.308 Brass variation

ronl · August 11, 2014, 11:06 PM

I was loading with some ABT and BHA Match brass the other night and was surprised to find the rim diameter on the BHA brass was so small that it wouldn't even lock in my Forstner trimmer. It measured around.465, whereas the ABT brass was fine but only measured .470. The specs in the Sierra manual list the rim diameter as .473. The cases are all once fired and all work just fine in my rifle. Just an interesting fact.

Bart B. · August 12, 2014, 06:12 AM

Industry specs (SAAMI) say the rim diameter can be from .463" to .473". Some company's tools are not made to accommodate those tolerances.

August 11, 2014, 11:06 PM	#1
ronl Senior Member Join Date: December 2, 2007 Posts: 1,100	.308 Brass variation I was loading with some ABT and BHA Match brass the other night and was surprised to find the rim diameter on the BHA brass was so small that it wouldn't even lock in my Forstner trimmer. It measured around.465, whereas the ABT brass was fine but only measured .470. The specs in the Sierra manual list the rim diameter as .473. The cases are all once fired and all work just fine in my rifle. Just an interesting fact.

August 12, 2014, 06:12 AM	#2
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	Industry specs (SAAMI) say the rim diameter can be from .463" to .473". Some company's tools are not made to accommodate those tolerances.