Josh Smith
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Here is a bit on 1911 lower lugs and lug bump:
I found this on my Rock Island when troubleshooting a failure into battery.
Barrel lug bump is not good. An improper radius on the bottom lugs will allow them to crash into the slide stop pin, reshaping the lugs and causing the dreaded Three Point Jam (yes, it's attained proper-noun status in my mind) when it slows due to the crash.
The link is only for pulling the barrel down out of battery.
Some folks (and 1911a1 military specs) call for the slide stop pin to use the link to either partially or wholly put the barrel back into battery when the slide goes forward.
Now, this is not the way the system was designed and it can break the link.
So riding the lugs is a good thing. In other words, if you pull the link out, the barrel will have trouble dropping down at speed -- and don't fire it like this; you'll shear the top lugs! -- but it should have absolutely no trouble going back into battery.
To fix lug contact, first stone off the high spots, then check the radius and contact.
The easiest way to check lug contact is to use contact fluid (I need some more!) or just a sharpie. Color the lower lugs and cycle a few times. If you're riding the lug as you should, you'll get something like this:
Uneven contact is not a good thing; this picture shows uneven contact.
I stoned the high side just a bit and it is now perfect.
Correct radius is shown here:
See how the hole is partially hidden by the lower lugs? This assures the lugs will ride the slide stop cross pin into battery.
Shown is the link on my stock Rock barrel after I repaired the lug bump damage and radius. If you can do this, there is no reason to weld up the barrel lugs or replace it.
Regards,
Josh
I found this on my Rock Island when troubleshooting a failure into battery.
Barrel lug bump is not good. An improper radius on the bottom lugs will allow them to crash into the slide stop pin, reshaping the lugs and causing the dreaded Three Point Jam (yes, it's attained proper-noun status in my mind) when it slows due to the crash.
The link is only for pulling the barrel down out of battery.
Some folks (and 1911a1 military specs) call for the slide stop pin to use the link to either partially or wholly put the barrel back into battery when the slide goes forward.
Now, this is not the way the system was designed and it can break the link.
So riding the lugs is a good thing. In other words, if you pull the link out, the barrel will have trouble dropping down at speed -- and don't fire it like this; you'll shear the top lugs! -- but it should have absolutely no trouble going back into battery.
To fix lug contact, first stone off the high spots, then check the radius and contact.
The easiest way to check lug contact is to use contact fluid (I need some more!) or just a sharpie. Color the lower lugs and cycle a few times. If you're riding the lug as you should, you'll get something like this:
Uneven contact is not a good thing; this picture shows uneven contact.
I stoned the high side just a bit and it is now perfect.
Correct radius is shown here:
See how the hole is partially hidden by the lower lugs? This assures the lugs will ride the slide stop cross pin into battery.
Shown is the link on my stock Rock barrel after I repaired the lug bump damage and radius. If you can do this, there is no reason to weld up the barrel lugs or replace it.
Regards,
Josh
