Loading 5.56/223 Reloading Confusion

[Range Hound]

The more I read and search about loading rounds for an AR-15, the more confusing it seems to get. Some of the data almost seems to contradict. I am using a 55 Gr FMJBT with H335 and CCI 41 primer. Seems this would be pretty simple but the data is not lining up.

Case 1 FPS:

Hornady Reloading Manual: 23.4Gr producing 3000 fps w/ non-magnum primer

Speer Reloading Manual: 26.0Gr producing 3067 fps w/ magnum primer

Some say that Hornady is conservative, but the fps are not in line between a magnum primer and a standard primer.

Case 2 Casings:

One starts reading posts and say that an LC casing should loaded different than say a Remington 223. I can see this maybe at a maximum load due to the pressure difference between case volume (wall thickness of casing). However, if loading to a middle of the range what's the deal?

Then there is the make sure that you separate your LC into like headstamps because of the difference in casings?

I have been loading for rifle and pistols for years and never seen this much confusing data. Sure keep your casing grouped by mfg for highest accuracy but....

Case 3 Powder:

Newer H335 is burning hotter than the old H335 so it needs to be loaded accordingly. This would appear to be a possibly litigation issue for the mfg. since burn rate is critical.

Maybe I have over complicated the issue. Just my rant for the day.

 

[rcmodel]

I think you are looking at apples & oranges.

In my books, Speer used a 22" 1/12 twist Ruger 77.

Hornady used a 20" 1/7 Colt H-Bar for 5.56.

And a 26" 1/12 Remington 700 for the .223.

SO, two different rifling twists, in two different action types, in three different barrel lengths, with three different barrel manufactures.

Little wonder the data doesn't match!

rc

 

[hershey]

i think rcmodel hit the nail on the head, i got multiple manuals, and then mix in on line data from manufacturers and you get countless contradictions. depending on your goals, you might have to use that rule of load low and work up, or just take a basic load and be happy, i load a plinking load for most of my guests to shoot that is lighter and cheaper than what i load for myself or an experienced shooter.