What size round cleaning patch is most efficient for .50 cal barrels?

2-1/2" unless the store is selling the 3" for the same price.

2-1/2sare tough to find in stores -- round ones even tougher. Isometimesbuy the square 2-1/2"s online. Otherwise, I'm finding square 3" or similar that are used for 12-16 gauge shotgun bores.

I tried the 2" once. They are a tad too small to do a proper cleaning job for 50-cal rifles. They are better served for 45-cals. The most imprortant matter with patches is getting the all-cotton ones. I hate the poly-patches. They sometimes don't want to come back up after reaching the breech.

I got about 250 of those left that I strictly use for wiping the ML exterior now.

I think these below are my Best Buy right now for a throw-away patch. You get 300 that are 3" for $4.72. If you have a Meijer store near you, they sell these.

http://www.midsouthshooterssupply.com/item.asp?sku=000601205S

2 1/4" seem to work. Those are the store bought size.

These patches from T/C work nicely for me in .50 caliber ML's.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=271437

How many of you when you patch a bore use two patches? I use two, so that the jag and patch is a really nice tight fit. I get my patches back that way and I can even see rifling marks on them sometimes so I know I am getting into all the right places...

maybe my store bought Rusty Duck are 2 1/2inch. I am out of them and measured the jar and then figured they would not have ran them the full 2 1/2 inches into it but I could be wrong... Actually I use scrap patches. I get them at Wal Mart and they come in strange sizes. I cut a chunk what I need, make sure I get a tight fit and swab away....

I tend to make my own cleaning patches using old flanel shirts and other suitable cotton material. I find they fit the bore tighter so I don't have to double patch like Cayugad described. My patches average about 2"x2" give or take a quarter inch or so usually smaller because the material is thicker.