New Reload Data Caught My Attention . . .

[Dom]

and my eyes opened a little wider to comprehend what happened.

I looked thru my Speer, Sierra, Hornady, Nosler load books to get a starting reload for my new three seven five.

Loaded up 5 rounds at the starting point, 5 more 1 grain heavier, and 5 more 2 grains heavier, which would still put all loads from low to the middle and not max.

All went well, no signs of pressure, and I got at or minus 1 MOA after five shots using them all. So, I said to myself, lucked out again, first try out and I’m done.

But wait, I had ordered the “One Shot – One Caliber” reloading book, and it just came in. Lo and behold, they’ve adjusted their loads for exactly what I was shooting. I open it up, find the bullet and powder combination I used, and my STARTING load was already a full grain OVER their maximum load listed. That’s when my eyes opened wide.

Seems they’re using some new electronic data measuring system. The load out of the manual was a few years older, when a different pressure system was used.

Just for info, I guess it’s a good idea to “update” your load books every few years. Not sure if I’ll keep that load or try something within the latest specs.

Since I didn’t notice any pressure, not sure if I’ll just march on or back off. I’ve got a fair amount of bucks tied up in the rifle and don’t really feel like pushing the envelope. But that is an excellent load combination – IMR 4064 pushing a 285gr Speer Grand Slam. Waidmannsheil, Dom.

[Dutchboy]

There are some differences in measuring pressure between the old cup methods, and the newer piezo ( and strain gauge) methods.

Still, those differences remain theoretical for all but a few reloaders. For the "common loaders", velocity is the best pressure gauge out there (and it's a good one).

If you are higher than book speed, you are higher than book pressure. So, in my opinion, if you have a standard rifle, a chrony will answer your questions.

That said, there are tremendous differences within the belted brass universe. For example, I have a 7mag, and FC brass holds 83 grains of water. Wby brass holds 89.5 grains! That's 8% difference!

Before you lose too much sleep, see what the case capacities were of the brass they used. It may have been substantially different from your brass. Likewise, a long throat (seating bullets long) can have a significant impact on loading data. FWIW, Dutch.

[Rocky Raab]

I wouldn't lose sleep over it, Dom.

The new figures are not only adjusted for CUP versus PSI but are also likely adjusted for the oldest rifle in that round. Assuming yours is a new or newish rifle, it's stronger than the old ones.

Dutchboy's advice is good. Match the velocity and you'll be matching the pressure (assuming the components are the same as the book's).

I never recommend using OLD reloading data - components DO change - but using recent data is probably fine even if it isn't the newest. Again, that assumes a newish gun.