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Thread: One-sided gas burns on .45 ACP factory ammo casing; shot from HK45

  1. #1
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    Default One-sided gas burns on .45 ACP factory ammo casing; shot from HK45

    Hi All,

    I am a new to the HK world, as well as the .45 ACP round. I went to the range last week and fired 100 round of factory loaded Federal Champion 230gr through a new HK45. These were the first rounds trough this gun. I collected several pieces of brass after my range session for inspection. I noticed that all of them had significant one-sided burn marks. Some of which were almost the entire length of the casing. I am attaching an image that compares 5, typical .45 casings to 2 of .40 - my current EDC caliber. I also use Federal Champion as range ammo in my .40 (more that 1500 rounds) and have not observed similar one-sided burn patterns.



    I have several questions:

    1. Is this normal for .45 acp in HK chambers given then lower pressures? Perhaps this could be a result of low pressure "plinking" rounds that did not fully expand to seal-off on the chamber? I will also add that the .45 +p test-fire rounds that can in the gun's case did not show the one-sided burns that I observed with the Federal Champion.

    2. Could this potentially affect/damage the chamber? During my cleaning, i noticed significant build-up on one side of the chamber that I could not completely remove.

    3. Since the build-up seemed to be on one-side of the chamber could this be an indicator of an out-of-spec chamber (i.e., roundness, cylindricity)?

    4. My concern was some burn marks almost covered the entire length of the casing and could potentially spew hot gas from the chamber towards the shooter. Does this pose a safety concern?

    Any comments would be appreciated.

    Thanks in advance.
    Last edited by TheFreightTrain; 01-03-2011 at 02:24 AM. Reason: spelling

  2. #2
    Really liking this HK Stuff Member
    SRG720's Avatar
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    I've had this happen to varying degrees with close to a dozen factory brands in my USP45.. nothing to worry about.

    The dirtier the powder used in the ammo the greater the discoloration..

    I've shot 9mm 'Champion' in a CZ75B and it did the exact same thing.
    Last edited by SRG720; 01-03-2011 at 02:39 AM.

  3. #3
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    Perhaps this could be a result of low pressure "plinking" rounds that did not fully expand to seal-off on the chamber? I will also add that the .45 +p test-fire rounds that can in the gun's case did not show the one-sided burns that I observed with the Federal Champion.

    This is the probable cause. I bet if you check the case rim for the extractor and ejector marks the smudging will be found to be on the top of the case. This is from the action unlocking without the case tightly sealed to the chamber walls. I have the same issue with my P30 and S*B 115 gr ammo. Hotter loadswill resolve that issue.

  4. #4
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    Quote Originally Posted by finnmike View Post
    This is the probable cause.
    Yup. Incomplete case obturation.

    My bunny fart reloads do the same thing. Keep an eye on the breech face, for possible gas erosion. Not likely with an HK; I have put thousands of those bunny fart loads through a USPc .45 and two HK45Cs with no issue. The Federal "economy" cartridges, in the maroon box, also do it to a lesser extent in my pistols.

    IOW, it is nothing to worry about.

    .

  5. #5
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    I've actually noticed this recently, with both HK45 and a M&P45. Happened with WWB rounds, so that must be the culprit.

  6. #6
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    Me too..I second the WWB rounds...I noticed this after going through 100 WWB then 100 Rem UMC then back to the WWB all in 40SW....only difference were the REMs were JHP.....

    I figured there was nothing to worry about since it was an HK!!!!

  7. #7
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    Quote Originally Posted by finnmike View Post
    [I] I bet if you check the case rim for the extractor and ejector marks the smudging will be found to be on the top of the case.
    I had some difficulties in finding the extractor marks, but after looking at some examples, it seems like the burns are consistently on the opposite side of the case (same side as the ejector). This corroborates well with my observation of excess residue in the left side of the chamber during cleaning. Seems like a combination of the extractor torquing the round and low power plinking rounds are the root cause. Good news is that after further reading and the replies to this thread, it seems normal for factory target ammo. I may try a couple of other brands (WWB, UMM, etc) but Federal has not failed me once so far.

    I am concerned about the comment on "breach-face erosion". Any additional comments on this?

    Cleaning the chamber was a challenge. I bought a nylon brush when I purchased the pistol, and scrubbed the chamber with H#9 solvent. It is still not completely clean. After reading the manual, seems like phos bronze is the recommended type. Looks like another excuse for a gun shop visit... I like those.

  8. #8
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    Quote Originally Posted by TheFreightTrain View Post
    I am concerned about the comment on "breach-face erosion". Any additional comments on this?
    Those smudges on your brass are the result of the case not sealing completely against the chamber wall, allowing some of the gas generated by firing to "leak" past the case. In extreme cases, this leakage can begin to erode the breech face, since that is what it contacts.

    Understand that this is RARE. Add to that the higher-grade steel HK uses, and I don't think you have anything to worry about. That's why I stated that my personal HK pistols have fired many thousands of reduced loads that have more smudging than you're showing... and no ill effects to the pistols.

    However, no free lunch. The residue in the chamber you noted can eventually become a problem, so go to Brownell's web site, locate their dedicated chamber brushes, order a half dozen or so, and use them every time you clean the gun. A regular bore brush will NOT get this residue... its too small in diameter. And the necessary reversing of the brush (do NOT push it all the way through- these brushes are tough stainless steel, larger in diameter than normal, and will likely scratch your bore) means it won't last a long time. I get about a dozen or so "cleanings" before the bristles have flexed enough to become loose, and I toss the brush. These brushes are not inexpensive, but if you balk at paying for them to keep your expensive, top-shelf pistol running smoothly, perhaps you should buy a Glock... :-)

    Don't spazz out over the erosion deal. Just be aware of the phenomenon, and look for it when you perform maintenance... and enjoy your HK.

    .

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