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Thread: Cannelure question

  1. #1
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    Default Cannelure question

    I think I'm spelling right... my question is, should I load bullets with a cannelure for use in my AR-15 or semi 308? As I understand it, it's to help hold the bullet in the case during recoil and the sometimes rough handling the rounds get in the magazine.
    I would like to load more of a match bullet for my AR, but I don't want my crimps to fail. Any ideas?


    Mountaintrekker

  2. #2

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    Quote Originally Posted by Mountaintrekker View Post
    I think I'm spelling right... my question is, should I load bullets with a cannelure for use in my AR-15 or semi 308? As I understand it, it's to help hold the bullet in the case during recoil and the sometimes rough handling the rounds get in the magazine.
    I would like to load more of a match bullet for my AR, but I don't want my crimps to fail. Any ideas?


    Mountaintrekker
    I use it in semi-autos. If you want to use a bullet that doesn't have one or put one in a different place on the bullet, the gear is available to roll your own. At one time C&H had a tool, but I kinda doubt it's around any more. I'm pretty sure Corbin still makes one. I'm way out of date, but they didn't used to be all that much money.

  3. #3
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    Default

    I concur with BrownBear, and prefer to use a bullet with a cannelure when loading for a semi-auto.

    However, a Lee Factory Crimping Die also works for bullets without a cannelure, and I've used it with a Dillon progressive press while loading noncannelured bullets for .223 (AR application). The crimps from the LFCD have appeared to hold just fine during feeding without nosing-in when chambered. My son has shot a few hundred of them without a single problem.

    I'll also mentioned that I no longer crimp for bolt action applications, even when loading for .375H&H. I used to do so, but I learned from our moderator (Professor Murphy) that crimping is really not necessary for bolt actions...and he's right. I'll also add that I have never had bullet creep in the box magazine of a bolt action rifle during firing of preceding rounds that were not crimped.

    Doc

  4. #4

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    Good point on the LFCD, Doc. And on the lack of need for most bolt applications.

    Another point to remember on all crimps, mountaintrekker. If you don't trim your cases to uniform length when crimping, you'll get really varying crimps and accuracy will suffer. In cases that are only slightly too long, you also stand the chance of bulging the neck slightly right below the crimp, producing a round that won't chamber. Kinda hard on feeding reliability.

    Without distracting too far from semi-autos and crimps, I will say that I DO crimp loads for my lightweight 375 H&H. On firing the gun accelerates back faster than the rounds in the magazine. It won't do it in a single trip to the bottom of the magazine, but if you leave the last round in the mag after firing the rest and add more, by the time you get back down to the bottom bullet it will be shoved well back down into the case if it's not crimped. Kinda special circumstance, but there on the list of worries in that one rifle anyway. And yeah, it kicks like the mules I used to pack.

  5. #5

    Default No Cannelure

    I don't know of any match bullets that have a cannelure. The drag would increase drag and reduce the ballistic coefficient. Competitive shooters seat their bullets to just fit the magazine or just off the lands of the rifling depending on the need to use a magazine. Therefore the cannelure may not fall in the right place. I donít think crimping is really the way to go either. Here is a good article that I found on another forum. It does talk about the importance of neck tension among other things.

  6. #6
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    Default

    There is no little doubt that a cartridge with a crimp in the cannelure is more rugged and less likely to be shoved into the case. This has never been the most accurate accurate ammunition for me. I've shot many matches in service rifle and other hi-power events with match bullets in 308, 223, 6,5-08 6.5-300 RSAUM. These in AR platform or M1-A's. None of these match rounds had cannelured bullets but generally they were crimped slightly with my tapered crimp die.

    Also, I've fired thousands of rounds through the AR platform rifles with no crimp at all and currently load the Sierra 150 grain HPBT match bullet for my Armalite AR-10 24" match gun with no crimp at all and with scope I shoot .5 MOA with this rifle. I shoot with 41.5 grains of Benchmark for a velocity of 2630 fps from 18" of barrel. These have more recoil than the 5.56 loadings. A good tip to keep rounds from getting stuffed is to use good brass with correct size expanders and load no more than ten or use the ten shot magazines. It is the full longer mags which subject rounds to more recoil pounding that stuff the round into the case. The 223 has never been a problem child with this until the brass loses elasticity. I polish my expanders down to a full .002" less than bullet diameter and toss the brass in the practice bin after a half dozen loadings.

    Generally cannelured bullets will be significantly less accurate than non cannelured and that is expected. I just don't think there is much of a problem with non-grooved, non-crimped ammo in any of the auto-loading rifles. Certainly when leaving the same five rounds in the bottom of a 20 round mag, when we top off the mag several times, we can see rounds being stuffed but generally, it isn't a problem.

    I shoot two Armalite 308's, an FAL and a Stoner 25 without crimps and they don't care.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  7. #7
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    Default

    Hey, thanks for the info everyone... I guess I'll have to load some non-cannelure rounds up and see.

    Mountaintrekker

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