Resized case length vs fired length

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  • Resized case length vs fired length

    Dear Grendelers,

    Just wondering what the difference of resized case length should be compared to fired length. I have a Stoney Point (now Hornady) case comparator set. I full length resized some of the fired cases and compared them against the fired length. I have the Redding standard two die set. The Barrel is the button rifled 24" Alexander Arms with matching bolt. I purchased it from Midway. I used the A 330 insert which places it in the middle of the shoulder of the case. The difference between the fired case and the resized case is .020"!The difference between a fired case and a new unfired case is .018". They are Hornady cases. This seems to be an excessive amount of difference. I checked the difference between a fired and resized .308 Win case from my Rem 700 and the difference is only .006" (Redding S-Bushing). I don't have headspace gauges for the 6.5 Grendel so I can't check the chamber directly. I decided to back the resizing die out so I have a .005" shoulder setback. I use a RCBS Rockchucker press so I have good rigidity so the setback is consistent. Does .020" sound like a bit too much or would .005" be too tight? I haven't reloaded these resized cases yet.

    Sincerely,

    JD

  • #2
    I have one Grendel, and one 6.5CSS. I set my die so that the shoulder of the shorter chamber gets set back .002. That way, the longer chamber only gets set back about .003 or .004. I am more likely to have malfunctions if the bullet is seated too far into the rifling than from the shoulder not fitting. And I let the rifles get pretty dirty prior to cleaning them.

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    • #3
      Thanks noone for your reply. If you full length resized your Grendel, what would the setback be? Would it be as much as .020"?

      JD

      Comment


      • #4
        Originally posted by jdguitars View Post
        Thanks noone for your reply. If you full length resized your Grendel, what would the setback be? Would it be as much as .020"?

        JD
        I believe he sets the shouldr back .002.

        I set my die so that the shoulder of the shorter chamber gets set back .002.

        Comment

        • LR1955
          Super Moderator
          • Mar 2011
          • 3355

          #5
          Originally posted by jdguitars View Post
          Thanks noone for your reply. If you full length resized your Grendel, what would the setback be? Would it be as much as .020"? JD
          JD:

          Factory brass is normally a bit smaller so it will fit into a wide variety of headspaces. So, I wouldn't really worry too much if your fired brass, once sized, isn't as small as the factory brass.

          Easy way to check. See if your fired and then sized cases chamber and extract easily. If they do, you have bumped them enough. Most likely your sizing die was made well enough that when the case is inserted for sizing, you can't push it into the die anymore unless you cam-over or machine off some of the shell holder.

          Maybe the headspace is a bit on the loose side? And if so, does it really matter?

          LR55

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          • #6
            I guess I'm not making myself clear. When I set my die so it bottoms out on the shell holder, my case is .020" shorter than the fired case. If noone sets his die the same way, does he get the same amount of setback, that is .020"? I'm just wonderintg if .020" is a reasonable amount to expect. What I am asking is whether I have excerssive headspace in my barrel bolt combination or is this a proper chamber. I don't have headspace gauges for 6.5 grendel. When I resize my fired .308 cases out of my Remington 700 the difference is only .006". That is running the die fully down to the shell holder, not backing the die out so that is all I get.

            Thanks,

            JD

            Comment


            • #7
              LR19555,

              Guess you replied before I got my last one out. The Resizing die actually resizes shorter than the new brass by .002". I'm shure that the case remains a little fatter than new brass. I don't plan on getting a small base resizing die. I don't think there is one anyway. There are concerns if the headspace is excessive of case separation. All I am asking is IF .020" is excessive or is this is in the proposed SAAMI specificatoions for this cartridge. I guess I will just call Hornady.

              Thanks,

              JD

              Comment


              • #8
                .020 is a lot. Back the die out of the press to get the desired shoulder bump. You have the Hornady gauge so adjusting is simply a matter of trial and error.

                Comment

                • PA_Allen
                  Warrior
                  • Mar 2011
                  • 333

                  #9
                  Yes .020" is a lot. I use gage "B" for the Grendel and measure .001 to .005" difference between resized and fired cases depending on the brass and load. Use your headspace gage to set the once fired shoulders back 0.003 to 0.005" and you are good to go. Note that your die setting may be different for different brands of brass. I have to set my die slightly different between the Hornady and Lapua brass to get 0.003" setback for both.
                  Best
                  - PA

                  Comment


                  • #10
                    Thank you mserc and PA. I am going to assume that this chamber is at the outside margin, I don't have a headspace gauge. I guess I will buy a no-go and see if it goes. If it doesn't, I guess I will have to live with it. I will back the die out for a -.002" or so.

                    Sincerely,

                    JD
                    Last edited by Guest; 03-26-2011, 01:23 AM.

                    Comment


                    • #11
                      Here's a weird twist. I've only reloaded my first set of brass once, but after their initial firing, the cases did not grow one bit. I expected to need to trim them, but I didn't. Some actually shrunk a mil or two. Figure that one out... That was Hornady brass and Hornady New Dimension die which I'm not totally thrilled about the quality of. I've honed and polished it a little closer to my chamber now. Out of the box, it resized my .299 fired necks back to .285. The virgin brass came out of the box at .289, so I honed the die to resize the .299 to .289. Still a lot of brass working,but better than .285.

                      Hoot
                      Last edited by Guest; 03-26-2011, 04:30 AM.

                      Comment

                      • LR1955
                        Super Moderator
                        • Mar 2011
                        • 3355

                        #12
                        Originally posted by Hoot View Post
                        Here's a weird twist. I've only reloaded my first set of brass once, but after their initial firing, the cases did not grow one bit. I expected to need to trim them, but I didn't. Some actually shrunk a mil or two. Figure that one out... That was Hornady brass and Hornady New Dimension die which I'm not totally thrilled about the quality of. I've honed and polished it a little closer to my chamber now. Out of the box, it resized my .299 fired necks back to .285. The virgin brass came out of the box at .289, so I honed the die to resize the .299 to .289. Still a lot of brass working,but better than .285.
                        Hoot
                        Hoot:

                        I haven't had a need to trim Lapua Grendel brass. Not when new and not after firing it ten or fifteen times.

                        A year or so ago I guess Lapua issued a lot of Grendel brass that was about .001 under minimum length. Or at least that is what some loaders thought but who knows how good or bad their calipers were or how they measured the brass. Some guys were worried about safety and others accuracy.

                        The bottom line is that as long as the headspace is OK and the necks aren't so long as to cause mechanical problems when chambering, the neck length really means nothing unless it is way excessive or insufficient. And I mean so long that the neck pinches the bullet when it chambers or so short it won't hold or support the bullet during cycling.

                        The design and purpose of the Grendel cartridge and chamber is service use. Ask Alexander. I take it to the bank. Differences in chambers between .295 and .300 may mean something in terms of brass life (but so far it hasn't) but really mean nothing in terms of performance. Barrel quality does but not what chamber diameter is being used.

                        Given what I can recall from the previous Grendel forums, there were discussions galore about neck length. Not surprisingly, we found that trimming Lapua brass for length was a 'feel good' measure -- otherwise unnecessary either out of the bag or for a good ten or fifteen firiings. Same with turning necks. I won't say the same for guys who blow out 7.62 X 39 brass but that IMI stuff we used wasn't as high a quality as the Lapua or Hornady Grendel brass and blowing out brass overworks it to begin with.

                        So, guys who go through gyrations over the Lapua brass are more than likely damaging very expensive Lapua brass more so than they are getting any sort of performance improvement.

                        Just some comments from discussions from the last Grendel forum.

                        LR1955

                        Comment


                        • #13
                          I don't think you need to buy another gauge. I would just measure a fired case with your Stony Point headspace gauge and set your FL die to bump the shoulder back a few K. Then make sure it fits your chamber, slides in smooth and extracts smooth.

                          Comment

                          • CoolBarrelBill

                            #14
                            Does somebody have a drawing (with dimensions)of the 6.5 case?

                            Comment


                            • #15


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