Lube ring on cartridge mouth

Attachment 235196

Anyone know what causes this? I've never had this happen. I was working up some 357 loads. The rounds that had lube on the case mouth are the rounds that produced the best group of the day.

I'd venture a guess that when seating the bullet the lube got scraped off the sides by the case maybe put a touch more flair on the case mouth ?

Are you shooting 357 Magnums in a chamber meant for 357 Maximum?

Happened to me the other day using .44 mag ammo in a .44 mag super blackhawk

It means your brass is shorter than your chamber. Measure the brass and lube and that is the length your brass should be trimmed to. Try using Dan Wesson or 357 Max brass and trim to get to the right length.

Quote:

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Originally Posted by BudRow

Are you shooting 357 Magnums in a chamber meant for 357 Maximum?

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357 magnum in 357 magnum.

It’s a Marlin 1894cst.


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If everything is happy in the bore I call that a good thing,like getting a 'lube star ' on the muzzle. I get them like that with B/P cartridges it tells me the lube is being 'slung about' in all the right places. I.M.O.

I get that ring when I shoot ammo assembled with the wax gas checks, .060" thick dental wax cookie cuttered over the case mouth before seating the boolit. I haven't ever gotten that ring with traditional lubes in lube grooves, could it be you had an abundance of lube on the bottom of the boolit when it was seated?

A mag in a mag chamber still presents a funnel for the bullet to wobble or lube to fill. It's the price of accommodating shorter relatives, (38special).

That means you are getting a good seal. Seen it many times. Bollit upsets then squirts lube out and fills the transition cone. Lower the powder charge for less pressure and probably won't do it.

I shot 5 groups, charged 15.0-17.0 in 0.5gr increments. These rings were present on the 16.0 load, which (coincidentally, maybe not coincidentally?) was the best group.