Max case web expansion for 33xc?

[harry_x1]

I am firing 300 gran Lazers, 115 grain N570 at 3120 fps in my 33xc. I get around 0.0035" expansion at pressure band after one firing. Is that too much pressure? No heavy bolt, but do see ever so slight ejector marks. Primers are flat but not that bad.

 

[Benchrest Braxton]

I am firing 300 gran Lazers, 115 grain N570 at 3120 fps in my 33xc. I get around 0.0035" expansion at pressure band after one firing. Is that too much pressure? No heavy bolt, but do see ever so slight ejector marks. Primers are flat but not that bad.

thats totally normal (and safe)

have you tried h50bmg at all?

 

[Alex Wheeler]

We need to know exactly where your measuring. In the case body your numbers are fine, at the solid case head they are not. How far up from the bolt face are you measuring?

 

[harry_x1]

We need to know exactly where your measuring. In the case body your numbers are fine, at the solid case head they are not. How far up from the bolt face are you measuring?

I am measured fired brass where the pressure ring was formed. It is slightly further up the case from case head. For the virgin brass I also checked roughly same spot where pressure ring should form. I checked multiple fired cases and virgin cases to make sure I know the exact expansion.

Should I also measure at some diff space or do something diff? thanks for the assistance !

 

[harry_x1]

thats totally normal (and safe)

have you tried h50bmg at all?

Yeah, with H50 I was getting 3080 fps, 122 grain charge. But I experienced heavy bolt lifts in approx 4 out of 10 fires. I was not experiencing heavy bolt when I started, but it seems the barrel sped up after 200 rounds and the hot summers also make a diff. I did not experience any heavy bolt with the N570 uptill 117 grains and the velocities are higher as well. Hence switching to N570. I have also tried RL50 which also gave good results but was too sensitive to temperature variation.

 

[Alex Wheeler]

I am measured fired brass where the pressure ring was formed. It is slightly further up the case from case head. For the virgin brass I also checked roughly same spot where pressure ring should form. I checked multiple fired cases and virgin cases to make sure I know the exact expansion.

Should I also measure at some diff space or do something diff? thanks for the assistance !

So it sounds like your measuring the fattest part of the case. So your good. For pressure signs you would measure the solid web just above the extractor groove. But thats not the easiest thing to do.

 

[SKWERLZ]

Here’s where I measure.