Hornady Manual Data for .300 Blackout

IndispensableDestiny · Jul 12, 2013

The data in the 9th edition Hornady reloading manual for .300 Blackout is screwy.

First, they show a maximum cartridge length of 1.400. The SAAMI spec is 1.368. They show trim length of 1.390, but the SAAMI minimum chamber length is 1.378. I've been trimming to 1.365.

For all 110 grain bullets, they give a loaded COAL of 2.050. The 110 grain spire point is .820 long. So, .820 - (2.050 - 1.390) = .16 seating depth. That's a bit short for a .308 caliber bullet, is it not? Even if crimped? Using my 1.365 trim length, it's only .14 deep.

I'm thinking of using a COAL of 1.935 which will yield a seating depth of .25. Not quite a full caliber, but I think it's ok. If I go much shorter, I'd be compressing the powder -- Vihtavuori N110.

Any opinions?

Wreck · Jul 13, 2013

I trim to 1.360" and had luck loading 110gr HRN FMJ to col of 1.90" with Lil Gun powder. This is going to be my plinking load. I tried loading to COL of 2.05" but not seated deep enough, I found some load data that stated a col of 1.850" for 110 gr bullets but forget where I saw it. 1.90" fed and shot well in my AR. Good luck.

deesly1 · Jul 13, 2013

SAAMI spec show the maximum of 1.368 and minimum of 1.348. I trim to 1.355 so I can use a bigger spritzer bullet. I also use a Wilson case gauge to make sure the shell was fully sized properly.

mtlcafan79 · Jul 14, 2013

http://www.hornady.com/assets/files/9thEdErrata.pdf

Page 380, 300 Whisper/AAC Blackout
–
Case schematic and case (max and trim) lengths are from an early, non-standardized version. Max Case length should be: 1.368” and Case Trim Length should be: 1.358”.

IndispensableDestiny · Jul 14, 2013

mtlcafan79 said:
http://www.hornady.com/assets/files/9thEdErrata.pdf
Page 380, 300 Whisper/AAC Blackout
–
Case schematic and case (max and trim) lengths are from an early, non-standardized version. Max Case length should be: 1.368” and Case Trim Length should be: 1.358”.

Then their COAL is really much too long. They need to redo the entire section, including the load data, which is now suspect.

IndispensableDestiny · Jul 26, 2013

Wreck said:
I trim to 1.360" and had luck loading 110gr HRN FMJ to col of 1.90" with Lil Gun powder.

I seated to the 110gr spire points to 1.920 with N110 and it scattered all over. I'll try going a bit longer and back off the powder. I have a good load with Sierra 110 gr HP.

Wish I could get some 125 or 130 grain pills. I want to give the Barnes TTX a try.

frogman68 · May 31, 2015

Dredging up a old post as it seems Hornady hasn't updated their page
Doing some 300 loads Hornady calls for a COL OF 2.235 . My cases are 1.369 , bullets are 1.040 which gives 2.409 meaning with their COL only .174 is in the case (grove on bullet is .333 which is almost less than half to the groove) . My loads are 2.050 which is .185 less but puts the bullet at the groove. Am I putting to much pressure on the brass? To get there COL I would need to increase case length to 1.902 (2.235-.333) . Or am I overthinking this?

DaemonAssassin · May 31, 2015

frogman68 said:
Dredging up a old post as it seems Hornady hasn't updated their page
Doing some 300 loads Hornady calls for a COL OF 2.235 . My cases are 1.369 , bullets are 1.040 which gives 2.409 meaning with their COL only .174 is in the case (grove on bullet is .333 which is almost less than half to the groove) . My loads are 2.050 which is .185 less but puts the bullet at the groove. Am I putting to much pressure on the brass? To get there COL I would need to increase case length to 1.902 (2.235-.333) . Or am I overthinking this?

Back your seating die out to their recommended COAL and see how far down it seats the bullet. If it seats far enough in and does not have issues staying seated, then I would consider going down to 2.150-2.200 and letting it ride at that depth, or just leaving it at 2.235.

Hornady Manual Data for .300 Blackout

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