Where is the best place to get ballistic data, the powder manufacturer or the bullet manufacturer?

I am finding that when I look at loading manuals some of the maximum load charges in one book are the starting load charges in another, which prompts my question.

Check the dates on the manuals! Older ones use heavier loads than newer ones generally. Lots of online sources for load data. Powder manufacturers offer reliable online powder charge data, but don't discuss bullets for the most part. Bullet manufacturers seem less reliable for powder charge data, but offer data for ballistic coefficients, bullet shapes, diameters, weights. There's nothing mystical about load data, but you need to understand that lead bullets and copper jacketed bullets create different load specs.

I like to check a few sources for load data with any new caliber, get a feel for the data.

Interesting and valid question.....and It used to be easy....I went to Hodgdon's website and got the info....double check with a couple manuals and started loading.....

Today however with the very long and high BC accubonds I go to Nosler's website for loading data in accubonds. The longer bullets consume more of the case capacity and therefore raises pressures a bit more than the same weight of an interlock.

Hodgdon's data is specific about which bullet they are reporting on and includes the pressure they obtained with the given loads.....I believe Alliant does as well....at least which bullet is being used.


I'd strongly advise today's reloader to seek out several loading data sources and as always....start low and work up....Know the pressure signs and let your gun tell you!

everything you can get your hands on.. then quickload, ammoguide, personal experience and a chronograph

There is no one answer for this question. One thing that cannot be overstated is that manuals vary. They can vary because one company uses a different barrel than another, different pressure measurements, some develope data from a SAMMI standard barrel, some from a specific rifle. All of theses variables lead to different data. A perfect example of this is Sierra publishes both data for .223 in an AR-15 and a bolt action rifle. Generally they don't get to different from one another but may go a grain or two on way or the other. Sierra also has a tendency to have lower max loads listed than Hodgdon.

What this means is the best data sources are the manufacturer for the powder and bullet. They may not be the same but looking at what was used to develope the load, using a sensible starting load and not turning a .270 Winchester in to a .270 Weatherby Magnum are good starting points.

Personnally I use velocity and group to determine what I want a load to do. For example in my AR-15, I want a load that replicates or improves a specific ammo. Let's use M262 which is spec'd at 2750 FPS and shoots a great group out of my rifle, I can call a 9 at 600 yards with it so group is good. When I chronograph some I'm closer to 2900 than 2750, so why load it at 2750? First thing to look at is that all rifles are different. Different barrels can be fast or slow. So I look at a Sierras manual and see that x amount of Varget is expected to hit 2750 in an AR-15. Load five at his weight. Then look at the interval in load weight vs velocity. Incrimentally load up five rounds at each 50 FPS step to max load maybe on step below the 2750 load also. Chronograph these to see which load is the same velocity as M262 in my rifle. There may be no need to shoot all of the rounds loaded. Why go faster than what I am looking for? If the load I'm trying to copy is a safe load there is no reason to push it faster or add more pressure. After I match the velocity, which may be a couple of tenths between the step that Sierra has I'll shoot this load to make sure the group is the same. If the load has replicated the performance of M262, a Sierra 77 SMK in 5.56 or may have even improved the group slightly. I'll make a bunch up. If Varget won't do the same velocity go back to the book and pick another powder, say TAC and try again.