A question in another post made me go back and justify some of my load data. I found my load to be over max with the newest manuals I have. I developed the load a year or two ago with the current manuals at that time.

As the newer manuals come out, I find what was safe then are not safe now according to the manuals. My question is, do powders really change that much from year to year? The preformance and pressure signs have not changed on the load in question.

I quess I never thought manuals changed because powders changed. If so, you'd think powder manufactures would make the announcement and not leave to the bullet companies to post the changes in a 'newer' manual.

What do you guys do, stay with your developed loads or reduce charges when you see the new manual's data?

imo, you use what works in YOUR personal gun safely. max loads can vary widely among different sources of data. a load manual is a GUIDE that show what results they had when they tested/experimented with at that time, in that place, and in the equipment they used at the time whether it was an actual gun, or some other sort of pressure testing equipment.

each person is responsible for carefully working up his own load, under his conditions, in his equipment, and observing what is going on and knowing when enuff is enuff.

these are my thoughts on it anyway. max charges can vary several grains among different sources, and it is our duty to play it safe n work up from a lower charge to find true max in our gun.......n each gun can be different.

i reckon technically one should work up again with each new powder container, but that seems extreme unless there were radical powder changes, or you were nearly over max to begin with.

I wouldn't change a proven safe load receipe just because a new load manual came out with something lower.

The only time I would redevelop a proven load is when I ran out of a certain Lot# of powder. Loading manuals recommend reducing your safe max load 10% and working back up to your guns safe max, when changing Lot#'s if, you get a new Lot# of same powder from your supplier.

Never reduce H110 less than a published starting load, the same may be true for 296 but I've never used it.

Pressures can vary from gun to gun and pressure barrel to pressure barrel. This MAY be one reason why the receipes change from edition to edition.

I'm not telling you what to do. This is just my opinion.

The newest load data is "lawyer proofed" just as some guns (locks, 6 lb triggers, etc)are. The only way to answer your question about powders is to compare the relative speed (or pressure) produced by the two sets of data. I'm finding that most new books list loads that are quite a bit under than older data and produces pressure substantially below SAAMI specs. (And the SAAMI specs themselves are all over the board, often defined by the gun that the chamberings was introduced in. Check the difference in max pressure specks for the 25/06, 270, 280 and 284 compared to their SM and WSM equivalents; at least 10,000 psi, some closer to 20,000 psi, spread).
Conslusion: Powder hasn't changed that much. Most new data has a bigger safety cushion and is well below SAAMI limits.

LSS, I develop ALL loads using a chron. and check for several common excessive pressure indicators as I go. It matters more that a particular gun shoots well at a reasonable velocity than that I'm one grain more, or less, toward an arbitrary data max for powder weight.