overall formula for reloading choices

[coldtrail]

I have been reloading for a while but just 45acp. Always used the same load as all I did was target shoot. Then I got into .308 rifle. I like experimenting with different load charges with the different bullet weights. I always stay within the recommended load listed in the manuals. I am wondering, is there a formula that a person can use to determine how much powder to use for a given powder and bullet? There are so many powders out there but not all are listed. So I am thinking that there must be some way to determine how much is a safe limit for a given charge amount of any powder. For instance you wouldn't necessarily use a powder designed for pistol or shotgun but if you had to where would you start?

 

[JimKirk]

Would you dive into a pool with only 6" of water? Then why dive into a cesspool when there are thousands of tried and proven loads out there. Get yourself serveral recent reloading manuals, do your diving there. Lot of data from the powder. Manufacturers online too.

Jimmy K

 

[rcmodel]

+1

There is no formula like you want because there can't be.

Powder burn rate is not set in stone.
It changes depending on the cartridges case design, such as an over-bore magnum as opposed to a 45-70. What might work in one case might blow up in another.

That is why every company making bullets or powder pressure test loads for safe combinations that will give no surprises.

There is one product sort of like what you ask about.
There is a computer program called QuickLOAD that allows you to plug in about any wierd combination you can dream up, and it calculates an approximate pressure guess.
For only $150 bucks, you too can own it!

http://www.6mmbr.com/quickload.html

rc

 

[Sherri]

rcmodel

There is one product sort of like what you ask about.
There is a computer program called QuickLOAD that allows you to plug in about any wierd combination you can dream up, and it calculates an approximate pressure guess.
For only $150 bucks, you too can own it!

The more I read, the more I like having the range to myself.

 

[WNTFW]

Coldtrail,
There are a few articles here:
http://www.chuckhawks.com/index2k_reloading.htm
That may shed some light on why it doesn't work that way. They are about how burn rate is measured and the like.

My simplified version is to take the charge from a rifle case and pour it onto cement. Light it and see how slow it burns and was a little hard to light. Makes you wonder how it could even send a bullet out of the barrel. The heat and pressure affect the way it burns.

 

[243winxb]

For your 308, to get a wide range of velocity, Hodgdon has on there site "youth loads" and "Trail Boss" loading data. This will give you safe loads with more range/leeway for the caliber.

 

[coldtrail]

Thanks for the input and links. Yeah, it's a swamp out there should you wander off the reload manual trail. I read some of the articles and had to stop when my eyes started to bleed from all the technical stuff. I was hoping for a simple "A" plus "B" equals "C" type of answer. Of course, no such thing. I'll stick to the manuals for now and leave the BE for the pistol stuff. Neat picture of a rifle exploding from a factory error half charge burning too fast and raising the chamber pressure excessively. I would have thought it would have just given a slower bullet.

 

[MrOldLude]

I pondered something similar once. But I'm not on the bleeding edge of ballistics, and I have no need to try and push the envelope. So I decided to be less of a tightwad, and simply by different powders for that work well for different calibers.

Would it be nice to load 9mm, .38/.357, .223 and .30-06 all with one powder? Yeah. But it's not a priority.

 

[Hondo 60]

The more I read, the more I like having the range to myself.

Ya, but there's usually a reason when I'm the only one there.
Take today for instance.

Had to trudge thru a foot of snow, shovel around the door to get it open,
and it was about 10 degrees ( -12 celcius ) (building's not heated).

But, dang it, I wanted to get out of the house & go shoot

 

[RidgwayCO]

The only "one formula for everything" powder I know of is Trail Boss. Hodgdon says to mark the case at the depth of the base of the seated bullet, and then you can fill the case to the mark with Trail Boss. But be careful and avoid compressed loads like the plague, because the overriding rule is to NEVER BREAK THE DONUTS. Breaking the little Trail Boss donuts does bad things to the pressure, as the powder also relies on its physical geometry to help control burning rate.

Of course, Trail Boss isn't going to give you "fire-breathing" loads in anything. Tradeoffs... tradeoffs...

 

[mdi]

I'm sure some engineer specializing in firearms/balistics could do this mathematically. Powder burn rate, powder burn temperature, combustion chamber size, bullet weight, and prolly 10 more factors need to be known. Then plug all this info into some obscure formula and presto! you have a load.

 

[mdi]

OOPS!

 

[RandyP]

A related note is that there is a reason you won't find 'every' powder listed for every bullet or caliber combination. Many powders ONLY are safe within specific parameters of caliber and bullet design.

If you can't easily find the combination you want published, find load data for the bullet and use one of the powders they show. Easy, simple and safe.

 

[rmorgan]

but if there were only one magic dust powder for all calibers, bullet wts., loads, there would be no reason to have 8 or 10 different powders to play with. that would be wayyyy to easy.

 

[nelsonal]

I looked into it, when researching pistol powders for .223 pistols. There are formulas but they're very non-linear and end up being fairly complicated differential equations because burn rate is impacted by pressure, since few like working with them and most who do get paid for their day jobs at powder companies, quickload is the only option for hand loaders, even that can be unfriendly if math isn't your strong suit. Suffice to say, it's exceedingly complicated, with lots of room for very unexpected pitfalls, and the average handloader is generally working with very rudimentary tools to gauge pressure (extrapolations from external velocity is great, otherwise just evidence from the casing).

Simplified, powders used in pistols generally don't produce even poor performance in rifle sized cartridges, and powders used in rifles generally won't burn properly in pistol packages. The same is somewhat true between larger and smaller rifles or pistols.

If my warning didn't concern you an old equation in all it's glory can be seen on (the report's) pg 9 of this DoD study.

 

[fatman4570]

This formula will always works for any combination you want
Loading data from chosen manuel x 1= YL (your load)

 

[WNTFW]

Fatman,
Who is Manuel and why is he the chosen one?
How do we get in touch with him?

 

[howlnmad]

The only "one formula for everything" powder I know of is Trail Boss. Hodgdon says to mark the case at the depth of the base of the seated bullet, and then you can fill the case to the mark with Trail Boss. But be careful and avoid compressed loads like the plague, because the overriding rule is to NEVER BREAK THE DONUTS. Breaking the little Trail Boss donuts does bad things to the pressure, as the powder also relies on its physical geometry to help control burning rate.

Of course, Trail Boss isn't going to give you "fire-breathing" loads in anything. Tradeoffs... tradeoffs...

Could you provide a link to this information? I couldn't seem to find it on their website.

 

[RidgwayCO]

My information comes from a conversation with the good folks at Hodgdon. Call them at 913-362-9455, Monday through Thursday, 7:00am to 5:30pm Central Time. If they tell you something different, please let me know!

 

[FeelthySanchez]

The OP's sig line says it here: "I'd rather be lucky than good".

Would suggest a very good life insurance policy ........

 

[ArchAngelCD]

The only "one formula for everything" powder I know of is Trail Boss. Hodgdon says to mark the case at the depth of the base of the seated bullet, and then you can fill the case to the mark with Trail Boss. But be careful and avoid compressed loads like the plague, because the overriding rule is to NEVER BREAK THE DONUTS. Breaking the little Trail Boss donuts does bad things to the pressure, as the powder also relies on its physical geometry to help control burning rate.

Of course, Trail Boss isn't going to give you "fire-breathing" loads in anything. Tradeoffs... tradeoffs...

My information comes from a conversation with the good folks at Hodgdon. Call them at 913-362-9455, Monday through Thursday, 7:00am to 5:30pm Central Time. If they tell you something different, please let me know!

I got the same exact information from the same exact source as RidgwayCO.

Could you provide a link to this information? I couldn't seem to find it on their website.

howlnmad,
It's good you question anything you hear on the Internet and I highly suggest you verify the information for yourself. That's the only way you can be totally sure it's correct...

 

[howlnmad]

Hey guys,
I meant no offense or disrespect to anyone. Thank you for the number and the info. I'm sorry, I just don't believe in posting pet loads or asking for them. I don't even like to (not that I haven't) copy load data from a manual. It only takes one missed keystroke and someone gets hurt.

 

[RidgwayCO]

No offense taken. This is the internet, where EVERYTHING has to be verified, or else taken with a grain (or large bag) of salt...

 

[Sherri]

What was that business about breaking the donuts? I think that's something to do with flattened primers, but I'd like some confirmation.

I haven't yet had to plow my way to the shooting shack, but I have slogged through the rain. Sometimes, you just want to shoot, no?

 

[WNTFW]

Sherri,
Look for a pic of Trail Boss Powder. Donuts refers to the shape of the powder. Sort of reminds me of a deflated inner tube. The shape of a powder has an effect on burn rate / pressure curve. If we were to take a specific power and make into a finely ground dust it may react differently. Some of the rifle (stick) powders I use have a very fine hole through the center. Hard to see size hole, but it is there. The shape of an individual piece of powder change as it burns. The surface area changes as well. The hole helps the stick powder maintain a given surface area better. The OD is decreasing and the ID is increasing in surface area to balance out. Then there are coatings on the powder which also can affect things.