Underlugs and their function

Status
Not open for further replies.

Bacchus

Member
Joined
Dec 24, 2002
Messages
612
I was reading another thread earlier tonight on 44 special ammo and started thinking about underlugs on revolver barrels.

This is the link and the picture was posted by Stainz. The revolver in the bottom of the picture has a full underlug--

http://www.thehighroad.org/showthread.php?t=337619

So my question is--what is the underlug for and why are some revolvers built with "full" ones and others with shorter ones? Do they serve a functional purpose?
 
I'm not sure which order these really belong in but I'd say the purpose of the underlug is to:
1. Protect the ejection rod.
2. Add weight to the barrel for balance.
3. Enhance the look of the revolver.

That's my guess anyway.
 
Used to affect the balance of the gun. More commonly used for asthetic effect (witness the number of full underlug .357s today).
 
The underlug is to move the center of mass of the gun more forward and lower than the bore axis. This way, the weight of the gun works more effectively to counter recoil and reduce "felt" recoil. It won't reduce the absolute amount of recoil - that is dictated by the bullet weight, speed, and the powder charge weight. But adding a lug will make that same amount of recoil feel like less as moving the weight of the gun now requires more of that recoil, so there's less of it for you to feel as the gun rocks back into your hand.

A highly illuminating demo is to shoot a 4" K-frame model 66 (about 36 ozs, no lug), vs. a 4" model 686 L-frame (41ozs, full lug), vs. a 4" model 28 N-frame (41 ozs, no lug). Shooting the same 158gr. SJHP magnum rounds showed that the K frame was "snappy," the the biggest frame, the "N" was better, but the slightly smaller (than the "N") but fully lugged L the smoothest and most controllable of all. Even though it was dead even in weight, the lower, more forward distribution made the L the "queen" of the S&W .357 line up in my opinion.

For magnums, I find the lug highly desirable - it tames recoil and gets you back on to the target faster. I find it less critical with sub-sonic rounds like 45acp, 44spcl, or 38 spcls. It's still smoother, but there you find the extra weight out there more noticeable as it slows the pointing and handling characteristics of the gun.
 
Thanks for the info--it's good to see that I'm not the only one who prefers full underlugs. I hadn't thought about the weight/recoil issue.
 
Full underlugs do help reduce felt recoil and muzzle flip. So there is a plus there. Looks are in the eyes of the beholder, and I like all styles (no lug pencil barrel, bull barrel, partial under lug, full underlug), though there is something about the early pencil barrel, no lug Smiths that gives them a higher degree of class and elegance, IMHO.

Their is a cost to full underlugs. The extra muzzle weight makes the gun more ponderous to swing from target to target, because of the increased intertia (from the increased mass) out in front of your hands. So it takes more effort to start and stop the movement of the gun between targets. For example, my 6" no lug S&W Model 14 is quicker/easier to swing between targets than my 4" full underlug 686.

Since I load my 686 with 38 +Ps for home defense anyway (and I do prefer 4" guns for HD duty), I guess I have a really good excuse to buy a no-lug 4" Smith 38 Spl K-Frame someday :evil: .
 
The introduction of the Colt Python changed the revolver world like the introduction of the Glock 19 did for semi-auto's.

I personally think it is a matter of streamlining the look of the revolver and protecting the ejection rod. I believe it helps give a revolver, especially a 6" revolver, a weight forward feel when shooting that helps to control the recoil jump and probably assist in aiming (at least for me).

When I saw my first Python, I didn't want a revolver without the full underlug. At the time, I felt revolvers without the underlug were inferior. I have since learned different. I have both, but feel the revolver looks better with the underlug. That said, I never really wanted a Smith Model 617 with the full underlug as I felt it added weight that was not necessary. I never really looked at the specs to compare a Model 17 vs 622 weight. But I tend to prefer blued finish revolvers in general.
 
It's to protect the ejector rod and added weight for pistol whipping.

This is one of those critical handgun skills that I think too many shooters ignore. ;)
 
S&W introduced the full-lugged barrel on the 585/686 (L-frame) as a answer to the Colt Python for PPC competition in "leg matches". it was call the Distinguished Master for the PPC Distinguished Matches, which did not allow bull-barrels

in leg matches, competitors had to use wheelguns in stock configuations. while many competitors prefered the short action of the S&W, the Python had the advantage of their additional muzzle weight. the 586/686 could also used python speedloaders. S&W offered the factory option of an extra tall front sight so that folks could use a "neck hold" at the 50 yard line.

other that that, it's mostly for looks...mostly to copy the coolness of the Python :cool:
 
it was call the Distinguished Master for the PPC Distinguished Matches,

First time I have ever heard that. The name I recall is Distinguished Combat Magnum as opposed to the original Combat Magnum.
 
It's to protect the ejector rod and added weight for pistol whipping.

"I swear to God, I'll pistol whip the next guy that says shenanigans!" :D


As said in this thread, it's for balance and looks. I personally don't much care for a full underlug in comparison to one that just protects the ejector rod.
 
"I swear to God, I'll pistol whip the next guy that says shenanigans!" :D
"Hey Farva, what's the name of that restaurant you like with all the goofy sh*t on the wall and the mozzarella sticks?"
 
My favorite wheel guns don't have full underlugs. Just aims, feels and points better. Colt's marketing department is probably still chuckling over the effects of that Python.

S&W 19, 29, and a John Ross/Performance Center 500 on the way. Yeeha!
 
Colt's marketing department is probably still chuckling over the effects of that Python.

Sadly, I believe it has been a good long time since Colt's marketing/product development units have had a smug chuckle about ANYTHING they've done...:(
 
The underlug itself on an S&W revolver is not decoration; it is designed so the cylinder spins between centers and stays in alignment. The full lug is mostly to add weight toward the front. Some gunsmiths remove the underlug entirely, replacing it with a ball lock in the crane. IMHO, that is not a satisfactory solution even to a non-existent problem.

Jim
 
Early Pythons had the full length lug drilled hollow so there was not as much muzzle preponderance (Col Chas Askins term) as there appeared to be.
 
I always considered the full underlug to be of modest importance until I started shooting in action pistol matches.
If you want to shoot fast and get hits, the lug helps, a lot.
Try a "Prez": three silhouettes anywhere from five to ten yards out. Two hits in each, a reload, and two more in each.
If I do it back to back with a Python and a .357 Magnum (the Python's medium-barrel/no underlug predecessor), the Python wins by a mile, both in accuracy and time.
That test changed my mind. I may well prefer the slimmer lines of the .357 Model, the Python shoots faster.
 
My personal preferences,

Lugs for range use and competition on 4" to 6" barrels (5" w/ lug is about perfect on an N frame) and 8" tubes do not need lugs unless you are shooting at only one target, not transitioning.
That's raceguns. Now let's leave the racetrack and go to the real world.......
For any type of carry from the grocery store to the backwoods I'll take the pencil barrel hands down every time and not just for the ease of carry, they just point more naturally for me. I'll get the all important 1st two shots off just fine and more without the lug. Oh, and they look better. :neener: Although a fine firearm, I'm certain the lug on my S&W 617 is largely cosmetic.
 
Status
Not open for further replies.
Back
Top