Crimping .338 LM Rounds

Discussion in 'Long Range Hunting & Shooting' started by 805_Sniper, Feb 27, 2011.

  1. 805_Sniper

    805_Sniper Well-Known Member

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    I was wondering if anyone has had significant accuracy improvements with their hand loads when they applied a factory crimp on them? I just got a Lee Factory crimper for my .338 LM and before I remove the big bushing out of my rockchucker press, I wanted to see if I am gonna be just waisting time.
     
  2. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Some folks say they've seen accuracy improvements, and you've already got the die. Seems like something that you're rifle will tell you, if you run a few groups with and without.

    Very easy to overdo the crimp, so go slowly there. As far as I'm concerned, less is better, none is just perfect, unless you're using a cartridge that actually requires a crimp. Under normal usage, the 338 LM doesn't.
     

  3. padd54

    padd54 Well-Known Member

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    I agree, unless you are shooting a Semi-auto, I wouldn't use a crimp.

    Do you use a bushing die to control neck tension?
     
  4. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Padd54,

    Was the question for me, or 805 sniper?

    I prefer to use a bushing die AND a carbide expander for most of my applications. I set up my bushing to bring the OD to the point where the ID is just .002" under bullet diameter, or thereabouts. When done right, you can feel the expander ball pass out through the neck, but just barely. Very, very slight, and just enough to make sure that it's rounded out. Incidentally, I don't crimp rounds intended for semi-autos, wither. Never seen the need to and it generally hurts accuracy, so I don't do it. Tubular magazine fed chamberings, and revolvers are the only ones that get roll crimps or factory crimps, but I'm religious about using Lee's Carbide Factory Crimp dier for ALL of my auto pistol loading. Great die, and performs beautifully. Do that, and gage your ammo and you'll never see another jam again in a pistol.
     
  5. 805_Sniper

    805_Sniper Well-Known Member

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    yeah, I have a bushing die to resize the necks. I ordered it .002 smaller than the outside diameter of a loaded round. Some people say to go with .001 but I haven't had any issues with my loads yet... The only reason why I bought the crimper in addition to gaining better accuracy, was to ensure that the bullet seating depths weren't disturbed from recoil when I take it hunting this year. At the range I only chamber one at a time. I am using 92 grains of N560 with a 225gn Accubonds, giving me a muzzle velocity of ~3300fps. It is a pretty hot round but very accurate. I guess I will load up a few and see how they work... I will let you guys know the result, in case you were curious... thanks again for your advice...