Reloading the 6.8 spc

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  • coopermania

    Banned
    BANNED!!!
    Aug 20, 2011
    3,815
    Indiana
    Glock, I was finely able to get on Hodgdons website this morning, Of the 3 powder manufacturers listed there they have NO DATA for a 130 grain bullet. That should tell you something right there. Their data stops with a 115 grain bullet. When you chose to go beyond what a manufacture suggests you need to be experienced and educated in what you are doing.
     

    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    Lessons Learned: Dont do this at home!

    Before I continue I thought it sensible to list my lessons learned.

    I did some more reading after the reaction I received by my fellow members on this thread. I wont respond individually to all who commented, but I will list what I learned from the advise I received and from the extra reading I did:


    1. Start with minimum published data loads and slowly work up, not exceeding the maximum load. What is slowly working up? It appears that reasonable increments are 0.2-0.3 grains at a time.
    2. As you increase the powder weight watch for pressure signs. This is easier said than done since as soon as pressure signs appear, it is some times too late!
      Here is a good internet guide on reading pressure signs: http://massreloading.com/reading_pressure_signs.html
      Certainly when the primer pops thank god that your rifle is still one piece and your face is still round.
      For the 6.8 spc here is another link of what not to do: http://m.b5z.net/i/u/6132121/i/6.8_20SPC_20Performance_20Testing_20Report_1_.pdf or http://www.ar15.com/forums/t_3_121/369145_.html
      The team that tested the 6.8 spc pushed it out to almost 70,000 PSI and included pics of how the brass looks like under those pressures. Again don't do this at home!
      Note that when using CCI#41 primers, be very careful since they are harder than others. A slightly flattened CCI#41 primer is bad news.
    3. Once you reach the first load of acceptable precision you can vary the COAL and weight to optimize accuracy.
    4. In the absence of a pressure gauge (mainly because of expense and limited availability) internal ballistics software calculators (see http://www.kwk.us/powley.html) and published data can give a sense of how pressure is related to different loading parameters:
      • For fixed powder weight increasing COAL reduces pressure slightly, at the same time it also reduces velocity slightly. Adjusting the COAL however might allow you to tighten your groups. There is a catch however, if you seat the bullet too close to the lands you will also increase the pressure. However based on my measurements of distance to lands for my rifle with SPCII if you are loading using a magazine there is no way you can get close enough to touch the lands with the bullets I tested.
      • For fixed powder using a heavier bullet pressure goes up dramatically to dangerous levels:
        Compare the pressure between the Hornady 110 gr V-max


        and the Speer 130 gr SPBT


        shows about 10,000 PSI increase.
        Note that I compared the output of the Powley calculator and the Hodgedon published data and it slightly overestimates pressures.
    5. When published load data is not available for a bullet you want to load, look for forum data or data from an internal ballistics computer and follow lesson #1.
     

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    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    Range report: Hornady 110 gr V-max

    Again don't try these data as they are still experimental and they are reported by an inexperienced reloader!

    This post is to give more details on the data I mentioned at the beginning of this thread and everything was loaded and shot before I starte this thresad and received any comments or advise from the folks on this forum. Please note that in the future I will not be using these loads for any reason. Based on advise from this forum I have changed my reloading practices. I felt people might be interested to see exactly what I did.

    I based my choice of powder and powder weights on data found on the data collection chart posted on 68forum: http://68forums.com/forums/showthread.php?476-6-8-SPC-Load-Data-Chart and on the Hodgdon load data site. For H322 Hodgdon lists 27 gr min and 29C max. Although I started at 28 gr, I now realize I should have started at 27 and working up. 5 rounds were loaded for each parameter set.

    Bullet: Hornady V-max 110 gr
    Crimp: Lee factory light crimp

    The shell images below show sample fired cases from left to right: Hornady 120 gr SST factory load as control, #1, #3, #5, #6 from the table below.

    The target image below is the target clipping of #1 load below.
     

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    coopermania

    Banned
    BANNED!!!
    Aug 20, 2011
    3,815
    Indiana
    Dude you just don't get it...At 28 grains you have a HOT LOAD but yet you continue on. Wtf
    You should have stopped when you had the first signs of pressure. But yet you kept continuing on again and again and again. I understand you are new to this hobby of reloading , but I believe you are a person hell bent on seeing how fast you can push what you are loading. The silly part is the first load gave you the best accuracy and the hotter you loaded the larger the groups got with all but one group. I would have dropped my powder to 27.5 and then 27 grains. You are a bomb just waiting to explode.
    I and done here, Good Luck.
    P.S. you should bring a buddy who has a cell with him when you shoot.
    And pull all of your loaded rounds and get some education.

    You should ask yourself this question, How come nobody else here has been offering you any advice ?
    Answer = you scare the shit out of the guys here that reload.
     

    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    Dude you just don't get it...At 28 grains you have a HOT LOAD but yet you continue on. Wtf
    You should have stopped when you had the first signs of pressure. But yet you kept continuing on again and again and again. I understand you are new to this hobby of reloading , but I believe you are a person hell bent on seeing how fast you can push what you are loading. The silly part is the first load gave you the best accuracy and the hotter you loaded the larger the groups got with all but one group. I would have dropped my powder to 27.5 and then 27 grains. You are a bomb just waiting to explode.
    I and done here, Good Luck.
    P.S. you should bring a buddy who has a cell with him when you shoot.
    And pull all of your loaded rounds and get some education.

    You should ask yourself this question, How come nobody else here has been offering you any advice ?
    Answer = you scare the shit out of the guys here that reload.


    When I started writing the story these loads have been loaded and shot already about 3 weeks ago. This data was taken in the past before all the comments from the experienced folks on this forum were posted.

    I decided to report on the data as a lessons learned and what not to do, in case people are interested. I was about to report even more scary data I have on the 130 gr bullets I have with pics and details but I get a feeling people don't want to see such things reported, only success stories!
     

    Traveler

    Lighten up Francis
    Jan 18, 2013
    8,227
    AA County
    When I started writing the story these loads have been loaded and shot already about 3 weeks ago. These data happened in the past before all the comments from the experienced folks on this forum were posted.

    I decided to report on the data as a lessons learned and what not to do, in case people are interested. I was about to report even more scary data I have on the 130 gr bullets I have with pics and details but I get a feeling people don't want to see such things reported, only success stories!

    To the contrary. We want you to be prudent, enjoy the hobby, and not be injured.
     

    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    To the contrary. We want you to be prudent, enjoy the hobby, and not be injured.
    Definitely I understand people's reaction,

    I freely admit I had a rough start with this hobby and the comments did send me back to the drawing board.

    I will close this chapter and will report in the future when I have gotten reasonable data.
     

    akalma

    Active Member
    MDS Supporter
    Nov 24, 2008
    718
    МоКо
    Also pay attention to C.O.L. As per hodgdon it is 2.260" but Glock357 has used longer C.O.L. His velocity is close to max but only one load (#4) has exceeded the max. For H322 the starting load for 110gn is 27.0 and max is 29.0C, so 28.0 is not unusual.
     

    FlatsFlite

    Active Member
    Aug 6, 2012
    691
    King George, VA
    There is no "max velocity" in limiting your loads, however you are correct about the COL and everyone else missed the fact that SPC II has a longer chamber than a SPC I which means lower pressures as well. Very similar to .223 vs. 5.56 chambers only there is a greater difference between SPC I, SPC II and a chamber like my 6.8 ARP. All three can shoot SPC I loads, the SPC II and ARP can handle Tac-loads and the ARP can go a little beyond that, at least mine can.

    I run 28.5 gr behind 115 SMK because it's the most accurate in my rifle, but it candle quite a bit more (31+ gr) before pressure signs appear.
     

    Blacksmith101

    Grumpy Old Man
    Jun 22, 2012
    22,154
    Just another caution note when the data published by known reliable sources only mentions one powder weight assume this is the maximum load, unless otherwise noted, and reduce that load about 10% for a starting load and work your way up from there.

    Any data posted from an unknown source such as an individual should be treated with the same caution you would use if someone gave you a box of reloaded cartridges from an unknown source. Break them down, use the powder as fertilizer, check all components, then work up your own load incrementally. Very few people are willing to risk shooting someone else reloads or trusting their data.

    Most experienced reloaders have multiple books and regularly cross check the data as a sanity check before working up a new load. If two or more reliable sources are noticeably different or you can't find more than one recommendation approach those loads very cautiously and use baby steps. We all want everyone safe because kabooms and injuries mean bad press and that leads to increased regulation.
     

    coopermania

    Banned
    BANNED!!!
    Aug 20, 2011
    3,815
    Indiana
    What you guys are failing to realize is that our friend Glock357 is shooting a 6.8 SPC II and the load data you are looking at is for 6.8 SPC (I).


    Flats, Nowhere that I have seen has the OP menioned that rifle was a 6.8 SPC ll
    Under the specs of what upper he bought this is what was listed.
    Coming next:

    1. Upper: Bison 6.8 Remington SPC 20 inch fluted with target crown:

    Now let's remember he has blown at least one primer,Admitted he has loaded very hot loads and cratered a bunch of primers. Also loaded 130 grain bullets with a powder that has no data from the manufacture for 130 grn bullets and it was a compressed load at that. He has been hotrodding and was heading for a massive failure. All he wanted to do was to see how fast he could push each bullet and then tell the world all about it. Who would want to sit at the bench next to him ??? Not me.... he needs to crawl before he walks.
    And just because a given load is safe in your rifle does not mean it will be safe in the OPs , mine my brothers or anybody else's. You gotta do a ladder and work up the loads in your own rifle.
     

    coopermania

    Banned
    BANNED!!!
    Aug 20, 2011
    3,815
    Indiana
    Bison Armory only sells SPC II barrels and uppers.

    That may be true Jim, But the facts of what's happening here still don't change.

    Now let's remember he has blown at least one primer,Admitted he has loaded very hot loads and cratered a bunch of primers. Also loaded 130 grain bullets with a powder that has no data from the manufacture for 130 grn bullets and it was a compressed load at that. He has been hotrodding and was heading for a massive failure. All he wanted to do was to see how fast he could push each bullet and then tell the world all about it. Who would want to sit at the bench next to him ??? Not me.... he needs to crawl before he walks. And just because a given load is safe in your rifle does not mean it will be safe in the OPs , mine my brothers or anybody else's. You gotta do a ladder and work up the loads in your own rifle.
     

    FlatsFlite

    Active Member
    Aug 6, 2012
    691
    King George, VA
    Post no. 3 clearly states Spc II

    Judging by the photos, I see no pressure signs in the primers. However ole boy was jumping up there a little fast and knowing one's rifle is the key. Published data is not safe in some albiet very few rifles. Start low, and go slow is my motto, but I'm not afraid to color outside the lines.
     

    coopermania

    Banned
    BANNED!!!
    Aug 20, 2011
    3,815
    Indiana
    I wanted to save this for later to keep the suspense going, but here it is:

    The primer that popped was on a Hornady case using CCI 41, Speer 130 gr SPBT bullet, COAL 2.308 inch H322 30 gr (corrected from 30.5 stated earlier). That was after I shot about 10 rounds of that ammo and observed partially flattened primers. The load was really hot but I also think that I might have enlarged the case too much. Hornady brass was a pain to deprime and uniform. They crimp their primers and it takes a lot of work to uniform and reprime without a primer pocket uniformer tool.

    Later tonight I ll describe how I worked up these loads and add pictures of the case heads as a surrogate of pressure measurements.

    That may be true Jim, But the facts of what's happening here still don't change.

    Now let's remember he has blown at least one primer,Admitted he has loaded very hot loads and cratered a bunch of primers. Also loaded 130 grain bullets with a powder that has no data from the manufacture for 130 grn bullets and it was a compressed load at that. He has been hotrodding and was heading for a massive failure. All he wanted to do was to see how fast he could push each bullet and then tell the world all about it. Who would want to sit at the bench next to him ??? Not me.... he needs to crawl before he walks. And just because a given load is safe in your rifle does not mean it will be safe in the OPs , mine my brothers or anybody else's. You gotta do a ladder and work up the loads in your own rifle.


    Your right Flats, I missed the spcII chamber, but I still stand by what I have said. I don't believe he posted any pictures of the 10 hot rounds with flatened primers with a compressed charge and 130 grn bullet. Nor did he post a pic of the blown case.
     

    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    Reading pressure signs for the 6.8 SPC

    Sorry for the long gap between my posts. I was busy reloading and shooting. I am getting ready to post a more successful reloading experience in a new thread, and I prepared a picture of case heads at different pressure levels. Given the comments above I think it will be useful to post it here. Most of the cases are for the Speer 130 gr with H322 powder, but I also included 3 factory loads:
    Hornady 110 gr v-max
    Hornady 120 gr SST
    S&B 110 gr FMJ

    This picture is for my own reference but others could benefit from it. Please note that the cases were reloaded once from previously fired factory loads. Many of them had swipes from the original firing of the factory load.

    Also as a response to the previous comments. Now that I know better I wouldn't ever continue shooting after I reached signs that look like #5 or #6.
     

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    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    That may be true Jim, But the facts of what's happening here still don't change.

    Now let's remember he has blown at least one primer,Admitted he has loaded very hot loads and cratered a bunch of primers. Also loaded 130 grain bullets with a powder that has no data from the manufacture for 130 grn bullets and it was a compressed load at that. He has been hotrodding and was heading for a massive failure. All he wanted to do was to see how fast he could push each bullet and then tell the world all about it. Who would want to sit at the bench next to him ??? Not me.... he needs to crawl before he walks. And just because a given load is safe in your rifle does not mean it will be safe in the OPs , mine my brothers or anybody else's. You gotta do a ladder and work up the loads in your own rifle.
    I have only blown one primer and only hot loaded one bullet. This was the first and last time.
     
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