Safely extrapolating load data

[Tokimini]

I'm getting some 55 grain Bergers for my 204 (9 twist barrel) and am having trouble finding load data for my preferred powders, which are R10X, A2230 and CFE223. Is there a way to SAFELY extrapolate load data for the 55s using Bergers published data for 40 grain bullets as a basis? If it would be a little dicey I did get load data from Berger for Viht N140, Benchmark and Varget but I have too many powders all ready. I'd really like to use what I have on hand.

[Nor Cal Mikie]

The Accurate Arms data only shows up to a 40 grain V Max with AA2230. Start charge (with 40s) is 23.4.
If it was me and I wanted to see what I could get, I'd start with 23.0 and work up real slow. Might even back down to 22.5 and work up from there?
I ran into a situation with the .204 Ruger and AA2230 in a 16" rear grip Savage. LOTS of pressure problems. Stiff bolt and damaged cases. No listing for the bullet I was working with and the shorter barrel. Had to back WAY OFF to get anywhere.
Start low, go slow, work your way up and you might find that it will shoot to your liking. Never know till you try.

And I might add, I'am not one for jumping from one powder to another just because someone found a killer load with a different powder. You go after that new powder and you end up not knowing the real potential of the multi selections of powders you've already got on hand.
Get a powder and work it to death. Then work it some more. Work it till you can't get anymore out of it.
Almost everything I shoot can be loaded with AA2230 and AA2460 with SUPER results. Havn't found a reason to change to anything else yet.

[Bill K]

Hodgdon's data site shows a 50 grain bullet with CFE 223.. I would check it out and go slightly below their start load and work up slowly. Either CFE or 2230 should work for you, but go low, slow and with caution. Bill K

[Tokimini]

And I might add, I'am not one for jumping from one powder to another just because someone found a killer load with a different powder. You go after that new powder and you end up not knowing the real potential of the multi selections of powders you've already got on hand.
Get a powder and work it to death. Then work it some more. Work it till you can't get anymore out of it.
Almost everything I shoot can be loaded with AA2230 and AA2460 with SUPER results. Havn't found a reason to change to anything else yet.

Exactly. CFE223 and A2230 are my go to warm weather powders and the R10X shoots bugholes in the cold. I really don't want to screw around with a new powder if I don't have to.

[futuretrades]

I agree with the previous posters. Just remember, a heavier bullet will use a lower powder charge. For me, I would drop the powder charge by 2 full grains, and work up from there.

[RAMOS]

RL10X for me, year round with two different bullets. I don't let them 'bake' in my vehicle, however. I have, when forced to, extrapolated using percentages of charge weight and bullet weight from two proven loads for SMALL differences. The problem (RISK) being being that the math is linear while the pressure change may not be. Not sure if I said this very well and, certainly not encouraging anyone to play Back Yard Ballistician!

[Tokimini]

The problem (RISK) being being that the math is linear while the pressure change may not be. Not sure if I said this very well and, certainly not encouraging anyone to play Back Yard Ballistician!

That was my concern. If it's exponential instead of linear it could get nasty real quick. I've also heard too light a load could result in over pressure, so there is a fine line there. This is going to take some thought.

[RAMOS]

Have no doubt, an overly reduced load can result in a bad, bad situation. Basically, the primer flash travels over the top of the powder (horizontal case), igniting way too much powder at once. In a normal charge, the primer ignites one end of the charge and then it burns to the other end of the column.

[Tokimini]

Have no doubt, an overly reduced load can result in a bad, bad situation. Basically, the primer flash travels over the top of the powder (horizontal case), igniting way too much powder at once. In a normal charge, the primer ignites one end of the charge and then it burns to the other end of the column.

Now it makes sense. I could never figure out how less powder could result in more pressure.

[Bill K]

Believe the name for this condition is "Detonation". In other words, rather than build/burn slowly, the burn is instant and pressure really spikes. Bill K

[Nor Cal Mikie]

And there seems to be something about the small calibers (like the 20 and smaller) where a 1/10th. of a grain in powder difference will really show pressure signs. Think there might be a "fine line" where you'll be working with but I wouldn't let that scare me away from using ANY powder. Watch for a good seal on the neck/chamber and see if the bugholes will show up.
Velocity wouldn't be my main goal. Small groups is what I would be after.

[RAMOS]

Thanks, Bill. I scratched and scratched my head trying to remember the proper term! I kept thinking 'flash-over' but, that is from the movie about about the firemen so I knew that wasn't it.

[Rick in Oregon]

Jon, I think the term you're thinking of may be "detination" or a dirivative of it? (Too small amount of slow powder in a case with excessive volume for the given load.)

[truckerwalt]

I assume you mean 35 grain bergers. I use 30.9 grains of cfe-223 and rem 71/2 primers. my savage 12 with a 26 inch bbl has shot a group at .185" @ 100 yd.

[Tokimini]

I assume you mean 35 grain bergers. I use 30.9 grains of cfe-223 and rem 71/2 primers. my savage 12 with a 26 inch bbl has shot a group at .185" @ 100 yd.

Nope, 55 grain Bergers, the big boys.