Sizing issues

[243winxb]

a piece of fired brass is 1.194"

Bump shoulder back .002" or as much as .005" from the fired brass @ 1.194" Measured from case head to datum, using the correct tool.

Do NOT use the same brass fired in the auto or the bolt gun.

NEW Separate brass for each rifle.

 

[DShortt]

Nevermind.

Popcorn time.

 

[243winxb]

I don't want to discuss shoulder bump either. It's on my list right under seating primers

A very good idea. These 2 subjects seem to bring out all the internet "experts"
Me included. But always good for a lol. .

Any one remember-
F. Guffey ? Using a feeler gauge between the top of the shell holder and the bottom of the sizing die, in a reloading press, to set shoulder bump?
Works well. Go for a crush fit when closing the bolt. No need to remove extractor or ejector.

 

[WSnyder]

A very good idea. These 2 subjects seem to bring out all the internet "experts"
Me included. But always good for a lol. .

Which is exactly why I try really hard to not get involved in any reloading discussions. Signal to noise ratio stinks

 

[kenhwind]

How much deflection is there in that t7 turret head?

I have a T-7, not much deflection but it is there.

 

[dellet]

* All of these measurements are done with a bump gauge.
The shoulder measures 1.188" from base to datum on unfired brass.
The same dimension on a piece of fired brass is 1.194"
In order to get the bolt with the firing pin assembly removed to close with the weight of my finger on the bolt handle require that I bump the shoulder to 1.1855".

Lloyd

Somethings not right with your measurements. New brass chambers but is over .003 longer than the brass that is sized and won't chamber.

It’s not length, it’s more likely diameter. The base was resized more with the thinnner plate on the co-ax.

And it possibly broke trying to swage the web down.

 

[Doom]

All of these measurements are done with a bump gauge.
The shoulder measures 1.188" from base to datum on unfired brass.
The same dimension on a piece of fired brass is 1.194"
In order to get the bolt with the firing pin assembly removed to close with the weight of my finger on the bolt handle require that I bump the shoulder to 1.1855".

So the 1.188 case chambered but you need to go to 1.1855?

 

[Coyotefurharvester]

The RCBS SB 6ARC is designed to size to minimum SAAMI, so the case will fit any AR. Raise shell holder to top of ram travel. Screw die down until touches shell holder. Lower ram. Screw die down 1/4 turn. Lock in place. I don't mix SH/die brands. Set die gutted, than install decapping rod, making sure it is positioned correctly.

 

[M-61]

I don't want to discuss shoulder bump either. It's on my list right under seating primers.
Every press has some change in it under a load. It could be the frame and/or the linkage. Just screwing the die down until it touches the shell holder does not get the full travel of the ram because of the spring in the system. Many who have to overcome this call it can over when setting up the FL die. It's just a different description of what I'm saying.

In a single stage press there zero stretch in the press. Of course under reloading situations.
What cartridge requires the most force to fully resize? Maybe a 50BMG? How much force does it take in pounds?
The press has nothing to do with the quality of the ammo. However there are many that don’t agree. ( doubt it was personal tests, more of a keyboard test)
I’m I currently have 5 mounted presses.
You tell me how much weight to hang on the handle. Shell holder touching the die.
I have magnetic bases to hold my micrometer. I’ll measure the amount the press stretches, deflects, etc. I have nothing better to do. All my presses are on 1/4” steel top mounted on two 3/4” glued and screwed plywood. One, RCBS A-4 is mounted on 12 x 12 x 1 3/4 steel block on top of the aforementioned bench.
Bench deflection is not an option. However the magnetic mics would allow easy mounting to the press. Except for a Hood type which is aluminum.

 

[M-61]

How much deflection is there in that t7 turret head?

If it’s zero then the turret doesn’t turn.

 

[1shot]

Many thanks to all the offered responses. The fix,at least in the interim until my replacement jaws arrive from Forester if to shave a few thousands off the top of the shell holder.

 

[1shot]

So the 1.188 case chambered but you need to go to 1.1855?

It chambers with lots of force on the bolt handle, but not correctly. 1.1855" gives me the correct bolt closure.

 

[1shot]

Bump shoulder back .002" or as much as .005" from the fired brass @ 1.194" Measured from case head to datum, using the correct tool.

Do NOT use the same brass fired in the auto or the bolt gun.

NEW Separate brass for each rifle.

View attachment 1730911

I use Starline brass in my AR, Peterson brass in the bolt rifle. No mix and match.

 

[trebor244]

I recently started loading a cartridge that is new to me. (6 ARC) I purchased a FL RCBS SB sizer die and set it up in my co-ax press. Everything was fine until one of the shell plates gave up the ghost. NP says I, so I grabbed a #12 shell holder and moved everything over to my Redding T7 press. Now even though the shell holder hard bottoms out on the die, I'm still .0015 short of bumping the shoulder at all. In over 50 years of reloading I have never experienced this. I currently have a Redding 6 shell holder competition set of shell holders ordered in hopes that this will fix the problem, so we will see. Any thoughts on this issue would be appreciated.
Thanks,

Lloyd

Do you anneal the fired cases? A lot of issues arise when resizing from the 220 Russian (parent case) that can be corrected in the annealing process. I too noticed that but I changed to a Redding type "S" die (full length) and experimented with different bushings. I believe that Redding and Hornady male a "small base die" for a gas gun.

 

[1shot]

I anneal all my brass when brand new, then after each firing. The die I am currently is an RCBS small base die.

 

[dellet]

It chambers with lots of force on the bolt handle, but not correctly. 1.1855" gives me the correct bolt closure.

It’s not 1.1855” that is giving you bolt closure if fired brass is 1.194”, unless you’re measuring wrong or the chamber stretches lengthwise when firing.

If new brass will not chamber easily that is shorter than fired brass, either the new brass is the wrong diameter, or the chamber is. It’s possible that it is shoulder angle, but needing to push the shoulder back .010” to correct the angle is unlikely.

I would expect to be able to see a scuff on brass that won’t chamber or is hard to extract. It’s time to blacken the case with a sharpie and see where it rubs.

It’s also worth sizing without expanding the neck and trying fit.

 

[J.d. Popkes]

My New Year’s resolution is still intact. This doesn’t count as a comment, my rules.

 

[6.5 forever]

It’s not length, it’s more likely diameter. The base was resized more with the thinnner plate on the co-ax.

And it possibly broke trying to swage the web down.

Yup this^^^°°°

 

[Doom]

It chambers with lots of force on the bolt handle, but not correctly. 1.1855" gives me the correct bolt closure.

But you said fired was 1.194". This doesn't jive with your 1.1855. It also doesn't jive with the SAAMI minimum headspace of 1.1901" If you size to 1.855 you will grow the case about .009" on each firing. I don't know if the chamber is 1.194 or not but it's probably slightly longer. You will be sizing for a quick case separation. You are probably dealing with the diameter issues others are mentioning and it is probably at the 0.200" line or slightly above.

EDIT: If this brass was shot in a AR you should not use it in a bolt gun unless you use the small base die to resize it. I'm betting it was.

Apologies to @dellet for duplicating his info!

 

[1shot]

Yup this^^^°°°

It’s not 1.1855” that is giving you bolt closure if fired brass is 1.194”, unless you’re measuring wrong or the chamber stretches lengthwise when firing.

If new brass will not chamber easily that is shorter than fired brass, either the new brass is the wrong diameter, or the chamber is. It’s possible that it is shoulder angle, but needing to push the shoulder back .010” to correct the angle is unlikely.

I would expect to be able to see a scuff on brass that won’t chamber or is hard to extract. It’s time to blacken the case with a sharpie and see where it rubs.

It’s also worth sizing without expanding the neck and trying fit.

Now this makes sense. I will take some more measurements when I get off work.
You are correct that the brass grows .009 on the first firing, but grows very little with subsequent firing.