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What causes this?

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22 January 2004, 17:06
jpothof
What causes this?
Let me preface this with I've been reloading for awhile now, but am relatively new to straight-wall handgun reloading.

Anyways, I noticed that the spent cases coming out of my .480 ruger seem to have a fair amout of powder residue on them. It comes off with a good tumbling except for a handful of cases. I am using published max loads from speer and have even gone .5 grains higher than published. Seems to happen regardless of powder charge. Cylinders are clean and accuracy is very good. I also haven't shot this thing in weather above 25 degrees yet, and most shooting is taking place in the teens. (Gotta love Wisconsin winter). Anyways, its not causing me any problems, I'm just curious. I would think that it would happen from the case not expanding fast enough or shrinking down too fast. The bullet is crimped pretty hard if that maks a difference. Let me know what you all think.

Jeff
22 January 2004, 18:43
bfrshooter
jp, nothing to worry about! I think it has something to do with the cylinder gap. My brass always looks that way. If I shoot my loads out of the Marlin rifle, the brass comes out clean.
23 January 2004, 03:59
Swede44mag
The same thing happens to me on all of my handguns. Some powders dont burn as clean and leave more residue. It is nothing to wory about, try different powders some will smoke less and clean off easier than others. Hope this helps

Swede44mag
23 January 2004, 20:26
liljohn
What powder are you using?

It's caused by a small amount of powder gas getting between the case and chamber walls before the case has had the chance to expand tightly against the chamber. I've found it happens most with either very light loads, or loads using slow powder. Loads slightly over mid range with fast powders, or slightly heavy with medium powders, seem to eliminate the problem by quickly expanding the case before the bullet has had time to jump into the forcing cone.
23 January 2004, 21:12
derf
I used to get that all the time with H110 in my SBH's. derf
24 January 2004, 04:08
475Guy
You might try polishing down your expander about .0015" and that would give you better bullet pull.
24 January 2004, 08:37
bfrshooter
475, thats not the answer because you can see the grease grooves and drive bands through my brass they fit so tight.
24 January 2004, 11:10
jpothof
I'm using H110, haven't tried any other powders yet. Like I said before, its not causing me any problems, it just sparked a little curiosity. Thanks for all the replies so far.

Jeff
24 January 2004, 15:23
475Guy
That's strange, since I shoot a 475 Linebaugh, I never seem to have that kind of problem. Maybe a change to a different powder like Lil Gun?
27 January 2004, 09:05
ScottB
I know that once you get some lead residue inside a chamber, it burns in and just gets worse over time. I suppose it prevents the case from properly expanding, which allows blowback, which increases residue, which further prevents proper expension, allowing blowback, increasing residue.....

I found this by keeping careful track of which cylinders were the worst culprits. A good thorough cleaning pretty much had it back to normal, and use of gas checks kept it that way.