on revolvers what is an underlug?

[ruger22]

I hear this refered to as a "good feature" or "adds strenth" or "handles hot loads".

Is this true?
What part is the underlug?

 

[Pietro Beretta]

An underlug is the part under the barrel, also refered to as having a full underlug (S&W 629 Classic) as apposed to the S&W 29 with a short underlug.

It adds weight to the barrel and balances the revolver out while aiming...makes the barrel look more "beefier". The S&W 629 Classic has a full underlug

 

[bokchoi]

The underlug is the part under the barrel that looks like a "second barrel" that runs the entire length of the barrel, which is essentially nothing but added metal underneath the barrel to increase weight.

I don't have picture posting capability, but if you do an image search on Google, almost all S&W 686 revolvers have an underlug, while certain other revolvers like the S&W Model 28 Highway Patrolman usually do not.

The underlug, while it adds weight to the revolver, typically is seen as a good feature in that it reduces felt recoil and makes the gun generally more pleasant to shoot. I wouldn't say that extra weight neccessarily makes a gun stronger or more able to handle hot loads, though if felt recoil is reduced, then I can believe that there may be a beneficial effect on the gun's overall longevity.

 

[Master-G]

It's not really for adding strength but rather adding a bit of extra weight to help dampen recoil. Here's what it is:

 

[Rigmover]

Have to agree with Master-G it keeps the recoil down and easier to control youre shots have a S&W 629 Classic with full metal lug and i shoot that one better then my model 28 .357 magnum that doesn't have one makes the gun look meaner lol.

 

[9mikemike]

The one in the pic is referred to a a full underlug, there are partial underlugs that extend just beyond the cylinder rod.