Working up CB loads

[mag_01]

:coffee: ----In working up loads for CBs can I use J---- bullet info with similar weigh boolits as a guide? Do or should I reduce the load and if so by how much % wise to be safe and with the Idea in mind that I may be able to reach to some degree J-----bullets velocity's and power levels?----7mm----30-30---308 etc.




Play all hands you are dealt well and just maybe you will come out a winner

[MtGun44]

The lead alloys that we use are very similar to journal bearing alloys
and they have very low coefficient of friction against smooth steel, like
a crankshaft journal or a barrel interior (your's IS smooth? ). So, as
far as the CB with j****ed bullet data, I'd expect higher velocity with
the same weight bullet and same powder charge. You can probably
lower the charge 10-15% and get about the same vel. The issue is
typically leading the bore at high velocities with CBs. As you go to
higher and higher velocities, you need stronger and harder alloys or
heat treating to higher hardness/strength, plus GOOD lubes. Most
references say you can get about 2200 fps max with straight linotype
alloy with most rifles. I have never tried to go that high, most of my
bottleneck (7x57 and 30-06) experience is with ~150 gr range of wts
and estimated 1300-1400 fps, with good results, like <1.5" at 50 yds
right off the bat. Send me your e-mail and I'll e-mail a couple of
small pix of some nice groups with my Ruger 7x57 and 150 LBT
CBs. I have read that accy falls apart rapidly at higher velocities
with CBs, but have never gone over about 1800-1900 fps with CBs
myself.

Anybody know how to insert an image into a message? The image
icon asks for a URL, which I don't have, since the images are on my
computer.

The velocity comments above are definitely true in revolvers, as a matter
of fact you can frequently get higher velocity in a .44 mag with CBs and with
lower pressures than with j****ed.

Also, it may not be obvious, but linotype will shatter on impact, so is
not a good alloy for hunting. Heat treating wwts may get you hard enough
to run at the high velocities, but most of CB shooting is about laid back
low intensity stuff rather than high vel stuff. I do get "high vel" in my .44s,
but that is still way low by .30-06 stds.

Bill

[NVcurmudgeon]

MtGun44 has already addressed, and very well, the question of maximum loads using jacketed vs. cast boolits. Two things that I have learned about working up a good CB load are to work up a powerful to maximum load in the hottest weather you expect to use your new load in. That way you will have confidence that your new super accurate load will be good at all temperatures. I have more than once worked up a load in mild CA winter, only to have it go sour on hot summer days. The other painful truth is that "one swallow does not a summer make," and it is especially true with cast bullet accuracy. I don't believe in the accuracy of a promising CB load until it has delivered the goods on at least three different days.