Loading 223 is filler required?

[mikemc]

I am getting ready to cast and load for an AR. I bought a NOE mold which should be here in the next few days. Looking in the Lyman reloading manual is states I can use 700x which is perfect because thats what I use for my 45acp. Now the question is I know the 5.6gr is calls for will not even come close to filling the case. Do I need to put a filler in to take up the extra room? I have been reloading for a long time and I know you should never put a real light charge like that in a rifle case. Thanks for the help.
Mike

[Bullshop]

700X is a very fast powder and I doubt you will need a filler with it. Your caution about using light charges in bottle neck cases only applies to much slower powders. The 700X is not one of them.
I dont load for auto loaders but have doubts that the 5.6gn of 700X will cycle your action. I think that will require more volume of slower powders, something like 4895 or that burn rate area. I might be wrong though.

[mikemc]

That makes sense thanks for the info. I will give it a try and see if it will run the action.

[303Guy]

There is logic behind the use of such a fast powder in a self loader and that is that it won't cycle or more importantly, half cycle the action. I'd say that in such a small volume case, powder positioning would be of little if any, benefit with a fast powder. While Bullshop is quite correct about the reduced loads, the danger of reduced loads of fast powders is the chance of double charges. Exercise extreme caution and put in place anal procedures of checking and double checking to avoid double charges. One trick to avoid blow-ups is to use a load that is half max so that if a double charge does slip through, nothing will happen.:Fire:

I'm not being over-cautious - many a soul has lost a gun using light charges of fast powder, even with 30 years of safe reloading experience. It can happen!