300 BLK out question

625TC · January 17, 2018, 03:01 PM

I have read so much on the subject of why you can or can not use 300 BLK out in a 300 Whisper barrel. Does any one here have any experience or good advice on the matter ?

T. O'Heir · January 17, 2018, 03:42 PM

The .300 Whisper is 1.374" long in case length. The BO is 1.368" long. Headspace is different.

625TC · January 17, 2018, 04:05 PM

Thank you

Reggie Perrin · January 17, 2018, 05:43 PM

There is also the matter of the .300 Whisper designed to have cases formed from .221 fireball, with the original .22 cal neck opened up to .30, whereas the Blackout was designed so cases could be formed from .223 Rem, by cutting them off at the shoulder and necking the result down to .30. Forming .300 Whisper from .223 usually requires turning the necks, the Blackout was designed to avoid this additional step. This has the effect of the Blackout potentially having thicker case necks (.334 maximum diameter per SAAMI) and some Whisper chambers may have neck dimensions too small for the thicker Blackout necks to release a bullet without excess pressures.

625TC · January 17, 2018, 07:52 PM

thank you

444 · January 17, 2018, 08:26 PM

This doesn't mean anything but I have a .300 Whisper made by SSK as well as a .300 Blackout made by Ruger. And I interchange the cases at will.

I have never formed a case from .221 Fireball; every case I ever fired in my Whisper was formed from a .223 case or was a factory .300 BO case.

625TC · January 17, 2018, 08:31 PM

thanks for that. I have formed them from both 221 and 223 but have avoided the 5.56 cases. This was for the Whisper. Just a curiosity I wonder what the result would be if a Blackout reamer was run through a Whisper chamber ?

Mobuck · January 24, 2018, 09:05 PM

Gee, I haven't noticed any diff. I've shot factory loads of both labels in a couple of 300 something or other uppers w/o noticeable issues.

January 17, 2018, 03:01 PM	#1
625TC Member Join Date: January 15, 2018 Posts: 67	300 BLK out question I have read so much on the subject of why you can or can not use 300 BLK out in a 300 Whisper barrel. Does any one here have any experience or good advice on the matter ?

January 17, 2018, 03:42 PM	#2
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	The .300 Whisper is 1.374" long in case length. The BO is 1.368" long. Headspace is different. __________________ Spelling and grammar count!

January 17, 2018, 08:26 PM	#6
444 Senior Member Join Date: November 20, 2000 Location: Ohio Posts: 3,968	This doesn't mean anything but I have a .300 Whisper made by SSK as well as a .300 Blackout made by Ruger. And I interchange the cases at will. I have never formed a case from .221 Fireball; every case I ever fired in my Whisper was formed from a .223 case or was a factory .300 BO case. __________________ You know the rest. In the books you have read How the British Regulars fired and fled, How the farmers gave them ball for ball, From behind each fence and farmyard wall, Chasing the redcoats down the lane, Then crossing the fields to emerge again Under the trees at the turn of the road, And only pausing to fire and load.

January 17, 2018, 04:05 PM	#3
625TC Member Join Date: January 15, 2018 Posts: 67	Thank you

January 17, 2018, 05:43 PM	#4
Reggie Perrin Junior Member Join Date: May 5, 2016 Posts: 11	There is also the matter of the .300 Whisper designed to have cases formed from .221 fireball, with the original .22 cal neck opened up to .30, whereas the Blackout was designed so cases could be formed from .223 Rem, by cutting them off at the shoulder and necking the result down to .30. Forming .300 Whisper from .223 usually requires turning the necks, the Blackout was designed to avoid this additional step. This has the effect of the Blackout potentially having thicker case necks (.334 maximum diameter per SAAMI) and some Whisper chambers may have neck dimensions too small for the thicker Blackout necks to release a bullet without excess pressures.

January 17, 2018, 07:52 PM	#5
625TC Member Join Date: January 15, 2018 Posts: 67	thank you

January 17, 2018, 08:31 PM	#7
625TC Member Join Date: January 15, 2018 Posts: 67	thanks for that. I have formed them from both 221 and 223 but have avoided the 5.56 cases. This was for the Whisper. Just a curiosity I wonder what the result would be if a Blackout reamer was run through a Whisper chamber ?

January 24, 2018, 09:05 PM	#8
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	Gee, I haven't noticed any diff. I've shot factory loads of both labels in a couple of 300 something or other uppers w/o noticeable issues.