BHN and accuracy
- Thread starter burbank.jung
- Start date
Ian
Notorious member
A lot of us here tend to think in terms of alloy blends and tempers rather than actual 'hardness' numbers. Sure, the kind of modern, sorted clip on automotive wheelweight alloy we have plus two percent 63/37 reclaimed, assayed solder gives me 13-14 bhn air cooled after a month of aging and I can tell you what it will do and in what guns when loaded a certain way (as well as what it will NOT do and what can be done to fix it), the Brinell number itself is meaningless even though consistently measurable. It is the properties of tin, antimony, copper, arsenic, and other things when added to lead that alter the characteristics of the alloy, not necessarily the direct hardness achieved with these alloys that makes the difference.
The conversation goes more like "my good groups are opening up in rifle X when I try to get past X velocity, but I really need another 200 fps to do what I want. It goes from groups to patterns with two different powders a burn rate or two slower, never shows a string tendency, just bigger patterns." One person might suggest adding some linotype alloy or bringing up the tin to balance the alloy and then playing with seating depth, another might recommend a bullet change to work better dynamic fit with the alloy already in use, still another might suggest water quenching the existing bullet and alloy to see what happens. We think in terms of manipulating properties and shapes of materials to get what we desire from the system rather than oversimplified and not very directly relevant things like measured bullet hardness (reasons why it isn't relevant having been soundly beaten into the ground already).
The conversation goes more like "my good groups are opening up in rifle X when I try to get past X velocity, but I really need another 200 fps to do what I want. It goes from groups to patterns with two different powders a burn rate or two slower, never shows a string tendency, just bigger patterns." One person might suggest adding some linotype alloy or bringing up the tin to balance the alloy and then playing with seating depth, another might recommend a bullet change to work better dynamic fit with the alloy already in use, still another might suggest water quenching the existing bullet and alloy to see what happens. We think in terms of manipulating properties and shapes of materials to get what we desire from the system rather than oversimplified and not very directly relevant things like measured bullet hardness (reasons why it isn't relevant having been soundly beaten into the ground already).
Bret4207
At the casting bench in the sky. RIP Bret.
I haven't seen you ask anything approaching a "stupid" question. You seem to want to learn and aren't hung up on a single aspect of the game to the exclusion of everything else.
Ian
Notorious member
Johnny, the truth is we make those kinds of loads up based on experience gleaned from experimentation, sharing among trusted people, occasional legitimate tested sources shared by generous people who have access to expensive equipment, and sometimes computer modeling with internal ballistics programs such as QuickLoad or GRS.
There are some basics like 10 grains of Unique or 14 grains of 2400 under a medium-weight bullet in the .30-30, or about 8 grains of any medium-burn pistol powder under a medium to light weight bullet in just about any .30 caliber cartridge larger than .30 Carbine, 16-18 grains of 2400 in the .30-'06, etc. etc. etc. that just work and are well-known safe loads from which a person can work DOWN in power and faster in burn rate under known-safe parameters of case volume, bullet weight, expansion ratio of the case body/bore diameter. Again, general background and experience.
The group here is pretty good about steering people in the right direction, if you got questions just ask.
There are some basics like 10 grains of Unique or 14 grains of 2400 under a medium-weight bullet in the .30-30, or about 8 grains of any medium-burn pistol powder under a medium to light weight bullet in just about any .30 caliber cartridge larger than .30 Carbine, 16-18 grains of 2400 in the .30-'06, etc. etc. etc. that just work and are well-known safe loads from which a person can work DOWN in power and faster in burn rate under known-safe parameters of case volume, bullet weight, expansion ratio of the case body/bore diameter. Again, general background and experience.
The group here is pretty good about steering people in the right direction, if you got questions just ask.
JWFilips
Well-Known Member
Try 6 to 7 grains Unique with that bullet you showed us the other day Should give you about 1200 fps
Red Dot would work also with 4.5 gr to 5 gr Should put you around 1100 fps All these can be tuned accurate at 50 yards!
Get yourself some American Select ( Same as Green Dot but I like it better) 5 grains would be a good start
Red Dot would work also with 4.5 gr to 5 gr Should put you around 1100 fps All these can be tuned accurate at 50 yards!
Get yourself some American Select ( Same as Green Dot but I like it better) 5 grains would be a good start
JWFilips
Well-Known Member
If you are interested in low velocity shooting you may find this thread of interest.
"Low Node" Shooting
"Low Node" Shooting
JWFilips
Well-Known Member
Also If you decide to try "Low Node" Shooting You have to be extra careful in the loading room! The safest way to Load your brass is To put powder in a case and place the case in a totally different part of your loading bench! This is to make sure you do not double load a case ( The light loads require so much less powder in a case that it is easy to pick up a filled case and try to fill it again! That could be dangerous! Also If you are shooting light loads you want to only use the fast burning powders Such as Bullseye, Red Dot, Green Dot, American Select or Unique. Most of these are light shotgun powders!
Stay away from the 4 numbered powders and I would not even recommend 2400 in small quantities!
Blue Dot, 5744, 4227, H4895 are not Low Node powders and should not be used in light loads.
I try to keep all my rifles below or slightly above the speed of sound. That is just my choice!
Using the Fast burning powders I mentioned above; None of these powders are used with more that 9 grains of powder, because of the pressure spike.
Shooting light loads safely and successfully requires a strict discipline! Be safe!
Stay away from the 4 numbered powders and I would not even recommend 2400 in small quantities!
Blue Dot, 5744, 4227, H4895 are not Low Node powders and should not be used in light loads.
I try to keep all my rifles below or slightly above the speed of sound. That is just my choice!
Using the Fast burning powders I mentioned above; None of these powders are used with more that 9 grains of powder, because of the pressure spike.
Shooting light loads safely and successfully requires a strict discipline! Be safe!
fiver
Well-Known Member
think of your powders in steps.
red-dot,,,, unique,,,, 2400,,,, h-110.
it works the same in pistol calibers and in rifle cases.
your bound by a maximum pressure,, no way around that.
so all you can work with is the amount of time the powder pushes on the bullet.
that translates into velocity windows.
900 fps,,, 1200 fps,, 1600 fps,, 1900 fps.
so what you end up with is a powder running into a pressure wall right about the time it hits half way through a velocity step, and your left deciding to step back a little or moving on to more of a slower powder which starts the whole thing all over again.
red-dot,,,, unique,,,, 2400,,,, h-110.
it works the same in pistol calibers and in rifle cases.
your bound by a maximum pressure,, no way around that.
so all you can work with is the amount of time the powder pushes on the bullet.
that translates into velocity windows.
900 fps,,, 1200 fps,, 1600 fps,, 1900 fps.
so what you end up with is a powder running into a pressure wall right about the time it hits half way through a velocity step, and your left deciding to step back a little or moving on to more of a slower powder which starts the whole thing all over again.
RBHarter
West Central AR
Unique....... I've seen tested data from 8-42kpsi . Really thought it would peak out around 25-28 but it runs top loads in 357 , 9 , and 40 .
Where it shines is that it is readable in rifles if you have black flakes left it's under 7500 psi , about 9000 psi they're goldish at 10-12000 they take on a dry leaf spider web effect and somewhere about 15000-15250 there's no flakes left and very little soot . It blacks cases a little but above 15500 it does rub off really .
It also lends itself to just backing it down until you get your numbers . I does do a weird plateau thing where the speed drops per step are almost nil .
Where it shines is that it is readable in rifles if you have black flakes left it's under 7500 psi , about 9000 psi they're goldish at 10-12000 they take on a dry leaf spider web effect and somewhere about 15000-15250 there's no flakes left and very little soot . It blacks cases a little but above 15500 it does rub off really .
It also lends itself to just backing it down until you get your numbers . I does do a weird plateau thing where the speed drops per step are almost nil .