I loaded some 44 mag rounds last weekend. This is what puzzled me. My old Hornady book show 15.2 grs of Bluedot as a starting load. Tested the ammo. A little on the hot side. Checked my new nosler book and it showed 15.0 grs of Blue dot as Max. load.. What gives?? Test gun was a smith & wesson 629 8 3/8" barrel. Thanks

bob300wsm there are a lot of variables in reloading. Sizing of bullets, ID of each barrel used, different burn rates in powders from lot to lot etc. etc.. That's why you drop down and load up to Max. I always pick the hottest documented load I can find. Drop back a few grains and proceed to work to Max. I usually get there. But every once and awhile depending on the gun or the load I'll get pressure before Max. That happens very rarely. But that is why a smart reloader uses those good reloading procedures.

Another reason to consult several handloading data bases before you start w/ a new cartridge or powder. I have 3 manuals & routinely check the powder sites for data when I go on to something new.

I have used this data in the past with no problems. Have been reloading for 20 years. I have always trusted this old Hornady manual. Used 16.7 grs in the ruger superhawk, no problems at all. For that reason is why i loaded down for the 629 smith. Some of today manuals go under for liability reasons.. i guess. Have used other manuals to load rifle and some pistol calibers, no pressure problems noted.

A Hornady bullet isn`t a Nosler, different bearing surfaces, jackets, and cores. Nor are the primers, cases and powders likely of the same lots even if they are the same brands.

The fact there is only 0.2 gr difference in max loads says alot about how well/similar they run their test procedures. I doubt any company wants to put out data that says their product won`t perform as well as the competitions. All of the reloading outfits load to SAAMI spec and report what they found to be max in their paticular test bed. The variation in components used, and equipment error, shows as slight variation in their max loads from other companies data.

Another reason to use and check with multiple reloading books is that mis-prints do happen. When I started reloading I had a book that lumped all 4831 powder together----I can tell you now that IMR-4831 and Hodgdons H-4831 are very different powders and should be treated as such. (However H-4831 & H-4831sc are the same)