question about boolit drag

[XWrench3]

i have been at this for a couple of years now, but this just occoured to me. i have been using the lyman cast bullet book for load data, and have done just fine by it. but i now am changing a variable, and i do not know the answer. first, i am loading 151g cast gas checked bullets in a 30-30. the variable is, instead of using #2 alloy, as the book states, i am using 1/2 w.w. & 1/2 linotype boolits that have been water dropped. so they should considerably harder than #2 alloy. how does bullet hardness affect pressures? or is the differnce so small, it will not be worth worrying about? :veryconfu

[peerlesscowboy]

All else equal I should think a harder bullet would raise pressure but I s'pect the difference would be so small as to not worry about? Someone correct me if I'm mistaken but I believe a jacketed bullet vs a cast bullet of the same weight in an otherwise identicle load, the jacketed load will be higher pressure :CastBoolitsisbest:

[onondaga]

The change in BHN with your new alloy will have only a small increase in pressure. You will note that your bullets will be about .001-.002" larger with the new alloy , but that is usually GOOD!

My guess is that you want to increase velocity/pressure and that is why you have changed alloy. Your bullet is probably a flat nose too for the 30-30. They smack good. I use ww: lino at 7:3 and my 7 day BHN is 14. My gas checked 151 gr FN bullets hold accuracy peak at 2150 fps in a 30-30. You will likely be able to go faster, but the expansion of your alloy will be poor to zero on game at that hardness with your new alloy. Be aware of that when hunting, shot placement will be more critical.

Air cooled bullets with your alloy will be more than needed in BHN and the air cooling is much more consistent than water dropping. Also air cooled bullets don't loose hardness over time as water dropped bullets do. My tests with water dropped bullets puts them the same hardness as air cooled bullets of the same alloy after 6 months to a year.

Gary

[XWrench3]

Gary, thanks! these are not for hunting, just go fast target shooting. something that will be close to the point of impact of "J" bullets (so i do not have to re-dial the scope at every change, until i get where i want to be group wise). i also have roughly 100 of this same boolit, made up in air cooled soft lead, for hunting. i was told shooting the same load as you practice with, only using soft boolits, will give good hunting results. and not to worrry about a little lead in the bore. after all, how many shots will you take actually hunting? made sense to me. when i get everything exactly where i want ti to be with the hard ones, i will shoot some of the soft ones and make sure p.o.i is at least close to the same. that will also give em a chance to see exactly how much lead it will leave in the bore.

[Larry Gibson]

Unless you are using a very fast powder, the bearing length of the bullet is already swaged within one bearing length travel in the riflingand there after the energy (psi) requred to move the bullet remains the same for both bullets regardles of BHN or alloy. This occurs well before peak pressure is reached. Any increase in psi (if any) will be very small and will fall within the normal shot to shot psi variation. It is the same with bullets that are over groove depth from .001 to .006". I have attempted to measure any psi variation with both harder or softer bullets and the over groove depth bullets and have failed. The average psi's remained consistent within expected variations.

However, a noticeable difference in weight from one alloy to another can vary the psi.

Larry Gibson

[Wayne Smith]

A gas checked 50/50 ww/Pb boolit, air dropped, if it fits the throat and bore, should shoot in a 30-30 equal with a bullet without leading. That's one of the beauties of this cartridge. I don't think you need a harder boolit unless you are trying to make this into a 30 Savage!

[XWrench3]

A gas checked 50/50 ww/Pb boolit, air dropped, if it fits the throat and bore, should shoot in a 30-30 equal with a bullet without leading. That's one of the beauties of this cartridge. I don't think you need a harder boolit unless you are trying to make this into a 30 Savage!


no, i tried that kind of stuff when i first started reloading. and i was fortunate enough not to wreck anything. a 30-30 is all it will ever be, and i have no interst in hot rodding it. i have a 300 winchester magnum if i want to go really fast. that being said, i do not necessarily want to load it down to 30 carbine either. i have already done that. it is ok for grins, and i actually find it interesting at times. that is one of the big advantages of making your own ammo. you can do what you want with it. the way i see it, the 300 mag casn be anything from a 30 carbine up to what it already is. my 45/70 can be anything from a 45 long colt, to a beastly kicking bear killer (hot 45/70). i will load near maximun with no qualms, working them up of course.

Larry, that information is good to know. i have never tried those expeiments. i guess i had not thought of them yet. i am still in the trying all kind of different loads, for both accuracy and performance.

i love all the good information and help on this board!