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Looking for some advice in barreling a stripped M1 receiver

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    Looking for some advice in barreling a stripped M1 receiver

    Hi, I recently acquired a Winchester M1 receiver that I wanted to turn into a rifle. I have a bunch of necessary tools and gauges to put a barrel on it (and finish reaming), but need some advice on choosing which of two brand new barrels I have on hand to go with.
    I have a Bula Defense Systems barrel, which initially would hand tighten slightly past TDC, obviously no good, so I peened/swaged the shoulder to where it is now 7 degrees before TDC when hand tight.
    I also have a Criterion barrel which is about 40 degrees (!!!) before TDC hand tight.

    I have read that given enough leverage and effort a Criterion barrel will index without cutting the shoulder (I have no lathe, or know anyone who has one), but I have the giant CMP wrench, and even a pipe extension, if needed. The BDS barrel should not take a lot of effort to index, but given the way I got it to 7 degrees, I don't know if that will be a reliable install. So feels like neither option is ideal. Would appreciate some advice for DIY approach, obviously if all else fails I can take it to a gun smith.

    #2
    This is what I would do in your situation. I would install the Bula barrel and check head space. If you think the barrel is tight enough when indexed and head space is ok, scribe the barrel and receiver, build the rifle, fire some rounds through it, check the scribe marks. Repeat until you are satisfied either to keep the barrel or change it. I would put the scribe mark under the rear hand guard but not install the hard guard during the test firing so it is easy to see if the barrel moves.
    If you install the Criterion barrel I would tighten the barrel as far as it would go, then loosen the barrel, tighten the barrel, loosen the barrel. Repeat multiple time until you get it indexed. Others may have better ideas but this is what I can think of right now.
    Looking for SA bayonets 922033 & 1045220

    Comment


      #3
      Originally posted by jak View Post
      This is what I would do in your situation. I would install the Bula barrel and check head space. If you think the barrel is tight enough when indexed and head space is ok, scribe the barrel and receiver, build the rifle, fire some rounds through it, check the scribe marks. Repeat until you are satisfied either to keep the barrel or change it. I would put the scribe mark under the rear hand guard but not install the hard guard during the test firing so it is easy to see if the barrel moves.
      If you install the Criterion barrel I would tighten the barrel as far as it would go, then loosen the barrel, tighten the barrel, loosen the barrel. Repeat multiple time until you get it indexed. Others may have better ideas but this is what I can think of right now.
      That sounds very sensible. I have built several ARs, but it’s my first attempt at building an M1; are there any objective ways of figuring out “tight enough”? I am sure it will feel tight by hand…

      Comment


        #4
        I agree with jak. As it is a Winchester receiver check the headspace with the Bula barrel installed. It may headspace with out reaming. Winchester made parts run from the hi side to the low side of spec. There are shims (washers) you cam purchase to get the barrel to index properly. Keep us posted as to how you solve your dilemma.

        Comment


          #5
          Originally posted by RDS View Post
          I agree with jak. As it is a Winchester receiver check the headspace with the Bula barrel installed. It may headspace with out reaming. Winchester made parts run from the hi side to the low side of spec. There are shims (washers) you cam purchase to get the barrel to index properly. Keep us posted as to how you solve your dilemma.
          Thanks. I did a bit more peening of the Bula barrel shoulder and got it to where it is hand tight at 9.3 degrees, which I think is just in the ballpark of acceptable. One thing I am a little unclear about: I am using

          Badger Ordinance Receiver/Barrel Timing Gauge
          The front goes where everyone measures from, in place of the front sight on the gas cylinder, but the back goes on the flat of the rear sight over the ears on sides of the rear sight, while some people like to use the flat machined part behind the rear sight when positioning rods. These flats are not exactly in the same plane on this receiver; they are off by ~0.3 degrees from each other. I guess I can set the rear of this gauge on that same flat part, as the measurement there seems more reproducible than between the ears.
          Also, found some AR shims on Amazon (of all places) in increments of 0.001" and 0.002". The ID and OD are a touch large, but maybe that's OK. with 9.3 degrees, I should not need them.
          Last edited by lp1911; 08-21-2021, 03:44 PM.

          Comment


            #6
            Are you going to use a machinist level or go by sight. Another poster on another site posted a trick he was told about at Camp Perry. A straight rod is placed thru the rear sight holes, the gas cylinder is installed and another straight rod is placed thru the hole in the front sight. You them sight down the barreled receiver and check that the rods are parallel. I am not a fan of this method as there are too many variables.

            Comment


              #7
              Originally posted by RDS View Post
              Are you going to use a machinist level or go by sight. Another poster on another site posted a trick he was told about at Camp Perry. A straight rod is placed thru the rear sight holes, the gas cylinder is installed and another straight rod is placed thru the hole in the front sight. You them sight down the barreled receiver and check that the rods are parallel. I am not a fan of this method as there are too many variables.
              I saw that video; he seems to know what he is doing. The badger ordinance gauges let one insert two straight edges and secure them so that one can do the same thing more or less, but more controlled. I also have an electronic angle measurement device, which I can place on top of these gauges too, which is how I have been measuring angles so far, so I will come close with the visual method and then use the electronic device for the last bit. At the moment I am waiting for the aluminum inserts for my vise. I have used a pull through reamer before as the first Garand I got was short chambered for some unknown reason, so I have the reamer. I suspect that after torquing the barrel, I will need to make sure that the tilt test works first.

              Comment


                #8
                So I torqued the barrel to ~TDC (assuming I was measuring reliably, which was not 100% certain). With the giant CMP wrench it was not hard, though it felt at the end like I may lift the table a bit . Tilt test passed easily with no wood. Had to do a little bit of finish reaming. It was close on the Go gauge before reaming, but one could still see light passing between the receiver and bolt lug. Matched up the various parts to get the timing to work. Built the rifle with CMP wood. Put on the sights and tried to get absolute windage to be centered in the rear sight (using a short range bore sight), which required the front sight to be more to the right than I would have liked. Perhaps I over torqued the barrel a bit, though the center of the tab between feed ramps is at 6-6:30, so maybe the receiver is not quite true? Or am I thinking about it wrong?

                I marked the barrel and receiver as suggested to see if barrel stays put. Will try it out at the range later this week.
                Attached Files
                Last edited by lp1911; 08-24-2021, 04:46 PM.

                Comment


                  #9
                  That is exactly why ordnance switched from a narrow base gas cylinder to a wide base gas cylinder. The position of your front sight looks fine. How large is your giant receiver wrench. Sarco had one about 4 foot long and weighed about 50 pounds. They also had a GI M1 Garand GI barreling machine.

                  Comment


                    #10
                    Originally posted by RDS View Post
                    That is exactly why ordnance switched from a narrow base gas cylinder to a wide base gas cylinder. The position of your front sight looks fine. How large is your giant receiver wrench. Sarco had one about 4 foot long and weighed about 50 pounds. They also had a GI M1 Garand GI barreling machine.
                    Thanks. I got CMPs latest medieval looking one which is like 3 ft long and I added another 2 ft with a pipe that just fits inside it
                    It is pretty heavy, though not very wide. I am sure if I tried to use the Criterion barrel it would work too, but if this barrel works out, I will save the other for another build.

                    Comment


                      #11
                      The wrench at Sarco was about 2 inches thick the entire length. It looked like a giant angled headed open end wrench that would be used on a M48 Tank. Never had a barreled receiver I could not break down using that wrench and never cracked a receiver.
                      Last edited by RDS; 08-24-2021, 07:15 PM.

                      Comment


                        #12
                        Originally posted by lp1911 View Post
                        Perhaps I over torqued the barrel a bit, though the center of the tab between feed ramps is at 6-6:30, so maybe the receiver is not quite true? Or am I thinking about it wrong?
                        On all my rifles the center of the tab is at 6:00. You can check the alignment again and then take it to the range.
                        Looking for SA bayonets 922033 & 1045220

                        Comment


                          #13
                          Originally posted by jak View Post
                          On all my rifles the center of the tab is at 6:00. You can check the alignment again and then take it to the range.
                          It's very close, I think only a couple degrees over, 6:00+ and I am referencing the follower arm as center, per picture above, not sure what other reference point to use.

                          So I went to the local indoor range and sighted it in at 45 yards. The rifle was quite accurate (clover leaves, when I do not screw up, though 45 yards is not a serious distance), but I had to move the rear sight windage about 6 MOA to the right (so my home laser sighting was nonsense). I shot 40 rounds of 7.62 NATO and with the exception of the first round whose casing got stuck, the rest of the rounds fed and extracted with no issues (early on there was one round that was not picked up, but after I came home I noticed there was some wood rubbed off under the op-rod in the cut out, which I then relieved a bit more). Checked the witness marks I made on the barrel and receiver, the barrel did not move (would 40 rounds be enough to cause it to rotate if not tight enough?). Since the rear sight was ~6 MOA to the right, I moved the front sight approximately a millimeter to the left, which is now rather close to the left edge, though the center of the front sight seems pretty close to the center of the barrel spline as per picture below. Now I am wondering if I under-torqued it a bit. I remeasured the relative angles, and the measurements seem to be within 0.3 degree of TDC, but I can't say I have good clear reference points that any of the tools I have can give me on the flats of this receiver that are precise and repeatable enough... I used RDS's trick of placing the barreled receiver on a level surface with front sight attached and rear sight taken off, and there was no wobble, so must be pretty close. Will re-zero later this week now that I moved the front sight.
                          Attached Files
                          Last edited by lp1911; 08-25-2021, 04:22 PM.

                          Comment


                            #14
                            Went for another 30 min of testing. An additional 80 rounds, including 16 rounds of, soon to be extinct, Russian steel 308, all fed and extracted perfectly. Barrel is not unscrewing itself based on witness marks, so presumably tight enough (hopefully if it were to move it would be in that first 120 rounds). Still had to adjust the rear sight 5 clicks (using NM rear sights, so 2.5 MOA) to the right at 45 yards, just shy of the first tick right of center. I guess I will just have to live with that, unless someone has any ideas on how to fix this...
                            Very accurate otherwise. Real zeroing will happen when I go to the 100 yard range, might be a while from now as it's more than an hour away...

                            Comment


                              #15
                              So I went to zero the rifle at 100 yards, but unfortunately at the end it seemed like I was chasing the zero. Turned out the barrel did move slightly. So I gave up on the Bula barrel and went with the Criterion one (the Bula one came off so easily that it was probably not to be). The Criterion barrel was a bear to put on. Did the tightening and loosening over and over, until finally stopped within 0.2 degrees of TDC. I used tape to protect the receiver, and did not notice that it got slightly damaged from the force, though seemingly in a place that does not interfere with function, except for rubbing against the stock and on the inside. See attached picture. Should I file off the part that protrudes slightly, or just let it scratch the stock and leave it at that?
                              Attached Files
                              Last edited by lp1911; 08-31-2021, 09:38 PM.

                              Comment

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