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02-05-2015, 12:57 AM
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Modifying Hardcast Crimp Groove
I'm considering using my lathe to cut wider crimp grooves in hardcast bullets (like the Buffalo Bore bullet profile) to avoid crimp jump in my 329pd loads. It'll be tedious, but less involved than a custom mold and casting. I'd save these rounds for carrying, and practice with unmodified bullets. I've been successful with a handful of trial bullets, no deforming from chucking. I'm curious if anyone one else has tried this or found a better way.
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02-05-2015, 04:42 AM
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No, but.....
No, but it sounds like an interesting project.
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02-05-2015, 05:01 AM
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Well that's certianly *different* .
Presuming the intended Big Picture Goal is the avoidence of bullet jump, the usual aproaches :
1. Try a different commercial cast bullet , that has a deeper crimp grove. A faithful rendition of a True Keith bullet would be one such.
2. Reduce the dia of the case expander to increrase case neck tension. Neck dia has at least as much effect as crimp oer se.
3. OP didn't specify his current crimp die , but the Redding Profile crimp die is generally considered to be the best.
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02-05-2015, 06:59 AM
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^^^^ Option #4 ^^^^
4. Trim your brass to [minimum case length - 0.010" ] before you resize it. Do not deburr the ID or OD of the case mouth. Now resize and bell the case mouth as usual.
When you resize and flare or bell the case mouth, you will remove the burr AND have a square edge case that gives a great roll crimp. I have done this for 38 years without a bullet jumping out of the case. A free fringe benefit is that the case neck usually cracks before you need to trim the case a second time. But after 15 reloads on a magnum case, it don't matter because you shot all the X's out of it.
I helped a friend that has a Marlin 45-70 lever gun. I loaded five rounds using cast bullets and this case prep. He became a believer when bullet movement stopped in the magazine tube.
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02-05-2015, 11:52 AM
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All good information; especially tip #4. Thanks for the comments. I am using Redding's profile crimp and haven't incurred jump with my standard load. I just happen to have some LaserCast True Shot 310 grain bullets I thought I'd load up just for kicks (no pun intended).These will jump crimp I'm sure without some extra care. The BB crimp profile allows for a very wide crimp, hence the thought I have to widen the groove on these bullets. I'll give it a try. Again, thanks guys.
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02-05-2015, 01:04 PM
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Interesting, but I've never had this problem. 99% of the bullets I shoot in my 5, .44 Magnums are lead. Some of my loads are too hot to list here and I have been using a Redding Profile Crimp Die for several years. I have cast bullets from Lee, Lee Ranch Dog and Lyman/Ideal molds and I have purchased LBT bullets, and none have "jumped crimp" even with max. loads. Could there be some other contributing factor to your "bullet creeping" problem?
But it would be interesting to hear of your exploits in reforming crimp grooves and the results...
Last edited by mikld; 02-05-2015 at 01:07 PM.
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02-05-2015, 01:28 PM
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Tedious is putting it mildly. The alloy frame guns are prone to jump, especially with heavy bullets. Me, I would order a bullet mold from Accurate with the crimp groove you want. For about $125, beats the hours spent trying to modify a handful of bullets. Most Keith style bullets have more than adequate crimp grooves. With 300gr bullets in the 329PD will be bullet jump. That will be brutal to shoot.
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Last edited by fredj338; 02-05-2015 at 01:30 PM.
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02-05-2015, 01:40 PM
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The problem is not the crimp, it is the re-sized case dimensions, or the projectile is sized too small, and in all likelihood a combination of both.
It is a well established fact that brass tension is the number one remedy for stopping bullets that jump crimp. There is no way a sliver of brass by itself is going to firmly hold a projectile subjected to roughly 2.5 tons of rearward pressure per square inch. If memory serves, that is roughly what a 240-grain bullet subjects a 44 Mag handgun to with a full tilt round.
Years ago in Handloader, Ross Seyfried wrote an article about this. He added photos, and looking at his handloads, the brass was so tightly married to the bullet you could see where the bullet's lubricant grooves were. Now: that might be a bit much, but were I betting man, I would bet a C-note his bullets didn't "jump crimp". Here is a link to the article: https://www.riflemagazine.com/magazi...d=212&magid=18
Take some 600-grit emory cloth and polish your sizer ball a touch. A couple or three thousandths is all it will take, and it won't hurt a thing. You might mike the bullets as well. Anything less than .430" is unacceptable in my opinion, and .431" is better.
FWIW, I have loaded for the 44 Mag since 1980 and have never had a bullet jump crimp. Maybe I am just lucky, but I think it is more a case of having the right dies, dimensionally sized correctly, and sizing all my own hard cast to .430".
Good luck.
Last edited by Doubless; 02-05-2015 at 02:28 PM.
Reason: Edited to add link to article
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02-05-2015, 02:18 PM
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If you can't get a proper crimp with your standard crimp die, pick up a Lee Factory Crimp Die and try it. If the LFC die doesn't stop the creeping I don't know what will.
Gary
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02-05-2015, 02:57 PM
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Quote:
Originally Posted by gwpercle
If you can't get a proper crimp with your standard crimp die, pick up a Lee Factory Crimp Die and try it. If the LFC die doesn't stop the creeping I don't know what will.
Gary
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The LFCD doesn't crimp any better than any other roll crimp die. Lee marketing hype.
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02-05-2015, 03:46 PM
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Last thing a cast bullet load needs is the LFCD . + 1 on the Redding Profile die .
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