Shoulder bumping with Redding Body Die - how consistent?

[RonR]

I am interested in others results when shoulder bumping with a body die and how consistent their results are in terms of set back.

Last night I bumped some freshly annealed Lapua cases and an estimated 75% or so were consistent .002 set back with remaining percentage split evenly with .003 set back to .001.

Is this what others are experiencing as routine?

Outside of the entry level Lee challenger press and related press slack/over-camming stuff can this be attributed to differences in the individual cases? (they are all from the same lot)

Regards all
Ronr

Givens:
- Lee challenger press and Redding body die
- Lapua cases, same lot
- Annealing method: propane torch and socket, duration developed with Tempilaq and help and interpretation of results from others here
- This will be my 4th season reloading.
- Application is for more accurate distance shooting at the range, reloading skill development
- Rifles – off the shelf bolts - shooting better as I get better

 

[yodave]

is your measuring tool good enough to catch that 1-2 thou difference every time??

I have a digital gauge with a v block on it, 3 decimal places.....your getting the same results as me.......

you've done good

rock chucker press from the early 90's........redding body bump die......annealed with a annie induction annealer proven with templaque

your ahead of my by a few hundred bucks in equipment, well okay a grand......excellent

 

[frigpig]

I found AFTER I purchased this that all my cases where actually the same after thinking they weren't. They should sell these with the body die.

 

[GreenBob]

How much was it?

 

[bigedp51]

RonR

The variation you find in shoulder bump is caused by brass spring back and brass hardness. If you pause at the top of the ram stroke for a few seconds your results will be more uniform during sizing. That being said you will always find variations and .001 plus or minus in my opinion is normal.

I buy bulk once fired 5.56 and 7.62 Lake City cases that were fired in a variety of different chambers. And pausing at the top of the ram stroke makes these cases more uniform in shoulder location and body diameter.

If I remember correctly normal shoulder bump for a bolt action is .001 to .003 and for a semi-auto is .003 to .006. So don't sweat the small stuff, you'll get gray hair far to early and drive yourself nuts.

Also the type case lube and how it is applied and buildup inside the die will effect shoulder location. I noticed I have less variations in shoulder location using home made spray lube of alcohol and lanolin and wiping the case shoulder off before sizing. Also remember the engineering term "Plus or minus a RCH"

 

[RonR]

I found AFTER I purchased this that all my cases where actually the same after thinking they weren't. They should sell these with the body die.

Neat point. Pardon my ignorance but what is that? The only thing I can think of off the top of my head is something from RCBS.

Regards
Ronr

 

[RonR]

is your measuring tool good enough to catch that 1-2 thou difference every time??

I have a digital gauge with a v block on it, 3 decimal places.....your getting the same results as me.......

you've done good

rock chucker press from the early 90's........redding body bump die......annealed with a annie induction annealer proven with templaque

your ahead of my by a few hundred bucks in equipment, well okay a grand......excellent

Yo, you make a great point. I have a couple sets of calipers and the cheap digital is what I was using at the time to measure results. My thinking is that either one of them is likely not accurate to an absolute datum but to measure from case to case it should be repeatable...but I may be totally wrong on that.

Economy of scale right now with the equipment and processes. If I ever pursue the long distance shooting thing, everything will step up. Right now everything matches well.

I am jealous of the induction heater you have and for sh%ts and giggles I've started to consider something to build with production in mind.

Thanks for the previous support and vote of confidence.

Regards
Ronr

 

[RonR]

RonR

The variation you find in shoulder bump is caused by brass spring back and brass hardness. If you pause at the top of the ram stroke for a few seconds your results will be more uniform during sizing. That being said you will always find variations and .001 plus or minus in my opinion is normal.

I buy bulk once fired 5.56 and 7.62 Lake City cases that were fired in a variety of different chambers. And pausing at the top of the ram stroke makes these cases more uniform in shoulder location and body diameter.

If I remember correctly normal shoulder bump for a bolt action is .001 to .003 and for a semi-auto is .003 to .006. So don't sweat the small stuff, you'll get gray hair far to early and drive yourself nuts.

Also the type case lube and how it is applied and buildup inside the die will effect shoulder location. I noticed I have less variations in shoulder location using home made spray lube of alcohol and lanolin and wiping the case shoulder off before sizing. Also remember the engineering term "Plus or minus a RCH"

Hi Ed,

Noted on the case variability as likely being the source as well as the point about splitting hairs.

You are absolutely correct that it's not something to be concerned about and keeping me grounded...but I am a freak when it comes to making sure that I "aim small miss small" with what I am doing reloading <<< again within the economy of scale of the tubes I shoot and obtain the shooting objectives the reloading process can give.

Having an idea of how well this bumping thing is behaving is akin to finding that powder charge weight that's forgiving within a .1 of a grain when throwing it, at least for myself.

I've read about the lanolin and alcohol mix. Lots of experienced dudes like yourself use it. I use the imperial wax. Mixing the lanolin from batch to batch is for myself just another variable that I could probably make inconsistently.

Neat point about the build up. I never considered that as something that would provide the variation I am experiencing. If a person was to hold the bumped cases in good light and good spectacles a person could make out faint wax ridges like dried up top soil in a garden from the case shoulder junction to the neck. Indications of pressure during the process for sure.

Always appreciate your posts and your time Ed.

Regards
Ronr

 

[Mystic Precision]

I am interested in others results when shoulder bumping with a body die and how consistent their results are in terms of set back.

Last night I bumped some freshly annealed Lapua cases and an estimated 75% or so were consistent .002 set back with remaining percentage split evenly with .003 set back to .001.

Is this what others are experiencing as routine?

Outside of the entry level Lee challenger press and related press slack/over-camming stuff can this be attributed to differences in the individual cases? (they are all from the same lot)

Regards all
Ronr

Givens:
- Lee challenger press and Redding body die
- Lapua cases, same lot
- Annealing method: propane torch and socket, duration developed with Tempilaq and help and interpretation of results from others here
- This will be my 4th season reloading.
- Application is for more accurate distance shooting at the range, reloading skill development
- Rifles – off the shelf bolts - shooting better as I get better

As you know, I use the Lee breech lock challenger press for all my match ammo. The press does such a good job with mid size cases, I don't see the point in changing.

The good part of the Lee, there is no cam over. This is a mechanical press... metal on metal stop. The shorter stroke reduces the amount of spring in the main shaft but you can deal with that by adjusting your die accordingly... if there is any spring back.

Let's assume your caliper is working properly, then the main culprit would be lube - type and amount of it. Imperial wax does a great job BUT it has to be even and cover the entire case. Sometimes, you miss a spot, or not consistent when applying and that can easily increase the resistance in the die.

I currently use Lanolin and Isopropyl alcohol mixture.... spray on, rub evenly... I tend to put more then necessary then remove from the shoulder and neck to reduce chance of dents. I will run into the body die with firm pressure at the bottom of the stroke. .. holding for a sec or two. move lever up about 1/4, rotate case 1/2 turn and size again. I feel that 2nd bump really ensures everything is even ... You can feel if there is any resistance in that 2nd pass. If not, that case is the same as the last one and so forth.

But don't sweat 1 thou of headspace variation..... other things more important then that.

Jerry

 

[frigpig]

Neat point. Pardon my ignorance but what is that? The only thing I can think of off the top of my head is something from RCBS.

Regards
Ronr

Redding comparator.

http://www.redding-reloading.com/online-catalog/37-instant-indicator-headspace-and-bullet-comparator

 

[Seagull]

Mixing the lanolin from batch to batch is for myself just another variable that I could probably make inconsistently.

It is actually quite easy and it last a long time. I bought a bottle of liquid lanolin and I think it will be a life time supply, ok, maybe a 10 years. The nice thing about it is, it is natural and any on your fingers helps with them cracking (after the alcohol has evaporated). Win, win!

 

[RonR]

... then the main culprit would be lube - type and amount of it. Imperial wax does a great job BUT it has to be even and cover the entire case. .... remove from the shoulder and neck to reduce chance of dents.

I never considered the viscosity of the wax potentially being a problem but after you explain it this way, if it's not evenly spread or too thick or "ridgey" in spots then then it would explain such things as dents. I guess the lanolin and alcohol mix ensures that the film is more consistent. I mean I am careful to distribute evenly and haven't noticed any dents but this point is very useful.

It is actually quite easy and it last a long time. I bought a bottle of liquid lanolin and I think it will be a life time supply, ok, maybe a 10 years. The nice thing about it is, it is natural and any on your fingers helps with them cracking (after the alcohol has evaporated). Win, win!

Too much support and use for this to be ignored. I'll pursue this in the future. However Ganderite's use of the Lee lube and mixing method is hard to not try either. For myself it makes a lot of sense.

I will run into the body die with firm pressure at the bottom of the stroke. .. holding for a sec or two. move lever up about 1/4, rotate case 1/2 turn and size again. I feel that 2nd bump really ensures everything is even ... You can feel if there is any resistance in that 2nd pass. If not, that case is the same as the last one and so forth.

Ugh...why did the rotate 180 and hit it again escape my thinking!!!!! (Feeling a little stupid at the moment.) Just like the lee collet neck die. Argh. The hold for a couple of seconds is where I thought I was providing variation. Darn it. This will reduce further variation I'm sure.

But don't sweat 1 thou of headspace variation..... other things more important then that.

Jerry

Yes, like my sanity lol.

Very much appreciated Jerry.

Redding comparator.

http://www.redding-reloading.com/online-catalog/37-instant-indicator-headspace-and-bullet-comparator

Thanks for the reply. I'll look into it.

Thanks all.

Regards
Ronr