Really dirty 44mag?

[buck460XVR]

The above notwithstanding, and in more-normal temperature conditions, I would think a magnum primer used with a powder that has the characteristics described here would make the problem worse. Why? I don't know the correct terminology as it applies to firearms' metallic cartridge ballistics, but in a 4-cycle automotive engine where a spark plug is the source of ignition a "too-hot" spark can cause "cavitation" and incomplete combustion (granted, the comparison may be apples to oranges but I know I'm not reaching too far when I read of rifle cartridges loaders talk of the tendency in some cases of a magnum primer to "spike" through a powder charge).

Kinda hard to "spike thru" a full case or a compressed load as is the case with most magnum loadings using IMR4227. Folks that have actually used IMR4227 have been experiencing unburned powder residue with it even at max loadings, it is the nature of the beast. Not a "cavitation" issue or the use of "too-hot" of spark. No difference with IMR4227 than with Unique, another notoriously "dirty" powder, especially at low charge rates. While it's so dirty, why is Unique still used by so many reloaderers? Versatility and performance. IMR4227 was basically a little known Magnum powder to most folks before the recent buying panics....one reason it was still on the shelves when everything else was gone. Many folks that tried it because it was the only thing left found it to be an excellent performer in magnum handgun cartridges when used within it's optimum charge rates(very similar to H110/W296). Even tho it can be safely downloaded, it produces the unburned powder residue experienced by the OP. It really likes heavy bullets, max loads in bigger cases and prefers long pipes. Is it a tad dirty? Yep, it is, and to some folks that is a turnoff. I actually preferred it when other folks didn't use it and it was easier to find. Used to be a thread about it on gun forums was rare, nowadays it's hard to look in the reloading section and not see a thread about it. Lately it seems to be asked for at the LGS I go to, as often as W231 and H110. Even tho it costs more than H110/W296 and does not give the velocities of H110/W296, it still sells, even with it's dirtiness.

 

[buck460XVR]

Too, the crimp issue is important as I am quickly learning here. As Airman Basic noted, "Bullet tension in the case is equally important as crimp. IME, too much crimp can actually decrease bullet tension." We don't want the bullet leaving the brass too soon/before the powder charge ignition peak...?

Overcrimping is an improper reloading technique, no different than over-belling or improper sizing. It takes a lot of crimp to be too much with a magnum powder charge and jacketed bullets. What one is doing when over crimping, is actually crushing/buckling the case, expanding the neck. Learning the difference, like many other aspects of reloading, comes from experience. With many slow burning magnum powders, a heavy crimp is what promotes complete ignition and gives maximum performance. This is true not only with IMR4227, but H110 and W296 also. Again nature of the beast. It's not that hard to put a heavy crimp in a .44 mag case without buckling it and without deforming the projectile.

 

[200Apples]

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10-4.

Thank you, buck460!