Originally Posted by
Larry Gibson
That's a good question.....N-204 is a single based powder with a burn rate between the 4350s and 4831. It is intended for "magnum" cartridges.
If you were loading for a bolt or single action I would suggest loading a case full [100% load density] under the heaviest jacketed bullet (assuming a 9" twist?) using SR magnum primers (do you have any?) and give it a try.
However, given you are loading for your son's AR (probable 7 - 9" twist barrel) a couple additional problems may arise; first the powder will probably not burn efficiently meaning it will leave unburned powder that will blow back into the action as it functions. Second the time/pressure curve will be slow which could mean excessive gas port pressure in an already over pressurized system (they are designed that way) and thirdly do not reduce the load to "work up", especially with lighter weight jacketed bullets as an SEE condition (or catastrophic pressure spike) could occur.
My recommendation is not to try it but wait until you can find a suitable powder.