Re: Makers 190 and CFE BLK subsonic
Posted: Thu Jan 02, 2020 10:38 am
More reverse engineering questions.
If
max length measured base to ogive 1.753.
Bullet nose length, ogive to tip is .630
OAL should be 2.383
Part of the problem is the .630 number seems to be measured at the wrong place, at.308 diameter. Should be measured at 300 diameter. Where the nose starts to transition to the bearing surface. I would expect that to make at least .850 difference. To have a max OAL of 2.145” that transition or shoulder would need to be .250+.
The bullet will start jamming/touching the bore when the diameters match. This varies with how the lead into the rifling is cut, but in general the diameter used for reference is 300”. Your 1.753” number should be at the bullets ogive, bearing surface to nose.
The bullets you have stop in the chamber with an overall length of 2.145” because of the place on the nose that is a larger diameter than 300 is hitting the rifling. Your tool should stop there also.
There a lot of ways to check where the bullet starts to jam the rifling. I simply hold the rifle muzzle up and bump the bullet down until when inserted with finger pressure, falls out under its own weight. I have plenty of ways to measure that, but that’s don’t really make sensethe simplest way for me.
It’s possible the bullet design had changed slightly and there is a longer taper than I remember. That’s the part in your photo that is mangled. I would not be able to see a couple thousandths in a photo anyway.
I know why your numbers did not make sense, and would probably be loading that bullet around 2.100”.
If
max length measured base to ogive 1.753.
Bullet nose length, ogive to tip is .630
OAL should be 2.383
Part of the problem is the .630 number seems to be measured at the wrong place, at.308 diameter. Should be measured at 300 diameter. Where the nose starts to transition to the bearing surface. I would expect that to make at least .850 difference. To have a max OAL of 2.145” that transition or shoulder would need to be .250+.
The bullet will start jamming/touching the bore when the diameters match. This varies with how the lead into the rifling is cut, but in general the diameter used for reference is 300”. Your 1.753” number should be at the bullets ogive, bearing surface to nose.
The bullets you have stop in the chamber with an overall length of 2.145” because of the place on the nose that is a larger diameter than 300 is hitting the rifling. Your tool should stop there also.
There a lot of ways to check where the bullet starts to jam the rifling. I simply hold the rifle muzzle up and bump the bullet down until when inserted with finger pressure, falls out under its own weight. I have plenty of ways to measure that, but that’s don’t really make sensethe simplest way for me.
It’s possible the bullet design had changed slightly and there is a longer taper than I remember. That’s the part in your photo that is mangled. I would not be able to see a couple thousandths in a photo anyway.
I know why your numbers did not make sense, and would probably be loading that bullet around 2.100”.