Is it possible?  Is it safe?  I'm an experienced reloader, having started back in 1972 but wish to first query the board before starting my search.  I'm talking 55 gr FMJ at 3240-3270 fps using my Dillion 550..

Big Al

There is no reason why it can't be done; Federal and Winchester don't have any voodoo that lets them break any physical laws.

You need to be good at getting things right; religious about case length and cleanliness, and willing to dump brass earlier as it will stress faster and fail.  Keep an eye on it.

Use a powder that is the same as the USGI loadings (WC-844 and WC-845 from surplus shops) or slower; but too slow will get you into trouble with port-pressure.  If trying slower powders, watch for the ejection pattern to change as a clue that the bolt speed is too fast.  If you go too slow you will lose velocity anyway, as anything slower than H380 or 4895 is too bulky to load that fast anyway.

There are a lot of "right" powders for this caliber out there; but you are not necessarily looking for the right target powder, but the one that gives you the velocity at a reasonable pressure.  I am not sure that canonical .223 powders (Varget, et al) will load enough powder to get where you want to be.

Make sure that the cases are a easy fit in your chambers; you may need small-base dies.

All of these, as you know, apply to any loading of the AR type, as with Garand and others prone to slam fires.  The powder worries are the ones applying to the velocity goals we have.

Do you have a chrono?  It's the best way to see if you are there; though I have used bullet drop as a useful tool.

I am trying the same thing myself.

I am currently using H-322 and the 53 grain sierra bullets.

The last load I tried clocked at 3180 fps. This was with a 25.5 grain charge of H-322 and the 53 grain bullet. No signs of over pressure are present on the brass.

I am getting approx. 3140 fps from Q3131a from a 20 inch barrel.

The next time out I am going to chrono some Lake City m-193 before I make any more powder adjustments.

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