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Discussion Starter · #1 ·
Newbie at reloading, how do you know if the crimping is
tight enough, read a couple other things in forum. like
a slight ring around neck how much more pressure do you
use than just seating the bullet, or I should say how much more
pressure do you use? practicing on 30/30's now ( primerless,
powderless) maybe I just haven't got the feel just yet

Any info would be really appreciated.
 

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bytor -
How much crimp depends on what one is trying to do... but in general: if one is working with cast lead loads, then almost no crimp is appropriate, ie, "de-bell" the mouth and that's it [otherwise, the crimp will strip lead off the bullet as it passes, reducing the bullet diameter and generally resulting in poorer shooting loads]. For jacketed loads where one isn't going to be stripping any gilding metal off, then a crimp which takes the mouth to the base (inner diameter) of the crimp groove is appropriate - something like reducing the mouth diameter by .010-.012". The other comment about crimping would be: more one crimps, and heavier one crimps, shorter the life of the case will be... so: if one is using powders which are hard to ignite, then crimp one must; but if one is using easy to ignite powders, then one can crimp heavily, but one can also get away with little of none... and the cases will last a lot longer. I hope that helps.

do shoot straight,
greg
www.gmdr.com
 

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Discussion Starter · #3 ·
I'm using sierra 150 grn bullets, with ...for now... IMR 3031
 

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bytor -

IMR3031 is a reasonably easy to light powder, as such I would only crimp enough to tuck the mouth into the groove (makes for easier chambering, ie, no edges to catch anywhere) and I wouldn't apply a heavy crimp. If you were using 4831 or rl19 or 22, then I'd crimp more - they're much more difficult to ignite powders.

The other point to keep in mind (and the lee factory die crowd might disagree), but a heavy crimp can destroy the plane/smooth surface of the body of a bullet, thereby reducing the BC of the bullet (just like the lube grooves of a cast bullet will do such).

A related thought: if the reason one needs/desires a heavier crimp is to help the ignition, one can achieve the same effect by sizing the neck a thou or so smaller and use the neck tension to retain the bullet a little longer... but without altering the shape/form of the bullet. [there's more effect to be had there than even with the heaviest crimp, ie, a crimp only affects .050" of the neck, a tight neck affects the whole length, thereby providing much more "sticktion" or retention time.]

hope that helps, and do shoot straight,
greg
www.gmdr.com
 

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Discussion Starter · #5 ·
thats what I'm using 3031..... hope to fire off a few rounds on Monday.
thanks for the help!!
 
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