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Am I Full length sizing correctly?

Space Jam Darimon

Private
Minuteman
Sep 5, 2021
35
4
USA
Hello,

I’m full length sizing some of my 6.5 creedmoor brass for my hunting rifle that has been once fired(was factory Hornady 143 Eldx).
I measured 5 random cases from the lot with my Hornady head spacing gauge for the caliper(used the proper attachment c375). They measured anywhere from 1.557 1/2 to 1.559. I measured the same 5 cases after full length resizing and they came out at 1.562. I think stuck them in a Lyman ammo/headspace tool and the head of the case sticks out just over the maximum.
I noticed after running them through the die that I was getting a ring on the bottom of the case, close to the head. I’ve attached a picture below.
I also noticed when running the case up into the die all the way up, that the shell holder wasn’t touching the die.
Am I don’t all of this correctly? I feel as I’m not although I followed the directions when setting up the die. Dies are Hornady Customs if that helps at all
 

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seems like your not bumping the shoulder yet so as said id slowly work the die down until your bumping shoulder back .002" from fired. Die will not always touch the shell holder.
 
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How do you know you’re bumping the shoulder back?

I ended up having to screw the die in about 5/8 more of a turn, going in 1/8 turn at a time. I grabbed the rifle that they are for and kept turning the die 1/8 a time until the case chambered nicely and not hard.
 
you'll know when your shoulder measurement is .002" less than your fired case. Once you start going down on the die you will notice that right at the bottom of the stroke you'll feel a little more resistance and that's when your contacting the shoulder.

Im not familiar with the hornady comparator as I use Sinclair ones but you have the one that indexes on the shoulder correct?
 
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How do you know you’re bumping the shoulder back?

I ended up having to screw the die in about 5/8 more of a turn, going in 1/8 turn at a time. I grabbed the rifle that they are for and kept turning the die 1/8 a time until the case chambered nicely and not hard.
Use the Hornady headspace tool like so
5FDC7528-1E49-4428-831D-56092D18C983.jpeg
Once you have the die set such that its bumping the shoulder to the extent required, index the die body, lock ring and press to ensure it goes back in the same position each time
45C67D27-FBB8-4894-8D48-B59ED0E2537A.jpeg
 
Im not familiar with the hornady comparator as I use Sinclair ones but you have the one that indexes on the shoulder correct?
Yes I do believe so. These are the ones I have. That look correct to you?
 
Hello,

I’m full length sizing some of my 6.5 creedmoor brass for my hunting rifle that has been once fired(was factory Hornady 143 Eldx).
I measured 5 random cases from the lot with my Hornady head spacing gauge for the caliper(used the proper attachment c375). They measured anywhere from 1.557 1/2 to 1.559. I measured the same 5 cases after full length resizing and they came out at 1.562. I think stuck them in a Lyman ammo/headspace tool and the head of the case sticks out just over the maximum.
I noticed after running them through the die that I was getting a ring on the bottom of the case, close to the head. I’ve attached a picture below.
I also noticed when running the case up into the die all the way up, that the shell holder wasn’t touching the die.
Am I don’t all of this correctly? I feel as I’m not although I followed the directions when setting up the die. Dies are Hornady Customs if that helps at all
Not that it matters a whole lot but, the closest gage to measure the headspace would be the D400. It will probably give you 8 or 10 thou lower headspace reading than SAAMI specs.
The line at the bottom of the case is good. You want to see that. Depending on the chamber to FLD dimension differences, don't assume that resistance felt when closing the bolt is always the shoulder of the case. With factory chambered barrels, it is more often than not the web that gives the feeling of resistance if the headspace measurement comparison is 2 or 3 thou less than your fired cases. So, if your chamber is on the short end of SAAMI spec, off the shelf FLS dies will be hard pressed to size the web enough because you can't get the case deep enough into the die while still obtaining minimum shoulder bump (-0.002 to -0.003) Don't be surprised if you feel a little resistance on some cases even when the headspace comparator is telling you the base to case datum is less than the unisized cases because it can be the web that is just a bees dick larger OD.
Once you're sure the base do datum is where it needs to be, you have 2 choices if the web is rubbing.
1) Run the cases deeper into the die to size the web down a little more which, as a result will increase the headspace. (reduce base to datum)
2) If the resistance at the web is minimal & no obvious bolt click, load em & shoot.
 
Comparator reading is more accurate than how it feels closing the bolt.
Well it's not if the web just forward of the 200 mark on the case is not being sized enough.
That was the point of my post. The comparator can be reading -0.002" of headspace & the bolt still has resistance closing on a case.
 
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How do you know if the shoulder hasn’t been bumper far enough compared to the webbing causing resistance? New to this reloading stuff and just want to do it right and take in what info along the way that I can.

So basically just take the longest head spacing out of the fired cases, whatever that reading is, minus .002 from it. Then set the die to where it’s sizing to that number and lock it in place. Then when I try and chamber an empty case, even if there some resistance, as long as it closes without a lot of force it’s fine?

Also one other question, why do you say the d400 will give the closest reading? Just curious as Hornady says the c375.
 
How do you know if the shoulder hasn’t been bumper far enough compared to the webbing causing resistance? New to this reloading stuff and just want to do it right and take in what info along the way that I can.

So basically just take the longest head spacing out of the fired cases, whatever that reading is, minus .002 from it. Then set the die to where it’s sizing to that number and lock it in place. Then when I try and chamber an empty case, even if there some resistance, as long as it closes without a lot of force it’s fine?

Also one other question, why do you say the d400 will give the closest reading? Just curious as Hornady says the c375.
Initially you dont have to bump the shoulders at all. Its up to you to determine what fits, and where exactly your chamber is with regard to headspace. The fired case headspace dimension will stabilize at some point with more firings. Since your fired cases grew longer, thats your gauge, use it. Push the shoulder till the case fits. If you're using small steps when adjusting your die down, you’ll detect the point where the previous case was slightly tight in the chamber, then the subsequent case falls right in. Thats your max length, write it down, and never accept anything longer. Now push the shoulder back .001-.002 from there. Write that down, thats your target dimension.

Forget about the web diameter. Sounds like its sizing properly as is.

Hornady lists .375 as the proper insert. The actuall datum line on a 6.5 Creedmoor per the specification is .400, and most people use the .400 insert. Truth is, it doesn't matter one bit.
 
Last edited:
How do you know if the shoulder hasn’t been bumper far enough compared to the webbing causing resistance? New to this reloading stuff and just want to do it right and take in what info along the way that I can.

So basically just take the longest head spacing out of the fired cases, whatever that reading is, minus .002 from it. Then set the die to where it’s sizing to that number and lock it in place. Then when I try and chamber an empty case, even if there some resistance, as long as it closes without a lot of force it’s fine?

Also one other question, why do you say the d400 will give the closest reading? Just curious as Hornady says the c375.
Yep, pretty much what Supersubes said.
You may not have to bump back if they're once fired because the cases usually won't be fully sized until around 3rd firing so, if they aren't causing problems on bolt close, prolly best to leave em another 1 or 2 firings.
Regards the Hornady comparator, I use the 400 but, as Supersubes said, it really doesn't matter cause it only compares.
 
How do you know if the shoulder hasn’t been bumper far enough compared to the webbing causing resistance? New to this reloading stuff and just want to do it right and take in what info along the way that I can.

So basically just take the longest head spacing out of the fired cases, whatever that reading is, minus .002 from it. Then set the die to where it’s sizing to that number and lock it in place. Then when I try and chamber an empty case, even if there some resistance, as long as it closes without a lot of force it’s fine?

Also one other question, why do you say the d400 will give the closest reading? Just curious as Hornady says the c375.
To answer you Q on how you know. If the un-sized cases measure longer base to datum than a case that you have sized, then it cannot be the shoulder causing resistance.
I've had a quite a few rifles do this over the years where the factory die doesn't quite size the web down.
Usually, most of the cases are ok & the ones that are tight I cull out. I've mostly only noticed this when bumping back 0.001" or 0.002".
The last rifle I bought has a very minimal chamber. A while back I bought some new factory Federal cartridges & every cartridge had some resistance on bolt close. Not much but, with the firing pin out of the bolt, every cartridge had slight resistance & chamber marks 360 around the web section. Headspace was fine, just the web was rubbing. After firing & resizing, only 2 rubbed out of 40 rounds but, I could see the slightest of marks on the web with all of them but no obvious bolt close resistance.
 
If your chamber is so tight that FC308 virgin brass sticks, then your rifle is defective. Only morons cut chambers that tight, i.e. .468” as only some small base dies can size brass enough for that kind of fit.
 
If your chamber is so tight that FC308 virgin brass sticks, then your rifle is defective. Only morons cut chambers that tight, i.e. .468” as only some small base dies can size brass enough for that kind of fit.
No, it's ok I had it checked. I have run other Federal & Win cartridges through & they didn't seem to rub as bad but, the chamber is minimum. I think it may have been that batch of cartridges. As i said, they weren't unusable, just rubbed slightly. I'd rather that than a Ruger I had years ago that left every case lop sided & stretched at the web.