are these 2 powders close enough too interchange data somewhat?

why the hell would you want to do that? there is enough data out there that you shouldn't have to.

never interchange data.

In a word, NO!!!.


There is a reason virtually every manual and instructor of loading tells people to "start low, and work up data for your rifle".

That's because data is not only NOT interchangeable between powders, it isn't even completely interchangeable between rifles, with all the same components. Sure, most of the time WHEN ALL COMPONENTS ARE THE SAME, it is safe enough at the very lowest pressure levels. But beyond that, you need to go slowly and learn what pressure signs look like, and how to detect them so you can keep your charges below unsafe areas.

quote:

Originally posted by ddhotbot:
are these 2 powders close enough too interchange data somewhat?

Probably only once in this life roger

quote:

Originally posted by ddhotbot:
are these 2 powders close enough too interchange data somewhat?

I'm not sure what you mean by "interchange somewhat".

In the one application where I have tried both powders (.22 K-Hornet), AA 1680 is significantly faster than RL-7. In fact, in this application, RL-7 was too slow for satisfactory use.

There are other cartridges (7.62x39 might be a good example) where either powder will provide good performance, but the charges for each will likely be somewhat different.

ok i guess what i mean is i can find load data for the rl 7 in the 22-250 can i lower these figures and start working up the aa1680 in my 22-250? thanks

quote:

Originally posted by ddhotbot:
ok i guess what i mean is i can find load data for the rl 7 in the 22-250 can i lower these figures and start working up the aa1680 in my 22-250? thanks

NOT SAFELY. The point is, their proximity to each other on a burning chart tells you absolutely NOTHING about their proximity to each other in real life burning rate and energy content/release. There COULD be a relatively linear relationship, or the relationship could be logrythmic (sp?). There is no way to tell just by looking at a chart.

For instance, you say "lower these figures"....just exactly how much would you lower them? Answer: "A guess." This is NOT an area in which you want to be guessing. The two powders are DIFFERENT. How they differ is UNKNOWN, in so far as what the chart tells you.

Their burning speeds may or may not be VERY different. The rate at which that burning speed changes as pressures rise may be different. The point at which the powder passes from just "over-pressure" to "detonation" may be different. Even if average pressures were the same, which I can assure you they are not, those are only averages...how much do the individual pressure peak "spikes" vary?

When a reloader follows well developed data, all those things are taken into account, along with many others. When a reloader guesses, NONE of them are accounted for.

Russian Roulette is safer than pure guessing at powder load relationships. At least in Russian Roulette, one knows the odds are 5 out of 6 that the hammer won't fall on a loaded chamber. Using powder data for one powder with another powder, one has no idea what the odds of severe danger are...

Hey ddhotbot, All the "Powder Manufacturers" have on-line Load Recommendations for their Powders. Just do a simple Internet Search for the Manufacturer of the Powder you are interested in and use what they recommend.

They have $$$millions$$$ tied up in Test Equipment, Facilities and Personnel just to do the Pressure Verifications. So, my recommendation would be for you to take advantage of it.

If a specific Powder is not Listed under the Cartridge you are wanting information about, it could mean that it was Erratic, Un-Safe, or it might just be outside the normal Burn Rate for the Cartridge/Bullet combination.
-----

If you decide to try an Un-Tested load, you might be fine, or you could create a lot of scrap, the need for a Doctor visit or be fitted for a Pine Box.

Best of luck to you.

quote:

Originally posted by ddhotbot:
ok i guess what i mean is i can find load data for the rl 7 in the 22-250 can i lower these figures and start working up the aa1680 in my 22-250? thanks

Okay, now I understand. It is better to use AA1680 data for a similar cartridge, then interpolate based on that. It is also better to use a slighly faster powder as a reference point, for obvious reasons.

My suggestion would be to look at Seafire's loads (found here on AR) using Blue Dot in the .22-250. AA 1680 is almost certain to be slower than Blue Dot in a given application, so using his loads as a guideline might be a reasonable approach. HOWEVER, you certainly need to know what you're doing, have a chronograph, carefully monitor all available pressure indicators, and have a significant amount of handloading experience before tackling using a powder for which professionally-compiled data does not exist. I've done it, and done it quite safely and successfully, but then I've been reloading for over 40 years and was lucky enough to survive some of my earlier "learning opportunities".

quote:

Originally posted by Alberta Canuck:

Russian Roulette is safer than pure guessing at powder load relationships. At least in Russian Roulette, one knows the odds are 5 out of 6 that the hammer won't fall on a loaded chamber.

Sorry, but I have to correct you.

1.) the chances are 6 out of 7 times you are lucky. We are speaking about the Russian Nagant triple action revolver with 7 chambers.

2.) it was NOT luck! The trick was, that experienced officers would listen to the clicks and "know" when there was a real chance, to shoot themselves.

Although I don´t know exactly, how it´s done, and for sure never will try personally.

Life´s risky enough, as ist is!

H

I accept your correction in its entirety, Sir.

Unfortunately, I made reference only to the North American version, played in my youth generally by acquaintances (and former acquaintances) who had only the S&W and Colt revolvers for the most part, and should likely have noted that. A few of those revolvers offered even worse odds, being 5-shot "pieces".

But at least the odds were easy to calculate in that risky (Russky?) game...unlike using loading data not intended for the powder at hand.


Of course, Stonecreek is correct too...

Some interpolation can be done with similar powders, by experienced loaders, who have learned to intuit using data stored internally from long practice and use. Enough experience can teach which powders burn "how", in various sized cases, with various weight bullets, of various diameters and other variables. But, it IS a learned approach which must be practiced carefully by those with much previous practice. It is NOT a field for the beginner who wishes to safely keep his eyesight and other attributes given him by God.

If you want to work up data to load your 22.250 with 1680... first check to see if there is any info in a cast bullet manual...

if there isn't, check to see if their is load data for a powder faster than the one you are looking to try... since your powder is slower, the data for the faster powder ( but close to that burn rate will be safe in your case)...

also don't start at max for the faster powder...

Since 2400, IMR 4227, H 4227, 5744 & SR 4759 are all faster than 1680... using the data off of one of those should give you a safe point of reference to work with on 1680...

however, work up from there, in half grain increments.... 1/3 grain increments is even better...

I don't know if 1680 will pressure spike or not...a pressure spike is where one charge is just fine, and then a few tenths more and it is blowing the case or blowing the firearm apart...

personally, I'd recommend you use IMR 4227 data and work up from there, but also on your max limt, I'd start worrying if I was getting close to what was listed in max charges for H 4198...
http://www.reloadbench.com/burn.html
if you need a burn rate chart...

if you don't have a lot of experience in doing this sort of stuff, I wouldn't mess with it...
because it is easy to screw up and easy to hurt yourself and ruin a firearm...

cheers
seafire

thanks guys! i am relativally new too rifle reloading and trying too learn. this is why i ask questions before i attempt anything i am not sure of.i purchased 8 lbs of this powder off of gunbroker,along with 9lbs of accurate 2495.i have never used any accurate powders but the price was good.i realize the 2495 is a spin off of the 4895 powders and the 1 i will be using the most for my 308 and 22-250.has anybody tried either of these powders?your opinions please! thanks for the help don