280 Ackley SAAMI Head space

[MagMan]

Yes the expander is on the stem.

 

[fremont]

Redding sells a set of shell holders that are shaved. You will want the competition set #1

I'm under the impression it's the opposite, e.g., they are incrementally higher to prevent pushing the shoulder down by .002" increments.

 

[Dmagna]

I'm under the impression it's the opposite, e.g., they are incrementally higher to prevent pushing the shoulder down by .002" increments.

I could be wrong. I thought they started lower and worked up. There is a wide range in the set.

 

[fremont]

I have a set; actually two (standard and belted magnum). I can't recall if there are 5 or 6 shellholders (the sixth would be a standard shellholder). The .010" shellholder is so that the shoulder is pushed down .010" less than SAAMI. You start there and try to see whether the case chambers; it not, try the same with the .008" shellholder. So on and so forth until the case chambers with a reasonably crush fit.

 

[nksmfamjp]

When you are actually FL Sizing does the die touch the shell holder?

In my experience, there is enough force/flex that when setup to touch, during sizing there is like 0.005" gap.

 

[59FLH]

Your smith cut the chamber to SAMMI minimum. As long as the rounds chamber your good.

 

[BadgeNJ]

Yes when FL sizing the die is touching the shell holder and you are correct on some of the cases it is .005 less than the fired case. The rounds do chamber so looks like I am good to keep doing what I have been. I really appreciate the help and feedback!!

 

[FEENIX]

If it is a new barrel, it deserves new brass, but that's just me. I too have the Redding competition shell holder set. Good luck

 

[Rooks]

I am new to this site but have received a lot of great info. I have a 280 Ackley SAAMI chamber and using Nosler brass. I measured the head space of fired cases at 2.137, full length sized the fired cases and they measure the same 2.137. I was thinking the FL sized case would bump the shoulder back more than the fired case? The gunsmith who cut the barrel requested the dies and sized brass before chambering the barrel. Thanks in advance.

Most die setup guidelines recommend screwing the die a small percentage past the point which it touches the shell holder creating a very slight cam over. You can creep up on it and achieve a .002" shoulder bump, easy peasy...

 

[Rooks]

If it chambers post fired as it did pre fired it's not done growing. Might take 4-6 shots. Even if it doesn't grow and you size the way you have been what is the problem? As long as it chambers fine

I am new to this site but have received a lot of great info. I have a 280 Ackley SAAMI chamber and using Nosler brass. I measured the head space of fired cases at 2.137, full length sized the fired cases and they measure the same 2.137. I was thinking the FL sized case would bump the shoulder back more than the fired case? The gunsmith who cut the barrel requested the dies and sized brass before chambering the barrel. Thanks in advance.

If it chambers post fired as it did pre fired it's not done growing. Might take 4-6 shots. Even if it doesn't grow and you size the way you have been what is the problem? As long as it chambers fine I'd leave it alone.

I second this practice, I do like to take the ejector and firing pin out when checking to see if it will chamber. I assume that brass has reached full expansion when the bolt will not fall closed on a fired case but will after being bumped .002" with zero help from me on bolt closure.

 

[Ranger1994]

What Rooks said.....
BadgerNJ what die set do you have?
With RCBS standard dies you raise the ram, screw down the die until it touched the ram, lower the ram and screw the die in 1/8 1/4 more to get cam over. Otherwise are you even resizing the brass if you dont?
I guess make sure you're following your die instructions.

 

[BadgeNJ]

I have the Redding Ackley die set and the directions are to set the die so it is touching the holder, I have it set a little lower so the shell holder is up against the die at the top of the stroke.

 

[ThrdKllr]

If it gets to where it's tight chambering the resized brass, get a new shell holder and lap .001-.002 off the top of it. Then throw it in the box with the dies. One of the cheap diamond hones at Harbor Freight will take 2 thou off pretty fast and keep it flat.

 

[cajun]

I believe the Redding shell holders let you size less not more. The die manufacturers instructions are pretty generic. At least you are measuring while sizing which is good. I have some dies that need to be turned past contact and full came over with an RCBS press to bump the shoulder .002. Then I have some that if you follow the directions you are pushing the shoulder back .010 to.012 every time which is a recipe for a case head separation. The point is there is a .010 tolerance in a saami chamber dimension. If you are on the long end you should be careful sizing brass. If you are on the short end you may have to have full came over just get minimum shoulder bump. And there are some rare cases where you get a die that will not push the shoulder back. This is usually a chamber to minimum or maybe below and a die that is not quite sizing to minimum. There are tolerances in everything. Make sure all the slack is out your press. If your brass chambers easily you are good. If you start feeling resistance closing the bolt and your die is not bumping the shoulder you can try another die or sand .002 off the shell holder.