I have 4,000 rounds of reprocessed military .556 brass. I was going to build varmint handloads for an older Sako L461. Am I safe using the .556 case for this application in a rifle that says the chambering is .223? I know the "leade" from case mouth to rifling is/can be different so I want to insure what I handload is absolutely safe. Should I back-off on the loads since military brass are thicker-walled cases? I really appreciate any input you folks can provide so I insure I am being safe and not abusing the rifle. Is bullet weight an issue?

Use any weight .224 projectile you want. Just start out your first loads to the published minimum powder charge and work up to the most accurate load, looking for signs of excessive pressure along the way. You use the term "leade". I assume you mean "cartridge overall length", C.O.L. Use the same C.O.L. as published also. Most of the more popular bullet/powder manufacturers have their minimum/safe loads published online for easy lookup. Stick with these at first and you won't do any harm to your Sako. After you determine the most accurate bullet/powder combo you can then adjust the C.O.L.
Good Luck and do yourself a favor and buy the latest manual for the brand of bullet you will be using so you have it on your bench. There are a lot of helpful tips in those manuals and don't forget about the vast amount of knowledge from this forum.
P.S. It is 5.56mm and not .556mm.

Fishin' Magician

I used to buy mil-surp brass by the five gallon bucket full for prairie dogging.

It took some work to get them resized, cleaned, primer pocket crimp removed and ready for reloading.....but they worked quite nicely.....and yes....one of the guns I shot them through is a Sako L-461

Some military brass is lighter than some commercial brass. Weigh your cases to see how yours compare. LC 04 was the second lightest of 11 in the sample below.

Some case weights here:
http://www.6mmbr.com/223rem.html

Bruce

Match the bullets length to the barrel twist. Good info here. http://www.6mmbr.com/223Rem.html

In 223, military brass is not thicker than commercial brass. I recently weighed out cases made by Remington, Winchester, Federal, PMC and Lake City. Average weight between all varied by only 1.5 grains. In 308 military cases may be heavier but I have yet to see it in 223 brass.

From a dimension standpoint, there is no difference between 223 and 5.56 brass. Load them up and shoot away.

Fishin' Magician, the leade is the throat. The .223 has a longer throat and different throat angle. There is no difference in the brass dimensions and minor chamber dimension differences, 5.56 is a hair longer to allow for carbon build up between cleanings. Work up as normal, you may or may not end up with a lighter load. Clymer has the dimensions of .223 and 5.56 chambers posted.

Soooo, I am correct that "leade" refers to the gun and "C.O.L." refers to the cartridge? Thank You for setting me straight.

Fishin' Magician

Fishing: "Soooo, I am correct that "leade" refers to the gun and "C.O.L." refers to the cartridge?"

Correct in both instances.

Leade is that portion of a chamber in which the bullet lies free from rifling contact.

C.O.L. = Cartridge Overall Length.


Loading data from a specific bullet or powder maker is no more or less 'accurate' or 'effective' than data from any other credible source. The books all tell us what their research team achived during their tests, period. The final results we get from ANY data source is ourselves, not from the books.

All books have admonitions to "Start low, slowly work up to the max listed limit unless you see excess pressure signs earlier". That rule, and only that rule, keeps us safe and covers any component or weapon variables. And does so far better than blindly beliving any book.