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Causes of Low pressure -223

Discussion in 'Handloading and Reloading' started by gifbohane, Jun 13, 2018.

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  1. ponchh

    ponchh Member

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    I will say one more time, slower burn equals more velocity.
     
  2. Demi-human

    Demi-human Member

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    I believe that burn rate has more to do with bullet exit timing, for accuracy, than barrel lenght.

    The AR is not new, a simple poll of reloaders would show heavier charges for the specific component combination.
    (Of course published data is best.)

    Obviously a chronograph can not tell one how high the pressure is. But none of the related system components are strange or wildcat. I suspect they could take more.(My opinion only, facts are best!)

    Having said that, I have a wonderfully accurate load with TAC for my AR that functions, is very light and sends a V-max fifty grain bullet through the same one inch square. At a sedate twenty four hundred feet per second.
     
  3. Varminterror

    Varminterror Member

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    Over simplified theory, pseudo science, and tongue in cheek rules of thumb don’t trump real world results. I’ve ran literally hundreds of AR’s over chrony’s, from 7” to 31”, specialty pistols from 9” to 17”, bolt guns 16” to 32”, revolvers 1.8” to 18”...

    The powder which gives the best velocity for a given pressure on the long barrel will transfer to the short ones just the same. Fast powders for short barrels and slow for long is a myth. A guy might be able to match the same velocity with less blast and flash in a short barrel, but generally not at the same peak pressure, and generally not commonly so. Burn efficiency and blast aren’t the only metrics for barre

    If H335 is too slow for 223rem carbines with 55grn pills, then Varget has a LOT of explaining to do!!! And I’d reiterate the sentiments above - 3031 is the only powder on that list faster than H335 - 2520, 2495, 748, and AR Comp are all slower than H335...
     
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  4. MEHavey

    MEHavey Member

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    Wow.
    Well, you go ahead and tell the OP to simply go to Lyman and stuff 27gr/H335 down the case.
    It'll have enough pressure to efficiently burn then.

    Forget that pseudo science that might actually be going on explaining the comparitive results ... and comparisons with other powders.
     
  5. MEHavey

    MEHavey Member

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    Given my love of Voodoo, here's the in-order/rationale list I might try this weekend in the Sporter:

    223_55gr_short_Barrel_High_Road.jpg
     
    Last edited: Jun 14, 2018
  6. Varminterror

    Varminterror Member

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    I'm a QL user, since 2003 when I was developing munitions on contract, and held my Type 6. That's not voodoo or pseudo-science. But I'd appreciate some clarification of your statements:

    First, I'll outright say: I don't live and breath on burn efficiency. If I'm not using the firearm for defense, the muzzle flash doesn't come into my planning. I've played with running highly efficient loads, never panned out as directly correlating to low ES or precision. High load densities do, high burn efficiencies don't - psuedo science, in my experience.

    But you stated this, to the OP's claim of using H335, for those playing the home game:

    Suggesting instead a list of powders, presumably recommended because you felt they were NOT "too slow for a short barrel":



    Then followed up with another list of powders in your last (transcribing from your excel screenshot):

    AR-Comp
    H322
    RL 10X
    VV N140
    Accurate 2015
    IMR 4198
    RL 12
    VV N133
    VV N130
    VV N120


    So - revisiting this particular statement:

    Given this list of powders and the relative burn rate table from the experts who fed their data into QL - I'll say, if there's science behind the statement asserting H335 as "too slow," then I'm confused:

    AR-Comp (stated to be equivalent in burn rate to Varget) = Significantly Slower
    H322 = Faster
    RL 10X = Faster
    VV N140 = Significantly slower
    Accurate 2015 = Faster
    IMR 4198 = Faster
    RL 12 = Slower
    VV N133 = Slightly faster
    VV N130 = Faster
    VV N120 = Faster
    IMR 3031 = Slightly faster
    Accurate 2495 = Slower
    Accurate 4064 = Slower
    Winchester 748 = Significantly Slower
    Accurate 2520 = Slower

    So out of your 15 suggestions, 6 are slower. Notably, first on BOTH of your lists is AR Comp, significantly slower than H335...

    If H335 is too slow, can you clarify why 6 powders SLOWER than H335 aren't too slow?

    burnchart1601op.png [​IMG]
     
  7. ArchAngelCD

    ArchAngelCD Member

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    GIGO Just because QL tells you H335 only gets an 85% burn doesn't make it so. If you use a NATO rates primer or a magnum primer that will change. You can not rely on one program to make your decisions. Shooting reloaded a real rifle will tell you different. Again, H335 is faster than all but one of the powders you listed and was used by the military. QL is not correct here and it's misleading you. (WC844=H335)

    I don't care what the program says, shooting it in the real world proves it wrong.

    This has moved so far OT when the powder itself had nothing to do with the velocity achieved. The barrel length caused the discrepancy, not H335.
     
  8. MEHavey

    MEHavey Member

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    That about says it all.
    A Powder Burn Rate Chart is only one of more than five/six different factors that affect pressure/velocity/burn rate/final energy dump in a particular barrel length.
    https://s33.postimg.cc/a9ytcujj3/ARComp_Factors.jpg
    But speed does play in the amount propellant burnt over time/length and whether you're dumping it out the end of the barrel.
    (and yes. I can sweep together particles on the bench in front of the muzzle after an inefficient firing session -- and they will burn)

    That QL shows H335 doesn't even make the top ten in that list/under those conditions is enough for me.
    I'm done here... and just going to SHOOT it this weekend.

    I'll let you know.
     
    Last edited: Jun 14, 2018
  9. Dudedog
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    Dudedog Contributing Member

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    I did mention that I thought Lyman's data was on the high side and that it was higher than Hodgdons.
    27gr seems a little high to me so don't just stuff 27gr of H335 in a case.
    I went back and highlighted where I said Lyman's data was higher than Hodgdons earlier.
    Be safe, work up to MAX charges, and of course remember the listed MAX may be higher than your MAX.
    If it was me I would believe Hodgons MAX more than Lymans, they don't make the powder. but they sell it.
    I never went above 25.5 so I can't say about 27. (around 24.5 seemed the sweet spot)

    BTW what does QL say about 27gr with a 55. To high I would guess.
    Lyman used a Sierra SPT #1360
    24.3 3142 35,200 CUP (pressure seems low here) 27.0 3270 49,100 CUP (so not PSI and no real accurate way to convert)
    Universal receiver 24" barrel 1 in 12 They also show they used a 20" AR 1 in 7 but don't mention which were used for the data they show.
    Is was thinking in 49 they did or maybe I am just not seeing it in 50.
     
    Last edited: Jun 15, 2018
  10. Walkalong

    Walkalong Moderator Staff Member

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    A lot of people run 24 to 25 Grs H335 under a 55 Gr FMJ in .223 with good success. How efficient it is etc I don't know, but I do know it has been a very popular powder for this application for a long time.

    Speer used to show a max of 27.0 Grs H-335 under a 55 Gr FMJ, and many years ago I shot a bunch of Winchester 55 Gr FMJs over 26.5 Grs of it in a Mini 14.
     
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  11. kwg020

    kwg020 Member

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    I'm going to disagree ME
    The only "fast" powder you mentioned was the 3031. The other 3 are much slower.

    As for H335. Start at a minimum of 24 but preferably of 25 grains. In a short barrel I recommend AA2015, RL10x or 3031. But, H335 is a versatile powder.

    kwg
     
  12. rskent

    rskent Member

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    If you are married to 55 grain projectiles You might want to go up (work up safely) to around 25.3 grains of 335 with a magnum primer. If you’re not, you might want to try (again, work up safely) around 26 grains of 335 with a magnum primer under a 52 or 53 grain projectile. I’m no powder expert (or anything expert) but I like 335 in 223.
     
  13. MEHavey

    MEHavey Member

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    This thread started on the unexpected-low velocity results when the OP used a listed charge of H335 behind a 55gr projectile in his 16" AR. It quickly descended into a discussion of slow(er) Burn Rates and defense of H335 as being faster (on the Internet burn-rate charts) than many of the QuickLoad-Recommended powders that would exceed H335 performance.

    I'll have to back off my blanket statement that H335 was too slow, and instead caveat the statement by saying that H335 was too slow at the pressures generated by a low powder charge.

    That brings up of whole issue of progressive powders -- the mainstay of modern cartridge ballistics -- and what we mean by "Burn Rate."

    Published/listed/charted Burn Rates are static measures that relate to the beginning of combustion. They tell you absolutely nothing of what that burn rate is doing during combustion. Some powders' burn rates dramatically increase w/ pressure (i.e., progressive burn); and some powders actually slow down as pressure rises (degression -- some classics here being 4227 and 5744). Of progressive powders, how fast they rise is a also a differential characteristic between different powders.

    Even those whose burn rates rise, however, eventually heel over and begin to slow down as burn begins to complete -- and just where that knee in the curve is also plays a crucial role in the final game we call "Internal Ballistics"

    Of the two powders we argued over, one was H335 (listed as faster in the charts) and the other -- supposedly optimal -- was AR-Comp (listed as marginally slower). So why should the "slower" powder performer better? Because it's not actually slower once the game's afoot, nor does it burn for the same pressure rise time.

    Take a look at what's actually happening as burn progresses between the two powders:

    H335_v_AR-_Comp_Burn.jpg

    Note that while H335 is slightly faster at the start (Ba= 0.630 vs AR's 0.620), AR-Comp's progressivity is much higher -- and so it's burn rate actually surpasses H335's very quickly. Note also that H335's burn rate drops off at 47% burn. while AR-Comp's continues to accelerate out to 62%. (Note also that while H335 is a somewhat more energetic powder (3,980 kJ/kg) than AR-Comp (3,740), the AR-Comp powder eventually gets to burn faster/apply energy longer.

    The result is that while H335 is a very good powder for full-up 223 loads, AR-Comp becomes a better match for end performance once all the dust settles -- and "Burn Rate" charts are totally useless unless one digs very deeply into what actually happends when the ballon goes up.

    INCIDENTALLY:
    Knowing what I know now, I went out yesterday and ran an H335 test at predicted full power:
    223REM Armelite/M4 / H335/ 25.7 / OAL:2.24”
    Predict QL-16"= 54,948psi/2,995fps / 96/95 Fill/Burn/CCI-41
    Actual Vel (Oehler) = 2941± 04

    Calibrating now on actual fired-case volume and adjusting "effective" BurnRate to match, I ought to get another 80fps out of it before I hit actual 55ksi.
    (But that's chasing something I don't really need)
     
  14. mjsdwash

    mjsdwash Member

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    I have chronoed several lots of H335, in 4 rifles, with two chrono's over the years, and to reach 2900 FPS in a 16" you need around 25 grains. I used to load as high as 27, and yes, I do have a published manual that lists that load, and got 3150-3200 from a 16". While I know Hodgdon lists your loads, they are well below starting loads in my manuals. Your velocity is right what I would expect. Most testers use 24+ barrels with sealed breaches. For example, heres Noslers starting load for 55gr at 24grains. https://load-data.nosler.com/load-data/223-remington/ I do not recommend exceeding their max, when I was loading up to 27grains, while i did not see any initial signs of pressure, I did have SEVERAL head separations on the third firing.
     
    Last edited: Jun 17, 2018
  15. 243winxb

    243winxb Member

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    MEHavey- Quickload.

    Assumption - Definition-
    With so many models, chambers and other variation in AR 223 , live fire is the only way to know what works.
     
    Last edited: Jun 17, 2018
  16. mjsdwash

    mjsdwash Member

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    I see a lot of information here, but to answer your question, your chrono and scale are right, your technique is right, but you load is extremely light according to most sources. Unfortunately, the powder manufacturer is your source, and they are the safest one to trust.
     
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  17. Walkalong

    Walkalong Moderator Staff Member

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    I'm on board with that.
     
  18. gifbohane

    gifbohane Member

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    Thank You all for the great info.

    I conclude that I need more powder. Going to add more incrementally but not exceed 25 grains.

    My remaining question is what should I key off of? Take the FPS to 2900 and stop OR wait for the rounds to show signs of overpressure?
     
  19. MEHavey

    MEHavey Member

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    See bottom Line of Post#38
    "Calibrating now on actual fired-case volume and adjusting "effective" BurnRate
    to match [measured velocity], I ought to get another 80fps out of it before I hit
    actual 55ksi."

    QuickLoad gets you into a 1st-data-point environment wherein -- with a chronograph --
    you can now reliably adjust parameters to match reality outside that first data point
    for that weapon.





    (in case y`all haven't figured it out, I use QuickLoad as 1st-rule-of-thumb architect's planning, and handloading w/o a chronograph ... to be like construction w/o the tape measure.
     
    Last edited: Jun 17, 2018
  20. Varminterror

    Varminterror Member

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    Quickload is a great tool, but it certainly doesn't support ANY of your claims such H335 is too slow, and X, Y, and Z powders are better choices.
     
  21. billybob44

    billybob44 Member

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    I load 25.0g H335 with a 55g fjmbt and get about 3030 fps out of a 20" AR
    ^^^^This..I have loaded/shot a LOT of this load..It rocks any AR I have had it in.

    FWIW: If you can find the Military (WC844) powder, you can load the same charge..Bill.
     
  22. spitballer

    spitballer Member

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    Some years ago I was researching the early development of M16 ammunition and learned that IMR3031 was used in M193 for a time, but the muzzle velocity was around 3200 fps (the requirement was for a round that would 'penetrate a steel pot at 500 yds'). which is gonna be hard to achieve with such a short barrel using the max allowed 24.6 grains - they must have used more. Wouldn't it be smarter to just buy M193 ammo though
     
  23. Dudedog
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    Dudedog Contributing Member

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    You need to sort of do both.
    Work up to 2900 watching for signs of pressure if that's the vel your after and you can get there. I have no way of knowing if 2900 is safe in your rifle with your components. (probably, but know way for me to know)
    A rough # for the MAX sort of combining data from different places is somewhere around 25.5.

    http://www.6mmbr.com/223Rem.html
    About halfway down click on the green Sierra boxes
    Note: Their AR Data is lower than their non AR data, the flip side is 5.56 is allowed to run more pressure than .223
    Hodgdon
    55 GR. SPR SP Hodgdon H335 .224" 2.200" 23 3018 40,800 CUP 25.3 3203 49,300 CUP
    Of course these are different bullets than you have

    If you have no pressure signs you could possibly go higher carefully if you want more velocity, but I would trade better accuracy for 50-100fps. in most rifle rounds.
    (others would rather have the extra velocity, no right or wrong answer as long as the ammo is safe)
    I generally don't like to exceed listed MAX charges and don't recommend that anybody else does, do so at your own risk.
    In my .223 there is usually a sweet spot (node) middle to mid-high and going higher or lower than the sweet spot shows up on paper. It varies of course, some guns/calibers are happier right around MAX.

    =======================================
    Thanks for the additional info MEHarvey.
    =======================================
     
    Last edited: Jun 21, 2018
  24. MEHavey

    MEHavey Member

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    You apparently didn't read the implications of post #38
    (and the fact that H335 is dramatically slower than AR-Comp for almost 2/3rd of the burn cycle)

    Still, H335 isn't a bad powder at all when loaded near SAAMI/factory/mil-power levels.
    (and it meters like water)
     
    Last edited: Jun 18, 2018
  25. ArchAngelCD

    ArchAngelCD Member

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    The OP did not load to the max charge. He was using the wrong data, data for an all copper bullet like I said in Post #9. The max charge according to Hodgdon is 25.3gr under that 55gr bullet the OP used.

    I'm fairly sure upping the charge to 25.0gr H335 will "fix" this. BTW, there was no real problem from the start. The OP 's only complaint was his chronograph didn't report the velocities he expected. Low charge = low velocity especially when not using a magnum primer with a ball powder.

    I'm done here since this thread is going in circles. Good luck...
     
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