RF bullet engagement

Jerry H

Jerry H

Different Drummer
How much bullet land engraving do like for Eley match? 0 to 4 driving bands or if its critical .000-.170 or reamer "C" dimension length .560 to .735 Please use which ever measurement you are familiar with. I can deal with any these dimensions. TIA
 
Jerry,
If it were me I would contact Richard Gorham. He probably builds as good a rimfire as anybody. I can give you contact info.
 
Jerry H said:
How much bullet land engraving do like for Eley match? 0 to 4 driving bands or if its critical .000-.170 or reamer "C" dimension length .560 to .735 Please use which ever measurement you are familiar with. I can deal with any these dimensions. TIA
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Jerry,
I would like to know if you ever got an answer to this question.
What is the amount of engraving in most match chambers?
I have a Walther that is engraving the bullets as much as .165 inches. It makes the bolt hard to close. Is this way too much? It is a factory action/barrel and chamber.
 
No. Most didn't know the chamber dimensions. However I feel the majority engraves between the second and third band. I settled on probably a rather unique chamber. I set the chamber as follows. .225 x .565 C depth and then 2 degree transition to .224 setting the first band .030 into a 2.5 degree lead. This sets most of the driving bands in the .224 part while attempting to get a clean release of the case mouth. In summer temps the front of the rim extends .030 when inserted by slight finger pressure. At cooler temps, there is more resistance but not like a pure .575 C depth chamber that is engraving the rifling through the bands. Accuracy seems to be the same at .575-.600 and this odd setup without the heavey closure issue. Engraving depth doesn't seem to be critical with RF as compared to CF.
 
Jerry,
So from what I understand from your chambering is that there is significant engraving but no hard to close bolt. I need to solve my problem of the hard bolt closure. I'm not sure how best to go about it.
Here is a picture of several bullets chambered in my rifle. The one on the left is Eley Black Box. Does this look like those from your chamber?
kkj1.jpg
 
No, those look no more than .575. You are actually almost to the case mouth about .555. My chamber has very little engraving, only a short .030 "jam" with the 2.5 degree throat cone taper on the front of the band at the nose. No rifling appears on any of the bands. The method is use a .225 reamer for the case and a .224 reamer for a long "throat" and lead.
 
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