Yet another shoulder bump question

[DLT]

Here goes the rundown. I set up my bump for a new chamber by stripping my bolt and using twice fired brass to get my die (RCBS FL) set by feel. I was just wanting to try a different way of setting them up. Anyways I anneal in the dark with a propane torch usually 5-6 seconds per piece every firing. My lube is hornady unique, I do not get any on the neck or shoulder. While sizing I always have 5 seconds of dwell time. I have noticed that more often than I’d like I get a snug bolt close it’s not much but I can tell there’s a difference. Today I was sizing and figured I’d like to get to the bottom of what’s going on so I was checking each piece of sized brass in my rifle checking for a snug bolt. The ones that measured .448-.449 had zero issues. I did have snug closing on the ones that measured .450. I would take those cases, lube again, and run through my die a second time with 5 secs dwell time and they would come out .447 -.448. The press is a fairly new mec marksman. What is causing my inconsistencies ? I’m using 223 starline brass 4 firings and only in this chamber. Thanks

 

[J.d. Popkes]

Redding comp shell holders and camover??

 

[DLT]

Redding comp shell holders and camover??

I am using a standard shell holder

 

[David Christian]

Any chance your annealing time is off and when you are resizing those longer pieces the shoulder is getting crushed?

 

[J.d. Popkes]

I am using a standard shell holder

In my opinion that’s the problem. Good annealing, good lube technique, camming over, no expander ball. My opinion……

 

[DLT]

Any chance your annealing time is off and when you are resizing those longer pieces the shoulder is getting crushed?

I guess the time could be off a fuzz here or there but What do you mean longer pieces the shoulder getting crushed ?

 

[DLT]

In my opinion that’s the problem. Good annealing, good lube technique, camming over, no expander ball. My opinion……

I assume my annealing is ok. I try and smear as little lube as I can around the body as I know it doesn’t take much, how do you expand your necks if no expander ball ? A mandrel ? When I pull my cases off the expander ball in these rcbs dies there isn’t enough resistance to pull on the shoulder but a hornady set I bought first for this rifle acts like the neck is going to get ripped off the case.

 

[J.d. Popkes]

I assume my annealing is ok. I try and smear as little lube as I can around the body as I know it doesn’t take much, how do you expand your necks if no expander ball ? A mandrel ? When I pull my cases off the expander ball in these rcbs dies there isn’t enough resistance to pull on the shoulder but a hornady set I bought first for this rifle acts like the neck is going to get ripped off the case.

I’d suggest bushing dies and mandrels.

Bushing dies for sure.

But the Redding shell holders, to me, are the most important.

 

[LHSmith]

Always having used either Rockchuckers or Redding Boss presses, I have never found increased time in the die (i.e. dwell time) to have any effect on sizing. I also have never found running brass through the FL die a 2nd time to change anything. Loading for SR BR it is typical to get brass that requires more sizing than others. It is just the nature of cartridge brass- some resist sizing more than others even when fired the same number of times at the same load parameters. I do my adjustments by using die shims. Competition S/H's are an alternative. Different presses may have different amounts of flex.

 

[DLT]

I’d suggest bushing dies and mandrels.

Bushing dies for sure.

But the Redding shell holders, to me, are the most important.

Why would a case not get sized the first time through with plenty of dwell time I thought, but get sized the second time around ??

 

[DLT]

Always having used either Rockchuckers or Redding Boss presses, I have never found increased time in the die (i.e. dwell time) to have any effect on sizing. I also have never found running brass through the FL die a 2nd time to change anything. Loading for SR BR it is typical to get brass that requires more sizing than others. It is just the nature of cartridge brass- some resist sizing more than others even when fired the same number of times at the same load parameters. I do my adjustments by using die shims. Competition S/H's are an alternative. Different presses may have different amounts of flex.

Well for what ever reason the cases got pushed back as they should the second time around in this press. I guess nothing is guaranteed 100% but I studied and studied over this press before pulling the trigger. Never seen the first negative on it that I can remember

 

[J.d. Popkes]

Why would a case not get sized the first time through with plenty of dwell time I thought, but get sized the second time around ??

Flex in your press/linkage

Brass not being identical

 

[DLT]

Flex in your press/linkage

Brass not being identical

Would it be easy found ? Or how can I check it

 

[J.d. Popkes]

Try it on a couple pieces of brass

Take the decapping assembly out

Cam over on your regular shell holder, it’ll bump those too much but if you’re doing the rest correctly I’ll bet the shoulders are all the same.

 

[J.d. Popkes]

Would it be easy found ? Or how can I check it

Put an indicator on it if you want. There’s going to be a couple thousands of flex.

 

[DLT]

Put an indicator on it if you want. There’s going to be a couple thousands of flex.

On all presses or one that has issues ? And do you mean to set die up to cam over, then measure and see if the cases measure the same ?

 

[K22]

Before you go out and spend a ton of money on more equipment, I've using standard RCBS die with expander balls for 50+years without any issue whatsoever.

Expander Ball Discussion:
Are you getting any significant drag on the expander button? If so, are you lubing the inside of the case neck? Most expander balls are oversized and have a rough surface. I polished mine with very fine emery cloth to produce a "glass like finish" which significantly improves expander the neck without lengthening it. Also, by reducing it .001" often produces better fit.

Sizing Discussion
What are the fired datum line measurements versus the sized measurements? If the die is not touching the shoulder, then you could be extruding (lengthening) the case. You don't need to purchase competition shell holders. You can adjust your sizing die in small increments to find the optimum shoulder set back.

Although you don't need these either, I use Ship Shims which fit under the lock ring of the die to simplify making sizing corrections. These range from .003" to .010" and provide a full range of easy adjustment without having to reset your FL die. Available at Brownell's and are much cheaper than competition shell holders and quite frankly work better, at least for me.

I cannot comment on annealing since I don't use this process, but I wonder if any inconsistency in the process could be causing a problem.

The only thing I can think of that's causing the first sizing to be off is that you have a lot of flex in the press, or the sizing die in working loose, or you do not have sufficient cam over so that the die is at least touching the shoulder, or somehow the annealing is affecting the consistency of the brass but as I said, I do not anneal so this comment may not be applicable. It would be interesting to see the fired datum line measurement and the sized measurements. Is the shoulder being pushed back enough and consistently?

 

[J.d. Popkes]

On all presses or one that has issues ? And do you mean to set die up to cam over, then measure and see if the cases measure the same ?

Yes/Yes

 

[LHSmith]

I am not familiar with your press. I watched the video by MEC and am puzzled by the fact that once you hit TDC the handle will still move lower. Your press might not have true cam-over. My Redding Boss press has a roll pin stop that can be removed and the ram will go past cam-over. I tried it that way, but put the roll pin back so it provides cam-over. The Rockchuckers have the bottom link hitting a linkage strut- Both my presses have a hard stop -preventing the handles from further movement which means the ram is at TDC.

 

[K22]

I forgot to mention in my post that I had a lot of Remington cases that had a wide range of case head space. I don't know if this was due to some metallurgical or forming issue.

Some required shoulder set back after only one firing, and others had to fully fired formed which took several firings to achieve. I had to segregate those cases and just size with zero set back until the case were fully fire formed.