1. Attention: We have put together a thread with tips and a tutorial video to help with using the new software. Please take a moment to check out the thread here: Trapshooters.com Tutorial & Help Video.
    Dismiss Notice

receiver metal hardness

Discussion in 'Uncategorized Threads' started by JerryP, Aug 20, 2007.

Thread Status:
Not open for further replies.
  1. JerryP

    JerryP Active Member

    Joined:
    Jan 29, 1998
    Messages:
    1,753
    I would like to know the relative hardness of popular receivers compared to a BT99, which seems to be pretty soft. I know the high end guns are supposed to be harder steel but what about guns like the KX5, Kolar and Perazzi?
     
  2. TOOLMAKER 251

    TOOLMAKER 251 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    3,398
    Don't let hardness sway your choice of buying a brand of shotguns. I know of at least 1 old BT-99 that has over 200,000 shells thru it. Perazzi's (the newer ones) are about as hard as the Brownings. My Perazzi MX-8 is case hardened a few thousands deep. Krieghoff's (K80's) are case hardened. I think Dan Orlick put over a million shells thru his Ljutic. If you take care of most brake open shotguns, they should last more then 1 life time.

    George
     
  3. g7777777

    g7777777 TS Supporters TS Supporters

    Joined:
    Jan 29, 1998
    Messages:
    9,353
    Dont know but hardness has nothing to do with strength

    regards from Iowa

    Gene
     
  4. AJJ

    AJJ TS Member

    Joined:
    Jan 29, 1998
    Messages:
    55
    I have a 15 year old Ljutic 73, that does not have a mark / indentation on the receiver face, I have a friend that has a two year old Perrazi, that has had a lot of shells throught it in that time, it has the primer diameter indented into the face of the receiver, which I would guess to be 0.010" deep ( that is ten thousands of an inch ) I consider that to be soft material. AJ.
     
  5. TOOLMAKER 251

    TOOLMAKER 251 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    3,398
    GN7777777, Your wrong on your statement and you never worked with metal. AJJ you are right about the Ljutic's I have one I got new in 1996 and not a mark from primer hammerings. I have a MX-2000 with around 20,000 but no indentation yet. My TM-1 which is a Ithaca import is indented, and so is the MX-8 even with the casehardening.
    George
     
  6. TOOLMAKER 251

    TOOLMAKER 251 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    3,398
    PerazziBigBore, and GN7777777 let me give you a little lesson on strength and hardness. Lets take AISI 4140 steel as an example. Tensile strength MPa as measured at different hardness, at 22 rockwell C scale it has a strength of 814, at 30 C 965, at 52 C 1795 and at 55 C 1965. So hardness does play a part in strength.

    George
     
  7. g7777777

    g7777777 TS Supporters TS Supporters

    Joined:
    Jan 29, 1998
    Messages:
    9,353
    Tool maker are we talking about tensile strength or yield strength? Ultimate strength or breaking strength

    Lets not be so fast-- we didnt say all the recievers had the same steel

    and different steels are affected differently with hardening

    Without looking 4140 up-- lets say you are right --

    But another steel that is softer or harder may have totally different Tensile and yeild levels

    Just as another steel of exactly the same hardness as 4140 might have greater or lesser tensile or yeild strengths than 4140 has

    It depends on the steel

    Then there is the matter of ductiliy

    Finally there are guns that you discussed that have surface hardening- the effects of that are totally different

    regards from Iowa

    Gene
     
  8. TOOLMAKER 251

    TOOLMAKER 251 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    3,398
    Just correcting your remark a few posts back that hardness had nothing to do with strength. It has alot to do with strength, and I am talking about tensile, yield, and compressive strength.

    George
     
  9. g7777777

    g7777777 TS Supporters TS Supporters

    Joined:
    Jan 29, 1998
    Messages:
    9,353
    George you made a good point and it was in the explanation that I was wrong

    But two different steels that have the same hardness could -- actually would --have totally different strength levels

    the two could -- actually would also have totally different ductility

    Thus their applicability for gun parts -- would be totally different

    Harder isnt always better nor is it always stronger

    regards

    Gene
     
  10. jnoemanh

    jnoemanh TS Member

    Joined:
    May 20, 2007
    Messages:
    526
    It's more complicated than that, Gene. Take the example of 4140, a grade which might be used for a good quality receiver. It can be heat treated and tempered to most any hardness. Beyond that, it can be surface hardened, as in the older cyanide case hardening (those pretty colors seen mostly on older guns), or surface hardened by nitriding. Thus you can have a receiver with a core hardness of say RC48 - really tough and crack resistant, but with a RC60 surface, highly resistant to wear. That's why those silver-colored receivers are so resistant to scratching, they have a thin (few thou) nitrided surface over a tough core. If the entire receiver were that hard, it could shatter like glass.

    Silver nitrided receivers are not to be confused with nickel plated, which look somewhat similar, but are not nearly as hard.
     
  11. g7777777

    g7777777 TS Supporters TS Supporters

    Joined:
    Jan 29, 1998
    Messages:
    9,353
    Exactly right jnoemanh

    Thats why nitriding is generally a good process-- Krieghoff changed to that several years ago

    The nitriding also has anti corrosion properties

    Gene
     
Thread Status:
Not open for further replies.