chamber problem?

[spitfire_er]

Ide load two or three different charges and see if the line migrates between the charge weight groups.

 

[liseo]

I finally had the opportunity to test the rifle with ammunition that I reloaded myself.(left case)
The only change made was to lengthen the throat so that with Sierra MK 168 grains, leaving with a COAL of 2,800 ", it has a jump of 0.030".
It is noticed that the soot formed a different design.
It is not a definitive test, but there seems to be nothing wrong with the chamber.(22 LR spent case for comparison)

 

[Dusty Stevens]

Have you read tony boyer’s book? He talks about how perfect your neck thickness is now

 

[WSnyder]

^^^^Boyer says if you have that solid line neck clearance is too tight.

 

[liseo]

Dusty/Wnysder

I am using Lapua brass(loaded case neck measure.337"/.338") and the chamber neck is nominal .343"
Measured .3425" after firing.
Is neck turning a option, to increase the clearance?

 

[WSnyder]

I would think that what you have would be plenty of clearance. Are you positive the reamer is .343"? I've seen Palma 95 neck specs all over the place so there isn't a standard anymore. I use a 95 Palma w/ .3425" neck. My brass measures .335" with bullet seated but that's only because that is where the brass cleanup up, not because I needed that much clearance.

 

[WSnyder]

After extending the throat the soot on the brass looks normal. It has the sine wave of soot that looks like a 2 lug bolt.

Thinking out loud: Initially the bullet was below the shoulder and into the case, did the deeper throating move the shank of the bullet above the base of the neck? If so I'd think that is your answer. Likely the base of the neck has a little extra material (AKA the dreaded donut) that is common to find and when a bullet is seated pushes the material out possibly causing a tight clearance problem.

 

[JLittle]

I found a step in the neck of a Palma rifle that I had traded into some years ago. It had a soot line very similar, but you could actually feel the step with a sharp edge. It was a ‘95 Palma. I set it back a little and ran in a 2011.