Still doubts about shoulder bump...

[Bora72]

could that possibly be your bolt raising up/tilting slightly when cocked?

It could be that way, as it could also be that the press piston/shellholder and the die are not aligned

 

[Bora72]

Put it back in the rifle and while pushing the bolt forward run the handle up and down a few times. Then what do you have?

the paint on the head comes off but in a limited area

 

[Bora72]

Look at some paint below the extractor

 

[Doom]

I disagree with your first couple of sentences.
Actually measuring before the case is sized and afterward is the only way to know exactly how much you are sizing the case.
With any other method, you are guessing.

We don't disagree on that. I wasn't implying you don't determine the amount of setback on the case by firing and resizing. You can't assume that the case measurement is the chamber dimension. Even after several firing the case will not grow to match the chamber dimension but it will be close. The issue comes when trying to decide what may be causing resistance to the bolt closing.

 

[Ccrider]

Even after several firing the case will not grow to match the chamber dimension but it will be close.

Not necessarily true. Dependson how hot the loads are.

 

[DaveTooley]

Look at some paint below the extractor

you're worrying about something that
1. is completely out of your control
2. It affects nothing other than your mind

 

[Webster]

Oh, I forgot, I anneal the necks after every shot.

Give us your details on how you anneal.

 

[Bora72]

you're worrying about something that
1. is completely out of your control
2. It affects nothing other than your mind

Why?

 

[Bora72]

Give us your details on how you anneal.

Soon as possible

 

[Bora72]

I noticed something odd when I resized the cases to 1.485" (+ or - .0005"), but I had good consistency according to what you explained.

However, when I raise the ram and the case begins to engage the die, the case head pops up on one side and separates from the shellholder.

It seems as if the press ram and the die are not aligned on the same vertical axis.

Do you have any suggestions or tests I can perform to verify this?

 

[Bora72]

Soon as possible

This is my annealer, hand made by myself.

 

[Coyotefurharvester]

Your observation could be the expander/decapper assembly is not centered in the mouth of the die or case(rod bent/loose?). Make sure the shell holder is clean/free of lube.

 

[Webster]

This is my annealer, hand made by myself.

Looks like you did a great job. What temp do you think the necks are reaching. I don't see a color change in the video?

 

[Bora72]

Your observation could be the expander/decapper assembly is not centered in the mouth of the die or case(rod bent/loose?). Make sure the shell holder is clean/free of lube.

The shell holder are free of lube and debris.
I removed the decapping unit, I use a separate expander die.

 

[Bora72]

Looks like you did a great job. What temp do you think the necks are reaching. I don't see a color change in the video?

Thanks.
I think 750/800ºF.
The color change, look

 

[ELR LVR]

Look at some paint below the extractor

Case heads are not always square
also over time, they get pounded off square if they started out square
(the bolt slop allows very slight rise in the trigger area so the bolt is no longer square to the raceway)
I recently shaved .002" off the head on 10 cases to square them up to see if it affects anything
Have not tested them yet
and I expect to see nothing different,
the gun shoots in the .2's' or better now
if it holds in the .1's then I may attribute it to squred case heads
if I see no improvement, then I will not worry about square case heads
---
Your case heads are likely not perfectly perpendicular to the chamber centerline
is what you may be seeing
---
to conduct the sharpie marker test you are doing now, you need to ensure your case heads are perpendicular and perfectly flat to begin with

 

[Bora72]

Case heads are not always square
also over time, they get pounded off square if they started out square
(the bolt slop allows very slight rise in the trigger area so the bolt is no longer square to the raceway)
I recently shaved .002" off the head on 10 cases to square them up to see if it affects anything
Have not tested them yet
and I expect to see nothing different,
the gun shoots in the .2's' or better now
if it holds in the .1's then I may attribute it to squred case heads
if I see no improvement, then I will not worry about square case heads
---
Your case heads are likely not perfectly perpendicular to the chamber centerline
is what you may be seeing
---
to conduct the sharpie marker test you are doing now, you need to ensure your case heads are perpendicular and perfectly flat to begin with

Ok, you made yourself clear, for now I don't have to worry, especially with a mass-produced rifle.

This is the accuracy my rifle allows me (beginner ), 35.3gn RS50, 139 Scenar, OAL 71mm (2.795"), Harris bipo, tactical rear bag, 100m (109yd):

 

[ELR LVR]

Ok, you made yourself clear, for now I don't have to worry, especially with a mass-produced rifle.

This is the accuracy my rifle allows me (beginner ), 35.3gn RS50, 139 Scenar, OAL 71mm (2.795"), Harris bipo, tactical rear bag, 100m (109yd):

That's phenomenal! is that a 4 or 5 shot group there?
The fact you are using a bipod also shows your technique for holding the rifle, pressure etc is very good.
Since bipod discipline can be something that takes awhile to learn to get the gun to react the same every time

 

[AlNyhus]

An 'O' ring between the die and press and in place of the shell holder clip can be helpful for alignment.

 

[Webster]

Thanks.
I think 750/800ºF.
The color change, look

You cannot anneal at 750/800F. you may be stress relieving. You need to be at about 1050/1100F to anneal. The neck should just turn red for 1-2 seconds.

When I look at the charts I compare 15% cold work reduction in thickness to the several temperatures. It seems like a good guess at % cold work since we don't know the actual %. The trends are what I look at rather than the actual numbers. The next chart in the report was 600C=1112F this is much higher than I want. The shortest time in the study was 15 seconds at temp in a lead bath. The sample had thermal couples on them and time was time at temp

What I see is practically nothing happens at 15 seconds at temp at temp in a lead bath.

There are many scales for reporting hardness this study used the Rockwell H scale. The cold work was achieved by cold rolling a small plate about 1/8" thickness to various thicknesses. Don't jump on they are not cartridges. The numbers basically give you an idea of what's going on.

Results:
15% cold work 30 seconds at 842f showed a .8 RH increase. 10% cold rolled showed 2 unit decrease. Probably within the error because they are different pieces of metal even though they were processed under similar conditions.

1/2 hr at temp before grain size changes.
450C=842F

550C=1022F




Below are the results of my annealing study done at work on cartridge necks annealed in a small laboratory accurate furnace. I chose 15 sec hold time in the furnace since I didn't know how long it took the neck to reach temp. 5 minutes at 800F the hardness only dropped about 2 units HRB sale.