Do I need to crimp at all?

Discussion in 'Ammunition & Reloading' started by taylor, Feb 13, 2012.

  1. taylor

    taylor Bronze Supporter Bronze Supporter

    Messages:
    1,059
    Likes Received:
    143
    Location:
    Willamette Valley
    Feedback:
    24   0   1
    I had been having crimping problems and went to the library and checked out 3 books on reloading. In all 3 they said if I'm loading for target or plinking not to crimp at all. That the sizing will hold the bullet in for lite to medium loads. But for heavy defensive or long range loads a crimp is needed.
    What do you guys think? can I get by just seating the bullet?
  2. FortRock

    FortRock Bronze Supporter Bronze Supporter

    Messages:
    312
    Likes Received:
    76
    Location:
    Bend/Salem, OR
    Feedback:
    29   0   0
    Many straight-walled pistol case have built in taper crimps within the seating die. 9', 40's, 45's don't really require further crimping. I roll crimp all 357's and 44's for best performance and to prevent forward creep under recoil. I use Lee crimpers on my rifle loads and it works well. There are bullet manufactures that make 357 and 44's without canalures. Putting a roll crimp on these projectiles can have deliterious effects. I stick with cannalures bullets for those two but have had good results with slick bullets in 9's, 40', and .45's. I have an interesting article I saved long ago about getting a good roll crimp and seating depth if you are interested.
  3. 2506

    2506 Well-Known Member

    Messages:
    1,094
    Likes Received:
    356
    Location:
    Seattle
    Feedback:
    2   0   0
    I don't crimp any of my rifle loads, for whatever it's worth.
  4. sava6e

    sava6e Member

    Messages:
    114
    Likes Received:
    5
    Location:
    Portland
    Feedback:
    3   0   0
    i crimp rifle loads if im shooting a semi auto, reduces the chance the round could hang up pushing the bullet into the case and creating additional pressures on the chamber
  5. pinne65

    pinne65 Member

    Messages:
    112
    Likes Received:
    5
    Location:
    Hillsboro, OR
    Feedback:
    1   0   0
    I don't crimp some very light plinking loads for 45 colt. AFAIK you crimp for two reasons:
    1 - prevent bullet creep under recoil.
    2 - allow for proper ignition and enough pressure buildup before the bullet leaves the cartridge.

    Why crimp? - TheFiringLine Forums
  6. deadshot2

    deadshot2 Well-Known Member

    Messages:
    2,408
    Likes Received:
    531
    Location:
    NW Quadrant WA State
    Feedback:
    0   0   0
    The "Crimp/No Crimp" discussions should always be divided into two sections. One for Rifle and one for Pistol. The reason for crimping remains the same it's just that there are more "reasons" with pistol than Rifle.

    For pistol rounds, especially those shot in revolvers where any bullet movement under recoil might jamb the cylinder it's highly recommended. To rely totally on "sizing" assumes that all cases, regardless of levels of work hardening, won't spring back too far and will still grip the bullet sufficient to keep it from moving. A crimp into the cannelure of the bullet adds a level of insurance that you won't have a jambed cylinder and then have to hammer some bullets back into place before you can even unload it. For auto loaders it's usually just a matter of the "crimp" being the process of ironing out any bell or flare created so the bullets can be easily seated.

    In the world of rifle handloading, crimping is usually only required when the round is being fed from a tubular magazine when recoil can cause movement in the "stack" to hammer bullets back into the case. Autoloaders also need a crimp in most cases. This is due to the harsh handling of the round by the mechanism which jambs a bullet into the chamber with little or no finesse, unlike in a bolt action. Any flaw or damage to a magazine that doesn't allow smooth transition into the feed ramps can push a bullet back significantly which under the right circumstances can cause really high pressures and damage. Bolt actions don't require crimping with very rare exceptions.

    There is another circumstance where crimping is highly recommended, even by the powder manufacturers. Some powders can cause secondary explosions in the barrel if they are not fully ignited in the cartridge. For this reason the powder manufacturers recommend a heavy crimp to hold the bullet in place until more of the powder is ignited. An example of this is W-296 in magnum loads.


    For me, my press is set up to crimp all my 9mm loads as well as .223 loads. Each tool head has a Lee Factory Crimp die in the last station. It doesn't take any more effort and the cost of the die is inexpensive. It's just a simple insurance measure as far as I'm concerned. That said, NONE of my .308 rounds are crimped but those rounds are truly "Hand Crafted" with cases annealed, necks turned, and neck tension carefully controlled.

    Get to know all the aspects of the round you're loading, apply crimps where appropriate, and if you think it's too hard, just do it as a separate step with a Lee Factory Crimp Die.
    evltwn and (deleted member) like this.
  7. Hook686

    Hook686 Active Member

    Messages:
    528
    Likes Received:
    134
    Location:
    Northern California
    Feedback:
    0   0   0
    I roll crimp all my .357 magnum loads, even the light loads ... 1e) 5-6 grains of Unique.
  8. djthemac

    djthemac Member

    Messages:
    101
    Likes Received:
    21
    Location:
    eugene
    Feedback:
    6   0   0
    What are you loading? Pistol crimping is neccessary to remove case belling and prevent feeding issues. I use a lee factory crimp die for both pistol an rifle cartridges fired out of a semi auto platform. I dont crimp bolt action 308 rounds
  9. deadshot2

    deadshot2 Well-Known Member

    Messages:
    2,408
    Likes Received:
    531
    Location:
    NW Quadrant WA State
    Feedback:
    0   0   0
    Just to add a little to my previous comments, one can crimp when loading for applications that generally call for it in order to prevent problems or they can just wait until that problem occurs and THEN start crimping.
  10. Blitzkrieg

    Blitzkrieg Well-Known Member

    Messages:
    9,380
    Likes Received:
    4,412
    Location:
    WA
    Feedback:
    60   0   0
    I taper crimp everything
  11. dennisf

    dennisf Member

    Messages:
    98
    Likes Received:
    4
    Location:
    Battleground, Wa
    Feedback:
    0   0   0
    When I did my first runs of 9mm for the SR9, my stuff was all over the place at the range. I was really bummed. Some one asked me if I did the factory crimp thing and at that time did not include that operation. I did some research and asked a couple of the gunsmiths from the club. What I think I understand is that when you use the bullet seat die, set for crimping, you are trying to crimp a bullet that is still sort of in motion so that leads to the inaccuracy. I ordered the Lee Factory Crimp dies for the rounds that I load most and have not had a problem since. It made an immediate difference with my loads. I have since been setting up the Lee turret press to include the crimp in the basic reloading rather than a separate operation.