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 Little confused about .300 blackout vs .300 whisper
1Andy2  [Team Member]
12/5/2010 6:50:27 PM EST
I've got a .300 whisper trim die for making .300 whisper from .223
But I'd also like to be able to make .300 blk brass.

Is there some reason I couldn't just use it to trim to 1.368" instead of 1.350" to make .300 blk brass?

For that matter, could someone fire .300 whisper ammo in a .300 blk barrel?
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GGGBeo50  [Member]
12/5/2010 7:02:56 PM EST
300 BLK = 1.368" max -1.348" min case length. You are safe. Might want to get the 300 blk sizing die for the shoulder taper sake. That being said, I would expect all 300 blk barrels to be capable of firing 300 whisper ammo safely unless otheriwise stated.

http://300aacblackout.com/

• Case length is 1.368 +0.000 -0.020

RobRat  [Team Member]
12/5/2010 7:12:33 PM EST
Also watch the neck thickness. Some chambers were cut with clearances based on necking a 221 Rem Fireball up to 30 cal (thin brass at neck), other chambers were cut necking down the straightwall section of a 5.56 case (thick neck). Shoot a case with a thick neck, in a tight necked chamber, and you may find lots of unwanted pressure.

Wildcats are always tricky, you need to know what you've got. I can see some guy buying a used 300 Whisper upper, and throwing some off the shelf 300 AAC BLACKOUT ammo in there and getting into trouble.

I'm glad they are standardizing things.
rjrivero  [Member]
12/5/2010 7:55:58 PM EST
Does anyone know if there is a company reaming the 300 Whisper or Fireball chambers to the 300 AAC BLACKOUT? I think I'm ready to go this route, but I'm trying to do it on a budget.

Thanks.
1Andy2  [Team Member]
12/5/2010 9:05:43 PM EST
Originally Posted By RobRat:
Also watch the neck thickness. Some chambers were cut with clearances based on necking a 221 Rem Fireball up to 30 cal (thin brass at neck), other chambers were cut necking down the straightwall section of a 5.56 case (thick neck). Shoot a case with a thick neck, in a tight necked chamber, and you may find lots of unwanted pressure.

Wildcats are always tricky, you need to know what you've got. I can see some guy buying a used 300 Whisper upper, and throwing some off the shelf 300 AAC BLACKOUT ammo in there and getting into trouble.

I'm glad they are standardizing things.


So I guess the real test will be to make some .300 whisper and then measure the OD at the neck, correct? .334 or less = good to go?

I've got ALOT of once-fired .mil 5.56 brass. That's what I'm going to try making it from.
mak91  [Member]
12/6/2010 2:15:44 AM EST
There is a guy on silencertalk that says he is going to convert them for $50 + shipping http://www.silencertalk.com/forum/vi...7&hilit=reamer
rjrivero  [Member]
12/6/2010 1:33:10 PM EST
Originally Posted By mak91:
There is a guy on silencertalk that says he is going to convert them for $50 + shipping http://www.silencertalk.com/forum/vi...7&hilit=reamer


I sent him a IM on silencertalk, but haven't heard back. I'm kinda excited to try this round out! I'd like to do it on a budget, just to try it first so I'd rather not get saddled with a $400 Noveske if I can get away with a cheaper alternative.
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