1911Tuner
Moderator Emeritus
Here's an area that is probably gonna draw some fire. Some of the the things that I do to insure feed reliability are slightly off the scale, and on one particular mod, I notice in Kuhnhausen's bible that it's a strict NO-NO because it will destroy the frame. I think maybe Mr. Kuhnhausen is assuming that every frame is dead centered in the middle of tolerance spec...Sometimes, with some frames, we have to alter a little here and there to optimize feeding.
Be aware that whenever I set up a pistol to feed reliably, there are two approaches, each one dependent on what the gun is to be used for. If the gun is strictly a range toy, and will see heavy use, the feeding cycle isn't as smooth as for a carry gun that will see limited use. The reason being that the slicker it feeds, the more the stress on the lower lug and slidestop pin. Simply put, the slide goes to battery so fast, that the feeding cartridge doesn't bleed off as much momentum as on a pistol that hasn't had these
modifications done.
Forewarned, we proceed.
As we've come to understand, the tilting barrel of the 1911 pistol has a funny quirk by design. That is...as the barrel moves forward, it also moves upward. This is true whether the barrel rides the link as it swings up, or if it cams up on the slidestop pin. Most factory pistols do ride the link to some degree, and here is where we can often find the small amount of modification that will make the pistol feed like greased grain through a goose. If you swing the link to about 30 degrees forward of vertical, it's easy to check for the riding condition. Look closely at the slidestop pin hole at this position. If you see any of the link between the radiused corner of the lower lug and the slidestop pin hole..it's riding the link to some degree. In other words, even though the link isn't bearing any of the load of vertical lockup, the center-to-center spacing between holes is a bit too long. When the spacing is too long, the barrel will not only move higher in relation to the barrel's forward movenment...it will rise faster. Sometimes this creates a condition of stem bind because the round is trying to enter the chamber at an angle...and the angle is getting steeper as the round pushes on the barrel throat.
To fully understand the effect of barrel rise on feeding, lock the slide to the rear and push the muzzle against the edge of a table lightly to keep it in the bed. Lock a loaded magazine in, and release the slide with your hand and guide it slowly into battery. You won't even feel the round hit the ramp or throat because the barrel remains static.
SOMETIMES...we can simply install a slightly shorter link and reduce this. If you go this route, be sure that the barrel isn't stopped by the link as it falls to the bed during the linkdown. Easy check. Remove the slidestop and slip it back through the frame and link. with the arm hanging vertically. Remove the recoil spring. Pull the slide fully rearward and hold the barrel as far down and back as it will go. No need to push too firmly on the barrel...just hold it in position. Ideally, the slidestop should swing freely without bind. Just a tiny bit of bind is okay, as long as it isn't too tight. If you can swing the link with the end of a Q-Tip while holding the other end without the stem flexing, it's okay. If not, then you'll need to go back to the original link and elongate the hole.
You can use a round needle file to do it, but a much better way is with the good old Dremel with a blue stone that you can find in the Dremel section at Lowes or HQ. It's the one made for sharpening chain saw cutters, and they come in packages of two.
Being very careful to keep the stone square with the link, set the Dremel on half-speed and open up the hole at the end close to the lug. Use a light "swinging" motion in the hole's radius to elongate the hole slightly. Remove only enough material to allow the slidestop pin to lightly bear against the radius in the lug as it pivots around the front of the lug on its way to vertical. Check often by coloring the lug with a felt-tip marker.
Put the gun together and hand-cycle it several times and check to see if the color is starting to be worn off. When you get the pin to just start removing the color...stop. It's not critical to get full bearing on the lug at the front radius...all you want it to minimize the effect of the link on barrel rise. In any event, if you have to remove more than about .003 inch from the hole, it's time to look at a shorter link.
Don't remove material from the bottom of the link UNLESS your shorter link is better fitted to the lug when in the vertical lock position...AND..the shorter link puts the slidestop pin in a bind with the barrel down and back. Removing material at the bottom of the hole will delay barrel linkdown timing, and possibly cause the locking lugs to be struck by the slide as it recoils. This can quickly and effectively destroy the barrel and/or the slide.
Better to lengthen the hole at the top.
Test the feeding by using a dummy round...or a live one if you're VERY careful.
Remove the recoil spring and plug. Draw the slide fully rearward and lock in a FULLY LOADED magazine. It would be good at this point to have correct tension on the extractor, but not entirely necessary just yet.
Put the tip of your index finger on the back of the slide and push it into battery. Push smoothly and briskly, but don't use a lot of force. About 10 pounds on the back of the slide should do it. If all is well, the round should strip and feed with just a little resistance as the slide goes to full battery.
If it doesn't, remove the extractor and re-test. If it feeds smoothly, the extractor has too much tension. It nothing changes, you're not quite through yet. There is still a light stem-bind condition present. Most of the time, this will make the pistol much more feed reliable, even though there is some resistance. This is the point where I usually stop when I'm tuning a range beater or heavy use pistol. For a carry gun, I take it a step further...and here's where it gets a little dicey because it involves a light modification of the barrel and possibly the frame. Careful and patience are the key words. This is the area that Kuhnhausen caustions against, and if it's overdone just a tiny bit, it can ruin a frame.
The bottom line is that if this modification alone gets your pistol running after seeing an occasional failure to go to battery, you can stop here if you're comfortable with it. If your pistol is a dual-purpose gun that you carry and shoot a lot, it would probably be best to stop at this point. You've achieved a balance between super-slick feeding and keeping stresses off the lower lug and slidestop pin. I have several pistols that are
relegated to either strictly carry...or strictly range use, so I can have it both ways. On the carry guns, shooting is limited to quarterly test-firing before being detail cleaned and put on R&R. On reassembly and return to duty, another magazine is fired to insure function.
Stay tuned for part 2
Be aware that whenever I set up a pistol to feed reliably, there are two approaches, each one dependent on what the gun is to be used for. If the gun is strictly a range toy, and will see heavy use, the feeding cycle isn't as smooth as for a carry gun that will see limited use. The reason being that the slicker it feeds, the more the stress on the lower lug and slidestop pin. Simply put, the slide goes to battery so fast, that the feeding cartridge doesn't bleed off as much momentum as on a pistol that hasn't had these
modifications done.
Forewarned, we proceed.
As we've come to understand, the tilting barrel of the 1911 pistol has a funny quirk by design. That is...as the barrel moves forward, it also moves upward. This is true whether the barrel rides the link as it swings up, or if it cams up on the slidestop pin. Most factory pistols do ride the link to some degree, and here is where we can often find the small amount of modification that will make the pistol feed like greased grain through a goose. If you swing the link to about 30 degrees forward of vertical, it's easy to check for the riding condition. Look closely at the slidestop pin hole at this position. If you see any of the link between the radiused corner of the lower lug and the slidestop pin hole..it's riding the link to some degree. In other words, even though the link isn't bearing any of the load of vertical lockup, the center-to-center spacing between holes is a bit too long. When the spacing is too long, the barrel will not only move higher in relation to the barrel's forward movenment...it will rise faster. Sometimes this creates a condition of stem bind because the round is trying to enter the chamber at an angle...and the angle is getting steeper as the round pushes on the barrel throat.
To fully understand the effect of barrel rise on feeding, lock the slide to the rear and push the muzzle against the edge of a table lightly to keep it in the bed. Lock a loaded magazine in, and release the slide with your hand and guide it slowly into battery. You won't even feel the round hit the ramp or throat because the barrel remains static.
SOMETIMES...we can simply install a slightly shorter link and reduce this. If you go this route, be sure that the barrel isn't stopped by the link as it falls to the bed during the linkdown. Easy check. Remove the slidestop and slip it back through the frame and link. with the arm hanging vertically. Remove the recoil spring. Pull the slide fully rearward and hold the barrel as far down and back as it will go. No need to push too firmly on the barrel...just hold it in position. Ideally, the slidestop should swing freely without bind. Just a tiny bit of bind is okay, as long as it isn't too tight. If you can swing the link with the end of a Q-Tip while holding the other end without the stem flexing, it's okay. If not, then you'll need to go back to the original link and elongate the hole.
You can use a round needle file to do it, but a much better way is with the good old Dremel with a blue stone that you can find in the Dremel section at Lowes or HQ. It's the one made for sharpening chain saw cutters, and they come in packages of two.
Being very careful to keep the stone square with the link, set the Dremel on half-speed and open up the hole at the end close to the lug. Use a light "swinging" motion in the hole's radius to elongate the hole slightly. Remove only enough material to allow the slidestop pin to lightly bear against the radius in the lug as it pivots around the front of the lug on its way to vertical. Check often by coloring the lug with a felt-tip marker.
Put the gun together and hand-cycle it several times and check to see if the color is starting to be worn off. When you get the pin to just start removing the color...stop. It's not critical to get full bearing on the lug at the front radius...all you want it to minimize the effect of the link on barrel rise. In any event, if you have to remove more than about .003 inch from the hole, it's time to look at a shorter link.
Don't remove material from the bottom of the link UNLESS your shorter link is better fitted to the lug when in the vertical lock position...AND..the shorter link puts the slidestop pin in a bind with the barrel down and back. Removing material at the bottom of the hole will delay barrel linkdown timing, and possibly cause the locking lugs to be struck by the slide as it recoils. This can quickly and effectively destroy the barrel and/or the slide.
Better to lengthen the hole at the top.
Test the feeding by using a dummy round...or a live one if you're VERY careful.
Remove the recoil spring and plug. Draw the slide fully rearward and lock in a FULLY LOADED magazine. It would be good at this point to have correct tension on the extractor, but not entirely necessary just yet.
Put the tip of your index finger on the back of the slide and push it into battery. Push smoothly and briskly, but don't use a lot of force. About 10 pounds on the back of the slide should do it. If all is well, the round should strip and feed with just a little resistance as the slide goes to full battery.
If it doesn't, remove the extractor and re-test. If it feeds smoothly, the extractor has too much tension. It nothing changes, you're not quite through yet. There is still a light stem-bind condition present. Most of the time, this will make the pistol much more feed reliable, even though there is some resistance. This is the point where I usually stop when I'm tuning a range beater or heavy use pistol. For a carry gun, I take it a step further...and here's where it gets a little dicey because it involves a light modification of the barrel and possibly the frame. Careful and patience are the key words. This is the area that Kuhnhausen caustions against, and if it's overdone just a tiny bit, it can ruin a frame.
The bottom line is that if this modification alone gets your pistol running after seeing an occasional failure to go to battery, you can stop here if you're comfortable with it. If your pistol is a dual-purpose gun that you carry and shoot a lot, it would probably be best to stop at this point. You've achieved a balance between super-slick feeding and keeping stresses off the lower lug and slidestop pin. I have several pistols that are
relegated to either strictly carry...or strictly range use, so I can have it both ways. On the carry guns, shooting is limited to quarterly test-firing before being detail cleaned and put on R&R. On reassembly and return to duty, another magazine is fired to insure function.
Stay tuned for part 2
