Loading manual data differing

FlGunner

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So I'm loading for my tikka 300 wsm. I'm using 178 ELDx and H4350. Well at the bench tonight I looked at 2 different Hornady manuals to see what primer they recommend in their tests. While looking I referenced load data for 178-180 grain bullets. 10th edition list max at 63.4 H4350 and the 9th edition lists 65.2. Just wondering if any of you guys ever notice data changes over time with companies. I've often wondered why that is. I'm assuming lawyers have something to do with it and maybe marketing.
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Data constantly changes. Thats why they print new manuals. Powder lots change, bullets change and are added, primers vary, guns used in tests may differ, this list goes on. All good reasons to keep your reloading manual library current. Hornady is usually good about that. If you go to the powder maker sites you will find the data differs from Hornady.
 
Yeah I've noticed all over that data varies across manufacturers and I try to stay up to date. Just like all rifles are different and components vary. Just thought I'd ask to see how folks go about taking in the changes and what they do. Going to try and shoot a ladder this weekend and see how the old Tikka does.
 
I've seen changes when coal changes, case changes, barrel mfg, gun brand and/or primer is different with the same data produced by the same company. There's no way that lot variation can be that much! Throat was probably shorter or longer based on charge weight differences.
 
I know some of the LRH members have quite a collection of manuals. Like others have stated the variability of test rifles and components can have a fairly significant impact on charge levels. Some shooters are very adept at reading pressure, but some are less able to accurately read pressure signs. I wish there was a true comprehensive source out there with the equipment and resources to scientifically test and publish results for reloaders. A good Chrono and meticulous observation while working up charges is the only way I know to find the right load combination.
 
I would guess that it's probably because of the GMX being a monolithic and probably longer than anything else they offer in that weight range. They didn't have it in the 9th edition.

I think the 11th looks mostly the same as the 10th, there are more cartridges in the 11th though.

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Check the comparison between IMR and H 4350s. Yep probably adding ELD bullets and GMX bullets changed the overall charge weights. Don't like loading manuals that use several different bullets of the same weight to provide load data, I prefer load data for a specific bullet.
 
With that many bullets listed there are a lot of variables. There is also a lot of variation, lot to lot in powder. I've gained or lost 200 FPS with no other changes than lot number. That has to translate to pressure difference.
 
Yes
So I'm loading for my tikka 300 wsm. I'm using 178 ELDx and H4350. Well at the bench tonight I looked at 2 different Hornady manuals to see what primer they recommend in their tests. While looking I referenced load data for 178-180 grain bullets. 10th edition list max at 63.4 H4350 and the 9th edition lists 65.2. Just wondering if any of you guys ever notice data changes over time with companies. I've often wondered why that is. I'm assuming lawyers have something to do with it and maybe marketing.
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Yes. A very few years ago I saw one of my favorite ammos in one of my favorite calibers change the muzzle specs drastically down.
 
I have reloading manuals dating back into the 60's. I am alway adding to my collection. I don't throw out any of them. Things are alway changing. Best to start out with lower powder loads and work up. I didn't do that once and went to the top load. Blew out a primer first fired case. Never did that again. learn the hard way. You can also at the same time do a ladder test and bullet seating test to some extent.
 
Check the comparison between IMR and H 4350s. Yep probably adding ELD bullets and GMX bullets changed the overall charge weights. Don't like loading manuals that use several different bullets of the same weight to provide load data, I prefer load data for a specific bullet.
I think in years past, Hornady had their monos in a different page, so that was nice.
 
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