Bolt Carrier Group Sale

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    • #109282
      wildbill
      Participant

        It has been state numerous times that we should all have spare BCGs in case ours goes down and needs to be replaced, well just saw a sale pop-up on some and wondered if anyone new anything about these or had experience with them.

        SAA – AR-15/M16 .223/5.56 (also 300 AAC/Blackout) Complete Bolt Carrier Group (BCG) 9310 MPI Tested Retail $89.99 Sale $67.99

      • #109283
        JohnnyMac
        Participant

          Whether it matters or not, I’m not sure anyone can say, but mil spec bolt material is carpenter 158 , not 9310.

        • #109284
          HiDesertRat
          Participant

            Got curious about this and found this:

            Why 9310 Steel in an AR-15 / M16 Bolt?

            Posted by Nathan Schueth on 12th May 2016

            “9310 is not MIL-SPEC, it’s better than MIL-SPEC”

            Last week Faxon announced the release of their GUNNER series of Modern Sporting Rifle bolt carrier groups. Its been a pleasure working on the carriers and we are thrilled to have them released to our customers to rave reviews. We were able to create something never done before: A steel carrier, keeping forward assists, full-auto compatible, and less than 6.5 ounces!

            One of the questions we have been getting is why we opt to not follow the “Mil-Spec” for our bolts, specifically why we are not using Carpenter 158 steel for the bolts?

            The answer is simple: “Mil-Spec” is just the minimum requirement and metallurgical technology has caught up to design of the AR-15 since its creation.

            The reason for Carpenter 158 as the “Mil-Spec” is rooted in history when the AR-15, chambered for the lower pressure .223 Remington round was upgraded to the higher pressure 5.56 NATO loads. The original material selection for the bolt was found to have inadequate service life. The military went searching for better material, constrained by the size of the bolt. Carpenter Technologies’ 158 blend of steel was selected as it provided adequate strength and wear characteristics. It has been the “Mil-Spec” since.

            Since the creation of Carpenter 158, the metals industry has continued to innovate, creating new blends of steels. 9310 is a AISI standard grade of tool steel that makes it about ~7% stronger than “mil-spec” Carpenter 158 steels, when appropriately treated. Its commonly used in the aerospace industry where toughness, impact strength, and solid wear characteristics are required.

            From the base material, we took what we liked from the “Mil-Spec” and continued development. Our 9310 bolts are still magnetic particle inspected (ensures consistent material), shot-peened (surface strength), and heat-treated (for shock, abrasion, and wear) like the Mil-Spec. With 9310, the heat-treat is critical and all steps are completed with full certifications.

            From there, Faxon opted for nitrided bolts instead of manganese phosphate finihs. “Nitriding” or nitrocarburization is applied for us via Quench, Polish, Quench method. The process imbunes nitrogen into the steel hardening the surface, reduces friction, and increases corrosion resistance. We use the same process on all of our barrels. This creates a slicker, more corrosion resistant bolt that is simulatneoulsy harder to resist wear.

            As such, the combination of 9310, correct treatment methods, and QPQ create a better bolt; one that exceeds “Mil-Spec”.

            Also, the manufacturer of the bcg, SAA, is an ISO 9001 certified company which equates with a consistent, high level of quality products.

          • #109285
            HiDesertRat
            Participant

              @wildbill,

              @ $67.99, great find. They also have a nitride processed bcg for $2 more. :good:

            • #109286
              wildbill
              Participant

                Thanks for the information ordering now. :yes:

              • #109287
                DuaneH
                Participant

                  I am not a metallurgist. BLUF.
                  9310 can be sourced from china, korea or the US. Is there a difference in the materials? Yes.
                  How much? Couldn’t say as it depends on the batch and QC.

                  Carpenter 158 is a proprietary alloy similar to P6 tool steel but it is made by Carpenter (duh). They only make it and sell it in large batches and it is more expensive.

                  Is 9310 better than Carpenter? I would say yes, ASSUMING that it is quality steel to begin with and has been heat treated properly.

                  Carpenter is less sensitive to varieties in heat treatment.

                  What it boils down to is trust. How much do you trust SAA over say Colt, FN, LMT, etc?

                  It’s up to you.

                  I will say with nitrided bolts. I have a few (9310 and all I could get at the time) that I rotated to emergency spares after the sruface began chipping. Ferrtic nitriding hardens the exterior of the steel. And what happens when steel gets harder?

                • #109288
                  HiDesertRat
                  Participant

                    I also no nothing of metallurgy. I did find this though, just a snippet of all of it:

                    Carpenter 158
                    2016-03-07 09:35:04 Origin: Remark:0 Click:271
                    Technical specifications of low content of carbon die steel Carpenter 158 data sheet, Carpenter 158 Chemical compositions,Carpenter 158 Mechanical property from Steelmaking, ESR melted, Blooming, Hot forging, Hot rolling, Heat treatment, Straightening, 100% Ultrasonic test, Cold working or rough turned machining. Technical specification, ASTM A681-2004. We also possess the advanced precision machining equipments for catering for your different special requirements.

                    TECHNICAL DATA SHEET: Carpenter 158
                    OFFICIAL TEST REPORT: issued by TUV – SGS – BV
                    MATERIAL CATEGORY: cold work alloy tool steel
                    CHEMICAL COMPOSITION (WEIGHT – %)
                    C (%): 0.05~0.15
                    Si (%): 0.10~0.40
                    Mn (%): 0.35~0.70
                    P (%)≤: 0.030
                    S (%)≤: 0.030
                    Cr (%): 1.25~1.75
                    Ni (%): 3.25~3.75

                    the manufacturer…get ready..Haihong of China

                    We are a State-owned military enterprise with more than 12,000 employees and 4 plants with a strong commitment to enhancing customer productivity, profitability and safety. Founded in the year of 1965, Located in Chinese biggest special steel manufacturing industry base and processing center.

                    So it is about trust as you say. I seem to have read that the carrier itself can be from 8620 steel and other variations, but the bolt is a bit more crucial as to its composition and properties. Found this on a firearmshistory blog also, re C158:

                    The interesting thing about Carpenter 158 is that it is a proprietary steel alloy and its formula and method of manufacturing are not publicly defined. Therefore, there is no SAE standard for it and the sole manufacturer of this steel is a company called Carpenter Technology in Pennsylvania. They do not manufacture this steel continuously and only do a certain number of mill runs per year, which means it is not always available. They also only sell this steel in large amounts and require the customer to buy a lot of it at a time. Therefore, only large companies like Colt, Fabrique Nationale (FN), Daniel Defense etc. can afford to buy this steel.

                    (20,000 lbs is the smallest order btw, hence just the big dogs get to play)

                    However, C158 isn’t the only steel alloy used to make bolts. Bear in mind that the US military selected C158 in the 1960s and there have been other (and sometimes better) steel alloys developed since then. For instance, some manufacturers use 9310 or 8620 steels to make bolts. The advantage of these steels is that their chemical compositions and manufacturing methods are publicly specified by SAE (Society of Automotive Engineers – the organization responsible for specifying standards for different grades of steel in the US) and there are many manufacturers of these steels. Therefore, supply is less of a problem. Also, 9310 and 8620 steels can be purchased in small quantities and are therefore suitable for smaller manufacturers who cannot afford to buy large amounts of C158 steel at one time. If machined and heat treated properly afterwards, bolts made of 9310 steel can be even better than C158 steel. Another steel alloy used for bolts by some manufacturers is Aermet 100 (which is also used in the landing gear of jet fighters aboard US aircraft carriers). This is actually another proprietary steel alloy made by Carpenter Technology and is reputed to be far superior to C158 and 9310 steels. However, it requires a double hardening treatment process after machining to reach its full potential. In general, bolts made of 9310 steel are the cheapest to produce, followed by bolts made of C158 steel, and bolts made of Aermet steel are the most expensive. However, bolts for AR15/M16 made of 9310 or Aermet 100 cannot be called “mil-spec” even if they exceed the military standard specifications, since the US military specification says that only C158 steel should be used for the bolt of a M16.

                    The above mentioned 8620 steel is also used by manufacturers to make bolts for certain rifle models. For instance, it was extensively used in World War II for the M1 Garand rifle. Actually, the original M16 rifles also used bolts made of 8620 steel, but the US military found that the bolts were wearing out after 40,000 – 50,000 shots, which is why they went with C158 steel for the bolt. Still, 8620 steel is used for other parts, for instance, the bolt carrier and the receiver. This is because this steel is suitable for casting, welds very well, has very good machining properties and can be heat-treated to become tough and strong. The M1 Garand and the M14 both use 8620 steel for receivers.

                    So much minutiae. Again, trust of the manufacturer is important. As far as nitriding, you have a point with the brittleness of the bolt. Wonder about the process in relation to the carrier itself. Anyway, interesting thread with good learning points.

                  • #109289
                    DuaneH
                    Participant

                      I’ll tell you I am extremely picky of my steels.

                      The touted SAE standard is about the composition of the metal. The percentages of Fe, C, Mg, Ni, etc. What it does not address is the crystalline structure and the associated heat treating.

                      IIRC most 9310 bolt are machined from bar stock whereas C158 is not. Can’t remember off the top of my head, but I don’t think it is machined from bar stock.

                      What makes steel is the crystalline structures . In order to get the proper crystals, the conditions under which the steel is made has to be tightly controlled.

                      For example, the same forge can produce several different grades of steel. The same base elements can be combined to make car axle grade 4150 or ordnance grade 4150 depending on how tightly controlled the processes are.

                    • #109290
                      Weber
                      Participant

                        I’m more concerned with the quality assurance processes utilized by known manufacturers. This looks like a great deal, no doubt. But when the description states “drop in, check head-space,” I’m a little suspicious.

                      • #109291
                        HiDesertRat
                        Participant

                          Hey Weber,

                          Me thinks thats to pacify the lawyers in their company ie CYA, and for those with a serious penchant for the technical aspects of machinery, the usual caveats. Its sorta like reading those tags on the new toaster cords, “do not operate in the bathtub” and such. It is an ISO 9001 company, they just don’t hand that certification out like candy, it actually means they are significantly above the crowd.

                        • #109292
                          First Sergeant
                          Moderator

                            It’s your money spend it how you want.

                            My advice is to stay the hell away from anything like this.

                            If the price sounds to good to be true it is.

                            Most of the propaganda written about new steels is trying to sell a product.

                            Don’t get me started on nitrided bolts, nickel boron bolts or nitrided barrels.

                            Go with a known manufacturer that has good QA/QC.

                            FILO
                            Signal Out, Can You Identify
                            Je ne regrette rien
                            In Orbe Terrum Non Visi

                          • #109293
                            Yankee Terrier
                            Participant

                              try Sharps rifle company reliabolts and anybody’s “slippery ” carrier…the part that fails is the bolt…

                            • #109294
                              DuaneH
                              Participant

                                It’s your money spend it how you want.

                                My advice is to stay the hell away from anything like this.

                                If the price sounds to good to be true it is.

                                Most of the propaganda written about new steels is trying to sell a product.

                                Don’t get me started on nitrided bolts, nickel boron bolts or nitrided barrels.

                                Go with a known manufacturer that has good QA/QC.

                                Actually i would be interested in your input on those subjects other than the nitrided bolts that i bought cuz that was all that was available, i havent heard much about the others.

                              • #109295
                                HiDesertRat
                                Participant

                                  @First Sergeant,

                                  I would defer to your better judgement in this matter. Experience trumps IDKWIDK interwebz knowledge. I checked last night and happily learned my BCG is of Carpenter 158. Now to get a spare also. And to reiterate the one important point I did make above, I know nothing of metallurgy. In the practical sense anyway. And to DuaneH, thanks for your insight as well. It is nice to be able to have sane, logical discussion no matter the topic.

                                • #109296
                                  DuaneH
                                  Participant

                                    @First Sergeant,

                                    I would defer to your better judgement in this matter. Experience trumps IDKWIDK interwebz knowledge. I checked last night and happily learned my BCG is of Carpenter 158. Now to get a spare also. And to reiterate the one important point I did make above, I know nothing of metallurgy. In the practical sense anyway. And to DuaneH, thanks for your insight as well. It is nice to be able to have sane, logical discussion no matter the topic.

                                    I wouldn’t sweat the C158 as much as would who made the bolt.

                                    If you found out Daniel Defense was made with 9310 and Core15 (Good Time Outdoors) were made from C158. Whose would you trust?

                                    (I know that neither actually makes the bolt)

                                  • #109297
                                    Virgil Kane
                                    Participant

                                      I bought 2 bargain BCG’s, one from Aim Surplus and one that looks identical from the LGS. I bought them for backup and haven’t used them yet. When I pull the firing pin retaining pin, I almost destroy the pin getting it reinserted. The top tier BCG’s don’t have this problem.

                                      I recently bought a couple of Daniel Defense BCG’s from Primary Arms for $130 on sale. It’s probably worth the few extra dollars.

                                    • #109298
                                      HiDesertRat
                                      Participant

                                        Hey DuaneH,

                                        Thnx for the support. I, like most folks here, just want to load the gun, aim, and shoot (and hit the target in question), wash, rinse, repeat…and learn how to do it properly in the context of the situation at hand. And with the least amount of expenditure as possible. We all get it. No one here has a DoD contract with unlimited funds. So we all pool our knowledge and go where experience and our funds allow us. Fortunately the philosophy and teachings of Max molds and shapes us all to the best outcome. We are all beholden to him for his vision and determination to prevail in our coming tumultuous times.

                                      • #109299
                                        First Sergeant
                                        Moderator

                                          Actually i would be interested in your input on those subjects other than the nitrided bolts that i bought cuz that was all that was available, i havent heard much about the others.

                                          Which part are we talking about?

                                          FILO
                                          Signal Out, Can You Identify
                                          Je ne regrette rien
                                          In Orbe Terrum Non Visi

                                        • #109300
                                          DuaneH
                                          Participant

                                            Actually i would be interested in your input on those subjects other than the nitrided bolts that i bought cuz that was all that was available, i havent heard much about the others.

                                            Which part are we talking about?

                                            You said don’t get me started on Nitrided bolts, Nickel Boron bolts, etc.

                                            And Nitrided barrels. Sounds like you have a strong opinion, which is probably worth hearing.

                                            Other than my experience with nitrided bolts chipping and hearing about chrome and NiB bolts peeling I don’t know of any other issues.

                                            I have some nitrided barrels. One of which is on my competition AR.

                                            Nitrided barrels are growing in popularity. (because they are cheaper, so I have been lead to believe.)

                                          • #109301
                                            First Sergeant
                                            Moderator

                                              You said don’t get me started on Nitrided bolts, Nickel Boron bolts, etc.

                                              And Nitrided barrels. Sounds like you have a strong opinion, which is probably worth hearing.

                                              Other than my experience with nitrided bolts chipping and hearing about chrome and NiB bolts peeling I don’t know of any other issues.

                                              I have some nitrided barrels. One of which is on my competition AR.

                                              Nitrided barrels are growing in popularity. (because they are cheaper, so I have been lead to believe.)

                                              Issues with the nitrided bolts, chrome bolts and NiB bolts are the same that you listed. It’s all a gimmick to sell a product. None of them give you any noticeable advantage over a standard BCG.

                                              It may be easier to clean carbon off of the chrome or NiB but people obsess over that way to much.

                                              Nitrided barrels-Cheaper? By how much? What is your life worth? We know for a fact that chrome lining works. We have several decades of real world use to back it up.

                                              How much testing has gone into nitrided barrels? I have seen the videos and the write ups stating that they are good to go. But where is the actual testing that has been done on them under sustained combat conditions?

                                              I know some think I continue to beat a dead horse, but I am going to keep at it until it is nothing but dust.

                                              We are not talking about rifles that you pull out once a month and maybe shoot a couple of magazines out of it. We are not talking about the majority of AR owners that will be lucky if they shoot 500 rounds a year. We are not talking about the jackasses that will never take a class. We are not talking about the ARF crowd of “just as good as” and “parts is parts”.

                                              We are talking about rifles that you may have to bet your life and your families lives on. You want to have the confidence that it is going to work when you need it to work under all conditions. We know what that standard is and a nitrided barrel ain’t part of that standard.

                                              FILO
                                              Signal Out, Can You Identify
                                              Je ne regrette rien
                                              In Orbe Terrum Non Visi

                                            • #109302
                                              DuaneH
                                              Participant

                                                Im totally with you on chrome lining. All of my ar’s and m14s have chrome lined barrels.

                                                The exception is my competition ar and some nitrided uppers i bought during the sandy hook scarcity cuz they were cheap. Uppers are still brand new and currently for sale to the right buyer. :)

                                                I seem to remember reading a scanned copy of a technical report from (Crane naval?) about some nitrided 20mm barrels they tested. I cant currently find it, but i dont remember the results being all that impressive.

                                                PSA corporate sales rep is the one that told me nitriding was less expensive than chrome lining. I personally dont know. He was at a skeet shoot i was at pimping their wares

                                              • #109303
                                                DuaneH
                                                Participant

                                                  In case i didnt say it. Thanks for the input.

                                                • #109304
                                                  First Sergeant
                                                  Moderator

                                                    I have heard the same thing about it being cheaper.

                                                    I saw the same report from Crane.

                                                    For a competition rifle I wouldn’t worry about it.

                                                    It’s the whole “it must be better, because it’s cheaper” and “just as good as” for hard use rifles that seriously piss me off.

                                                    You’re welcome.

                                                    FILO
                                                    Signal Out, Can You Identify
                                                    Je ne regrette rien
                                                    In Orbe Terrum Non Visi

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