USING Converted/reformed WINCHESTER 7.62X39 Brass

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  • USING Converted/reformed WINCHESTER 7.62X39 Brass

    Hey, anybody have any experience with the Winchester brass? I am doing it for the fun of it. I know Hornady and Lapua have great brass, but I just wanted to get the whole Grendel Experience, and I love forming brass!

    I noticed that alot of the Winchester 7.62 brass is about 1.520" to 1.517". I am wondering about trimming it. My Hodgdon Annual Manual from last year is talking about trimming your Grendel brass to 1.515" trim to length, but AA's reloading data says that 1.520" is minimum. I am just wondering what people with any experience with Winchester are doing. I thought about trimming it to 1.515" so I can get them all to a uniform length for one thing but also because I am sure Alexander Arms is using Lapua brass and I believe the Hodgdon folks were too that is why the confusion. I would imagine that the 7.62 brass is internally different from either Lapua or Hornady factory Grendel brass anyway. I don't believe I'm going to hurt anything as it chambers fine and I'll be working with reduced loads anyway in case the cases are thicker. ( I need to do a capacity test I suppose.)
    The only factory Grendel brass I have is Partizan that Wolf put out, it's the crappy 123gn SP that I bought 3 or 4 years ago and had sitting on the shelf so I pulled the bullets and am getting some dimensions from that. I suppose I need to order some Hornady and some Lapua or AA and do that also, but maybe somebody can save me a little time??!!

    Any and all help is appreciated with load data for the Winchester 7.62 brass reformed to 6.5 Grendel.

    LHClarke.....
  • Longshot_34

    #2
    I have been doing that same thing until just this week. Here's my observations.

    I never had to trim. After I sized the brass it was ok. After fire forming I had no issues. Case capacity is less. About 2 grains less than published data using factory brass. Even then at times I was getting compressed loads. I had obvious signs of over pressure even with reduced charges. The head stamp was smeared pretty good. After only 3 rounds I was case split necks. I'm glad I was fortunate enough to score some wolf brass this week.

    Your mileage will vary. And I'm sure you can cut your load back to avoid the over pressure issue but at that point I think you're just wasting time.

    Comment

    • rasp65
      Warrior
      • Mar 2011
      • 660

      #3
      Longshot
      I measured my chamber length at 1.540" using this: http://www.sinclairintl.com/.aspx/pi...er_Length_Gage
      When I reload for bolt guns I trim them .005" less than max. For gas guns I like to keep it to .015" below max. That being said I have not had to trim any of my converted 7.62x39 Win brass other than to make them uniform length. I believe all that extra room is for safety when a rifle has sustained a lot of rounds without cleaning but I don't usually shoot more than 200 rounds before cleaning. My Win brass is 2 grains of H2O less than the Lapua which I found to be 35.8 Gr. of H2O. I also use a Powley computer to find the internal volume of the case with various bullets and using powder density(VMD) I can see the the load density of different powder charges. What I have found is generally 2 grains of powder less volume in the Win cases.

      Comment

      • longdayjake

        #4
        Two grains less powder capacity? That has not been my experience with winchester brass. Maybe 1 grain less but not 2 grains.

        Comment

        • Longshot_34

          #5
          About two grains is what I said. Obviously the available case capacity for your powder with vary with how deep you seat your bullet. Have either of you two had signs of over pressure on your converted brass?

          Comment

          • rasp65
            Warrior
            • Mar 2011
            • 660

            #6
            Yes I have had some that were overpressure and it rendered them unusable. Deep marks from the extractor and ejector, casehead expanded and primer pocket opened up.

            Comment


            • #7
              Thank you very much for the feedback. It is great to know that about the amount of decreased capacity and the brass being less than wonderful. I will surely be buying some Lapua or Hornady this week without doubt. I guess the IMI is the only way to go if you get in a bind and have to reform 7.62. I'm sure Winchester will work for a couple of loads but the price difference isn't just a huge amount. With the number of reloads most get with the Lapua, it's just a much better choice all around. Thanks again for all the information, it is greatly appreciated!
              \
              LHClarke

              Comment

              • pinzgauer
                Warrior
                • Mar 2011
                • 440

                #8
                I'll preface this by saying that with the current brass supply improving I'd not recommend buying 7.62x39 cases just to fireform into Grendel.

                But if you have them already, especially IMI, they are quite usable. Yes, there is reduced case capacity, and if you use published loads for Lapua you'll be overpressure. But if you follow good reloading practices and work up to loads you'll find that although max loads will be less powder, the velocity loss is not as much as you might assume. IE: 10% less case capacity does not translate to 10% lower velocity.

                There was quite a bit of data on this in the old forum which has been lost. LR1995 published his results, and my experience has confirmed his findings.

                I'm averaging 7-8 reloads on IMI before neck splits and primer pockets force retirement. Given what I paid for the IMI and all other alternatives were unobtainium, it's been a good option for me.

                If hot, maximum loads are your desire, you'll never reach full grendel potential with fireform 7.62x39 brass. If inexpensive, accurate moderate loads are OK, then it's an option to explore.

                Regarding overpressure- really watch you COAL... that's the fastest way to hit it. Given the comments about compressed loads I suspect this is part of the problem. Certain bullets cause problems with the Grendel case/throat combination due to seating depth, and that's magnified with the lower capacity cases. 120g AMAX is one of them, and the 123g Scenar is another, I believe. Yet the 120g SMK and 123g AMAX work fine.

                While I shoot wolf occasionally, I actually prefer the IMI for reloading over the Wolf cases. But for max loads I'd use Hornady or Lapua one.

                Comment

                • rasp65
                  Warrior
                  • Mar 2011
                  • 660

                  #9
                  I agree with pinzgauer especially with the availability of the Hornady brass. I outlined an inexpensive method of measuring COAL accurately here: http://www.65grendel.com/forum/showt...jump-amp-crimp

                  Comment

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