I have a custom Hart manufactured target rifle in 6mm PPC with a Remington model 700 action as the basis. I do not shoot in competition, I do shoot just for fun. I'm using 65gr Hornady Vmax and Berger 68gr HP bullets and although both are impressive, Berger has produced 5-shot, 100yd groups of 0.195", 0.288" and 0.382."
However, every now and then, perhaps 5 out of 50 hand-loaded rounds won't chamber. If I knock the bullets out, those cases chamber with just slight resistance. With the bullet seated, the bolt won't lock up at all but I also have had to use a mallet to help open the bolt.
Fired cases are larger than resized, and all resized cases have the same measurements found in the 50th Edition of the Lyman Reloading book.
So the problem seems to be confined to the presence of the bullet, yet when I measure the outside mouth diameter of a seated bullet in one cartridge that DOES chamber with one that does not, there is no difference in that measurement. The heads of the cartridge cases also have the same measurement, as does the point where the shoulder drops to meet the neck as well as the measurement of shoulder set-back after resizing (from the base to the datum line).
The overall length of the cases is within accepted range between 1.505 - 1.515. Difficult to chamber cases with a measurement of 1.504" have occurred.
I suspect the chamber tolerances are very tight in this rifle but I'm stuck or a reason to explain why some finished cartridges chamber while others won't. All cases are Norma. Any suggestions will be appreciated.
However, every now and then, perhaps 5 out of 50 hand-loaded rounds won't chamber. If I knock the bullets out, those cases chamber with just slight resistance. With the bullet seated, the bolt won't lock up at all but I also have had to use a mallet to help open the bolt.
Fired cases are larger than resized, and all resized cases have the same measurements found in the 50th Edition of the Lyman Reloading book.
So the problem seems to be confined to the presence of the bullet, yet when I measure the outside mouth diameter of a seated bullet in one cartridge that DOES chamber with one that does not, there is no difference in that measurement. The heads of the cartridge cases also have the same measurement, as does the point where the shoulder drops to meet the neck as well as the measurement of shoulder set-back after resizing (from the base to the datum line).
The overall length of the cases is within accepted range between 1.505 - 1.515. Difficult to chamber cases with a measurement of 1.504" have occurred.
I suspect the chamber tolerances are very tight in this rifle but I'm stuck or a reason to explain why some finished cartridges chamber while others won't. All cases are Norma. Any suggestions will be appreciated.