Shoulder Bump Help

May 20, 2017
28
1
3
Centennial, Colorado
#1
I am reloading 308 with annealed 1x fired Lapua brass and a forester full length sizing die and reeding competition shell holders. I was trying to bump the shoulder back two thousandths and I couldn’t get there even after screwing the die down to have cam over.

Does anyone have any ideas of what I should do to get the two thousandths shoulder bump?

Thanks in advance for your help.
 
Sep 27, 2008
893
13
18
California/SFO
#2
Use a regular shell holder set to maximum cam over and measure your shoulder bump with that and then go from there . The Redding Competition shell holders DECREASE shoulder bump .002" at a time using the +.002 to +.010 shell holders. Most of my 308 dies using a regular shell holder will shoulder bump -.005" from 1.630" SAAMI minimum when set at Max cam over.

I use the Redding Competition shell holders often to adjust shoulder bump. They work fine for me.
 

Sheldon N

Blind Squirrel Finds a Nut
Sep 24, 2014
2,444
305
83
Pacific Northwest
#4
One thing to check is that on 1x fired brass you may not be fully expanded to the chamber depending on whether you shot a hot load or not. You only need to bump back 0.002 from a fully expanded piece of brass, not on all pieces.

Pull the firing pin out of the gun and you can feel whether there is resistance when closing the bolt on a piece of sized brass. If there's no resistance, you don't need to bump the shoulders further.
 

Xander3Zero

Just a normal dude.
Aug 10, 2017
413
118
43
Rhode Island
#5
In my limited experience, I have never seen a piece of 1x fired brass not fit in the chamber it was fireformed to.

In my opinion, you should just neck size and load the brass up for a second firing and re-evaluate. If you are not set up to neck size, or you just want to FLS every loading, then you will need to try the standard shell holder to see if that helps you get a shoulder bump.
 
#6
I tried the regular shell holder and I still was not able to get a shoulder bump with the Lapua brass.

I tried some FGMM brass I have with the same die setup and +.002 shell holder and I got two thousandths shoulder bump. The FGMM brass was fired in the same gun and was annealed.
 

JOE62

New Hide Member
May 30, 2018
11
0
1
#8
If you are not getting bump back on the Lapua brass, evidently it doesn’t need bumping. It can take 2 or 3 firings to get brass fully formed to your chamber if using lighter loads.
 
#9
Hmm, how are you measuring the shoulder and what measurement are you getting on the federal and lapua brass after firing (untouched).
I am using a hornady comparator. On the Lapua I am getting 1.6215" untouched on the federal I am getting 1.6220" untouched. This could be an indicator of what Joe is saying about lapua needing more firings to fully fire form.
 
Nov 25, 2012
824
84
28
63
Southern NM
#10
Do not rule out your die needing to be trimmed. I experienced this with Forster FL die for a 6mm Dasher. Sent the die back to Forster with some fire formed brass and they took a couple of thousands off the base of the die and problem solved. Their CS is excellent.
 

JOE62

New Hide Member
May 30, 2018
11
0
1
#11
If you think the die might need trimming,I would cut down the shell holder first. Different brands of brass will have different amounts of spring back. Even different lots of the same brand. You’re only half a thousandths (5 10 thousandths) difference in the two you have. If your die is sizing the sides of the Lapua Brass more it could actually end up longer. From what I’ve heard and not from actual experience is that Federal brass is softer.
 
Sep 27, 2008
893
13
18
California/SFO
#14
Saami chamber datum is 1.630 min to 1.640 max, are you using the .400 marked adapter?.

O/P is using the Hornady Comparator. He is NOT going to get a reading of 1.630" for the SAAMI minimum. I've used two Hornady .400" inserts and got two different measurements off of a case sized to 1.630". One had a bevel / Chamfer on the insert's edge of .011" and the other .019" Giving readings off of the 1.630" shoulder of 1.619" and 1.611".

I was able to confirm these readings using a 1.630" 308 Win Go gauge.
 
#16
If you think the die might need trimming,I would cut down the shell holder first. Different brands of brass will have different amounts of spring back. Even different lots of the same brand. You’re only half a thousandths (5 10 thousandths) difference in the two you have. If your die is sizing the sides of the Lapua Brass more it could actually end up longer. From what I’ve heard and not from actual experience is that Federal brass is softer.
My Lapua brass is growing when I size it. Untouched it measured 1.6215" and after resizing as much as I could I was getting 1.6230".

Is it worth getting the die trimmed or should I get another die all together like a redding.
 
Sep 27, 2008
893
13
18
California/SFO
#18
Is your press bolted to a very sturdy bench? I ask this because I ran into this with a friend who had a press bolted to a flimsy bench and he was getting a bit of press flex which hindered shoulder bump. After reinforcing the bench, he got the shoulder bump sizing he needed.

If you could turn your die into the press just a tiny bit more, you might get to where you need to be. A 1/8 turn gives you .009" movement. Just a slight turn of 1/24th might do it.

Last resort is to have the die trimmed, or take a shell holder and sand it down .005".
 
#20
Is your press bolted to a very sturdy bench? I ask this because I ran into this with a friend who had a press bolted to a flimsy bench and he was getting a bit of press flex which hindered shoulder bump. After reinforcing the bench, he got the shoulder bump sizing he needed.

If you could turn your die into the press just a tiny bit more, you might get to where you need to be. A 1/8 turn gives you .009" movement. Just a slight turn of 1/24th might do it.

Last resort is to have the die trimmed, or take a shell holder and sand it down .005".
I know it is a sturdy bench. I am using a Hornady single stage press. Maybe I should look into upgrading that...

I don’t think I can turn the die much more. And I think I would have to turn it in more than just 1/24 because my brass is still growing. I’ll try it though.
 

Sheldon N

Blind Squirrel Finds a Nut
Sep 24, 2014
2,444
305
83
Pacific Northwest
#23
No issues with a hornady comparator here. Lots of people use them without problem.

From my recollection, virgin Lapua 308 brass was 0.005-0.006 short of fully expanded brass that had been fired multiple times. Went and checked my data book. I had virgin brass at 1.619 and fired brass at 1.625, was bumping to around 1.623. Your numbers won't match exactly, this is just a reference point.
 

JOE62

New Hide Member
May 30, 2018
11
0
1
#24
Nothing wrong with the Hornady Comparator. You just have to remember it isn’t for absolute measurements. It’s for comparing fire formed brass to resized brass. Keep at it. You’ll get it figured out.
 
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