swaping bullet brands in loads?

[aldar]

here's the question. can you or have you, taken the listed loads from a differnt brand of bullets as long as their the same weight?. for example, I'm loading a .280 with 140gr bullets. In the sierra book a max load of IMR4831 is 54.4, in the nosler it's 56grs and in the Swift it's 53.5. quite a bit of difference with the same weight bullet. All the bullets are similar so I just don't understand the big difference's.

[STexhunter]

Different bullets have different ogives (bullet shape) more bullet surface on rifleing,which can cause different pressure levels.  Different manuels especially from bullet manufacturers have different load data for their particular bullets.  I have got by with same load data on different bullets but, I usually don't load max.  I always refer to 2 or 3 manuels and compare their load data for any given bullet weight and choose a load that both accept and work up looking for pressure signs.  Just my 2 cents worth. 

[beemanbeme]

It seems that each bullet company has their own idea of how to make say a .308 bullet with regards to ogive and diameter. 
If I'm loading a bullet that is different from the books I have, --which would be an oddity since I have most of them--  I do a work up toward the lowest max among the books.  If I reach that without any pressure signs, I may venture toward the next max and so on.
I don't motor my rifles at the top end and have swapped bullet brands while keeping the same proven load.  I know this is a absolute no-no and I should end up blind, with most of my fingers missing and smoking shards of steel sticking out of my head but it hasn't happened yet.
In truth, I find most reloaders will make component switches with a good deal of common sense and very little angst.

[warf73]

Look at each bullet if you have them, each bullet is different in length (as in barring surface) so in turn you would reach MAX SAMMI pressure at different powder charge weights. The larger the barreing surface is the more resistance you will get.

Good to see you have 3 different manuals to reference data from. Also bookmark the powder companies web sites, so you have more reference material.

Warf