extrapolating load data

[Char-Gar]

I have been reloading since the late 50s. If we didn't extrapolate data back in the day, there would be precious little shooting. Bullets of a similar weight were considered fungible...IF... we used the starting loads and worked up. Nobody in their right mind would start with Max loads!!! Still works the same way today.

[meh]

Maybe my OP was unclear, my target was "full-house 357 Mag loads", I only mentioned speed as the Data I found for those powders and similar projectiles seemed to max out in that 1600 range, so I put that number in parenthesis, and in hindsight it appears to have given the readers the wrong impression.

To be honest with you, I didn't pay any attention to it to begin with, and I didn't really understand why velocity was worth discussing. If I had been thinking more clearly at the time, I would not have responded on that subject at all, but in for a penny... Tangents happen.

[meh]

I have been reloading since the late 50s. If we didn't extrapolate data back in the day, there would be precious little shooting. Bullets of a similar weight were considered fungible...IF... we used the starting loads and worked up. Nobody in their right mind would start with Max loads!!! Still works the same way today.

This. But I do find it annoying that manuals will tell me the COAL (usually) but not bother to mention the length of the bullet they used. Who hasn't substituted bullets? But the single biggest factor with a given powder charge isn't the bullet composition, rather the seating depth. If I just knew the seating depth they used, I'd have better insight into whether my maximum charge would likely to be less than, or more than, their maximum. I was recently developing some loads for WST (the pandemic having pushed me to try something new), and I wasted some time because my initial trial loads were all very light. The reason for that was using a 200 grain RNFP, and their data was for a 200 grain SWC. In .45 ACP, there's more than the average difference between the length of these two bullet shapes, and the SWC is seated substantially deeper. I still wouldn't have seated my RNFPs as deep, but at least I'd have then known that I was loading to shallower seating depth and to expect lower pressures. If it had been the other way around, published load data with an RNFP and I had SWCs, I'd have known not to bother loading any at, or very close to, their published maximum charge. I would just find it helpful.

[uscra112]

I have been reloading since the late 50s. If we didn't extrapolate data back in the day, there would be precious little shooting. Bullets of a similar weight were considered fungible...IF... we used the starting loads and worked up. Nobody in their right mind would start with Max loads!!! Still works the same way today.

Heck, ,that's how Elmer did it. Increase the load until the cylinder blew out.

[Char-Gar]

Heck, ,that's how Elmer did it. Increase the load until the cylinder blew out.

For the record: I have never destroyed or damaged in the slightest any firearm by handloading.

[ddixie884]

Heck, ,that's how Elmer did it. Increase the load until the cylinder blew out.

I'm sorry sir, but your information is not correct. Elmer Keith only ever blew one cylinder and it was with Kings Semi-Smokeless Powder. If you have any documentation to prove your assertions, please post them with dates and publications. This kind of baseless allegation is the beginnings of internet gossip.

[uscra112]

And that was my intention......../sarc

[1006]

Regarding HS7 data: I believe HS7 was previously sold as Winchester W571. You might find more cast data for W571.

Also, the Laser Cast reloading manual has some HS7 data.

[JonB_in_Glencoe]

I appreciate the input so far.
Glad I posted this before I got to far into the planning, because between suggestions here and another forum, I got some things to thing about. I have a large pile of the NOE boolits cast up, using them for 9mm...so that's why I thought about using some in 357 Mag, now I'm reconsidering that, and maybe using a longer/heavier boolit...maybe even using a GC style boolit. There is no shortage of full-house data for the standard 158gr boolits.
Thanks...

Yesterday, I shot some loads using N110 and a NOE 160gr SWC.
The 13.3gr load did what I was looking for. More accurate than a load I worked up a few years ago, using H110 with the same boolit. The N110 sure metered nice.

[Conditor22]

IF I could find ball/flattened ball powders that gave great results in ALL my guns I'd be happy to get rid of all my flake and stick powders.

Just finished doing load workups for 55grn and 62 grn swaged bullets for 3-223's using BL-C(2) ( flattened ball). Dial-in the powder dropper and the charge never changes


Jon, at the price Brownells, is selling N110 for it should load itself

[JonB_in_Glencoe]

Yeah, I know. I got these 2 lbs of N110 for a very good price a few years ago...and just want to use it.

[justindad]

I record the bullet length and OACL for all of my hand loads, and interpolate load data based on case volume. Keeping the record of bullet lengths & OACL has been useful.

And to beat a dead horse - I’m comfortable interpolating, but not extrapolating.

[MT Gianni]

To interpolate is to go between a start and max charge. To extrapolate is to assume that since a Speer 150 gr bullet is listed as a max with XX gr of XYZ powder a Hornaday 150 gr is also safe. i suspect most of us do that. It would also be assuming that since 7 gr of powder Q is listed at 700 fps and the table tops out with 10 gr of powder Q at 1000 fps that 11 gr gives you 1100 fps. I hope that none of us does that.

I would start with measuring of the bullet bearing surface and comparing it to the one listed. I believe that is as important with cast as weight is do jacketed due to ogives, tapers and jacket thickness.
i have never shot and of the VV powders and consider HS7 to be at the top of the medium powders. In a perfect world this would be where we tell you to go buy some 2400/296/H110/AA9 and go to work.
If I chose to do this, I would look at each fired case with a magnifying glass at each progression, including the start.