I was out at the range today shooting my .38 Super when the barrel lugs (where the link pin connects too) sheared clean off the barrel. SS barrel 4.25". I only have about 500 rounds through her and I only feed it Winchester 147 grain factory loads. Got a 14lbs recoil spring and I don't let the slide slam home on an empty chamber.
What would be another cause for the lugs to shear off besides weak metal.
The barrel I have is one of the finest in the industry. I do not want to mention their name yet as I am still resolving the issue with the manufacturer. I will post pics of the lug later.
The first thought is that it was not installed correctly. It did not contact the VIS, but came back to rest on the link... which will shear the lower lugs in no time.
How clean is the break? I would lean toward the metal failure if the evidence supports it.
In referring to the sticky entitled "How to Increase the Life of Your Barrel", could the problem have been caused by backside of the lugs stricking the frame upon linking down?
Also someone mentioned the term "VIS". What is it?
VIS, vertical impact surface, the area on the frame that the lower lugs (hopefully) contact at link down.
VIS..."Vertical Impact Surface" of the frame
HIS..."Horizontal Impact Surface" (cradle) of the frame
Any chance that increase slide speed caused by a 14# recoil spring could have contributed to the failure?
The 14 lb. recoil spring is Colt factory standard for 38 Super.
And YES the lugs on my barrel is making full contact with the frame upon linking down also the barrel is making contact. The lug contact must be the culprit. That would mean no warranty for me.
The upper portion of lower barrel lugs should strike the VIS hard. Sheared lower lugs typically indicate the lower portion of the lower lugs are striking the VIS. Another cause could be the fillet where the rear of the lower lugs meet the barrel was sharp cornered and not a rounded transition.
Typically, the link is fitted to the barrel's lower lugs. The front of the lugs may have to be relieved to avoid/eliminate barrel bump. Intentionally using a longer link will affect link down, so thread carefully after fully understanding how this will affect the pistol.
You can relieve the bottom of tho barrel lugs so they don't show impact at linkdown when using sharpie or layout fluid. Mark the back of the lower lugs, assemble the slide, bushing, barrel with fitted link, frame and slide stop assembly. Pull the slide back 1/2 to 3/4" out of lock up, barrel down. With a hard rubber or leather mallet tap the barrel up to simulate linkdown impact. Disassemble and read the marks on the rear of the lugs. If the lower portion of the lugs show signs of impact in the marker, then touch that section lightly with a smooth file, up on the lugs, not across. Or one can have the frame VIS machined to prevent lower lug contact and acquire the 'bowtie' impact pattern. Do a search on 'bowtie' and you 'll get some good script on it. The bowtie is what you should get doing it either way.
Is the VIS even or does it have a slight counterbore centered on it?
It is even from where it connects to the barrel all the way to the bottom. Also the lug has very sharp corner not a rounded transition.
There is picture on this link that shows how my frame look. It is post #97
http://forums.1911forum.com/showthread.php?t=120227
There can be couple reasons and perhaps variations. The broken barrel is history, period. So the important thing is the replacement be fitted correctly.
When the slide is in recoil it pulls the barrel with it, by design the link tethers the barrel to the frame. By the time the slide has traveled .250", two things must have happened, one the barrel radial lugs must be fully disengaged from the slide, and two, the back of the barrel lower lug must strike the VIS to stop it. If the link is stopping the barrel the result can be a broken link, link pin, or lower lug. If the radial lugs are still engaged, be it ever so little, when the lower lug strikes the VIS, the lug will shear, eventually, if not within a few hundred rounds.
As has been mentioned this may not be felt when hand cycling, and why understanding and checking a new barrel's timing is so important.
Note, a SS barrel will tear with less stress than a carbon steel, but the fault isn't in the material, it is the fault of the fit.
A Kart barrel would be the least likely to shear off the lugs.
A Kart is machined from a 4150/4340 chrome-moly forging vs. 416R stainless bar stock.