Home Forums Reloading 10mm Ammo Reloading 10mm – Things to consider…

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    • #1279
      The_ShadowThe_Shadow
      Moderator

      The normal cartridge overall length for 10mm is 1.2500″ to 1.2600″. Some magazine and guns can handle slightly longer loaded ammo.
      Why is the cartridge overall length important? It has to fit inside the magazine. The bullet design has to be such to allow the proper fully seated cartridge to not be in contact the truing cone/free bore areas.
      The semi auto feeds from the magazine and the slide needs to move rearward enough to get behind the cartridge sitting on top the magazine. As the slide is moving forward it pushes that cartridge forward at the angle of the feed lips design, so the nose of the cartridge is set to slide up the feed ramp and enter the chamber. The cartridge enters the chamber at an angle we call the “TIPPING ANGLE” and the case head has to slide up the breech face as the bullet’s nose makes some contact in the upper portion of the chamber for the slide to continue in battery lockup.

      Things to watch out for when trying to reload used cases. Damaged cases, split, cracked, bent/damaged case rims and bulged or worse “SMILED” cases. It should be noted that “SMILED” case with a distinct line have started to shear on a molecular level and should be discarded! Also some makes may not be suitable for upper performance re-loadings. When in doubt through it out!

      Sizing dies can do certain things during the resizing process. They are designed to squeeze the outer diameter of the casing to a usually slightly smaller diameter. However many do not size the area just above the extractor groove cut because they have a rounded radius for the die body or carbide sizing ring and the lower portion of the casing doesn’t make contact to fully size them.
      What can be done to remedy this issue? There are special dies from Redding and LEE called “Push-Through” / “Bulge Buster” that will let you size the entire casing to include the case extractor rims. I personally use the LEE 10mm/40S&W Factory Crimp Die making use of the CARBIDE sizer with great success for this operation. In testing I have found that this process makes for uniformly sized cases and has even improved the roundness of the case heads and primer pockets.

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    • #1284
      The_ShadowThe_Shadow
      Moderator

      Many people have questions about CRIMPING for the 10mm. Understand the design and use of your dies for each process!
      Adding a slight TAPER CRIMP greatly improves reliable feeding and mor uniformed overall performance. Adding the taper to the edge pushes it inward to smooth the transition because 10mm is a straight wall cartridge.
      The case is usually opened and flared some at case mouth expansion which makes the inner mouth uniform and allow for the projectile to enter.
      Most all of the die companies provide some type of crimp section for their various dies. What a lot of people don’t fully understand is that for semi auto cartridges crimping really should be done as a separate step after the bullets are fully seated to the proper cartridge overall length.
      Why is this important? If you are trying to seat and crimp in the same step the case starts to slide up in the die’s crimp area while the projectile is still being pressed into the case. Here is what can happen.

      The bullet construction if a very good quality true COPPER JACKET, being pressed into the case may not give to the pressure the taper crimp is applying and the case can buckle. That can cause loose bullet tension and affect the burning properties of the powder yielding differing results.

      Now if bullet construction is softer say PLATED or of LEAD ALLOY while they are being pressed downward the case mouth being squeezed inward may cause the bullet to snag on the case opening and bullet material might roll up on the very edge. This can cause an issue of coming in contact with the end of chamber cut which might prevent a full in battery lock up!

      Therefor if you are working with a single stage press or don’t use a separate crimp die you would do well to fully seat without any crimp being applied to allow your bullets unrestricted movement. I like to set my seater/crimp die (they are capable of both processes) for the exact proper crimp with the die’s lock ring set. So, when I am seating projectiles, I have a 1/8″ die spacer ring I place between the press and the die lock ring to raise that die up such that the case mouth doesn’t make contact with the “TAPER CRIMP” and seat all of my charged cases with bullet to proper cartridge overall length. Whan that is done, I remove the die spacer, back off the bullet seater stem and run them back up the die as set for a proper TAPER CRIMP to finish them. This has proved to be the best way for improved feeding ammo!
      Don’t make your ammo angry or your self!

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    • #1314
      The_ShadowThe_Shadow
      Moderator

      What about cleaning your brass???
      Dry Media Tumbling / Washing or Ultrasonic / Wet Tumbling with Steel Pins
      While all methods will work, some are better than others!

      Dry tumbling with media like crushed walnut, corn cob, rice or other has been used for years. While it does a good to fair job of cleaning it isn’t perfect. Primer pockets can trap media and may not clean the primer residue. Carbon & stains can be tough as well.
      Polish can be added to the media to help polish the cases, but it can also make the media gunk up somewhat, also medias can sort of wear out over time.
      I have found that using a small amount of charcoal lighter fluid added to my media and letting it run for a while till all of the media is loose and not clumped together before adding the casings. This has rejuvenated some of my old media because the polish is washed from the media and can once again add a good shine. It also holds down dust.
      What about the dust? Adding some 1″ x 1″ squares of Scott’s Blue Shop Towels does a great job collecting any dust. Some people use pieces fabric softener sheets. Word of caution: fabric softener sheets can get gooey if using the charcoal lighter fluid in the media. What a mess “Don’t Ask!”

      Soap & Water can do a fair job of cleaning. Black Powder users use this to help clean the corrosive properties from the BP fouling. Drying the cases thoroughly is a must.

      Have seen where people are using Lemi Shine in the wet tumbling process. It can be used if not putting too much in the wash mixture!
      A word of CAUTION HERE!: The product can chemically leach the zinc out of the brass casing. This is why the casings turn pinkish color or copper look. Brass is an alloy of Copper and Zinc. Testing small batches may let you know if the mixture is working correctly.

      Wet processes do great jobs for cleaning cases and the pins scrub the inter areas really well. However, they need to be dried thoroughly. They should be inspected especially (those like bottle neck styles) as they may trap a bubble of liquid inside due to surface tension. Or those that use pins may have them get stuck to the inner surfaces of the casings. Therefore, inspect to be certain nothing is stuck inside.

      Range pick up brass: What has been found inside them?
      Spiders & webs, other bugs, moisture/dirt/sand/debris, even pebbles/gravel, also other caliber brass that fit inside the casings!

      In closing inspect you brass to satisfy your curiosity…

    • #1860
      fbenfben1fbenfben1
      Participant

      I have added a few cap fulls of Windex for years and that has worked well using crushed walnut and corn cob, this has not clumped up or made the media gunky.

    • #1318
      Mk319Mk319
      Participant

      I have no affiliation with this seller but stumbled on this by accident several years ago shortly after jamming my 1050 on a 5.56 case that was partially filled with pins. When I said partially filled I mean packed in so bad I couldn’t get them out and gave up and tossed it all in the trash. https://sleepinggiantbrass.com/product/stainless-steel-tumbling-media/ I have heard media like this can also be had from Amazon.
      Also if you buy a rotating media separator and fill the bottom with enough water your cases submerge on the lower part of the cycle helps getting the surface tension broke so most of the pins come out. Some always seem to get past stuck in the flash hole though. Yeah I’m not a pin fan.

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