300 Blackout Load Data

The #1 community for Gun Owners of the Northeast

Member Benefits:

  • No ad networks!
  • Discuss all aspects of firearm ownership
  • Discuss anti-gun legislation
  • Buy, sell, and trade in the classified section
  • Chat with Local gun shops, ranges, trainers & other businesses
  • Discover free outdoor shooting areas
  • View up to date on firearm-related events
  • Share photos & video with other members
  • ...and so much more!
  • motox79

    Active Member
    May 24, 2010
    155
    damascus
    hey, this is KINDA off topic, but i'm curios....are you using an adjustable gas block? i have a SI defense barrel, chambered in .300 fireball, that i just can't get to cycle. the gas port is in the pistol position (i think its .081"), i have a JP adjustable gas block, shooting 125gr with 19.8gr H110. I can get them to cycle the bolt, but it will not extract. When i shoot a 220gr with 9.8gr of 110
    it will cycle, eject, etc. but will not strip the next round and chamber it. Any thoughts (short stroking?) I'm a newb. to reloading, and to this round. I've done a bit of research, but i'm still missing something. Also, i was thinking of scraping this project and just going with a blowback Tok upper (cheaper to shoot, no gas block to mess with) Thoughts on that. Thanks
     

    BenL

    John Galt Speaking.
    hey, this is KINDA off topic, but i'm curios....are you using an adjustable gas block? i have a SI defense barrel, chambered in .300 fireball, that i just can't get to cycle. the gas port is in the pistol position (i think its .081"), i have a JP adjustable gas block, shooting 125gr with 19.8gr H110. I can get them to cycle the bolt, but it will not extract. When i shoot a 220gr with 9.8gr of 110
    it will cycle, eject, etc. but will not strip the next round and chamber it. Any thoughts (short stroking?) I'm a newb. to reloading, and to this round. I've done a bit of research, but i'm still missing something. Also, i was thinking of scraping this project and just going with a blowback Tok upper (cheaper to shoot, no gas block to mess with) Thoughts on that. Thanks

    My Blackout doesn't have any issues with subsonics, even unsuppressed, and I'm not using an adjustable gas block.
     

    BenL

    John Galt Speaking.
    Ben, what setup are you running? (bolt, barrel, gas postition, etc) thanks

    CMMG 16" upper, pistol length gas system (non-adjustable), standard bolt, and a middy spring/buffer/buffer tube.

    It shoots factory 220gr and 208gr Amax's (11.0gr of Reloader 7; ~1010fps) very reliably without a suppressor.

    blackout.jpg
     

    HokieCasey

    Active Member
    Aug 7, 2010
    834
    St Mary's
    Looks like some more official load data is being posted over on quarter bores forums.

    Though for me I seemed to do okay with 17.5 of h110 for a 125 grain Hp. Was in a 16" aac barrel
     

    motox79

    Active Member
    May 24, 2010
    155
    damascus
    yeah, i'm starting to lean towards out of spec brass, or a tight chamber.....gonna break out the old calipers tonight.....anyone know a good place to get a go-no go guage in .300-.221?
     

    Edward78

    Active Member
    Apr 4, 2009
    527
    Newburg, MD SoMd
    Your problem is the powder you are using for a ar platform you can not use H110 on subsonic loads it is great for Supersonic but not the subsonic it will not create enough pressure to cycle the bolt completely. You need to use AA1680. Also H110 is position sensitive and should be used unless you are filling most of the case capacity with powder and with subsonic loads you do not so stay away from H110 on your subs. I am using a non adjustable YHM Lo Pro gas block on a Wilson Combat 16" barrel Carbine length gas system and have not had any over or under gassed issues on Super or Subsonic loads. Here is a link to some AA1680 load info bellow.

    http://www.scribd.com/doc/38398925/Sierra-300-Whisper-Loading-Data


    hey, this is KINDA off topic, but i'm curios....are you using an adjustable gas block? i have a SI defense barrel, chambered in .300 fireball, that i just can't get to cycle. the gas port is in the pistol position (i think its .081"), i have a JP adjustable gas block, shooting 125gr with 19.8gr H110. I can get them to cycle the bolt, but it will not extract. When i shoot a 220gr with 9.8gr of 110
    it will cycle, eject, etc. but will not strip the next round and chamber it. Any thoughts (short stroking?) I'm a newb. to reloading, and to this round. I've done a bit of research, but i'm still missing something. Also, i was thinking of scraping this project and just going with a blowback Tok upper (cheaper to shoot, no gas block to mess with) Thoughts on that. Thanks
     

    Edward78

    Active Member
    Apr 4, 2009
    527
    Newburg, MD SoMd
    My loads are a little hot for sure but not to hot to be unsafe in my rifle but others my not be able to achieve that velocity safely. If you reload use LC or comparable brass (PMC Federal Win Remington and so forth are to soft) and thick primers made for Ar's like CCI military, wolf or tula .223 primers and you should be able to get a little more out of you rifle with out the brass failing but do so at your own risk.

    2300fps is great; I wonder what the factory 125gr accutips are running at.
     

    motox79

    Active Member
    May 24, 2010
    155
    damascus
    actually, the subs run better! i can occaionally get it to cycle a sub properly. sometimes it will shortstroke the subs (ejects fine, strips and chambers the next round, but does not trip the sear, there is no "click" to make the firearm go "bang"!) Also, most of the case IS filled in the subs (the 110 is supposed to be pretty bulky. The supersonics seem to be the problem. It will blowback the carrier, but the case stays in the chamber, the next round will jam into it.
     

    Edward78

    Active Member
    Apr 4, 2009
    527
    Newburg, MD SoMd
    actually, the subs run better! i can occasionally get it to cycle a sub properly. sometimes it will short stroke the subs (ejects fine, strips and chambers the next round, but does not trip the sear, there is no "click" to make the firearm go "bang"!) Also, most of the case IS filled in the subs (the 110 is supposed to be pretty bulky. The supersonics seem to be the problem. It will blow back the carrier, but the case stays in the chamber, the next round will jam into it.

    OK I misread your original post sorry but the 1680 is the best powder for subs it should solve your short stroke problems you are having. Now for the Supersonic loads you say it is not ejecting is it messing the rim up on the brass it does not eject. I am just thinking maybe you are having a problem of over gassed with the Supersonics and the bolt is opening to soon and that can cause a none ejection issue but that should be almost tearing the rim off the case when it does not extract the round. Now if it is not tearing your brass up it must be a bad extractor or the extractor spring is week.
     

    BenL

    John Galt Speaking.
    A little off topic...

    Ed- Are you making your own brass? if so, is it a huge hassle? Do you anneal the cases?

    I've had headstamped brass back-ordered for a few months now, and don't see it coming in any time soon. I saved a bunch of LC brass just in case I wanted to give cutting my own a try.
     

    Edward78

    Active Member
    Apr 4, 2009
    527
    Newburg, MD SoMd
    A little off topic...

    Ed- Are you making your own brass? if so, is it a huge hassle? Do you anneal the cases?

    I've had headstamped brass back-ordered for a few months now, and don't see it coming in any time soon. I saved a bunch of LC brass just in case I wanted to give cutting my own a try.

    Yes I have made about 500 pieces of brass it is a little time consuming but not to bad once you get the hang of it. There is allot of ways to cut it down but I use a small brake line pipe cutter and cut 1/16" bellow the shoulder then final trim after I size it down. I did anneal the first 50 I made and have read many places that it is not necessary and I have not noticed any difference between the annealed and not annealed brass in my opinion and have reloaded them a few times and have not had any problems with cracked cases yet so I will not be annealing anymore. Lake City and other military brass is the best brass to use I have had issues with primmer pockets in my hotter loads with PMC, R-P, Winchester, and FC brass. to soft and pockets opens up to much FC was the worst of course.
     

    motox79

    Active Member
    May 24, 2010
    155
    damascus
    ed
    hey, thanks for the tips. i'm gonna give the new powder a try. I was using the 110 since its kinda bulky and burns fast.....guess maybe a little too fast. I'll keep you guys updated.
     

    motox79

    Active Member
    May 24, 2010
    155
    damascus
    oh....and i'm not ripping the rim off the brass.....so i'm gonna try a different BCG i have lying around and see if that helps too. Thanks a ton for all the info guys
     

    SkunkWerX

    Ultimate Member
    Jul 17, 2010
    1,577
    MoCo/HoCo border
    OK guys, I'm going BlackOut. Sorting some .223 brass right now for trimming/forming, the .300 dies are en-route.

    Any idea where I might find 1 lb. of AA1680 in the DC-Baltimore corridor?
    Or even NorVa?
     

    Edward78

    Active Member
    Apr 4, 2009
    527
    Newburg, MD SoMd
    OK guys, I'm going BlackOut. Sorting some .223 brass right now for trimming/forming, the .300 dies are en-route.

    Any idea where I might find 1 lb. of AA1680 in the DC-Baltimore corridor?
    Or even NorVa?

    If you don't mind going south a bit you can go down to Ashland Virginia Green Top has it at a decent price at that.

    Eddie
     

    SkunkWerX

    Ultimate Member
    Jul 17, 2010
    1,577
    MoCo/HoCo border
    If you don't mind going south a bit you can go down to Ashland Virginia Green Top has it at a decent price at that.

    Eddie

    Thanks Ed, if/when I get down that way I can look them up.

    Update: I have cut/formed/primed 200 BLK cases as of now.
    Not too bad, just time consuming. Definitely a cabin-fever sport.

    Using a mini lathe to do the cutting/trimming. Going to build a repeatable indexing system in order to hit the same measurement each time.
    I'm finding if they are rough cut to ~1.348 to 1.350, then after sizing/forming they end up in the ~1.358 - 1.360 length range.
    Measure twice, cut once.
     

    Rockzilla

    Ultimate Member
    Feb 6, 2010
    4,516
    55.751244 / 37.618423
    Lake City and other military brass is the best brass to use I have had issues with primmer pockets in my hotter loads with PMC, R-P, Winchester, and FC brass. to soft and pockets opens up to much FC was the worst of course.

    Agreed with above good luck here with LC brass.. FC flat out sucks..just sell it as scrap, primer pockets blow out..just a thought...

    -Rock
     

    Users who are viewing this thread

    Latest posts

    Forum statistics

    Threads
    274,916
    Messages
    7,258,539
    Members
    33,348
    Latest member
    Eric_Hehl

    Latest threads

    Top Bottom