In other words what does it take to make a 55 grain 5.56mm FMJ bullet go 3260 FPS as a minimum?
And what does it take to make a 62 grain 5.56mm bullet go 3100 FPS as a minimum?  Both from a 20" barrel.  

I will be using lake city m193 and m855 brass.  I want to duplicate the factory loads so I can re-use my brass and get the same results as when I first fired them.

I don't reload but I know someone who does and is competent at it.  If I give him the components, he will do the necessary work and assemble them for me.  What brand and how much powder should be used?  What brand and kind of primers?

The original primers were crimped, and the brass had but one sizing.  Making 5.56 loads, from reloads, is not advisable.

Then again, it is your fingers and eyes, make your own risk reward calculation.  But a little time with a ballistics calculator, should make it clear, the difference isn't worth it, and the value of reloading is more accurate ammo, not some minor difference in drop at 300.

5.56 Factory loads are on the ragged edge of 'do-able', like older .270 Win factory loads.

First of all, there are about 10,000 posts in the last 24 hours asking the same question, those just like this will get locked by a Mod because it's been answered 1,000,000+ times!

#1 It's unsafe to use reloads made by someone else
#2 The ONLY safe way to make a load is to work up the load for YOUR rifle. EVERY rifle is different.
#3 To work up a load seeking a speciffic velocity you need a chronograph
#4 You CAN'T duplicate Military 5.56 ammo for several reasons (IE: The powder they use is unavailable to the public, the brass is Virgin Brass and the Primers are Crimped)
#5 Who cares if you bullet is going 3260 FPS with 1" groups at 100 yards?  When you can work up your own load that might only be at 2960 fps that will produce 1/4" groups at 100 yards and cost less $$ by using less powder!!
#6 If you are asking these questions at all, the fact is you shouln't be even attempting a MAX load as you will probably just get hurt and/or damage your rifle.

Seriously I'm not trying to be a dick, but for god sakes this question is asked 100 times a day, you guys could atleast LOOK at the threads before posting!

-Masta

Masta speaks the truth. If you are determined to attempt this, be very careful. No one can tell you how to get those results with your rifle. You need to test and work up the load you want.

Just be aware, you will be on the ragged edge.

In other words it is not an advisable proposition and if you had to ask then you probably shouldn't be attempting it in the first place.

I chronoed Canadian Green tip at an average of 3025FPS at 70 degrees F out of my 20 inch Colt.

M855 is fairly easy to duplicate.

Forget about trying to duplicate M193.

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