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Do I need to crimp a 338WM load?

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  • Do I need to crimp a 338WM load?

    The title says it all. I have previously only loaded lighter calibers; this is my first foray into the magnums. I know I had heard whisperings about crimping, but nothing definitive. What does everyone here think?

  • #2

    No need to consider crimping a 338 WM.


    • #3

      Well, usually not. But, depending upon the brass condition and the reloading die or neck button... maybe?? One way to tell is to fully load the rifle, fire all the rounds except the last then measure the length of the last round. It will have been thumped by the front part of the magazine the greatest number of times.


      • #4
        I agree with George. Watch that round that lives in the bottom of the mag through three or four loadings.

        But would I crimp? You bet your bippy if I was using a BAR 338.
        "Lay in the weeds and wait, and when you get your chance to say something, say something good."
        Merle Haggard


        • #5

          If I were you I would seriously consider a tapper crimp on your ammo. WHY? Because it won't hurt anything and it might resolve a future problem you could have. ALSO, it is only a matter of running ammo you have finished loading through one extra die. The die is pretty inexpensive ( LEE makes a cheap one) and will last a lifetime. Also, one day you may try or need to use this ammo in a different rifle. This might help you to avoid MURPHY'S LAW; Remember ammo manufacturers crimp theirs.


          • #6
            .338 crimp

            No crimp is needed for a .338 round in a bolt action rifle. Mine have worked just fine for the last 30 years with out a crimp.


            • #7
              It's not absolutely neccessary, but with a heavy recoil rifle like the 338 it's a good idea, especially if you've got a cannelure groove on the bullet, and the resulting seating depth is to your satisfaction.

              If crimping was a bad idea, the factorys wouldn't do it, and they crimp near about everything.
              Smitty of the North
              Walk Slow, and Drink a Lotta Water.
              Has it ever occurred to you, that Nothing ever occurs to God? Adrien Rodgers.
              You can't out-give God.


              • #8
                I'm a crimper in heavy recoiling repeaters.
                Vance in AK.

                Matthew 6:33
                "But seek first the kingdom of God and His righteousness, and all these things shall be added to you."


                • #9
                  Crimp them if ya can .
                  I had one bullet jump on me and it jammed when I cycled it in .
                  Was shooting 300 Grain Round nose Herters bullets with crimp groove full house loads .
                  While at my shooting range on my third shot I bolted in another round and I could not close the bolt .
                  I had to hammer the bolt back (soft blow hammer )and left the bullet engaged in the rifling which I also had to hammer out with a long wood dowel rod .
                  The bullet jumped enough out of the case due to the heavy recoil .
                  Crimped them after that and not a problem since !!!!!
                  I also am a crimper !!!!!!!

                  Practice does not make perfect !!!!!
                  Perfect Practice makes perfect !!!!!!!!!!

                  USS SARATOGA CV-60



                  • #10
                    Here's a speriment for you. I haven't tried it with my 338, but didn't need to after trying it in my 375:

                    Take a handful of uncrimped rounds. Load the mag and one in the chamber. Shoot all those but the one in the bottom of the mag. Refill the mag and do it again, just like you would if the gun wasn't empty but you used a lull in the ation to reload. Shoot those till you get down to the one in the bottom of the mag.

                    Don't shoot that sucker! Look at it and I'll guarandamtee you that (at least in my 375) the bullet is going to be pounded way down into the case. The good lord only knows what the pressures would be if you touched it off.

                    Crimp em.
                    "Lay in the weeds and wait, and when you get your chance to say something, say something good."
                    Merle Haggard


                    • #11
                      OAL measuring

                      Yep, Two magazines worth of pounding should be a good test. If you're testing rounds with exposed lead tipped bullets it's kinda hard to get a good before and after measurement of length by going tip to base. If you don't have a bullet comparator (or seating plug) mounted on your calipers then just mark the round to be tested with a very fine tipped marker. Draw the line around the bullet where it meets the case neck. Shoot the one or two mags of ammo then look at that last round. If the bullet has been pushed in at all it should show at the line placed around the bullet at the junction with the case mouth. Just a thought for an alternative method of checking changes to OAL.


                      • #12
                        Good suggestion George. I was using a bullet with a cannelure, but this is a great way to check ones without.
                        "Lay in the weeds and wait, and when you get your chance to say something, say something good."
                        Merle Haggard


                        • #13
                          OK, so I'll try firing a few and checking the one left in the mag. One question, why would rounds for repeaters need to be crimped, but not for bolt actions?


                          • #14
                            If by "repeaters" you mean levers with tubular magazines, it's because the bullets are stacked end to end, driving back into each other each time the gun recoils.

                            Crimps aren't necessary in bolts if the recoil isn't so great that the bullets slam against the front of the magazine box each time you pull the trigger. How much recoil? Depends on the caliber, bullet weight and gun weight.

                            One of my 375's is an ultralight built on a Remington 700 action- the one with the floorplate release in the front of the trigger guard. It's my favorite 375 to carry because it's so light, but it's ugly as sin. Recoil knocks my trigger finger forward off the trigger and it hits the release. Kinda embarrassing when all your spare cartridges fall on the ground, so it's got a big strip of duct tape holding the floorplate closed. Beauty is in the eye of the beholder, and all that. Without a HEAVY crimp, that particular rifle will drive the bullet in the bottom of the mag almost a quarter of an inch back into the case- on the first shot!
                            "Lay in the weeds and wait, and when you get your chance to say something, say something good."
                            Merle Haggard


                            • #15
                              To Crimp or not to Crimp...


                              Everyone is giving out good advice but I have a suggestion.

                              I crimp some heavy caliber loads and others not. That heavy caliber starts with 338 caliber.

                              If you crimp, two things are important. First make sure all cases are the same length. Trim to trim-length before loading. Secondly, seat the bullet without a crimp to desired length. To do this back off the seating die body a turn or two then screw in only the seating stem to get desired seating depth. Then back off the seating stem and screw down the seating die body to achieve desired crimp.

                              If you over crimp or have a case that's too long, it will bulge the case below the crimp and the round likely won't chamber. Also, donot crimp without a cannellure or crimp groove, it will be inconsistant and likely bulge the case mouth.

                              A good way to keep bullets from being pushed into the case under recoil is to fill the case with powder. Actually a slightly compressed load is best. Some cases cannot be filled with any available powder but the 338 WM can be filled with at least a half dozen powders and will perform admirably well. 4350, RL-19 and 4831 depending on bullet weight and type, are good choices.

                              Crimping cartridge cases is usually detrimental to accuracy unless it is exactly the same case after case. In other words it's just another variable that has to be controlled. If you have good quality brass that isn't worn out crimping isn't usually necessary in the 338 Mag unless the rifle is very light and the case isn't full.
                              Is there nothing so sacred on this earth that you aren't willing to kill or die for?


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