Lube buildup at throat.

[cs86]

I noticed the last time I went shooting with my XDM .45acp that I was getting enough buildup of lube at the throat of the barrel to stop the action short of going all the way forward. I was using MP452200 HP boolits lubed with carnauba red sized to .452. After so many shots I started to swab out the lube and keep shooting. It seemed to have lube streaking about 1/2" to 1" down the barrel before it was shiny the rest of the way. Is this normal for this lube? What would your assessment be?

I was trying to do some ladder tests and focus on aiming, but found myself focusing on whether or not the action was completely forward.

[geargnasher]

Switch to BAC, or soften your C. Red with some Vaseline so it clears out of the front of the chamber every shot. Also, don't over-crimp, just taper-crimp enough so the cartridges reliably fall home in a clean chamber, no more. Switching to a faster-burning powder may help as well.

Gear

[cs86]

I have some ben's red made up. Would that work in a pistol or is that more for rifles. I've tried felix in 9mm pistols and with the softer lube I seemed to get a build up of lube around the back of the case around the ejector pin. Is this the cause of soft lube... maybe to light of a load not making a good seal around the case?

I do keep the crimping light. just enough to take the flare off.

[grampa243]

i use ben's red in 45acp and 9mm,

it does sound like you are getting a lot of blow back around the shell.

[btroj]

Bens lube won't build up like that.

CR can do that easily, colder temps make it worse. It also is a gummy, sticky residue that grips cases and slows the round entering the chamber. This exacerbates the buildup at the front stopping the slide short of full battery.

Like gear said, add a bit of Vaseline to soften the mix or change lube entirely.

[RobS]

It seemed to have lube streaking about 1/2" to 1" down the barrel before it was shiny the rest of the way.

Are you sure this is lube? Never seen lube streaking 1" into the barrel but I've seen leading like this especially in an XD/XDM due to the short throat. If you want run a dry patch down the barrel to take out the lube and see if there is leading. The short throat could also be scraping off lead and small deposits or slivers of lead collect at the end of the chamber and mixes in with the lube which can cause issues with full battery.

[cs86]

there was a slight bit of leading mainly in the corners of the groove (I only noticed with this when cleaning), but nothing excessive like I've seen in the past with different lube. When I would run a bullet into battery and take it back out you could see the lube from the chamber that stuck around the case mouth and bullet from previous firing.

[geargnasher]

Switch to Ben's Red and see if that doesn't fix it. If not, switch to a faster-burning powder. If that still doesn't fix it, it might be time to ream the throat. The MP 45-200 has a very blunt SWC shoulder that doesn't like sharp/nonexistent throats like most of the plastic pistols have these days. Leaving enough flare on the case to center the boolit in the chamber before firing will usually fix any boolit shaving problems from the sharp front boolit shoulder and sharp throat entrance edge (this shaving will cause smeared leading in the bore), but if you're still having slight leading issues after working out the lube and powder you might consider changing boolits, or reaming the throat so the boolit doesn't shave and has an easier start into the rifling, both of which can help keep lube from blowing back into the chamber as well as helping cure the light leading issue.

But trust me, Carnauba Red is best reserved for high pressure handgun and rifle loadings. Ben's Red should be perfect, especially since you already have some made. Put it to use!

Gear

[cs86]

Thanks for the advise. I guess it's back to pan lubing a few to give a try. I don't really want to empty my lubrisizer that is full of CR. Main reason I tried going with CR is because it worked well in the .357 mag. What is a recommended way for reaming the throat? I think this is something I'd look into in the future. I'm guessing this is why I have light leading on one side of the barrel in both my 9mm and .45acp. I'm guessing from what you describe is that the bullet leans into the bottom throat edge and shaves.

[RobS]

What is a recommended way for reaming the throat? I think this is something I'd look into in the future. I'm guessing this is why I have light leading on one side of the barrel in both my 9mm and .45acp. I'm guessing from what you describe is that the bullet leans into the bottom throat edge and shaves.

http://castboolits.gunloads.com/show...1911-Throating

[geargnasher]

The extractor and/or gravity bearing on the case, lots of things make a cartridge favor one side of the chamber.

Gear