What rounds to crimp ?

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  • TexMex247

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    Ok, so it's probably been beat to death all over the internet and maybe even here before. I guess I'm too lazy to search for and old thread to confirm. However, I can't help myself and still gotta ask... which rounds do you crimp, how much and why ?

    In the 13 plus calibers that I reload, they all get finished off with the Lee FCD. Always heavy on a mag round or a big bore lead round. Probably more medium on my 9mm loads since I'm loading mostly plated. Even my hunting ammo for a 280 Remington gets the treatment.

    Lately I'm chasing better groups in a AR10 platform .308. Instinctively I crimped like I would have for the AR15. Light w/o cannelure, medium with one. Recently I read about some competition shooters who claimed better groups without a crimp.

    For most everything I load for I feel pretty confident in the ammo I'm making with just about everything on par or better than factory ammo. Since the 308 is not there yet, I'll call upon the collective here at TGT for some sound advice. Do you crimp ? What for and how much ? Not looking for exact measurements just your experience.
     

    Tactical Panda

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    The advice I've always heard was, crimp for autoloaders for better reliability, don't crimp for bolt actions for better accuracy, or rather, better consistency . But I'm like you, I use the Lee factory crimp for everything, mainly my M1. I doubt I shoot well enough to notice that level of difference anyways.
     

    Maverick44

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    What rounds do I crimp? If the gun has significantly heavy recoil that might cause the bullet to move in the case neck, or if the round is going into an auto loader, they get a crimp. How heavy that crimp is depends on the gun and the round. Some guns are very rough on the ammo and require ammo that has a decently heavy crimp. Others, not so much.

    If you're loading for something like 30-06 in a bolt action, a crimp is not necessary. For precision shooting, I am getting very tight groups with 6.5 Creedmoor in a bolt action with no crimp.
     

    lbbf

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    I don't crimp any of my rounds. 9mm, 40s&w, 380, 223, 22-250, 270, and 458SOCOM. All no crimp and never had a problem.
     

    robertc1024

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    Only .357's, .44 mag & .38 spl wadcutters. On autoloader rounds, when I'm seating the bullet, I just make sure the seating die is low enough to make sure the diameter of the rim is correct. I learned my lesson on .44 mags though. At one reunion I had some .44 mags that Orbitup shot that walked the bullets out and tied up his lightweight birdshead revolver. The bullets were cheapo Berry's or something and had no cannelure. I was afraid to crimp them too much and cut through the plating. Ever since, only cannelured bullets for magnum pistol rounds for me.
     

    LinuxAssailant

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    Only .357's, .44 mag & .38 spl wadcutters. On autoloader rounds, when I'm seating the bullet, I just make sure the seating die is low enough to make sure the diameter of the rim is correct. I learned my lesson on .44 mags though. At one reunion I had some .44 mags that Orbitup shot that walked the bullets out and tied up his lightweight birdshead revolver. The bullets were cheapo Berry's or something and had no cannelure. I was afraid to crimp them too much and cut through the plating. Ever since, only cannelured bullets for magnum pistol rounds for me.
    I didn't want to chance the full-house .357 Mag reloads locking up the cylinder, so I only do 158gr Jacketed, or Semi-jackets in .357 Mag for this reason... WELL, that AND I got the motherload of 158gr Semi-Jacketed HPs on clearance for about $0.1393/each... :D

    I haven't had 9mm, or .38 SPL walk yet, but I crimp everything, as I don't own anything bolt action, as of yet... but it's on the wish-list.

    Roll crimps I go medium-heavy,
    Taper I go firm.
     
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    AgedWarrior

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    For the AR 10, if you are going to crimp, do so only when you have a cannelure, and then a medium crimp. The problem that will arise with crimping .308, or any bottleneck rifle cartridge, is when the case lengths are not consistent. This will cause a small variance in crimps from round to round and can reduce accuracy. Keep case length trimmed consistent for best accuracy. Keeping your brass sorted into batches fired the same number of times is helpful too if you are going to crimp them. Crimping induces a variable that you need to minimize for accuracy. I never crimp rounds for my bolt guns.
    Be very careful with crimping on some straight walled cases because some headspace on the case mouth; .450 Bushmaster for example.
    Regarding handgun ammo, I taper crimp for semis and roll for revolvers unless shooting semi ammo like .45 ACP out of a revolver. Heavy roll crimp on big bore magnums and such.
     
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