Jaeger
05-18-2016, 05:48 PM
When my barrel was new I could get an oal consistent each time. Now my measurements are kinda all over the place as in 020" apart on average. The barrel has 500 ish rounds through it.
My question is: is this common because of the throat being worn down? Has anyone else experienced this? I'm getting different measurements even using the same bullet over and over.
I'm just guessing throat wear but how do I keep my bullets .010" off the lands if I can't find where that is????
I drop a 223 bullet down the barrel to free the 260 lead when it's stuck in the lands. When new the barrel would let go of the 260 bullet instantly. Now it takes 2-3 drops to free it most of the time.
Gun shot good last time out I just wanted to know for my own knowledge and now it's driving me nuts lol
I should add I'm using same oal case and the last of the 500 round lot I started with to measure. Even keeping the tool and pressures I put on the back of the bullet the same I still can't get the measurements to be consistent
Get an RCBS case micrometer. Take a fired case so you know it fits your chamber. Put a hacksaw cut down one side of the neck (to relieve tension) and barely insert a bullet. Take the ejector pin out of the bolt. Carefully and gently insert this dummy round into the chamber and very gently close the bolt on it. Removing the ejector pin ensures a very gentle entry. The bullet will touch the lands and be pushed back into the case. Equally and carefully pull the bolt back and eject the case. You now have a perfect dimension from case head to the lands. The RCBS micrometer will give you a notional dimension which you make a note of. Subtract the amount of jump you want from this notional dimension and make a note of it. Now put your seating die in the press and back off the seater. Put your dummy round in the press, raise the ram and, holding it in position, screw down the seater adjustment until you just feel it touch the bullet. Apart from doing this about 10 times to get an average the job is done and takes less time to do than I took to write it.
My question is: is this common because of the throat being worn down? Has anyone else experienced this? I'm getting different measurements even using the same bullet over and over.
I'm just guessing throat wear but how do I keep my bullets .010" off the lands if I can't find where that is????
I drop a 223 bullet down the barrel to free the 260 lead when it's stuck in the lands. When new the barrel would let go of the 260 bullet instantly. Now it takes 2-3 drops to free it most of the time.
Gun shot good last time out I just wanted to know for my own knowledge and now it's driving me nuts lol
I should add I'm using same oal case and the last of the 500 round lot I started with to measure. Even keeping the tool and pressures I put on the back of the bullet the same I still can't get the measurements to be consistent
Get an RCBS case micrometer. Take a fired case so you know it fits your chamber. Put a hacksaw cut down one side of the neck (to relieve tension) and barely insert a bullet. Take the ejector pin out of the bolt. Carefully and gently insert this dummy round into the chamber and very gently close the bolt on it. Removing the ejector pin ensures a very gentle entry. The bullet will touch the lands and be pushed back into the case. Equally and carefully pull the bolt back and eject the case. You now have a perfect dimension from case head to the lands. The RCBS micrometer will give you a notional dimension which you make a note of. Subtract the amount of jump you want from this notional dimension and make a note of it. Now put your seating die in the press and back off the seater. Put your dummy round in the press, raise the ram and, holding it in position, screw down the seater adjustment until you just feel it touch the bullet. Apart from doing this about 10 times to get an average the job is done and takes less time to do than I took to write it.