Type 1, Type 2, SAAMI - I forget

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  • TitanNV
    Bloodstained
    • Dec 2015
    • 33

    Type 1, Type 2, SAAMI - I forget

    I forget if Type II and SAAMI are the same thing.

    I have a horrible memory.

    [I do recall the bolt face (.135 or .136) is a Type II thing.]
  • cory
    Chieftain
    • Jun 2012
    • 2985

    #2
    0.136" bolt face is the "SAAMI" beowolf (grendel) bolt.
    "Those who sacrifice liberty for security, deserve neither." Benjamin Franklin

    Comment

    • bwaites
      Moderator
      • Mar 2011
      • 4445

      #3
      It's a Grendel SAAMI chamber or its 264 LBC, Grendel II, etc. Any but the Grendel SAAMI chamber may use Grendel bolts or the .125 face depth bolts depending on how the manufacturer headspaced the chamber. Type I and Type II is an artificial construct started by Black Hole to distinguish between the .125 (Type I) and the .136 (SAAMI Grendel or Type II) in their nomenclature.

      Comment

      • TitanNV
        Bloodstained
        • Dec 2015
        • 33

        #4
        Thanks.

        I am trying to confirm my Doubelstar barrel and bolt listed as "6.5 Grendel Type II" is the same as my Wolf Precision/Anderson upper with a supposed SAAMI .135 Bolt (lol) are the same spec. Or at least close enough to swap bolts and the like without fear of malfunction or worse.

        Comment

        • NugginFutz
          Chieftain
          • Aug 2013
          • 2622

          #5
          Originally posted by TitanNV View Post
          Thanks.

          I am trying to confirm my Doubelstar barrel and bolt listed as "6.5 Grendel Type II" is the same as my Wolf Precision/Anderson upper with a supposed SAAMI .135 Bolt (lol) are the same spec. Or at least close enough to swap bolts and the like without fear of malfunction or worse.
          Bottom line, TNV: If it says "Grendel Type II", the odds are very high that it is not a SAAMI Grendel chamber. What you have there is essentially a .264 LBC with a wider throat. The Grendel II, and other variants like it, are reamed without the signature compound throat of the SAAMI Grendel.

          Try not to confuse this with the term "Type I" or "Type II". As bwaites described above, that only refers to the bolts.

          Irrespective of the chamber, though, you can use a caliper to measure the bolt face depth to see if both of your bolts are at .136" or at .125".
          If it's true that we are here to help others, then what exactly are the others here for?

          Comment

          • TitanNV
            Bloodstained
            • Dec 2015
            • 33

            #6
            Originally posted by NugginFutz View Post
            Bottom line, TNV: If it says "Grendel Type II", the odds are very high that it is not a SAAMI Grendel chamber. What you have there is essentially a .264 LBC with a wider throat. The Grendel II, and other variants like it, are reamed without the signature compound throat of the SAAMI Grendel.

            Try not to confuse this with the term "Type I" or "Type II". As bwaites described above, that only refers to the bolts.

            Irrespective of the chamber, though, you can use a caliper to measure the bolt face depth to see if both of your bolts are at .136" or at .125".
            Ahhh now I think I get it. Never realized there was a difference in the chamber as well.

            So, basically, even if the bolt face is the same on both bolts, one still has to worry about the chamber and headspace issues?

            Comment

            • LRRPF52
              Super Moderator
              • Sep 2014
              • 8569

              #7
              Bolt depth doesn't determine chamber.

              Chambering determines what chamber it has, and however the person reaming wants to set up bolt face depth is up to them.

              I don't know of anyone who chambers SAAMI and uses a shallow bolt face depth where there isn't enough extractor lip mass, but you could do it.

              I personally only look for manufacturers who use a SAAMI chamber with a Grendel bolt, the face depth being only one of many differences that separate Grendel bolts from others. There is also:

              * Bolt length (Grendel bolts are longer than 5.56 bolts.)
              * Extractor pin hole location
              * Extractor shelf dimensions
              * Metallurgy and processes
              * Extractor metallurgy, processes, and dimensions

              A manufacturer would be better off dropping any mentioning of confusing and undefined terms like "Type I" or "Type II". It makes it difficult for customers to understand what is even going on, especially since there are literally zero industry standards for those terms, whereas there is an industry standard for SAAMI and what has been tested extensively to work with 6.5 Grendel in the AR15.
              NRA Basic, Pistol, Rifle, Shotgun, RSO

              CCW, CQM, DM, Long Range Rifle Instructor

              6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

              www.AR15buildbox.com

              Comment

              • va_connoisseur
                Warrior
                • Oct 2016
                • 103

                #8
                Originally posted by LRRPF52 View Post
                Bolt depth doesn't determine chamber.

                Chambering determines what chamber it has, and however the person reaming wants to set up bolt face depth is up to them.

                I don't know of anyone who chambers SAAMI and uses a shallow bolt face depth where there isn't enough extractor lip mass, but you could do it.

                I personally only look for manufacturers who use a SAAMI chamber with a Grendel bolt, the face depth being only one of many differences that separate Grendel bolts from others. There is also:

                * Bolt length (Grendel bolts are longer than 5.56 bolts.)
                * Extractor pin hole location
                * Extractor shelf dimensions
                * Metallurgy and processes
                * Extractor metallurgy, processes, and dimensions

                A manufacturer would be better off dropping any mentioning of confusing and undefined terms like "Type I" or "Type II". It makes it difficult for customers to understand what is even going on, especially since there are literally zero industry standards for those terms, whereas there is an industry standard for SAAMI and what has been tested extensively to work with 6.5 Grendel in the AR15.
                Thanks for the information, as a newbie to the Grendel world this is good to know. Of the five items you listed, what should a new person should be looking for? Are there measurements or locations that I need to know.

                Comment

                • LRRPF52
                  Super Moderator
                  • Sep 2014
                  • 8569

                  #9
                  Grendel bolt length is 2.810"
                  Face depth is .136" (-.003" allowable)
                  Metallurgy is guarded by different vendors, but generally a certain type of 9310 alloy with certain heat treatments, shot peening, MPI, destructive testing of a certain % per batch.

                  There is nothing the consumer can really do other than check 2 of these dims, so it's best to source parts from reputable manufacturers and brands.
                  Nobody has done more testing than AA, and AA tests things that most 5.56 manufacturers aren't even aware of, since 5.56 is so well-vetted over the last 6 decades.

                  We've had some vendors that entered the market with really good bolts, then on subsequent production batches, something dropped in QC or specs and they no longer were holding up, especially looking at bolts and extractors.

                  I know AA works hard to maintain their standards with bolts and extractors, which is an endless battle with machine shops, kilns, and finishers.

                  The AA Hard Use bolt has a totally different surface treatment than most bolts on the market, as well as some external features that distinguish it from the rest.

                  I've had zero problems with standard AA bolts over the years, running thousands of rounds on them.
                  I'm also having no problems with the first batch of Underground Tactical bolts that PF used, with their own sources extractors that were nitrided, but it appears that something changed for the worse with Underground. Don't know what happened, but such is life.
                  NRA Basic, Pistol, Rifle, Shotgun, RSO

                  CCW, CQM, DM, Long Range Rifle Instructor

                  6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

                  www.AR15buildbox.com

                  Comment

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