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Old 04-22-2017, 06:22 PM
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Kiwi cop Kiwi cop is offline
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Originally Posted by Skip Sackett View Post
Lyman data can be just as wrong and any other and is wrong unless you use their EXACT same data and components.

EVERYONE'S data is like that, by the way.

Personally, after a bad experience with Clays and Lyman data I started using the POWDER COMPANY'S DATA FIRST!

That would be my suggestion to all of you. Put the Hornady book down, the Speer book down, the Lee book down and go to the folks that made the powder. The data is free for the most part, and, available on the web. Win/win in my book. Then, if you want to venture into other territory, go to the published data from other sources.

For the last 15 years or so, that has been my approach to what data to use first. I had one incident before I started using that "theory" and none since.

Take it or leave it.
Even manufacturers data can be misleading from lot to lot Some time ago I decided to go to Tightgroup powder as a multi-caliber option (38 Special/44.40 and .45 ACP). With the .45 I shoot 200 gn jacketed truncated cone (similar to a SWC) projectile out of my Springfield 1911 A1.

The Hodgson site lists two 200 gn loads for Tightgroup in .45 ACP, 5.2 gn max with a Speer JHP for 884 fps and 5.4 gn for 957 fps with a LSWC. As I only needed 850 fps to make power factor (870 for a safety margins) I settled on a 5.1 gn load. Across the chrono it made PF but during a comp recently my loads, from a new batch of three cans of powder I bought after initial load development, failed to make PF and I ended up shooting 45 minor for the weekend.

Afterwards I set about working up a load that made PF and ended up at 5.8 gn to make PF with a slight safety margins. Even 5.6 gn failed to reach 850 fps. There is no noticing each increase in recoil, extraction is fine, cases are not overly expanded and POA/POI is the same as previously.

So now every time I buy powder the first thing I do is load 20 or so rounds using the previous powder lots' data and head for the chrono.
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