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Old September 16, 2010, 02:14 PM   #1
Dukezern
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Crimp or No Crimp?

I've managed to get back into reloading for about a year and half now. I just purchased a .22-250, and want to load my own loads. Many of the bullets offered for the.22-250 do not have a crimping canular. I have never loaded any rounds that did not have a crimping canular, and have always been under the impression that if a canular was not present, you don't crimp the round. Do I have that correct? If correct, and no crimp is required for bullets without a canular, what keeps the bullet from jumping out from the recoil of previous rounds, particularly if one is using magnum loads, like a 7mm Rem. Mag., or 300 Win. Mag., for example? All of the reloading manuals I have offer bullets without a crimping canular for magnum rifles, and I've heard that the recoil from such loads can cause the bullets to move in the casings.

I know this is a pretty elementary question, but I can't seem to find the answer in any of these reloading manuals. So...I decided to ask the pros.

Thanks, guys!!
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Old September 16, 2010, 02:21 PM   #2
Rico567
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For something like the .22-250, I'm assuming you're shooting varmints or targets. I can't see any reason why anyone would want to crimp this round. Crimping, to me, is dependent on a combination of:

1) how heavy the recoil of a particular round is

2) what type of magazine is being used

3) what type of action

4) a few cases where the powder manufacturer specifies a crimp

Heavy recoil may produce movement in subsequent bullet in the magazine. A tubular magazine always mandates a bullet crimp, for obvious reasons. Autoloaders such as AR-15, Garand, etc. should be crimped. There are fairly rare cases (I believe Winchester 296 is an example) where a powder manufacturer specifies a heavy crimp for proper propellant combustion.

Hope this helped....like a lot of questions in reloading, this doesn't really have a simple answer.
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Old September 16, 2010, 02:32 PM   #3
Brian Pfleuger
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You don't need a crimp for proper function but you may find that slightly crimping the round improves consistency with some powders. The extra force required to start the bullet moving helps get good ignition started.

I've loaded the 22-250 with Benchmark, H380 and Win748 and achieved sub-moa accuracy with no crimp on any of them.
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Old September 16, 2010, 02:41 PM   #4
azredhawk44
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The decision to crimp or not will often be determined by your case tension after resizing.

I learned recently on the High Power range that if I use the following order of operations on brass:
1. Resize.
2. Trim to length.
3. Deburr/chamfer mouth.
4. Prime.
5. Load/seat

and I use no crimp (I was shooting 168gr A-MAX bullets), I end up with very inconsistent velocity.

That was because my trim operation used a hand lathe that put a collet into the case mouth while the cutter trimmed.

This collet made my case neck tension go all wonky.

I resolved it (on the remainder of the batch of ammo) by adding a crimp using a Lee Factory Crimp die. This DRAMATICALLY reduced vertical stringing in my results downrange at 500 yards. I don't own a chrony, so I am unable to determine if the velocity of a load is consistent.

Ideally, case neck tension will hold your bullet.
If your case neck tension is messed up, you can crimp to resolve it (hopefully).

Beware trimming your cases after sizing them though. It will mess up your neck tension if you use a collet to do so.
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Old September 16, 2010, 03:18 PM   #5
Dukezern
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Thanks, guys. This has been helpful. As a sidebar question, when do you trim your casings...before or after you resize? Everything I've read seems to say "after" resizing. However, I've also read that many reloaders trim the casings prior to resizing.
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Old September 16, 2010, 03:39 PM   #6
demigod
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After resizing. That way you know what your final overall case length is.
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Old September 16, 2010, 03:54 PM   #7
Dukezern
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Thanks, Demigod. Yeah, that's what I've been doing...trimming after resizing.
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Old September 16, 2010, 09:43 PM   #8
t45
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In my 243ack I neck size only and only size it partially. I have a tight neck chamber so I turn all the necks first.
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