Why can't I measure shoulder bump?

[ronemus]

• Is all brass created shorter than SAAMI initially?
• There are many different reamers/brands for the same cartridges, how different are the dimensions?

I find that new brass is fairly uniformly 0.006" short, which is also usually the SAAMI specification for minimum brass length. It also seems that factory chambers run to SAAMI max, and none approach minimum dimensions. That's probably done with malice aforethought so that the average consumer will be able to buy any ammunition and have it work in every gun chambered for that ammunition. That average consumer doesn't reload, and only cares that he gun goes bang when desired and that a "group" at "long" range (100 yards) is about the size of the vital zone of a whitetail. Those of us who work to higher standards of accuracy and precision have to put up with that because we're such a small fraction of the market, and because idiots (or their survivors) resort to the courts.

All that has me remembering the time I found a pile of brass on the range with a .308 headstamp that had straight walls (no sign of a bottleneck) - probably fired from somebody's Garand or deer gun in '30-06; the owner probably didn't recognize that there was a problem.

 

[KY_Windage]

If you can't get the brass sized to your liking, try a mod on the shell holder.
Chuck one upside down in a drill press and run it down on an "oiled sharpening stone". Comes out looking like it was factory made AND works like a champ!!
Measure first and when you've taken the right amount off, mark it so it doesn't get mixed up with a standard/non modified shell holder.
MUCH easier than trying to modify a die. And shell holders are ea$ier to replace than die$.

That does not sound as easy as unscrewing the FL die out of my press, walking 5 steps to my grinder, turning it on, grinding 1/16" off the bottom of the die and then giving the hole a quick wipe with some sandpaper. I've done that to several dies and never had to "replace" one yet. Can't imagine why you ever would.

The problem: the die is hitting the shell-holder too soon. Camming over isn't going to fix it, and neither is annealing. You have to either remove material from the shell-holder or from the bottom of the die. Which you do is purely personal preference. Either works fine.

Once you do one or the other you should have no problem setting your shoulders back as much as you want. Also, I find the Hornady comparator tools perfectly adequate, though you may have to use the bullet comparator bushings to measure some of your cases, if you are picky about exactly where on the shoulder you want to take the measurement.

 

[ronemus]

Once you do one or the other you should have no problem setting your shoulders back as much as you want.

Because the shellholder is a small fraction of the cost of a die, I tend towards modifying the shellholder. I have found on occasion that the problem I thought I needed to fix was actually something else, and I needed to back out of my attempted fix (just sayin').

 

[KY_Windage]

Because the shellholder is a small fraction of the cost of a die, I tend towards modifying the shellholder. I have found on occasion that the problem I thought I needed to fix was actually something else, and I needed to back out of my attempted fix (just sayin').

I have already paid for the die. I am never gong to sell it, modified or not. I am never going to have to "replace" it because of the modification. Even if, after shortening a die, I change to another rifle with a shorter chamber, so that the modification w/n/h been necessary, so what? The shortened die works for that one just fine, too.

It was the die that was spec'd out wrong, not the shell-holder. I like to correct the part that was made wrong.

I buy a seating die for every bullet that I seat for that rifle, so that once I get it set right I never have to mess with it again, or at least not until the lands move. But I can't buy just a seater anywhere, I have to buy the 2-die sets, so I have at least two or three spare, unmodified FL dies stored away for every one of their twin brothers that I ground down. I can therefore replace any of my FL dies for FREE should I ever need to, whereas a shell-holder is going to cost me $9.00 or something.

Anyway, like I said, it is purely a matter of personal preference.

 

[dkhunt14]

That does not sound as easy as unscrewing the FL die out of my press, walking 5 steps to my grinder, turning it on, grinding 1/16" off the bottom of the die and then giving the hole a quick wipe with some sandpaper. I've done that to several dies and never had to "replace" one yet. Can't imagine why you ever would.

The problem: the die is hitting the shell-holder too soon. Camming over isn't going to fix it, and neither is annealing. You have to either remove material from the shell-holder or from the bottom of the die. Which you do is purely personal preference. Either works fine.

Once you do one or the other you should have no problem setting your shoulders back as much as you want. Also, I find the Hornady comparator tools perfectly adequate, though you may have to use the bullet comparator bushings to measure some of your cases, if you are picky about exactly where on the shoulder you want to take the measurement.

It is possible annealing can fix it. I have seen annealed cases bump .005 to .006 more with the same die setting. It all depends on the brass. Occasionally you get a bad die that doesn't quite size enough or a gun at minimum headspace where you need to alter the die or shellholder. Matt

 

[KY_Windage]

OP is working with once-fired brass. Annealing is not going help him.

 

[bsekf]

I have always blamed it on non-uniform spring back. If you twirl the case in the comparator, the measurement will often change.

 

[cw308]

I never like to add any type of stress anymore , I'm the guy who snapped the lug bolts on my car from over tightening, learned my lesson a long time ago. I do remove the slop from my dies when setting up , even use a O ring under the lock ring , my sizing is consistent without stressing the press , maybe I'm just lucky . I wet tumble , brass is spotless and I use RCBS Case Lube and lube by hand , it sizes very easily . It could be sizing with brass that isn't properly clean and lubed makes the sizing more difficult? I know I'm gonna get jumped on for this one , Be Nice Guys.
Chris

 

[Orr89rocz]

I have an old set of bench rest dies (i think bonanza?) for a .257 rob that will not shorten a case more than a given amount no matter how much cam over there is and no matter how far down the die is screwed down. Not sure what that is all about but i leave it as is, there may be only .001” of bump back, still chambers fine with a slightly stiff bolt on close.

 

[Burnt Powder]

All of mine are .125

I’ve got probably half dizen or more brands of shell holders, other than one Pacific shell holder they are all within a .001or two. Keeping the ram and shell holder clean is very important too. I’ve faced several .001s off shell holders to get what I want and sometimes I like the thicker Pacific shell holder for various reasons. I have a lathe and make my own measuring standards, no special tool. Not concerned about what the measurements are, just how they compare and fit. My B&S dial calipers is a pretty danged accurate measurement tool! Good enough for handloading!

 

[Tokay444]

My dies don’t touch my shell holder. I get EXTREMELY repeatable bump, and runout numbers less than .001”, to the point I stopped checking. I don’t measure bump with a comparator on a caliper either (good for +/-.002”). I use a fixture with a dial indicator.

 

[M-61]

Anyway, never mind, I have no interest in what you to have to say.

If indeed this were true why do you reply?
Anyway your 'tone' and wording is uncalled for especially to Boyd Allen who has contributed much to this site.

 

[DJSBRS]

We arrived at the amount of time in the flames of the annealer that gave that result, while preserving enough hardness in the neck so that heavy bullets loaded in magnums, fed from magazines did not move. The press was a Forster B2, Later we found that the problem returned after a couple of firings, which indicated that, going forward, we would have to anneal every other firing to keep the bump uniform. The first time we tried cases, the anneal was not enough. We added a second to the dwell time in the flames and got what we were looking for.

You are exactly correct Boyd. And on some very rare occasions, a particular piece of brass will continue to give you problems due to that piece of metal make up. Do your self a favor and trash that piece off brass so you will have a piece of mind later on.

DJ

DJ's Brass Service

 

[BoydAllen]

You are exactly correct Boyd. And on some very rare occasions, a particular piece of brass will continue to give you problems due to that piece of metal make up. Do your self a favor and trash that piece off brass so you will have a piece of mind later on.

DJ

DJ's Brass Service

Thanks for the tip.

 

[MagnumManiac]

If indeed this were true why do you reply?
Anyway your 'tone' and wording is uncalled for especially to Boyd Allen who has contributed much to this site.

Because I felt like replying...just like I am replying to you.
This is your OPINION.

 

[K22]

Wow! Probably missing something here but I've never seen something so relatively simple be made so complex. A historical perspective from an "old fart."

No reason to get emotional or nasty - Remember, there is only two reason to size a case 1). So it chambers in the rifle preferable without significant resistance, and 2). So there's enough neck tension to hold the bullet.

Before all this gadgetry of bump gauges, case gauges, micrometer gauges etc. experienced reloader's learned that following the die mfg. instructions resulted in over sizing the case so they began a trial and error process of adjusting the FL die to produce just enough sizing so the case would chamber optimally to enhance precision.

They also learned that as cases aged from repeated firing some adjustment may be necessary to maintain this optimum sizing. The rifle's chamber became the ultimate gauge to assess optimum sizing. It was really quite that simple - it still is!

Enter the gauges which enabled reloaders to measure and record the exact amount of sizing. That was convenient and effective as far as it goes but it doesn't change the original premise as to why cases are sized.

Add in that each rifle, lot of cases, brand of cases, dies, and slop in presses can be different then it become obvious that there are no absolutes - you have to adjust to those variables to produce the optimum amount of sizing.

So the need for cam over vs no cam over may or may not apply. With my equipment, I can't get any shoulder setback without some degree of cam over depending of the variables involved. But my press and dies are over 50 years old. Also I use a variety of common brands of cases.

Now enter competition shell holders, shims, the Salazar "O" ring method to allow for precise and repeatable die adjustments without having to reset your die lock ring. They all work just fine if you know what your doing and why. It makes die adjustment easier but doesn't change the original premise.

I've loaded thousands of bottle neck rifle cartridges for close to 50 years using necks sizing, partial sizing and full sizing. I've never had a head separation even using the die mfg. instructions which, in most cases, I believe creates too much sizing for optimum precision.

The only times I've encountered sizing problems is with neck sizing and partial sizing since over time I'd encounter hard chambering in some rifles. Also, using cases fired in other rifle chambers would occasionally create sizing / chambering problems.

Bottom Line: resizing cases in not some mystery process especially with all the modern gadgets that make it easier to make adjustments but you're still trying to accomplish the same results that reloaders have sought since reloading began. Just stay focused on the purpose and don't get caught up in all the measurement mania.

 

[CA_Shooter]

I recently bought the redding competition shell holders. I needed to change my bump, and it took me about 15 minutes (including waiting for my Hornady lube to sit for 60 seconds per shell) to set up the right bump amount

I suggest the redding competition shell holders

 

[Tokay444]

I recently bought the redding competition shell holders. I needed to change my bump, and it took me about 15 minutes (including waiting for my Hornady lube to sit for 60 seconds per shell) to set up the right bump amount

I suggest the redding competition shell holders

If it took me 15min to adjust my die to the amount of bump I needed, it would be because I was doing something else for 13.
Just saying. Measure bumped case. Measure bottom of die to bottom of lock ring. Subtract and find the difference. Thread die in or out by the difference, and be done.

 

[Murray Brook]

@BoydAllen
In one of your prervious posts you mentioned you had a fancier way of setting up shoulder bump. I would be most interested in reading what you have to say on this. TKS

 

[BoydAllen]

@BoydAllen
In one of your prervious posts you mentioned you had a fancier way of setting up shoulder bump. I would be most interested in reading what you have to say on this. TKS

Since you asked.....With once fired brass, we really don't know how far short of tight at the shoulder in the chamber we really are. Most of the time simply sizing to equal the once fired dimension works fine, but if we want a better idea of just where we are you can try this. First of all take the primer out of one of your once fired cases. then put a piece of Scotch tape on its head and trim it so that it is like a washer on the flat surface only. Trim to the top of the bevel at the bottom of the rim, and cut out the part over the flash hole. Next take out your bolt's firing pin assembly, then try the fired round in your chamber, but do not force it at all. The bolt will probably not close. Then you use whatever tool you prefer to measure the head to shoulder of this case. Starting with the die backed out a little from touching the shell holder, perhaps a sixteenth of a turn or so, with the top of the die and bushing removed (To remove a bushing from a die that is in a press simply shove a neck brush into the bushing and pull it out.) lube the case and start sizing, making the slightest of adjustments, and then measuring until you see that the taped case is .001 shorter (head to shoulder) wipe off all the lube and try it in your rifle. If the bolt will still not close, adjust the die by so small an amount that you are really not sure that you moved it, relube, resize and measure the case so that it is .001 shorter, and then wipe off the lube and try it in the rifle. At this point you should be able to close the bolt with some feel, or the handle may drop. If it drops, you are there, unless it is for a hunting rifle in which case you may want to bump another thousandth. I shoot my match, and usually my varmint brass in rotation so that all of the cases in a set get fired and sized the same number of times, but even so, when only bumping .001 with brass that has not been annealed, for critical work you will want to check to see if they all have been bumped to the same dimension, the reason being that you can shoot small with all snug, or all relatively loose, but mixed will, in my experience open up your groups. Remember that one full turn of a die gives .071 of up or down movement in the press, so trying to do an adjustment of .001 can be tricky. If you blow it, and go past your mark, you can start again with another once fired case. I usually load at the range which allows me to fire the same case with a safe but warm load several times until the shoulder to head dimension stabilizes at a maximum and then set my die to bump back .001 from that, but there are times when I do not want to make a special trip just to set up a die and size a few cases. It is for those occasions that I came up with this method. Questions?

Added a little later: Obviously having a PMA Tool Micro die adjuster makes doing the adjustments very simple, and you could also use die shims, or Whidden's dies or lock ring that are set up for exact adjustments. In any case, this should give you the basic idea.