Inconsistent shoulder bump driving me crazy….help?

[jlow]

Looking for some help here on this from the experts.

I am using new LC09 223 brass fired once through my rifle’s Wylde-chamber. Measuring the brass with the Hornady L&L headspace gauge the case length is on the average 1.4602” with an ES of 3 thousands. I anneal the brass after every firing including this one. I adjusted the Redding Type S Bushing FL sizer die (with sizing button removed and no bushing) to bump the shoulders back about two thousands (got an average of 2.3 thousands), and this gives me an average length of 1.4579” but the ES of bump for the same 14 pieces of brass is 7 thousands...

For sizing, I use Imperial case sizing wax a touch on the wax case and rubbed with rotation on evenly on the case with my fingers – it’s a very thin coat.

What am I doing wrong here?

 

[Killshot]

Assuming EVERYTHING is tight (dies, shellholders, press linkages) and no play is at fault........

What kind of calipers are you using? You shouldn't be seeing a .003" spread in the measurements of recently annealed, just-fired brass.

 

[gotcha]

There are a number of variables that could be the cause. Start by chkng that comparator body & cup are held tight to the jaw & square to the opposite jaw. Take readings on 5 pcs of brass then repeat at least three times. Are the readings consistent?.......What happens if you turn/spin the case while reading? Do you hold the caliper to a light scource to insure the case head is perfectly flat to the jaw? Do you find that the moveable jaw flexes when taking readings? (cheap calipers will do this right out of the box)..... Start by QCing your measuring tools then procede to other possibilities. BTW, Sinclair offers a H/S cup that makes contact along the entire shoulder making it easier to square the case to the jaw. Hope this helps

 

[243winxb]

Brass has to be fired & neck sized only at least 3 times to get a true reading off the fired brass. If loading for an auto, start with the FL die backed off the shell holder .005" Test the sized brass to see if it fits the chamber. When the head to datum gets to long, the slamming of the bolt will set the shoulder back at least .001" Soft annealed brass maybe even more. The firing pin strike can set the shoulder back .006" or more in some rifles. I think this depends on the type of extractor & fit. The brass will expand forward, but not always to the full length of the chamber on firing.

 

[shanmoll308]

Inconsistent annealing method, varying temperatures from brass to brass may be your problem. Are you annealing by hand or using a machine? It may also be.. using inconsistent force on your press while your full length sizing. Re-setup your die to bump back again, this time use a firm downward force on your press each time while turning your die down incrementally and measuring for bump as you go.

Hope this helps.

Adrian.

 

[Keith Glasscock]

Lubrication and dwell time at the top of the press can also affect shoulder bump...

 

[LHSmith]

This "dwell time"....is that something from Tony Boyer's Book?

 

[mikecr]

Once fired isn't fireformed to any baseline yet, and definitely not needing annealing.
From here, lube is another factor.
And Measurement is always a factor.

I know I'm in minority, but I've tested various case lubes for bumping, and wax is by far my worst for precision.
The best that I've tried 'so far' is RCBS case lube. This is the stuff you put on their pad, but I'm better using a shop towel with a bit soaked in.
And it's slippery as astroglide,, but seriously, keep it off the night stand...

 

[jlc204]

I too was having inconsistent shoulder bump using a redding body die and imperial wax. I stopped applying any wax at all to the shoulder and my results became more consistent.

 

[Alex Wheeler]

Get some redding competion shell holders and set up a hard contact between shell holder and die. Problem solved.

 

[LHSmith]

I too was having inconsistent shoulder bump using a redding body die and imperial wax. I stopped applying any wax at all to the shoulder and my results became more consistent.

Good point. Any type of lube on the shoulder will create problems

 

[LCazador]

Get some redding competion shell holders and set up a hard contact between shell holder and die. Problem solved.

I'll echo this statement . You cannot just back the die off . Your die must abutt the shelllholder or your headspace dimensions will be all over the place .

 

[jlow]

Thanks guys for your input, some good questions and ideas here. So to answer the questions:

1) The calipers are a pair of Mitutoyo 500-196-20 Absolute Digital Calipers, I think they are generally recognized as being accurate.

2) I am fairly sure that the measurements are accurate. The reason is when I measure bullet seating depths with the same calipers using the bullet comparator instead of the headspace gage, I routinely get small ES i.e. today from 25 rounds ES= 2 thousands. I am always very careful when I put the comparator on the calipers, line them up carefully, tighten them down, and lightly giggle the rounds so that the true lengths get measured.

3) I agree that once fired brass does not have the best chance to give me true headspace, however that is actually a different question/problem than what is discussed here which is my ability to get consistent shoulder bump (i.e. regardless of whether it is the correct distance to bump). To avoid getting off topic, let’s put that to the side and help me deal with this specific issue first.

4) Annealing could be a problem. I am doing it by hand using a socket and drill driver. I am careful to hold it a consistent distance and I carefully time the duration of heating but I am sure that it is not as consistent as one of the machines we have been talking about. This could be one of the problem.

5) I would like to avoid a discussion of whether once fired brass needs to be annealed. It is a reasonable question but if it was done properly, it should not affect the ES of the bump.

6) Consistent force on the machine is possible but not likely. I am very careful when I pull the level. A good gauge of this is the consistent bullet seating depths that I usually can achieve. I do turn the die down slowly and carefully to get the proper degree of bump, and this is the reason why I can get the average 2 thousands bump that I was targeting for. The problem here is the ES of the bump.

7) Lube – I use a very thin layer of Imperial sizing wax which I understand is the best. I hear that mikecr thinks it is the worst and would like to hear more about this i.e. how that was determined and the rationale.

8 ) As for not applying lube to the shoulder, I guess if one was adding a lot of lube, that is understandable since it tends to collect there. My question for jlc204 is does he think my application of a super thin coat of wax could still cause this? Not pushing back on this as it is interesting, just trying to get more info.

9) I am very interested in hearing more about the Redding Competition shell holders, can you please elaborate in more detail as to why it is so much better?

 

[jlc204]

jlow,
A thin layer is all I was applying also...
For the life of me, I couldn't figure out my inconsistencies. I then stopped lubing the shoulder, because it is unnecessary, and results definitely improved. I began seeing all my cases within +/- .0005.
Just a suggestion for a possible easy fix.

 

[LHSmith]

When I was new to reloading, I noticed if I over-lubed a case, it would dent the shoulder. Apparently, the lube/wax has a propensity to migrate to this area. Another reason to regularly clean out the dies.

 

[necchi]

3) I agree that once fired brass does not have the best chance to give me true headspace,

Is all the brass streached to the chamber the same?

What I mean is, did you measure all the brass before you bumped the shoulders?
It could be all the cases are not the same before you sized.
Over annealing could have softened some of the cases more than others, thus they're not acting the same in the die.

I'd lay off the annealing for awhile,, maybe get'm every 3-4 firings.

 

[gotcha]

Speaking from experience your LC-09 is TUFF, thick brass. You'll drive yourself crazy by not fire forming & NK sz. (only), 3 times as suggested. Keep track of your average H/S length after each firing. DON'T buy the competition shell holders until the brass is fully fire formed and you've proven your dies won't give desired H/S without being set above the shell holder. Your dies are most likely SAAMI spec. & not designed for the minimal H/S you desire. Due to press linkage tolerances & variations in lube application you must set your F/L die to make firm contact to the shell holder to get consistent shoulder set back. A Lee collet die would be excellent for NK. sizing. Reasonable $ too. .... Once you're fully fire formed you'll see less than .001" variance in H/S even if the annealing is a bit uneven.

 

[jlow]

Thanks again guys – more fruit for thought for me. Here are some answers and questions:

1) Regarding the lube question, I recognize the classical problem with too much lube and how it can dent the shoulders and the possibility that even a small amount of stuff can end up there and cause the slight i.e. 3-4 thousands bump. The question I have is would this happen with a Redding Type S Bushing FL sizer die that does not have a bushing in it? The reason I ask is I think this usually happen when using a regular FL sizer die that normally significantly under size the neck on the way down and so the lube from the bottom cannot get pass the neck and gets trapped in the shoulders. With no bushing in my die, it seems that any lube should be able to get out pass the necks?

2) For necchi, yes, as mentioned in the OP, all the brass are from the same batch that I brought new and fired once in my chamber. They did not have have the same length after firing but their lengths had an ES of 3 thousands. The example I quoted I measured every piece of brass both before and after bumping. I then subtracted the initial length from the final length to get the bump. The ES of 7 thousands is from this batch of bump numbers. I agree annealing variation could be a reason for my problem.

3) Gotcha – this was from a gas gun and so I have to FL resize. This question is for you and also zfastmalibu and LCazador, it involves “hard contact between sheel holder and die” and “ you cannot just back the die off”. I looked at my setup and the die is definitely backed off and not touching the die. I looked at the instruction from Redding and it says to “adjust to make contact with the shellholder when the ram is in tits uppermost position and then backed off approximately ¼ turn”. The real problem I have is how far down I seat the die is basically how I adjust headspace. If I am off the shell plate now and I adjust it down so that it contacts the shell holder hard, the shoulders will be bumped down too much. Where am I going wrong with this logic?

 

[gotcha]

Jlow, I feel your pain! I didn't consider your point in #3 'til after the last post. My apologies..... Traditionally a F/L die would be turned snugly to the shell holder to square the rough 7/8X14 threads to the shell holder to maintain co-ax of the sized case & compensate for press "slop" which causes eratic H/S. Frankly I don't know how the 1/4 turn off the shell holder could provide consistent H/S. A question better answered by Redding. Or a member here w/ 1st hand experience w/ your set of variables. Are your dies marked "Wildey"? are you SURE your brass is fully fire formed?

 

[Hopkins]

That is the reason others have mentioned the use of Redding competition shell holders. The different shell holders provide a range increase at battery of the die and shell holder for the distance between the shoulder of the die and bottom of the case head.