Does anyone NOT bump shoulders on FL resizing after initial firing on virgin brass?

[Nick Caprinolo]

Help me out here. I never neck size, always using a full sizing die. What is the need to bump size, if every case is passed through a full length sizing die. It seems to me that the die will size every case, to the same dimensions and bumping is not necessary. Over time a case will need to be trimmed, but why bump the shoulder?

I've reloaded the same brass as much as 20 times and never had a problem.

 

[golong]

Help me out here. I never neck size, always using a full sizing die. What is the need to bump size, if every case is passed through a full length sizing die. It seems to me that the die will size every case, to the same dimensions and bumping is not necessary. Over time a case will need to be trimmed, but why bump the shoulder?

I've reloaded the same brass as much as 20 times and never had a problem.

You are not doing anything abnormal/wrong. The question about bump is just the height of the die. It is not about FL vs NS, bushing vs no bushing.

By way of extreme example, if you run your FL die down to the shell holder and had a heavy over cam you would likely get enough bump to cause case-head separation after a few firings. If you backed it off 2 turns you would likely not get any bump. Somewhere in between all of this is a height that gets you the amount of bump you are looking for.

 

[Rocketvapor]

Nick,
FL sizing can be adjusted to bump a little or a lot or none.
You are likely bump sizing when you size. Not a problem.
The FL die squeezes down the neck and a mandrel opens it back up.
Pulling the mandrel out can stretch the brass.
Of course bushing dies can be set up to minimize this stretching.

The alternative, which take two steps is to BODY size, bumping as you see fit.
And
Neck size with a Collet die.
In my experience, grows very little, trimming less often, less brass on the floor

 

[Field_2_Fork]

Very interesting, I'm glad I saw this thread as it's helping me to understand what I just experienced.

I ran the first loads (87grn Berger VLD-H) through new Lapua brass in a Tikka M55 .243 last week, had a quick look at the fired brass this morning and they measured the same as before they were fired? (using Hornady head space guages and Mitutoyo calipers)

The loads were fairly stiff as I started at 43grn of Reloader 19, Berger lists a max of 44.7.

I assumed that this would have been enough charge to form the cases and was very surprised to see they weren't showing much if any change when measured this morning, perhaps another firing or two before I settle on final measurements.

 

[Bc'z]

After 1st firing
I start with a case comparator and get a measurement, next I set my die up using a feeler gauge .010 to start.
Size case and measure.
Did it push the shoulders forward? If so how far forward?
I subtract the amount it moved forward and go the corresponding feeler gauge.
Example, if shoulder moved forward .004 using .010, go to .006 feeler gauge.
This should keep shoulder in place while sizing the rest of the case.
Check against chamber to make sure it fits.

 

[Field_2_Fork]

After 1st firing
I start with a case comparator and get a measurement, next I set my die up using a feeler gauge .010 to start.
Size case and measure.
Did it push the shoulders forward? If so how far forward?
I subtract the amount it moved forward and go the corresponding feeler gauge.
Example, if shoulder moved forward .004 using .010, go to .006 feeler gauge.
This should keep shoulder in place while sizing the rest of the case.
Check against chamber to make sure it fits.

To use feeler guages like this I'm trying to figure out how you set the die initially? I suppose you run the ram up until the shell holder contacts the bottom of the die?

I using a standard Redding FL die set, no bushings in my toolbox, not yet anyways. I've only been reloading for a few years, 4 or 5 cartridges only, and am just now starting to look into how to be as precise as possible with what I have.

Thanks.

 

[Bc'z]

To use feeler guages like this I'm trying to figure out how you set the die initially? I suppose you run the ram up until the shell holder contacts the bottom of the die?

I using a standard Redding FL die set, no bushings in my toolbox, not yet anyways. I've only been reloading for a few years, 4 or 5 cartridges only, and am just now starting to look into how to be as precise as possible with what I have.

Thanks.

Raise ram to full extension, screw die down with feeler gauge between die and shell holder.

 

[Field_2_Fork]

Raise ram to full extension, screw die down with feeler gauge between die and shell holder.

That makes sense, I was trying to imagine putting the guage under the shell holder somehow. Thanks.

 

[JFrank]

That makes sense, I was trying to imagine putting the guage under the shell holder somehow. Thanks.

Well you can use the feeler under the shell holder but there is only about .010 to work with.
Brett’s method is sound
The results are the same either way.

 

[Bc'z]

That makes sense, I was trying to imagine putting the guage under the shell holder somehow. Thanks.

When your brass is fully fire formed and you need to bump the shoulder same thing applies.
Example, if the .006 feeler gauge keeps your shoulders in same location, .004 will move shoulders the desired .002.
Annealing helps to get a consistent bump and bullet hold in my opinion.

 

[Webster]

Got to measuring and asking some questions from more experienced guys. I always assumed in normal circumstances (ie. not fireforming a wildcat, in spec chamber, etc.) the brass filled the entire dimension after the first firing. Now im seeing some info that says that may not be true. So with that in mind, my logic is saying if im basing my shoulder bump off of the first firing measure, I may be oversizing.

If you can easily chamber a fired case it doesn't need shoulder bump.

 

[dgeesaman]

Got to measuring and asking some questions from more experienced guys. I always assumed in normal circumstances (ie. not fireforming a wildcat, in spec chamber, etc.) the brass filled the entire dimension after the first firing. Now im seeing some info that says that may not be true. So with that in mind, my logic is saying if im basing my shoulder bump off of the first firing measure, I may be oversizing.

Sure I’ve left the die a few thou long or more when I’m unsure of what headspace I want. After another firing I get a few pieces that open with a tighter bolt and I use those to base my shoulder bump.

Then I leave the die set there and FL size everything.

David

 

[searcher]

In my experience - factory new brass is sized much more than .003" under what your chamber will be. Often more than .005" After firing at least 25 rounds, measure every piece with a Hornady or similar tool from the shoulder to base. Generally, you will find them measuring differently, though at least several will be the exact same LONGEST length if your load was potent enough to fully blow the shoulders forward. That will be the measurement you will want to use as a basis for bumping shoulders. If using light bullets and not full-power loads - you might find that you won't know what your shoulder length will be till after several firings. Best route in a bolt gun to fully blown-forward shoulders is to jamb the bullets with a moderate load. You will find that your average shoulder measurement will be much more uniform.

 

[PopCharlie]

I use a Whidden click adjustable non-bushing F/L sizing die. I have set the lock ring to the desired shoulder bump. I have marked my press and screw the die in to the same depth every time. If the shoulder needs to be bumped, it gets bumped. I do check the cases using a bump gauge. I can usually feel it get bumped.

I did initially measure cases I fired twice to determine the headspace and figure out the bump.

 

[fatelvis]

I just run an expander through the neck of virgin brass to give .001-.003” neck tension, deburr/chamfer and load.

 

[TC260]

In my experience - factory new brass is sized much more than .003" under what your chamber will be. Often more than .005" After firing at least 25 rounds, measure every piece with a Hornady or similar tool from the shoulder to base. Generally, you will find them measuring differently, though at least several will be the exact same LONGEST length if your load was potent enough to fully blow the shoulders forward. That will be the measurement you will want to use as a basis for bumping shoulders.

That's been my experience too. Recently I picked a 35 Remington single shot hunting rifle and kept track of the measurements for a similar discussion on a more casual reloading forum than this one. Obviously not a precision rifle but with no brass/dies on hand at the time of purchase I picked up a box of core-lokts and measured all the base to shoulder lengths before firing. After firing, only 2 of the 20 measured the longest (closest to the true chamber length) and they were a full 0.006" longer than the factory loaded cases. IIRC the shortest case or two of the 20 only grew 0.001-2 over the factory rounds (0.004-5 short of the longest fired cases). Deer season came and haven't put a second firing on those cases yet but from experience I expect those two longest cases will only show negligible growth if any on the subsequent firing.