crimping

Discussion in 'The Ammo & Reloading Forum' started by rouser_00, Aug 7, 2008.

  1. rouser_00

    rouser_00 New Member

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    hi guys
    just a quick question.ill keep it short and sweet:)
    is it better to crimp??
    at the minute im just neck sizing in 243 and 308.my bullets are always sierra 85 grain amd hornady 65 grain v max for the 243 and 168 grain a max and 150 grain sierra for the 308
    what is the benifits of crimping or should i just forget bout crimping and stay with only neck sizing
    thanks guys
  2. Bindernut

    Bindernut Well-Known Member

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    Can depend on several things whether you crimp or not. If these are hard recoiling rifles or semi-autos, then I'd go with a bullet with a cannelure (crimp groove) and crimp them. Also, if you've got problems with the bullets "creeping" in the case under recoil is another reason to crimp.

    I don't do any .308 reloading, but in the .243 I never did use a crimp for the two bolt actions I had in that caliber. It just didn't kick hard enough to shift the bullet from where I seated it.
    I've got a 6lb 6.5x55 Swede that will shift the bullet under recoil so that one I do crimp.

    For the most part, when I reload I seat my bullets just short of the lands on the rifling for each particular rifle and many times that means the crimp groove doesn't line up with the case mouth anyway so those don't get a crimp either.

    Also, if the bullet doesn't have a crimp groove, the you don't want to crimp it either. A crimp on a non-grooved bullet can cause some really funky pressure spikes. If you do crimp, case length is critical to ensure a uniform crimp on all the cases too. And if you frequently crimp, I've seen that the case mouth will start cracking earlier than if you don't crimp since that crimp will get fire-formed back each time you fire...basically it's work-hardening the brass and it will get brittle faster than if you don't crimp.

    So I'd treat each rifle (and load) individually on whether or not you find it needs a crimp or not. I don't think you'd need to with either your .243 or your .308 but your situation might warrant it.
  3. Bindernut

    Bindernut Well-Known Member

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    Also, are you just neck sizing or full-length resizing? If neck sizing, that's typically done for max accuracy...basically keeping the main body of the case fire-formed to each rifles chamber. In that case you'd probably want to skip the crimp altogether since that just introduces another variable to get "just right" for max accuracy.
  4. h2oking

    h2oking Former Guest

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    As Bindernut wrote crimping can cause problems; I would agree and the way to eleminate most if not all those problems is to trim every case to the same length and debur every case mouth both inside and outside and never over crimp. I put a little bit of crimp in everything I shoot with the exception of target rifles where it is intended to be loaded one round at time. There is nothing worse than hitting an elk with what you think is a real solid hit, only to have him get up and the next round in the magazine has grown to the point it won't feed. I suppose having that happen when shooting a big ole bear would be worse but I have never shot at a bear.
  5. rouser_00

    rouser_00 New Member

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    thanks guys
    i just wasnt sure on it.but thanks for all the help and info.i think ill just leave the crimping then:)
  6. LDBennett

    LDBennett Well-Known Member

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    In general any cartridge that is going into a hard recoiling gun in a magazine (blind or removable or tube) should be crimped. Any ammo going into a semi-auto should be crimped as several rounds are in the magazine at a time and the gun man-handles the ammo in getting the cartridge from the magazine to the barrel chamber. Any ammo that is going to be used for hunting should also be crimped as who nows what its trip will be before being shot at game.

    All factory ammo is crimped regardless if it has a crimp grove in the bullet or not. The best crimp die to use has to be the Lee Factory Crimp Die. It uses a collet squeezing action to crimp and it can easily be adjusted for the best crimp in any bullet as long as the cases are uniformly and correctly trimmed.

    Trimming, by the way, is not an option but must be done whenever the sized cases exceed the maximum case length listed in the reloading manuals. Fail to trim and the pressure may sky rocket perhaps with damage to you and/or your gun. Un-trimmed cases that are too long hit the shoulder in the chamber and get forced into the bullet which tends to capture the bullet making the pressure skyrocket.

    LDBennett
    Last edited: Aug 8, 2008
  7. gandog56

    gandog56 Member

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    I like to use a Lee factory crimp die on all my pistol reloads. Don't know if they need it (except maybe my .454 Casull), but it just makes me feel better.
  8. LDBennett

    LDBennett Well-Known Member

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    I have some LEE Factory Crimp Dies (FCD) that must be 20 years old. Those early ones may have been made of a different steel alloy than the newest ones I have. LEE insists on using the minimal materials on all his stuff and in fact brags about that concept in his book. Anyway, the earlier FCD's would gall after a bit of use such that the collet would stick in the body. Judicious filing would remove the misshappend metal and the FCD would be good for some more reloading. The lastet ones have not shown that tendency.

    I like the LEE FCD's. They make excellent crimps in rifle and pistol cartridges. They seperate the bullet seating from the crimping so that the die is not trying to crimp while seating the bullet that last few thousandths. That has to make better more uniform bullet seating and better looking crimps with less damage to the bullet itself. But other manufacturers dies offer that. Where the Lee FCD's shine is the crimp is perpendicular to the case body rather than an angular motion which has to be easier on the bullet. When regualr crimping dies are used, inadvertent over crimping can expand the neck of the case so that it may not fit into the chamber of the gun. The FCD seems to not do that.

    Regardless of what some here think, I don't dislike everything LEE makes, just most of his stuff. His Collet Neck Sizing Only Dies are good too. Hopefully he has upgraded their material too as they suffer the same galling as the FCD's, at least in the past.

    LDBennett
  9. Millwright

    Millwright Well-Known Member

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    Why crimp ?

    Unless neccessary for mechanical or safety reasons not much reason to do it in light recoiling rifles - which has less to do with caliber than mass, BTW. Put that .243 in 2 lbs of gun with magazine and not only will recoil jolt your ancestors, it'll alter your carefully crafted handload OAL's as well......

    Seriously, the fine folks at Forster are exploring a "soft seat" concept for target shooting that has neck tensions so light the bullet is pushed into the case by contact with the leade with serious success. Completely the opposite of what most handloaders have been taught was "safe" for many years.

    In line with the above, I submit crimp is far more important to handguns than rifles in most cases. They recoil more and treat cartridges rougher in the reloading process if pistols. Wheel guns (revolvers) can be tied up by recoil creep so crimp is a good idea here too.

    Lastly, I submit, crimp is one way to ensure a consistent "bullet pull" which helps insure consistent early stage ignition and pressure rise in all firearms. We all know consistency is what accuracy is all about, too. >MW
  10. rainyday

    rainyday New Member

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    unless its a pistol round or a tube magazine, i dont crimp due to crimping will cause higher pressure. i shoot a 338 win mag and never have crimped a load and never will. even when i had my ar-15 i never crimped. as long as your neck or full lenght sizer is adjusted corectly,you shouldnt have any problems with bulletts moving on a 243 or 308( both of which i do load for)
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