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When loading 30-30 rounds for a lever-action, how much crimp shoud be used. The RCBS book recommends turning the seating die down until it touches the mouth of the case, then 1/8 turn more. This does not leave much of a perceived crimp. Is that enough ?? I guess one concern is the recoil causing the bullets to ease out of the cartridge, another is that some powders IE winchester, require crimp because of desired affect on powder ignition. I'm just not sure about how much crimp to apply. How does it affect accuracy?
RV Stallard
 
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RV,

You need just enough crimp to keep the bullets in the tube magazine from being driven deeper into the case from recoil and magazine spring pressure. If you can't move them by pushing the loaded cartridge hard against a block of wood, they're fine. BM

Bill
 

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RV

The answer depends on what one is trying to do... if one is shooting lead, then the answer is: as little as possible, ie, just enough to "unbell" the mouth [ie, although it's not a real problem with such thin brass as the 3030, but with heavier brass, as the bullet leaves the case, it is effectively swaged to a smaller diameter... and given that bullet diameter is so critical to shooting lead... you can guess how they shoot - in a test case, in the 300 wsm, with a moderate crimp, we watched .311" bullets become .308" bullets (we used an inertial puller to pull the bullets through the crimp).]

If your concern is the bullet being driven into the case under recoil - simply crimp lightly but at the top of the crimp groove such that the mouth of the brass will catch the meplat/ogive side of the groove, and hang there, ie, one is using the crumple strength of the brass to keep the bullet from moving any further rearward - a lot more strength than can ever be had from a crimp around the body of the bullet or around the body of the crimp groove.

If the concern is trying to more uniformly ignite difficult to ignite powders: two answers - the easy one is to use a different powder - a little crimp is not going to significantly help in the ignition, besides there are too many good powders out there today to put up with such; but if one really wants to help with the ignition - then under expand the neck of the case by a thou or two - the increased bullet tension will help 100x with the confinement/ignition vs having the last .050" of the mouth trying to do all the work (ie, a crimp). [this is why redding sells dies where one can dial in the "sizing" of the neck, in 1 thou increments.]

do shoot straight,
greg
www.gmdr.com
 

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we watched .311" bullets become .308" bullets (we used an inertial puller to pull the bullets through the crimp).]
Wow. Just goes to show you learn something new every day. I wouldn't have thought of that as I usually crimp lead the same as jacketed. Not no mo'. Maybe now I'll get some better groups-

Thanks :D
 

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skpp108 -

... did away with the crimp, and the groups got better...

www.gmdr.com/levern/2004-1021.jpg

very used win m70, 300wsm, 24" 1:10, win brass, wlr, 170gr rnfp OrgnTr, 2.595", herco 7gr,

I measure it at .60" [10 shots, from bench, varmint style (front rest, butt to shoulder), 50yrds]... a chronograph backing target.

do shoot straight,
greg
www.gmdr.com
 
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