Barrel life depends a lot on the kind of ammo used. With GI Ball ammo, the barrel life of a .45 auto is usually 5000 rounds or less before accuracy is gone. There are reports of .38 target revolvers, firing low pressure rounds with lead bullets, going as high as 100,000 rounds and still retaining good accuracy. .22 pistol barrels almost never wear out; more are ruined in cleaning than in shooting. A worn barrel won't blow up; it just won't shoot accurately any more.
As to match barrels, the term "match grade", even when used accurately (it is often just advertising hype), refers to accuracy, not safety. A match grade is more carefully made and more tightly held to specifications. In guns like the Model 1911/A1 types, it is usually larger in some outside dimensions so it can be fitted to the gun in which it will be used.
A note on production. All machined metal products, like guns, are made with cutting tools which wear as they cut the metal. A manufacturer sets a tolerance level for something like a chambering reamer. It is made to the largest size allowed and it is rehoned as it is used until it reaches the lowest size of hole allowed, when it is discarded. So, brand new barrels and chambers vary in dimensions. In the gun field, a standards institute, SAAMI, sets tolerances for chambers, ammo, loading dies, etc.
The point of all this is that match grade barrels are not allowed as wide a tolerance, so tools are discarded oftener, and so the barrels are more costly.
Jim
[This message has been edited by Jim Keenan (edited September 05, 1999).]