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Is my sizing die defective or am i just dumb

JelliedEagle

Private
Minuteman
Dec 1, 2020
16
1
Santa Cruz, CA
Im getting ready to start loading 6.5CM on a Dillon 550C, in a single stage manner, and I have a Redding 2 Die set (not sure model). I picked up some once fired brass, and the base to datum measurement is 1.558"-1.560".. but i screwed in my sizing die almost as far as it would go until it touched the shellplate, and the base-datum measurement is still the same at around 1.560" after sizing..

Am I missing something? the die is supposed to default size to minimum sammi spec, which is 1.541" for the chamber and 1.5368" for the cartridge I'm pretty sure. Also the brass fits right into my L.E. wilson case gauge, except it just needs to be trimmed down a hair..

So If somebody could shoot me some wisdom I'd appreciate it because I don't wanna blame the equipment since I'm probably the weak link here.
 
Shellplate set too high?

ETA:
Are you sure on your measuring technique?
If the brass fits into the Wilson gauge and the base is between the two steps, the headspace is acceptable.
Perhaps the chamber it was fired in was overly tight.
For the neck/trim length you have to set it base down on a flat surface.
 
I always tighten the screw holding my dillon shellplates as far as i can, until right before it won't turn anymore, so i don't think so. I read that one of the guys at whidden gunworks sands the bottom of his dillon shellplates to make the fit tighter so the brass doesn't move as much, but that shouldn't be required to size properly.
 
I have good measuring tools. and the brass won't chamber in my new odin gunworks upper. I use L.E. wilson gauges, and a forster datum dial with digital caliper obviously.

Is it possible that I need a small base die? I've thought of this, it just seems kind of whack that redding would produce a sizing die that couldn't size brass anywhere near min. spec.

redding is the only company that dillon sells dies for with regard to die sets they don't make themselves.. at least last year when I bought my equipment 6.5cm was the only set they didn't make. so I'm just kind of dumbfounded that the size is so off
 
Oh, man!!
Nothing like just placing the ball on the tee for some smartass, not unlike myself!!😄
 
If your fired brass wont hit your sizing die and your sized (unsized) brass fits in the LE Wilson gauge you have 2x points of reference saying your brass is at/under standard spec.

That same brass wont chamber in your new upper?

Does the bolt come to a hard stop when it tries to chamber your brass or more of a mushy sticky stop?

What about extraction, does it extract smoothly or need a good tug to get it back out again?

have you go/no go'd your chamber, it might be short?

If you have easy extraction it is most likely headspace related, if the brass gets stuck and needs a good tug to pull it is most likely case diameter related.

Edit: And have you tried a piece of brass that HAS been trimmed to length?
 
Is your Redding die set a FL resizer or just neck resizer. Have you used it in a single press and does it work fine on that?
 
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A small base die may or may not push the shoulder back more. I think in your case there is too much flex in the press. Put the die in a single stage press, and keep turning it in until you get the desired shoulder bump.
 
This is an uncommon, but not unheard of problem. What it comes down to is that the shell plate height + die size are too large together such that the case isn't getting sized enough/at all to be appropriate for your chamber size.

Two relatively easy things to do to fix this:

- Buy a set of different sized shell holders https://www.redding-reloading.com/online-catalog/35-competition-shellholder-sets

- Sand down your existing shell holder by securing some sandpaper to your bench top, using a little oil, and then just running it flat until a few thousandths are gone.
 
IMG_20210904_111659971.jpg
IMG_20210904_111632080.jpg


This is the "sized" and trimmed brass not fitting in chamber, and not going into battery.
 
Im getting ready to start loading 6.5CM on a Dillon 550C, in a single stage manner, and I have a Redding 2 Die set (not sure model). I picked up some once fired brass, and the base to datum measurement is 1.558"-1.560".. but i screwed in my sizing die almost as far as it would go until it touched the shellplate, and the base-datum measurement is still the same at around 1.560" after sizing..

Am I missing something? the die is supposed to default size to minimum sammi spec, which is 1.541" for the chamber and 1.5368" for the cartridge I'm pretty sure. Also the brass fits right into my L.E. wilson case gauge, except it just needs to be trimmed down a hair..

So If somebody could shoot me some wisdom I'd appreciate it because I don't wanna blame the equipment since I'm probably the weak link here.
When you say single stage on a 550, Do you mean just running 1 round through at a time and never fully loading the shell plate?

I would start with making sure the shell plate is flat and polish the bottom side of it to verify that.

Next, try seating a bullet in the #3 station, at the same time you're sizing, could be some flex in the 550 and the other could balance it out.

Lastly, if still having issues, take a couple thousands off the bottom of the die, so it can screw in further to size brass more.

Here's a video of tuning the shell plate for the 550 so you can see what I'm talking about.

 
..... loading 6.5CM on a Dillon 550C........ but i screwed in my sizing die almost as far as it would go until it touched the shellplate, and the base-datum measurement is still the same at around 1.560" after sizing......
Turn the sizing die in some more; 1/8 turn lowers the die about 0.009 inches. Do not hesitate to cam over a bit.
 
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"Once fired brass" -so not fired in your chamber?

Double check your trim length, although my bet is on neck sizing die, like someone mentioned above. I've bought one on accident before. Redding dies should size sufficiently on a 550, IME. Lets see pics of the die and your press setup.
 
Two relatively easy things to do to fix this:

- Buy a set of different sized shell holders https://www.redding-reloading.com/online-catalog/35-competition-shellholder-sets

- Sand down your existing shell holder by securing some sandpaper to your bench top, using a little oil, and then just running it flat until a few thousandths are gone.
The Redding Competition shell holders will NOT help if his die is not bumping the shoulder enough. They go from +002" to +010", not MINUS, which would give more shoulder bump.

The sanding down a regular S/H method can work.
 
I had the same problem with my 550 trying to small-base size brass first-fired in .mil M16s and M4s.

I don't have a lathe, surface grinder, or other machine shop tools, so I size on a single-stage press with a conventional shell holder. It allows me to skirt the problem of 550 shell plate thickness. Problem fixed.
 
So here's the deal.. nothing has changed with regard to the sizing die, as I'm still having trouble bumping the shoulder for some reason. gonna try "tuning" the shellholder probably.

with regard to the brass not chambering, I think I may have just been to gentle when charging, because I didn't want to get a cartridge hopelessly stuck in my new upper.. but since the brass was fitting in my wilson gauge I let the BCG chamber the brass with full spring force, and it chambered and ejected successfully. I tend to overthink things.. (dumbass) I thought that i should have been able to chamber the brass without much force, but forgot to take into account how much pressure the extractor/ejector pin require.

I'm still confused as to how the brass fits into my wilson gauge so easily and chambered in my gun, because the base-datum measurement is 1.548" but the sammi max chamber measurement for 6.5cm is 1.551".. I know a lot of chambers are made a little big, so maybe that's all it is.

In the future when checking to see if brass will fit well in my chamber, should i remove ejector and extractor or can i just eyeball how it fits? Is it possible for brass to damage the inside of the chamber or since it's steel its okay?
also, since sammi specs seem to be somewhat relative, what is a reasonable headspace range to shoot for, since the once fired I started with was at 1.560" and I was only able to get it down to about 1.548? (for now)
 
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Unless your drop-in gage was cut with the same reamer as your chamber, you're only going to see if the shoulder was pushed back enough, and if the case is too short or too long (requiring trimming)

It CANNOT tell you if your case body was sized enough to fit your chamber -- you can only determine that using your chamber. If you remove the bolt, does a loaded cartridge drop in completely without needing to be pushed in with a finger or the bolt? When you tip the muzzle straight up, does it drop under gravity? If not, you need to get a new sizing die.
 
I have cut a few thousanths off the bottom of several dies for use in my Dillon 550. Easiest way would be in a lathe. You could probably file, grind, sand a little off if you don't want to take it to a machine shop.

Also check to see if the die's overall length is too long to work or if the outside diameter is too big around to fit in the shellplate recess. I found that to be the case with some dies as well. I had to skinny up the bottom of the die so it would fit in the shellplate.
 
I had the same problem with my 550 trying to small-base size brass first-fired in .mil M16s and M4s.

I don't have a lathe, surface grinder, or other machine shop tools, so I size on a single-stage press with a conventional shell holder. It allows me to skirt the problem of 550 shell plate thickness. Problem fixed.

intelligence personified
 
So here's the deal.. nothing has changed with regard to the sizing die, as I'm still having trouble bumping the shoulder for some reason. gonna try "tuning" the shellholder probably.

with regard to the brass not chambering, I think I may have just been to gentle when charging, because I didn't want to get a cartridge hopelessly stuck in my new upper.. but since the brass was fitting in my wilson gauge I let the BCG chamber the brass with full spring force, and it chambered and ejected successfully. I tend to overthink things.. (dumbass) I thought that i should have been able to chamber the brass without much force, but forgot to take into account how much pressure the extractor/ejector pin require.

I'm still confused as to how the brass fits into my wilson gauge so easily and chambered in my gun, because the base-datum measurement is 1.548" but the sammi max chamber measurement for 6.5cm is 1.551".. I know a lot of chambers are made a little big, so maybe that's all it is.

In the future when checking to see if brass will fit well in my chamber, should i remove ejector and extractor or can i just eyeball how it fits? Is it possible for brass to damage the inside of the chamber or since it's steel its okay?
also, since sammi specs seem to be somewhat relative, what is a reasonable headspace range to shoot for, since the once fired I started with was at 1.560" and I was only able to get it down to about 1.548? (for now)

Measure the case that you chambered using the full force of the bolt. See how much it pushed the shoulder back.
 
Do you have a 6.5 Creedmoor Go headspace gauge? Forster gauges are set for minimum SAAMI spec.

Use your Forster Datum Dial to measure the gauge. What did you come up with for a measurement and what size hole did you use? The Hornady tool says use the 0.375" hole for the 6.5 Creedmoor but the SAAMI spec list the data measurement at 0.400". Their instructions say measure the neck and measure the shoulder, add the two and divide by 2 and that is how they get the 0.375". Not only that but there is a slight chamfer at the hole opening.

You will find that the Forster Datum Dial doesn't match the published length of your go gauge. That is because it is a comparator tool and not an inspection gauge. It will allow you to measure the fired case and sized case and compare the shoulder setback or lack of setback.

Your picture shows the bolt not fully closed but are you certain that the extractor was over the rim of the cartridge? It's hard to tell from the photo if the case is in the barrel completely or not.

If a fully sized case will not chamber than a small base die may be needed. As previously stated Redding does may shell holders that allow you to precisely bump shoulders and may solve your problem.
 
Do you have a 6.5 Creedmoor Go headspace gauge? Forster gauges are set for minimum SAAMI spec.

Use your Forster Datum Dial to measure the gauge. What did you come up with for a measurement and what size hole did you use? The Hornady tool says use the 0.375" hole for the 6.5 Creedmoor but the SAAMI spec list the data measurement at 0.400". Their instructions say measure the neck and measure the shoulder, add the two and divide by 2 and that is how they get the 0.375". Not only that but there is a slight chamfer at the hole opening.

You will find that the Forster Datum Dial doesn't match the published length of your go gauge. That is because it is a comparator tool and not an inspection gauge. It will allow you to measure the fired case and sized case and compare the shoulder setback or lack of setback.

Your picture shows the bolt not fully closed but are you certain that the extractor was over the rim of the cartridge? It's hard to tell from the photo if the case is in the barrel completely or not.

If a fully sized case will not chamber than a small base die may be needed. As previously stated Redding does may shell holders that allow you to precisely bump shoulders and may solve your problem.
Thanks for that piece of information regarding the Forster datum dial.. may have cleared up most of my confusion. I had my dial set for .30-06. This is why I titled the thread as such. stupid mistake. i just checked the brass under the .400 setting and its actually under spec, not over.
luckily I think I only ruined 3 or 4 cases.
 
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Shellplate set too high?

ETA:
Are you sure on your measuring technique?
If the brass fits into the Wilson gauge and the base is between the two steps, the headspace is acceptable.
Perhaps the chamber it was fired in was overly tight.
For the neck/trim length you have to set it base down on a flat surface.
You were right from the beginning, my Measurement setting was off.
 
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The brass was fitting in my wilson gauge
Shouldn't the fact that the brass passes the gauge test mean the brass has been sized to at least SAAMI spec, if not below?

I thought that i should have been able to chamber the brass without much force
Correct, it should take no force to chamber the brass.

I'm still confused as to how the brass fits into my wilson gauge so easily
As am I at the moment. If the brass fits your gauge, my understanding is the brass should be within SAAMI spec.

because the base-datum measurement is 1.548" but the sammi max chamber measurement for 6.5cm is 1.551".. I know a lot of chambers are made a little big, so maybe that's all it is.
Don't worry too much about these numbers just yet. What's important is the different measurements with YOUR particular gauges between brass fired in your chamber and brass after sizing, particularly the shoulder location.

should i remove ejector and extractor or can i just eyeball how it fits?
Definitely remove your ejector and anything else that adds force to closing your bolt fully into battery.

I am unfamiliar with AR15's, are the locking lugs part of the barrel assembly or machined into the upper?
Ideally you would want to remove your barrel and bolt and do this check by hand on a stripped bolt.

Is it possible for brass to damage the inside of the chamber or since it's steel its okay?
The brass wont damage anything, but don't force it either. Adequately sized brass will require no force to close the bolt.

since sammi specs seem to be somewhat relative, what is a reasonable headspace range to shoot for
Bumping the shoulder back .004 (four thousandths of an inch) under your fired brass is a good place to be.


The #1 thing you need to do right now is verify your chamber is within go/no go range, on a fully stripped bolt. Anything else is just speculation until this can be verified.