Powder for 4.5in barrel 5.56 AR

[WestTN2288]

So I just bought a 4.5in barrel 5.56 barrel with micro-pistol gas system.

I’m going to hunt with it (read: maximize velocity). From 10-18in barrels, I haven’t had barrel/gas length influence my powder choice. Generally the powder that gets the highest MV from longer barrels more or less translates to being the highest with a shorter barrel.

This feels like an extreme though. According to GRT I could nearly run CFE black or h110 and get a similar MV and more pressure at the gas port than something like TAC. I’m looking at bullets in the 55-60 range currently, but really only care about getting a killing bullet up to 21-2200FPS.

Is anybody running a 5.56 barrel this short? Did you change your powder when going this extreme? Just rock on with your regular loads? I appreciate any and all experience/advice on everything from powder/bullet selection, cycles problems/solutions, anything else I’m not thinking of…

 

[Formidilosus]

So I just bought a 4.5in barrel 5.56 barrel with micro-pistol gas system.

I’m going to hunt with it (read: maximize velocity). From 10-18in barrels, I haven’t had barrel/gas length influence my powder choice. Generally the powder that gets the highest MV from longer barrels more or less translates to being the highest with a shorter barrel.

This feels like an extreme though. According to GRT I could nearly run CFE black or h110 and get a similar MV and more pressure at the gas port than something like TAC. I’m looking at bullets in the 55-60 range currently, but really only care about getting a killing bullet up to 21-2200FPS.

Is anybody running a 5.56 barrel this short? Did you change your powder when going this extreme? Just rock on with your regular loads? I appreciate any and all experience/advice on everything from powder/bullet selection, cycles problems/solutions, anything else I’m not thinking of…

I’ve done 5.75 and 6” barreled AR’s extensively. Have not changed any loads-77gr TMk for hunting. Blackhills for factory and/or 23.5gr 8208 for reloads. Both are around 2,100-2,200fps MV.