Broken Bolts?

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  • Randy99CL
    Warrior
    • Oct 2017
    • 562

    Broken Bolts?

    New here and wondering...

    The bolt buy reminds me that I've heard of 6.5G bolts breaking. A few (or many) lugs breaking off because the bolt is thinner than the original design.
    Enough of a problem that some shooters carry a spare bolt?

    I understand that newer bolts are made from tougher steel and tested for cracks. Was this a problem once and is it something to be concerned with now?
    "In any war, political or battlefield; truth is the first casualty."

    Trump has never had a wife he didn't cheat on.
  • Drillboss
    Warrior
    • Jan 2015
    • 894

    #2
    Here we go again...

    There are lots of threads you can search and read on this topic. I only have several hundred rounds (not several thousand) through my barrels, but I've never seen a broken lug. That said, I have a spare bolt on hand. I also have a spare bolt on hand for my .223/5.56 rifles.

    Don't be concerned. Stay with the proper Grendel bolt face depth and you shouldn't need to worry about extractor problems either.

    Comment

    • rabiddawg
      Chieftain
      • Feb 2013
      • 1664

      #3
      I will repeat what I was told by some respected members. “Bolts are wear items. Replaceable “

      I have a couple complete spares as well as extractors.
      Knowing everthing isnt as important as knowing where to find it.

      Mark Twain

      http://www.65grendel.com/forum/showt...2-Yd-Whitetail

      Comment

      • VASCAR2
        Chieftain
        • Mar 2011
        • 6219

        #4
        For the price of the group buy bolts I like having a spare. I had an extractor fail after a several years of use with unknown round count. I ordered two replacement extractors so I still have a spare. I currently have three 6.5 Grendel AR-15’s so it makes sense to keep a couple of spare bolts and extractor. I have three 5.56/223 AR-15’s and have two spare 556 bolts.

        Recently I’ve read a couple of threads where people have had extractors fail. Any mass produced item can have improper heat treat or other issues. Today manufacturers need to test every lot of steel to verify it meets their spec. When my son worked for a manufacturer of electric motors they got a bad lot of out of spec metal. This caused a high failure rate where previously there had never been an issue. Up to that point they never verified the quality of new shipments of raw material. This almost forced the company to go out of business. The company took a huge loss but survived. They now inspect all new material shipments.

        Comment

        • bj139
          Chieftain
          • Mar 2017
          • 1968

          #5
          I got a new frame for my Toyota Tacoma because of substandard steel in the original American made frame.

          Comment

          • StoneHendge
            Chieftain
            • May 2016
            • 2009

            #6
            A broken extractor seems to be much more likely than breaking a lug. This was by far the best deal I could find by virtue of shipping cost.



            Can't speak to longevity, but this far it extracts like it's supposed to. Group buy bolt is a great deal for a spare, but having a spare extractor instead would likely cover a high percentage of failures. And if you have a grip/stock with storage, it can always be with you.
            Let's go Brandon!

            Comment

            • Lastrites
              Warrior
              • Apr 2017
              • 678

              #7
              I have a BRA's bolt, looks a lot like the group buy bolts, no issues so far but honestly not deep into it yet.

              Comment

              • 204 AR
                Warrior
                • Sep 2015
                • 239

                #8
                I've broken two. Stay away from Radical and Surplus Ammo bolts IMO. I currently have a Young, and the lugs are wider, and the hoop around the case head is noticeably and measurably thicker. The two broken ones were 7.62 bolts just to keep the record straight, though I don't feel that is to blame. They both went somewhere around 1400 rounds with a 243 lbc and 264 lbc.

                The Young is a beast of a bolt.

                Comment

                • bj139
                  Chieftain
                  • Mar 2017
                  • 1968

                  #9
                  Do bolts break because of excessive pressure rounds or is it just as likely to happen with mild loads?

                  Comment

                  • VASCAR2
                    Chieftain
                    • Mar 2011
                    • 6219

                    #10
                    With a quality bolt I suspect the culprit is the high pressure. Keep your hand loads under 50,000 and I would expect many thousands of rounds on your bolt in 6.5 Grendel. If a bolt breaks within the first 1500 to 2000 rounds running in spec ammo I’d suspect poor quality of material, design or hardening (heat treat, surface hardening ect) to cause the bolt failure.

                    Comment

                    • LRRPF52
                      Super Moderator
                      • Sep 2014
                      • 8569

                      #11
                      If only FN would have known to use a larger bolt on the SCAR-17, they wouldn't have all those broken bolts....

                      (7.62 NATO chamber pressure and bolt thrust is significantly higher than 6.5 Grendel, BTW.)




                      The only bolts I've personally broken have been 5.56 NATO after 10,000 rounds. I have a lot of spare 5.56 bolts.

                      Of the Grendels I own, I haven't seen as much as an unusually worn small part yet. This includes years of pressure ladders when doing initial load development testing on mostly my 16" AA barrel/bolt, and my Lilja 318 build with PF/Maxim bolt.
                      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

                      • brut28481
                        Warrior
                        • Mar 2016
                        • 117

                        #12
                        My lilja/maxim bolt sheared a tooth.....Been running 107 SMK with 30gr of XBR (2700 FPS). Didn't seem to be over pressured from brass marks??? I was thinking of replacing with a Young's but notice the Maxim bolt is 0.136" bolt face depth and Young's is 0.135", does the 0.001" shorter bolt face depth make a difference? Barrel is a Lilja AR24 drop-in.

                        Comment

                        • LR1955
                          Super Moderator
                          • Mar 2011
                          • 3355

                          #13
                          Originally posted by brut28481 View Post
                          My lilja/maxim bolt sheared a tooth.....Been running 107 SMK with 30gr of XBR (2700 FPS). Didn't seem to be over pressured from brass marks??? I was thinking of replacing with a Young's but notice the Maxim bolt is 0.136" bolt face depth and Young's is 0.135", does the 0.001" shorter bolt face depth make a difference? Barrel is a Lilja AR24 drop-in.
                          Brut28:

                          Sierra says that 28 1/2 grains of XBR is the maximum load for the 107 Sierra. https://sierrabullets.files.wordpres...ata-111617.pdf

                          You went for 30 grains of XBR, thus overloading the cartridge by a grain and a half.

                          And you are wondering why you sheared a bolt lug?

                          Good lesson learned. Do not go over recommended data with a Grendel. Particularly data from the same place that makes the bullet a guy is using.

                          LR55

                          Comment

                          • brut28481
                            Warrior
                            • Mar 2016
                            • 117

                            #14
                            Agreed, gotta be tough if your gonna be dumb! Anyone use the young 0.135" bolt face? I just picked up two monster bolts on the group buy. Thanks!

                            Comment

                            • LRRPF52
                              Super Moderator
                              • Sep 2014
                              • 8569

                              #15
                              Originally posted by brut28481 View Post
                              My lilja/maxim bolt sheared a tooth.....Been running 107 SMK with 30gr of XBR (2700 FPS). Didn't seem to be over pressured from brass marks??? I was thinking of replacing with a Young's but notice the Maxim bolt is 0.136" bolt face depth and Young's is 0.135", does the 0.001" shorter bolt face depth make a difference? Barrel is a Lilja AR24 drop-in.
                              .001" is within the tolerance spec for -.003" allowable from a .136" face depth.

                              Is your receiver face square?

                              Your load is in excess of both Hodgdon's and Sierra's max published loads. What's your round count?

                              What did your pressure ladder look like when you worked up the load using .3gr increments?

                              One thing I've seen with the 107gr SMK and 108gr Scenar is that they pressure up much more like their 123gr counterparts, and not much like most of the shorter 100gr cup and core bullets, which can really be driven with 8208XBR.

                              You do have to be especially cautious with 8208XBR when nearing max loads under a 107gr SMK or 108gr Scenar, as well as the 123gr weights.
                              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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