Do we want to use the .22 or the .25 bore brush?
Otis said to use the .25 bore brush for 5.7x28, but 5.7 uses .224" bullets. WTF, over?

I ran the Otis .22 brush through the PS90 bore and it was a tight fit, slightly tighter (I'd say, just a guess though) than my 5.56 AR-15 bore.

is it better to run the .25 brush through the AR-15 bore? Otis even lists a NSN for the .25 cal brush but not the .22 brush.

I would run the one that is closer to the actual bore size. Oversize to much and the brush will not work as effective as a correct fitting one.

I thought as much. But I am wondering why Otis said they use the 25 cal brush in their 5.7x28 cleaning kits.

Have any of you used CORROSION X, as a cleaner /lube.  They are our of Texas, I use it , am very pleased with it ... try thier web site...

I haven't tried it yet. So far I have used Militec-1, FP-10, the other stuff you can get at Walmart, Break Free CLP, and a few other more generic brands.

The CLP seems to work very well in cleaning up the powder from the chrome lined bolt carrier, but I am having difficulty scrubbing off hard deposits in the barrel extension, throat of the chamber, and on my AK piston top.

Get MC-25 from Mil-Comm.  Very good cleaner.  Have yet to find a deposit it will not take off.

Corrosion X is a very good product.  Especially their Aviation version.  Probably the best all round liquid based CLP out there.  Way better than BF.  I use it on some guns and around the house (hinges, locks, etc.).  Becareful with it around ammo because it is a very good penetrating oil and can deactivate primers.

My favorites are Eezox, FP-10, and CX Aviation in that order.

So which do you recommend for large, hard, and stubborn carbon/coked deposits?

Quoted: So which do you recommend for large, hard, and stubborn carbon/coked deposits?

Ooops...your right...didn't make any conclusion did I.  

MC-25 will get off just about any carbon buildup or blast marks you will find.  I have yet to see any carbon based fouling it will not remove.  It will NOT directly attack metal deposits (lead, copper), but it will strip all other contaminants off and leave bear metal.  Re-lube quickly.

I then follow up with Eezox as a CLP.  It is completely synthetic and seems to get that last bit of dirt that other cleaners miss.

MC-25 sounds a lot like the Slip 2000 Degreaser/Cleaner. Does it smell somewhat like Windex? The Slip 2000 degreaser does a hell of a job removing grease. It will dry out metal parts lickety split, but it does nothing for carbon. I ran a few patches through my bore and it came out pink/clean. Do you spray the MC-25 and let it soak?

The funny thing is that I ran a brush through my PS90 (only test fired at the factory) and ran a few patches only to find it come out pitch black/purple. I shined a light and examined the chamber, throat, and bore to find that it was "clean" (totally shiny and clean chrome lining). Where's the black stff coming from ?

from the bore. W/ a .22 dia barrel it is almost impossible to get a good look at the barrel.  sturbon areas show up as a slight shadow when viewed using a 140 Watt bulb and a white clean cotton patch.

never used the MC cleaners, but member Blankwaffle (?) has made serveral posts on how it works and its limitations.

edit member = Blankwaffe98