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Thread: To crimp or not to crimp

  1. #1

    To crimp or not to crimp

    Ok so this may have been covered already but will crimping the bullet make a difference? And why will it not be so critical to get the bullet touching the rifleing when chambers? Ok sorry I just read all about it.
    Last edited by Simjim33; 09-05-2011 at 23:38.

  2. #2
    One of the essential aspects of reloading is neck tension. Inevitably, it affects the pressure via what it known as "pull weight" or, the amount of effort needed to start the bullet moving. One of the "tricks" used to make loads more uniform with respects to pressure is to seat the bullet a few thou off of the rifling, in which case, pull weight (neck tension) might have little affect.

    One of the consequences of this technique is that loaded round -depending on the amount of bullet in the neck- might be less durable to the bumps and buffets of hunting, and they also may end up being too long to fit into the magazine. In this instance, a properly applied crimp may solve both problems. The neck tension is set by the crimp (with a great deal of uniformity) and the cartridge's OAL is shorter, allowing magazine function. Additionally, the loads become a bit less fragile.

    It is a myth that the most accurate loads must be seated to the lands of the rifling. They may be accurate, but there is usually a deeper setting that provides equal or better accuracy.

    Will a crimp work 100% of the time? That depends. So many people say "I tried a crimp on my last loads and the accuracy was poor, so I'm quitting." This is childish impatience. How can a person change a major part of the case dynamic and pronounce it bad after applying no experimentation? Dunno! But it happens. Crimps are something that is usually applied in degrees until a sweet spot is found. I have never NOT been able to find a really accurate load with crimping it requires some effort and thought to get right. When you do, however, it is usually VERY right.

    I crimp my Hornet which was giving OK accuracy until I applied a crimp. Then the groups shrunk marvelously. The one way to know is to give it a try.~Muir

  3. #3
    That's why I'm going to experiment with "cheap brass" I can get 100 PRVI rounds for 55 so I won't cry if I muck a few up. I certainly looks worth a try.

  4. #4
    Simjim33,

    I have loads of quality once fired brass you may be interested in some? Some decent makes like Norma and RWS

    Various calibres inc .308 .270 30-06

    PM me if you are interested

    Dennis

    P.S. Don't crimp its a waste of time and effort any you are simply adding aditional variants and ware/deformation to good brass.
    Dennis Groom, make every shot a good one

  5. #5
    Quote Originally Posted by Muir View Post
    I crimp my Hornet which was giving OK accuracy until I applied a crimp. Then the groups shrunk marvelously. The one way to know is to give it a try.~Muir
    I followed this advice with my Hornet, you know what, Muir was right

    Neil.

  6. #6
    Quote Originally Posted by dennisgrm View Post
    Simjim33,

    I have loads of quality once fired brass you may be interested in some? Some decent makes like Norma and RWS

    Various calibres inc .308 .270 30-06

    PM me if you are interested

    Dennis

    P.S. Don't crimp its a waste of time and effort any you are simply adding aditional variants and ware/deformation to good brass.
    What cartridges have you crimped? ~Muir

  7. #7
    PS: Ammunition makers don't share your views on crimping and use it routinely. This is a picture of Remington's "Power Level" high performance cartridge. They claim that in a given caliber it is the fastest and most accurate ammo they make. Note the crimp.~Muir
    Click image for larger version. 

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  8. #8
    Crimping some .223 loads really improved consistency for one load in particular for me.
    (The Unspeakable In Pursuit Of The Uneatable.) " If I can help, I will help!." Former S.A.C.S. member!

  9. #9
    For clarity, what kind of crimping are we talking about here i.e. cannulers and taper crimp, lee collet on non-cannelure etc?
    This area has always been a bit of a mystery to me and I've only dabbled once as I've only used one type of bullet with a cannelure.

    For interest sake a mild taper crimp on a Hornady SST gave 50fps more for the same given charge.

    Some guys I know swear by crimping with a lee collet crimp die.

  10. #10
    Hi i have loaded foe 14yrs now & basically i have always crimped that was 243/22.250 & 25/06. I do try uncrimped loads when i have found a sweat spot with a load of powder i may try uncrimp & crimp & play with seating depth. I use a very light crimp with the lee factory crimp die in 22.250 & 25/06 now. With the likes of the 25/06 with 75g v-max my seating depth has the bullet only 2-3mm in the case so i crimp them in to keep them there & help with the recoil etc. Iv had people struggle with a load & iv asked them do you crimp (NO) so i tell them to try & it genrally helps them. I tell them to use there best uncrimped load & crimp it & see how it works then hope this helps.

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