Inconsistent shoulder bump after sizing and ogive after seating

[thexman]

I know similar topics have been posted in the past, but I still couldn't figure out what caused to the issues I have, I am going to ask again.

I found after I FL size my lapua brass, I got different shoulder bump. e.g for 308win, the range is about to +/-0.001-0.0015. To make it as consistent as possible, sometimes I have to adjust the FL sizing die a bit.
Not sure if this is mainly caused by case lube/wax as mentioned in some of the previous posted thread or my budget caliper needs an upgrade?
I am using Redding Type S FL sizing die with bushing, without expander ball. All the brass gets deprimed, wet tumbled and AMP annealed before FL sizing. I also tried Redding competition shell holder set, but it doesn't seem make much difference.

For seating depth, I am suspecting it is related to inconsistent neck tension, but I am not sure what I missed or did wrong in the brass prep process. My process is FL size the brass with bushing without expander ball, then (trim if necessary) chamfer and debur. I use expander mandrel to open the mouth to preferred neck tension. Before seating, I apply some redding dry neck lube. But I still get about +0.001-2 difference in a batch of 30-50 rounds. Normally use ELD or SMK bullets.

If the difference in my shoulder bump and seating depth are out of normal tolerance range, anything I did wrong or missed in my process? Thanks in advance.

 

[Feniks Technologies]

I wouldn’t worry so much if you’re around .001-.0015

Several things could be the culprit and likely a combination of things.

Even just inconsistency in using calipers or the way the brass or bullet is sitting in the comparator can generate .001 or so very easily.

 

[straightshooter1]

I know similar topics have been posted in the past, but I still couldn't figure out what caused to the issues I have, I am going to ask again.

I found after I FL size my lapua brass, I got different shoulder bump. e.g for 308win, the range is about to +/-0.001-0.0015. To make it as consistent as possible, sometimes I have to adjust the FL sizing die a bit.
Not sure if this is mainly caused by case lube/wax as mentioned in some of the previous posted thread or my budget caliper needs an upgrade?
I am using Redding Type S FL sizing die with bushing, without expander ball. All the brass gets deprimed, wet tumbled and AMP annealed before FL sizing. I also tried Redding competition shell holder set, but it doesn't seem make much difference.

For seating depth, I am suspecting it is related to inconsistent neck tension, but I am not sure what I missed or did wrong in the brass prep process. My process is FL size the brass with bushing without expander ball, then (trim if necessary) chamfer and debur. I use expander mandrel to open the mouth to preferred neck tension. Before seating, I apply some redding dry neck lube. But I still get about +0.001-2 difference in a batch of 30-50 rounds. Normally use ELD or SMK bullets.

If the difference in my shoulder bump and seating depth are out of normal tolerance range, anything I did wrong or missed in my process? Thanks in advance.

With my .308 brass I found that having a somewhat long period for dwell time (the amount of time the case is fully in the sizing die before the stroke to remove it) helps a lot in reducing any spring back, which can be part of the issue you're having with the shoulder bump. And don't forget that your caliper is NOT a precision instrument, so there's going to be a little bit of variance there too.

In your process, you didn't say when you anneal or when or how you clean (if you clean at all). If cleaning after annealing isn't done, there could be an issue about the oxidation coating left behind causing variations in sizing resistance as that coating tends to act like sandpaper.

For me, my trimming, chamfering and deburring is the very last step. In my process, I get <.001 variance in my neck bumping on my annealed Lapua brass . . . mostly measuring <=.0005.

 

[thexman]

With my .308 brass I found that having a somewhat long period for dwell time (the amount of time the case is fully in the sizing die before the stroke to remove it) helps a lot in reducing any spring back, which can be part of the issue you're having with the shoulder bump. And don't forget that your caliper is NOT a precision instrument, so there's going to be a little bit of variance there too.

In your process, you didn't say when you anneal or when or how you clean (if you clean at all). If cleaning after annealing isn't done, there could be an issue about the oxidation coating left behind causing variations in sizing resistance as that coating tends to act like sandpaper.

For me, my trimming, chamfering and deburring is the very last step. In my process, I get <.001 variance in my neck bumping on my annealed Lapua brass . . . mostly measuring <=.0005.

Thank you.

I just follow others process, so after deprime, I throw the brass in wet tumbler with lemon shine and some dish wash liquid for about 2 hours, then brass dryer. After brass cool down, I go through AMP annealer machine to anneal each brass. After the brass cool down again, I apply case lube/wax to do FL sizing.

My trimming, chamfering and deburring is done after FL sizing and before expand the neck using expander mandrel. Not sure if there is any difference to do which one first.

 

[nn8734]

I know similar topics have been posted in the past, but I still couldn't figure out what caused to the issues I have, I am going to ask again.

I found after I FL size my lapua brass, I got different shoulder bump. e.g for 308win, the range is about to +/-0.001-0.0015. To make it as consistent as possible, sometimes I have to adjust the FL sizing die a bit.
Not sure if this is mainly caused by case lube/wax as mentioned in some of the previous posted thread or my budget caliper needs an upgrade?
I am using Redding Type S FL sizing die with bushing, without expander ball. All the brass gets deprimed, wet tumbled and AMP annealed before FL sizing. I also tried Redding competition shell holder set, but it doesn't seem make much difference.

For seating depth, I am suspecting it is related to inconsistent neck tension, but I am not sure what I missed or did wrong in the brass prep process. My process is FL size the brass with bushing without expander ball, then (trim if necessary) chamfer and debur. I use expander mandrel to open the mouth to preferred neck tension. Before seating, I apply some redding dry neck lube. But I still get about +0.001-2 difference in a batch of 30-50 rounds. Normally use ELD or SMK bullets.

If the difference in my shoulder bump and seating depth are out of normal tolerance range, anything I did wrong or missed in my process? Thanks in advance.

Let the target tell you what, if anything different, you have to do. Then work backwards from there…

 

[straightshooter1]

Thank you.

I just follow others process, so after deprime, I throw the brass in wet tumbler with lemon shine and some dish wash liquid for about 2 hours, then brass dryer. After brass cool down, I go through AMP annealer machine to anneal each brass. After the brass cool down again, I apply case lube/wax to do FL sizing.

My trimming, chamfering and deburring is done after FL sizing and before expand the neck using expander mandrel. Not sure if there is any difference to do which one first.

My trimming/chamfering/deburring is done at the last in my process because I use a 3-way trimmer and it indexes off the shoulders. So, with consistent shoulder bumps I get consistent case lengths.

Assuming when you lube your cases for sizing, you're not lubing the necks . . . which after annealing might be inducing various pressures on the shoulders due to the oxidation coating left on the outside and inside surface of the necks. This variation in pressure from the neck being pushed into the bushing might be effecting the amount of bump???

In my process, I always anneal after depriming and then clean my brass before the sizing process. Not having the oxidation layer on the necks not only helped with neck bumping but also the concentricity.

 

[Carlos Danger]

Check the accuracy tolerances on your caliper. Most don't relate they're not rated for the accuracy they display.

 

[Oldmauser]

I was asking myself the same question as OP. I follow pretty much the same process and frankly speaking I get 0.0005-0.001 variance in shoulder bump across 50 cases of Lapua brass on average. There are many reasons for this:
-variance in case wall thickness
-variance in case hardness (even after annealing)
- variance in amount of lube applied
- variance in force applied during sizing process
- sizing die itself- also cleaning/non cleaning of the die,
- last but not least: limitation of measuring device/ measurement errors

Of course, it's possible to get exactly the same shoulder bump in your brass, but you would have to control all the variables. With the variance I get I still can shoot 1/4 moa at 100m and for my needs it's ok.

 

[MarkyMark007]

the range is about to +/-0.001-0.0015.

you wont get better than that in any normal situation. this is very very good. if people say that they get better than that, you can bet that they are liying or they dont measure every case and they dont know their tolerances.

first thing is to contact your dies to shellholder very hard. this will eliminate any space. if you have bigger gap, try redding competition shellholders or put washers between dies and shellhoder.

next thing is to try different high-end presses, like mec, co-ax, turban.

maybe you can even sort your brass at those parameters, and see if next time you will get more consistent dimensions after sizing and seating bullets.

and this is about everything you can do.

Is your seating die micrometer accurate

Is your seating die micrometer accurate, not repeatable/consistent, accurate? When you move the micrometer .003 does it move the bullet depth .003?

www.snipershide.com

 

[Haney]

Have you tried a longer dwell time? If not you could give that a try to see if that fixes the spring back . You mentioned you suspect neck tension may be inconsistent . Have you tried running a mandrel in them after sizing or measure with a pin gauge ?

 

[thexman]

With my .308 brass I found that having a somewhat long period for dwell time (the amount of time the case is fully in the sizing die before the stroke to remove it) helps a lot in reducing any spring back, which can be part of the issue you're having with the shoulder bump. And don't forget that your caliper is NOT a precision instrument, so there's going to be a little bit of variance there too.

In your process, you didn't say when you anneal or when or how you clean (if you clean at all). If cleaning after annealing isn't done, there could be an issue about the oxidation coating left behind causing variations in sizing resistance as that coating tends to act like sandpaper.

For me, my trimming, chamfering and deburring is the very last step. In my process, I get <.001 variance in my neck bumping on my annealed Lapua brass . . . mostly measuring <=.0005.

Thank you.

I just follow others process, so after deprime, I throw the brass in wet tumbler with lemon shine and some dish wash liquid for about 2 hours, then brass dryer. After brass cool down, I go through AMP annealer machine to anneal each brass. After the brass cool down again, I apply case lube/wax to do FL sizing.

My trimming, chamfering and deburring is done after FL sizing and before expand the neck using expander mandrel. Not sure if there is any difference to do which one first.

you wont get better than that in any normal situation. this is very very good. if people say that they get better than that, you can bet that they are liying or they dont measure every case and they dont know their tolerances.

first thing is to contact your dies to shellholder very hard. this will eliminate any space. if you have bigger gap, try redding competition shellholders or put washers between dies and shellhoder.

next thing is to try different high-end presses, like mec, co-ax, turban.

maybe you can even sort your brass at those parameters, and see if next time you will get more consistent dimensions after sizing and seating bullets.

and this is about everything you can do.

Is your seating die micrometer accurate

Is your seating die micrometer accurate, not repeatable/consistent, accurate? When you move the micrometer .003 does it move the bullet depth .003?

www.snipershide.com

Thank you.

I am not sure if I describe the difference range clearly. What I mean +/- 0.0015 is say for 5 brass after resize, I could get something like
1.Exact -0.002 shoulder bump I am adjusting my FL sizing die for
2.On top of the -0.002 shoulder bump, I got additional 0.0015 shoulder bump, in total that's 0.0035 should bump
3.Additional 0.001 shoulder bump, total -0.003
4.Not enough shoulder bump, so that's -0.001 comparing to before sizing
5.Worst case, I've seen a few times in the last few hundreds rounds I sized, I got -0.0045(additional 0.0025) shoulder bump

I mean, +/- 0.0005 on top of the 0.002 shoulder bump I think that would be good, occasionally 0.001 is still acceptable for now. But my experience shows only about 30-40% of the brass I can get exact 0.002 shoulder bump, the majority of the rest are in the 0.003-0.0035 range, which I thought it might be too much(0.0015 under+0.0015 over, total 0.003 difference) for precision shooting?

Actually I am using Turban press and I hope it has nothing to do with the die itself, I am not sure how tight it needs to be fixed on the press, I normally just hand tie and make sure locking ring touches the top of the press without any movement.
I guess I could try sorting the brass and do additional cleaning before sizing after annealing next time to see if any thing will change.

Thank you for your advise.

 

[thexman]

Have you tried a longer dwell time? If not you could give that a try to see if that fixes the spring back . You mentioned you suspect neck tension may be inconsistent . Have you tried running a mandrel in them after sizing or measure with a pin gauge ?

Sure, I will give it a try next time when I size the brass, I think you got a point which could make some difference.

Yes, I am using expander mandral before powder charge

 

[BLKWLFK9]

Nobody has mentioned slop in your press or in how it's mounted to your bench. I was getting some inconsistencies and found that my mounting hardware had loosened a bit. Tightened it up and that helped dramatically. Either way .001 ain't making much difference. I've got about 4 different lot numbers of lapua dasher brass that have upwards of .004 in variance, yet still produce tiny little groups and low SDs. Don't sweat.001 or .0005

 

[MarkyMark007]

5.Waste case, I've seen a few times in the last few hundreds rounds I sized, I got -0.0045(additional 0.0025) shoulder bump

I mean, +/- 0.0005 on top of the 0.002 shoulder bump I think that would be good, occasionally 0.001 is still acceptable for now. But my experience shows only about 30-40% of the brass I can get exact 0.002 shoulder bump, the majority of the rest are in the 0.003-0.0035 range, which I thought it might be too much(0.0015 under+0.0015 over, total 0.003 difference) for precision shooting?

Actually I am using Turban press and I hope it has nothing to do with the die itself, I am not sure how tight it needs to be fixed on the press, I normally just hand tie and make sure locking ring touches the top of the press without any movement.
I guess I could try sorting the brass and do additional cleaning before sizing after annealing next time to see if any thing will change.

I had headspace also all over the space, just like you; maybe even more.
But now I purchase precise spacers-washers, to get hard contact with shellholder and the die, and it is way way better. But if you can get competition shellholders or custom, it will be way faster, because I must put washer on every piece of brass manualy.

And good press will help. You have very good press, but you can try others, if see if they work better for you.

And if you will sort your brass by headspace, please let us know if you fixed a problem, because I was trying to do that, but I wasn't very succesfull at this sorting.

 

[MarkyMark007]

Have you tried a longer dwell time? If not you could give that a try to see if that fixes the spring back . You mentioned you suspect neck tension may be inconsistent . Have you tried running a mandrel in them after sizing or measure with a pin gauge ?

How much longer? I am waiting for 5 seconds to have my brass in the die.

My friend is practicing to have 2 strokes; so he sizes his brass twice (2 strokes in 'one' operation; not sizing now and than after 1 hour)

 

[Barelstroker]

Thank you.

I just follow others process, so after deprime, I throw the brass in wet tumbler with lemon shine and some dish wash liquid for about 2 hours, then brass dryer. After brass cool down, I go through AMP annealer machine to anneal each brass. After the brass cool down again, I apply case lube/wax to do FL sizing.

My trimming, chamfering and deburring is done after FL sizing and before expand the neck using expander mandrel. Not sure if there is any difference to do which one first.

Thank you.

I am not sure if I describe the difference range clearly. What I mean +/- 0.0015 is say for 5 brass after resize, I could get something like
1.Exact -0.002 shoulder bump I am adjusting my FL sizing die for
2.On top of the -0.002 shoulder bump, I got additional 0.0015 shoulder bump, in total that's 0.0035 should bump
3.Additional 0.001 shoulder bump, total -0.003
4.Not enough shoulder bump, so that's -0.001 comparing to before sizing
5.Waste case, I've seen a few times in the last few hundreds rounds I sized, I got -0.0045(additional 0.0025) shoulder bump

I mean, +/- 0.0005 on top of the 0.002 shoulder bump I think that would be good, occasionally 0.001 is still acceptable for now. But my experience shows only about 30-40% of the brass I can get exact 0.002 shoulder bump, the majority of the rest are in the 0.003-0.0035 range, which I thought it might be too much(0.0015 under+0.0015 over, total 0.003 difference) for precision shooting?

Actually I am using Turban press and I hope it has nothing to do with the die itself, I am not sure how tight it needs to be fixed on the press, I normally just hand tie and make sure locking ring touches the top of the press without any movement.
I guess I could try sorting the brass and do additional cleaning before sizing after annealing next time to see if any thing will change.

Thank you for your advise.

In my experience you won't get the exact same reading every time.
I usually reload 50 or 100 at a time with +/- 0.001 for roughly 30% of cases. That tolerance might be more or less but, I don't worry about it.
I've tested some 243 & 308 cases for H2O volume difference & it's barely measurable if at all.
I don't worry about it. It's neither here nor there in the scheme of things.

 

[Cascade Hemi]

The real question is what actually has a positive or negative result on the target. The only real way to know is measure and log the ammo then record the shots in the group for correlation. Even then, there will still be uncontrollable variables. Striving for perfect is great but knowing when to settle for good enough is better.

 

[BCX]

I usually don’t use the cam over w my press. I press up into the sizing die, count to 3 press down, spin the case 180, press down, count to 3, done, than a mandrel to set neck tension.

Edit… I anneal w a AMP before sizing, every shoulder is spot on!

 

[dnchrist]

How much longer? I am waiting for 5 seconds to have my brass in the die.

My friend is practicing to have 2 strokes; so he sizes his brass twice (2 strokes in 'one' operation; not sizing now and than after 1 hour)

When I size, I pull the handle down, pause a few seconds, raise, rotate the case in the holder about 180 degrees, pull the handle down again, pause, raise, remove.

 

[straightshooter1]

When I size, I pull the handle down, pause a few seconds, raise, rotate the case in the holder about 180 degrees, pull the handle down again, pause, raise, remove.

Dwell time (pausing a few seconds) really helps with getting consistent sizing, particularly with bumping the shoulders. My dwell time for FL sizing is about 5 - 6 seconds (only need one stroke) as I'm lubing a case during that time with my left hand as I operate my press with the right. I don't use an expander ball in the die when FL sizing and use an expander mandrel afterwards.

 

[Baron23]

I'm not the most experienced reloading here by a long shot, but I do tend to wonder what we think we are trying to accomplish with striving for such small variations in shoulder bump as discussed there.

I'm sort of thinking we just want the cartridge to chamber easily and for the shoulders to not be radically far from the chamber wall but beyond that, what do we think we gain?

I find shoulder bump variation to come from a number of sources including how I operate the handle, pressure at the bottom of the cycle, dwell time as mentioned, and WTF knows what else.

I have not see where intense attention to achieving exact shoulder bump has contributed to precision of my ammo.

Cheers

 

[MarkyMark007]

reloading gurus are telling us that we must produce as consistent ammo as we can....

so we follow them like sheeps

 

[918v]

Check the accuracy tolerances on your caliper. Most don't relate they're not rated for the accuracy they display.

^^^ This

Unless you are using certified calipers, they are plus/minus .001”