's what the serious guys do. But that is mighty expensive.
So instead of that, you have guys buying factory rifles with whatever factory chamber that is within specs, and factory dies that are to minimum spec, buying all kinds of measuring gear and #### to try and match what professional shooters are doing (who are sponsored and get paid) because that's what works for them, so many other variables to take into the equations, but still, everything on here or online is neck sizing sucks.

Here is one of my "let's try this #### out" attempts at the range.
Left group is fire forming with garbage 120gr PRVI FMJ in a 6.5cm HB off the rack Savage 10.
Middle group is 140gr Nos HPBT bulk stuff,with the best I could do minimal FL bump and have it chamber after fire forming.
Last group is a Redding NS sized piece of brass after fire forming, same load as the bump.
These are just my results trying this FL bump stuff, sample of 1 guy, one gun, same load. Neck sizing has always given me better results.
The red bull is about 1/2", all shot at 100m

 

[Lead hammer]

As soon as you go from neck to FL size, your case capacity changes, so does your pressure, unless you adjust for it, it will be untuned. Also the seating die should be adjusted to accommodate the shoulder bump, it also can be out of tune. So a proper test of FL or body sized load needs a new load development.

 

[waynewjw]

Although a bit off topic from my OP, I finally used my Gong Joe annealer yesterday. Although the ultimate test of “do I know what the f*%k I’m doing” will only show with some range time, I was impressed with how easy it was to setup this piece of Cdn. Mfg. equipment. After watching a few more video’s and determine ideal time was approx. 6 seconds to correctly anneal my brass, I went ahead and annealed 100 rounds of 30-06, in sorted groups of once fired, trice fired and so on. So now back to the original topic, I will setup my 30-06 die to achieve the minimal bump when FL sizing and then use my collet die and see what results are achieved in the accuracy dept. once I hit the range, which may not be for awhile. I don’t need to confirm my theories at -5C and will wait for warmer climes to show up and then test my results. And the experiment goes on.........

 

[dan belisle]

Although a bit off topic from my OP, I finally used my Gong Joe annealer yesterday. Although the ultimate test of “do I know what the f*%k I’m doing” will only show with some range time, I was impressed with how easy it was to setup this piece of Cdn. Mfg. equipment. After watching a few more video’s and determine ideal time was approx. 6 seconds to correctly anneal my brass, I went ahead and annealed 100 rounds of 30-06, in sorted groups of once fired, trice fired and so on. So now back to the original topic, I will setup my 30-06 die to achieve the minimal bump when FL sizing and then use my collet die and see what results are achieved in the accuracy dept. once I hit the range, which may not be for awhile. I don’t need to confirm my theories at -5C and will wait for warmer climes to show up and then test my results. And the experiment goes on.........

Good to know. I'm going to start using mine this weekend. - dan