The first sign of excessive pressure is...

[nheninge]

Field data is this most important and velocity is a feel good thing because drop data is the most important. However, I routinely use the ES and SD as validation of my methodology for reloading. But if you assume even a 2% error at 2800 fps then that is a 56 fps error rate. If your chrony is consistently high or consistently low, then your ES and SD are just an indirect measure of actual ES and SD. That is why it would be nice to have a set of known velocities (i.e. 2500, 2600, 2700, 2800 fps) to fire over the chrony and estimate actual accuracy and repeatability over a range of velocities. Would be nice if there was a service that you could send in your chrony to for this validation process!

[montana_native]

Originally Posted by Michael Eichele

Youre welcome.

I was fortunate enough to have pulled my hair out with a smaller caliber that didnt eat my barrel up while I was trying to figure out what the he!! was going on.

I have actually done side by side comparisions for accuracy AND point of impact using two loads that I trust implicitly using the exact same powder but a different bullet type of the same or similar weight and two loads of the same bullet yet different powder. The results were very suprising.

For example, with my old 308 barrel, I had a 155 AMAX load of 42.5 grains of BENCHMARK and a 150 ACCUBOND load using the exact same charge weight and powder. Both loads from a clean barrel and fouled with one shot would shoot a very concistent 1/2 MOA. The POI was a bit different for each one. When I fouled with one or the other, it didnt matter which one I started with and shot a few more, then switched to the other bullet, the accuracy suffered quite a bit for a few shots then sometimes settled down. Whether or not it settled down depended on which bullet I started with. If I started with the AMAX, the ACCUBONDS would suck for a while and then settle in but if I started with the ACCUBONDS and switched to the AMAX, the AMAX never would settle in to normal levels. It is however way worse when you change powders. I have done ladder tests with one powder then switched to another using the same bullet and NOT cleaning only to come up with a "good" load, go home scrub her out, load more, go back to the range and never be able to duplicate the results without shooting 10 rounds of the load with the other powder.

I have read in magazines years ago that it didnt matter what you fouled with, just foul with 2 or three rounds of whatever and go hunting. I have never heard such bad advice as this. This is also why it took me a while to figure it out as I had bad info in my head.

Virtually everything you stated NOT TO DO, I have been doing with this gun. That has got to be why my "money load" will shoot 1/4 MOA one day and 1.25 MOA another.