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Short Mag Reloading Problem

Discussion in 'Guns and Ammo' started by Walleye 3, Aug 17, 2005.

  1. Walleye 3

    Walleye 3 Mongo

    I have a 300 and 270 WSM and they shot great, but the only problem that I am having is I can't get neck sized brass to fit back into the gun. I have to resize the cases a lot. I am turning the die down 1/2 more turn past where it touchs the ram to get them to fit. Does anyone have any ideas. I am using redding dies and have never had any problems with them before.
  2. Lundy

    Lundy Staff Member

    Wish I could help but the only reloading I do is pouring more powder down the barrel and pushing a new bullet down with a ramrod :)

  3. You don't say how many times you've neck sized these cartridge cases, but I expect it's quite a few. Since cartridge brass work-hardens, each time you fire and size the neck, it gets a bit harder, and also a bit thicker as the shoulder metal flows into the neck. Also, neck sizing coupled with this repeated hardening creates an eccentric condition - that is, the neck diameter is slightly out of alignment with the body case diameter, so the cartridge hits hard on one side of the neck and on the opposite side of the body in the chamber. This makes for sticky chambering, and could affect accuracy by misaligning the bulet in the bore. You might try a multi-stage solution on a small batch of cases:

    1. Use cases from the same lot.

    2. Clean/tumble the case bright after depriming

    3. Anneal the cases - stand the bases in a metal oppan with about 1 inch of water. Using a propane torch (Bernzomatic works good), heat the case neck and shoulder of each case until you just see the color start to sort of blue and immediately tip the case over into the water. This will stress relieve the neck and shoulder so you can return the concentricity.

    4. Run a full-length sizing die just enough to chamber so you don' feel the shoulder when the bolt goes to lock - make sure the rifle chamber is absolutely clean. Check the neck walll thickness and ream if necessary to SAAMI standard.

    5. Prime, load with powder and lightly crimp wad card, and fireform to fit the chamber perfectly.

    6. Neck size. Make sure the neck die shoulder radius just touches the shoulder.

    7. Trim the cases to length in SAAMI manual.

    8. Deprime, clean, load. Seat the bullet to just contact the rifling

    Repeat these steps after about each 5 to 10 firings. Watch for neck cracks and separation - if one out of a batch shows, throw them all away.
  4. Walleye 3

    Walleye 3 Mongo

    Thank You for the information. I should have told you that the brass that I am trying to neck size is once fired factory brass. I am trying to neck size brass that was just fired once in my guns. The problem is at the base of the case. After I neck size it, it fits into the gun until the last 1/4 inch where it is to large to chamber. This is winchester brass if that makes any difference. If you have any ideas why this problem maybe happening please let me know.
  5. OK, let's look at the other end of the case. What you describe is symptomatic of excessive chamber pressure, which is unlikely in a factory load and factory chambered barrel, but you need to do some digging - clean the weapon.

    1. Look at the casehead - Is the face burnished or flattened, or do the headstamp characters look thinner compared to the out-of-the-box round? Is the area just around the primer pocket shiny? Is there a significant indent from the extractor into the extractor groove? Is the bolt difficult to rotate/extract after firing? If one or in combination, you may have pressure problems.

    2. If you suspect high pressure, then look for cause - Does the out-of-the-box round chamber easily? If not, look for interference on the case shoulder, case neck, neck mouth - this can be done by applying a very light coat of your wife's favorite lipstick, just enough to see a film, on the entire round, chamber once and extract, and look for spots where it's clean. If the round is too tight to the shoulder, too tight to the neck, or if the projectile is being pushed back into the neck on chambering, you can get high pressure. This will cause the unsupported case head to swell into the bolt face (hence the burnish/polish marks and flattened headstamp) and to expand in diameter. Check the head diameter at the rim and just in front of the extractor groove from an unfired lot against the once-fired. If the head expansion is more than .0010" (.0005" preferred), indications are pressure problems.

    3. Obtain a headspace gage and check the weapon's headspace to SAAMI standards.

    4. Slug the bore and measure, once at the throat, and once at the muzzle. Compare to SAAMI specs. Overtight bores raise pressure.

    5. Get a chamber cast using Cerrosafe. Measure the chamber against SAAMI specs. Remember to measure the Cerrosafe right after knocking out the cast, as it expands a bit with age.

    6. Try a different lot from Winchester and another mfr if avaliable, and do all of the measurements and trials on these in #2 before firing any rounds. Record results and observations. If your weapon is within spec limits for the bore diameters (lands and grooves) and chambered properly, contact Winchester with your data and see what they have to say. If the weapon does not meet spec, contact the mfr and ask why.