Cartridge crimping

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BCJON

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As I am new to reloading, and for safety reasons, I thought that I would ask this question.
After reaching COL, I ended up crimping a couple of cases. Then thinking afterwards if I should be concerned with any increased pressures created by the crimping.
They are a 300wm cartridge topped with a 180 GR Hornady BTSP bullet with 70 GR of IMR 4350 powder and WM primer.
I'm not exactly sure if I should be concerned, but I thought that I better ask before firing these cartridges.:eek:
Thanks a lot.
Jon
 
you only have to worry if your bullets were touching the lands it could build up excessive pressures you don't need to crimp unless you have a tube magazine .
 
why do you need to crimp a 300 wm?i only crimp rounds for tubular mags that must be crimped. i don't think crimping is all that benificial.
 
It is also beneficial to crimp heavy bullets in heavy recoiling rifles and handguns to prevent the bullets moving forward under recoil and with some powders a heavy crimp is recommended to ensure better ignition of the powder, usually when using ball type powders in magnum cartridges. In your case the crimp won't hurt anything.
 
Do you really need to crimp your reload? A slight crimp just for the brass to hold the bullet in place will do. However, heavy crimping will defenitely increase pressure, but not that much. To be safe start low and gradually increase your load and check your brass for pressure sign.
 
Your link lists three particular rifles with one load each.Also all bullets were moly coated which may or may not make a difference.The differences were also very small,small enough to be within normal shooting error.I don't see this very small sample as really proving anything.

However,if crimping did normally improve accuracy would not all benchrest shooters crimp all of their loads?So how many benchrest shooters do you know that crimp their loads?I personally do not know of any.
 
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Do BENCHREST SHOOTERS even put them in a magazine. The cartridges are usually in their little case with each load dutifully recorded on each. Each cartridge is never subjected to any stress or rough handling, like what might happen in a hunting situation.
 
The so called test was to determine if crimping affected accuracy,nothing else.And for the record,I have never crimped any of my hunting loads and no bullet has ever moved in the case despite some being heavier recoiling cartridges like the 300ultramag,338x8mmremmag and the 375 h&h.If the brass is properly sized and the bullet is seated to a proper depth into the cartridge case,crimping is unnecessary.If the bullet moves in the case,you have problems with sizing,seating depth ,or the bullet dimensions.At one point sierra even took out ads in several shooting magazines warning people not to crimp any bullets without a cannelure.
 
stubblejumper said:
Unless you have a tubular magazine or are talking very large bore cartridges,crimping is totally unnecessary reguardless of the rifles action.
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Well, I beg to differ, but ymmv.
I put a crimp on rounds going through my ARs, M14 and all my pistols (all autos)
 
Well, I beg to differ, but ymmv.
I put a crimp on rounds going through my ARs, M14 and all my pistols (all autos
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I didn't say that you should not crimp,just that it wasn't necessary to do so.I never crimped the loads for my bar,mini14 or my ar-15 and had no problems at all.And my statement did specify rifles.
 
After more than 30 years of reloading, I've decided to go against conventional wisdom and once again begin crimping some of my ammo. I seat the bullets into the lands in my target rifles, so these will not be crimped. My hunting rifles from now on will have the bullets crimped in place, and I will only choose bullets with crimping grooves. There is no down side really - other than it is another step in the reloading process, as I crimp separately from bullet seating, with the seater stem removed from the die, or with a Lee factory crimp die. In my powerful rifles a bullet crimped into place is less likely to be driven back into the case from running into the front of the magazine box when the piece recoils. Crimping bullets into place appears to decrease the ES in velocity - anyone who doesn't own a chronograph needs to get one - and crimping has not shown to be detrimental to accuracy at normal hunting ranges. Lastly crimping bullets into place has not effected the life of my brass.
 
I have some Lee factory crimp dies,i agree crimping is not ness. on most rifles.But fooling around with my 223 and 243 I find that crimping with some bullets and loads reduces the group size sometimes in half.
 
I agree that crimping hunting bullets is not a bad idea but only ones with a canelure which are designed to be crimped I do crimp my hunting bullets but only on my larger calibers not my varmint guns.
 
Thanks guys, for all the informative responses.

I'm starting to realize that theres a little more to this than just adding some powder and seating a bullet on top.

Nice to know that there is a wealth of knowledge and experience here at your finger tips. Much appreciated.
Jon
 
BCJON said:
Thanks guys, for all the informative responses.

I'm starting to realize that theres a little more to this than just adding some powder and seating a bullet on top.

Nice to know that there is a wealth of knowledge and experience here at your finger tips. Much appreciated.
Jon
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Really, it all boils down to try-it-and-see. If you like it and it gives good results in your gun, who gives a damn what the other guys think.
 
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