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300 AAC Handloading data for 123 and 155 gr

acidone

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Minuteman
Nov 24, 2010
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Chicago, Il
I'm looking for some reliable reloading data on the new 300 AAC Blackout round. I'm going to be using this mostly in a bolt action and was wondering what the right powder and charge i should be using for 123 gr fmj and 155 smk bullets. Also, should i use a different powder and or charge if i decide to run those weights in an AR platform with a 16" bbl? Please help!!!
 
Re: 300 AAC Handloading data for 123 and 155 gr

H-110 powder seems to be the best store-bought powder for both the 123 and 155. I recommend the 135 MK over the 155 though. Or from a bolt gun, might as well use the Sierra 110 Varminter (but does not feed well from AR).

If you are trying to make 3-gun Major PF, then I would suggest a 175 MK and A1680 powder and loading to 2.26 OAL (which will need a modified mag to feed in an AR).

Same powder for AR and bolt gun. However, an AR may want a shorter OAL for the longer bullets to feed from a USGI mag.
 
Re: 300 AAC Handloading data for 123 and 155 gr

I don't want to give powder charges. Sierra is planning to add it to their loading manual though and will pressure test it.