Case separation 5.56mm Dillon Loader


November 15, 2008, 02:24 PM
What do your Dillion shell plates measure?? Method used to measure was a steel plate under the shell plate, an RCBS vernier dial caliber. Should they measure the same as a standard shell holder at .125" ??

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November 16, 2008, 11:42 AM
Just get a case gauge and set the die to size just enough to fit. The ammo will run in anything and the brass will last longer.

November 17, 2008, 09:39 AM
This old 5.56mm shell plate is like using 4 different sized shell holders. .124" to .116" a variation of .008" The shoulder is pushed back to much, depending on what slot you used to adjust the FLRS die, causing excessive head space on firing, with case seperations. Yes a Shoulder Comparator or a case gauge would work , but an extra expense $$ that should not be needed.

November 17, 2008, 10:16 AM
The “shoulder” being pushed back shouldn’t have any bearing on sizing the cases (unless you have warped the shell plate). They are just there so you can remove the cases from the die after sizing. A case gauge runs about $20, do you have to have one? No, but if you are having problems it just might be the best $20 you’ve spent in a while.

November 17, 2008, 11:15 AM
Perhaps your concerns would be better addressed in the Dillon Forum, not THR Forum.

November 19, 2008, 09:15 AM
550 plate dimensions should be .250? thick top to bottom, .132 +/- .005 from underside of the shellplate to top recess where the die contacts.
Standard shell holders are .125"

November 19, 2008, 11:36 AM
243winxb, the deck height of the shell holder from the deck to the top of the shell holder is .125, Redding sells + or _ shell holders, from $40.00 to $60.00, so there is an advantage to measuring shell holders with a height/depth gage, RCBS will exchange shell holders that are not within specification, and will forward all callers to Redding if the caller wants competition/bench rest shell holders. Why? I do not know, a feeler gage will can be used to duplicate all variations of special shell holders from -.012 (.017 under a go-gage) under SAMMI specs for a maximum sized case to my favorite, the .016 over minimum (.011 over a go-gage).

If you have a shell plate that has variations in deck height, let Dillon know, remember, the Dillon ram is hefty and the shell is not sized in the center of the ram, the shell in the shell holder holder is off set (cantilevered), on small cases, not a problem, with good lube on large cases there should not be a problem their either.

The variation in deck height of a shell holder plate is directly related to the amount the shoulder is moved back, again there is no support under the shell plate, the shell plate and ram must be tight and tough, you could purchase a lot of tools but measuring the distance from the head of the case to the shoulder would tell you if your Dillon is producing (ISO) same-o ammo from each station.

RCBS made an add-on progressive press called the Piggy Back l and ll, the maximum length case that could be loaded was the .223 Remington (5.56 NATO), the diameter of the ram and off set of the shell holder positions put the leverage too far out from center to have the leverage required to size larger cases.

F. Guffey

November 19, 2008, 11:47 AM
then there those that grind a shell holder to reduce the deck height and or bottom of the die to increase the amount the the shoulder is moved back, sizing is relative, if the shoulder is moved back by reducing the deck height, the body dimensions (diameters) are also reduced, something like using a small base die, again I do not know why, a feeler gage will duplicate the results of the misguided effort.

F. Guffey

November 19, 2008, 11:51 AM
sorry about that,

I do not know why someone would grind a shell holder and or the bottom of a die, I know why someone would cut the top of the die off, it helps to do a good job if an in-line, angle and butt grinder is used.

F. Guffey

December 14, 2008, 02:12 PM
fguffey, The purchase of a Wilson Case Gage shows the ammo to be on the small side, the shoulder pushed back to much, but still within specification. Dillon will exchange the shell plate. Also thinking that some of the LC brass is brittle. Possibly from using the wrong cleaning agent on the brass, depleating the zinc in the brass. The neck seperates from the body on firing and on neck sizing on 4% of the brass. Possible other causes, brass loaded to many times (3). Or load to hot? Time will tell when i start with new brass.

December 14, 2008, 03:20 PM
This was loaded in the 80's and put in storage. after being fired 2 times. Some come apart on 3th firing, some on neck sizing. 5.56mm chamber. The body of a fired case just behind the shoulder measures .005" larger than a flrs round. The case is shorter after firing. The photos are of brass that came apart in the neck sizing die. The expander pulled the neck off. Yes they were lubed with RCBS lube. Brass looked normal before entering the die.

December 14, 2008, 06:28 PM
I've have the same problem reloading 7.62 x 54R that had been in garage storage for too many years for the guy to remember. Most of the brass was Norma if I remember correctly. The loads were hot enough to cause the bolt to be a bit stiff.

I size on a RCBS Rock Chucker and each time I ran the brass back through I lost a few more to the same break as in your photo. I could feel a small bump on the inside of the shoulder and could see small stress cracks on some "good" cases using a microscope. I finally shot the lot and pitched the brass.


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