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Going to start reloading my first 45-70 . I have made up several dummy loads to see how they will cycle through the chambering no problems. My question is what is the better crimp the ( bullet seat crimp or the factory crimp)

I got two defferent styles of bullets (300grain)

http://www.midwayusa.com/viewProduct/?productNumber=123570

http://www.midwayusa.com/viewProduct/?productNumber=600541

I also can not believe the defferences between the loading manauls why the defferences
(IMR 3031)
speer; 55.0 gr = 1,639fbs
Lyman; 48.0 gr = 1,657fbs
Lee ; doesn't show a IMR
I would like to practice with a load at 1,400 fbs range and hunt with a loads at 1,600 fbs range
 

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Look at a dozen reloading manuals, and you'll get ten or eleven different ranges from low to high with every powder. Some powders aren't listed in every manual, for a variety of reasons. I have dozens of loadbooks and manuals going back 40 years, and I check half a dozen before settling on a load range for testing. But you also have to remember that powders are often reformulated by the factories, and they don't often make that fact common knowledge, they just do it.

My choice of crimps depends on the bullet........If it has an obvious crimp groove, I use a firm roll crimp. No cannelure, I use the FCD. Just make sure not to overdo the crimp. Warped jackets are not real conducive to accuracy. ;)
 

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another cause for the various "max loads" is the brass that was used. 45-70 brass comes in many "weights" which translates into brass thickness. Thicker walls, same outside diameter means inside diameter is smaller meaning said case has less capacity. Hope that's not too confusing.

Jeff
NRA Life
 

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Sweetwater said:
another cause for the various "max loads" is the brass that was used. 45-70 brass comes in many "weights" which translates into brass thickness. Thicker walls, same outside diameter means inside diameter is smaller meaning said case has less capacity. Hope that's not too confusing.

Jeff
NRA Life
+1

Please read the topic in the following link

http://www.marlinowners.com/forums/index.php/topic,80939.0.html

As far as crimps go, if its a cast bullet, I use a roll crimp, if its a jacketed and I want a crimp, I use an FCD; if there is no cannelure, I live without a crimp.
 

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Some ammo doesn't need to be crimped, MOST does. Revolver rounds need a firm roll crimp to keep the bullets from being pulled out the front of the case by recoil. Semi-auto rounds need a taper crimp to avoid bullet setback when they're being mashed into the feed ramp. Levergun rounds need a crimp so the spring pressure in the tube doesn't make the bullets collapse into the case. Bolt guns and single shots don't necessarily need a crimp, neck tension is often enough to keep the bullets from changing length.

But crimp serves another function, and that's holding the bullet in place until the powder charge has ignited fully, and allowed pressure to build to the proper level for complete ignition and consistent ballistic performance. It's also needed when dealing with compressed powder charges, to keep the bullet from "growing" after it's loaded.

Getting your dies set up to provide the proper amount of crimp is often overlooked as one of the simplest tricks for getting better accuracy. 8)
 

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Listen to PapaJohn! He know's from whence he speaks.

Good link, Travis!

Jeff
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"Getting your dies set up to provide the proper amount of crimp is often overlooked as one of the simplest tricks for getting better accuracy."

Papajohn, how does one set up their die to achieve the proper crimp?
 
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