Powder charge adjustments for jammed bullets

[MVW]

I was reading another recent thread on seating bullets to the lands and it raised a question in my mind that you might need to make adjustments to the powder charge when the bullet is jammed -- I would think a jammed bullet would have significantly different pressure characteristics than one that is 0.01 off the lands. For a max load this seems like this might be a problem. Is there any data on such matters

Thanks,

MVW

 

[Shynloco]

MVW,
I'm not quite sure what you mean by "data." In books I've read about bullet seating depth and the methods to ascertain what works best in YOUR PARTICULAR RIFLE, the admonition is usually to start at .050 out of the lands and to work your way closer by .010 while at the same time checking your fired casings/primers for signs of "pressure". Now I've always been taught to reduce your powder loads to mid range when going down this road and increase by .5 gr each time your increase those loads. From doing this on several of my rifles in various calibers, there was no SAME specific magic formula that worked in every caliber. In fact, pressure signs sometimes started appearing at .010 out and no pressure appeared even when I got into the lands and my powder was right up there when I was at "accuracy loads" values with a specific type of powder. So I think your premise is, in fact, valid for safety reasons. but not necessarily accurate for all rifles of the same cailber. Gotta run the test in your rifle and caliber, but I'd definitely drop the powder load to mid range (at least) to be on the safe side before your know if you have excessure pressure or not. And if you change powders in mid stream, gotta start over again because one powder may give you pressure and another will not. Hope that helps some. BTW, loading bullets into the lands DOESN"T always give you the best accuracy and may or may not give you signs of excessive pressure once you are in there.. Each rifle and load is different. Hope that helps some.

Good luck and have fun.

 

[RDavies]

My 284 needs about .5gns more powder for the same velocity if I jump .015" instead of Jam .015".
My 6x47 about .4gns
and my 6 dasher about .3gns.

 

[GSSP]

When I work up a "target" load, I typically start my pressure ladder .010" in to the lands. That way when I find either the max pressure or my accuracy nodes, I need not worry about pressure spikes. If it's a hunting load I start .010" off the lands and still work away from the lands.

Alan