1911Tuner
Moderator Emeritus
Disclaimer:
Success or failure with this exercise depends solely on the reader's
care and patience. Understand that if overdone, can result in expensive
damage to the frame of the pistol, and must be performed with that in
mind. I can assume no responsibility for any damage on the part of the reader.
Tuner
-----------------------------
Okay...Here's where the firestorm will likely begin. Several years ago, when I was goin' nuts in an attempt to get a Safari Arms-built 1911 to run, a neighbor stopped by to check out the exercise. I was in an open garage, and he heard the cussin'. This guy was a young adult that had been brain damaged after a car had hit him on his bike at age 12 or 13. He had a simple view of everything. He asked me what was wrong, and I explained to him that after trying everything that I was supposed to do, it still wouldn't work. He shrugged and said: "Then do something you're NOT supposed to do." In that suspended second, I learned something from a man with the mind of a child.
In the last thread, we saw that lowering the angle of entry into the chamber makes for a smoother feed. Virgil Tripp came up with a newly designed magazine that positions the round at a higher point in the grip, and the reason is to give the round a straighter shot at the chamber. I have to assume that Virgil also studied the round's impact on the
throat, and figured out that the higher it struck, the better. The drawback is that the mags are expensive at over 40 bucks a copy, and their function varies from gun to gun.
Enter the part that Kuhnhausen says that I'm not supposed to do...even though I've been doing it successfully for years. It involves first modifying the barrel...and finally the frame bed if necessary to get the desired results. With some frames, it's the ONLY thing that works. As I noted before, Kuhnhausen is probably going on the assumption that the frame on the bench is well within spec. When the frame is out of spec...the rules change. At least for those of us who can't afford to buy a new frame and start from square one.
To do this, you will need a smooth mill file and a Dremel with the large sanding drum. (They come in two sizes.) If you don't know how to follow a radius with a file, find a machine shop and have a machinist demonstrate, and then go practice it on some scrap round stock. It's simple to do, but hard to explain in writing.
The first approach is to radius-file the bottom of the barrel behind the lower lug. Go slow and follow the radius carefully. You should remove no more than .003 inch or so from the diameter. 20 bond typing paper averages about .004 inch thick, so you can see just how little is involved. When you go to the machine shop, it would be a good idea to take your file with you and have one of the guys remove the cutting surface off the edge of the file to prevent undercutting the back of the bottom lug. When you get through, clean up the corner at the junction of lug and barrel with a small round needle file. There shouldn't be a sharp corner there, but rather a smooth radius. Sharp corners lead to cracks.
Check the fit in the frame bed often to make sure it's mating up smoothly, and polish the filed area with a strip of emery cloth via the "Chattanooga Shoe Shine" method. Test-feed a round from a full magazine with the recoil spring removed. Lowering the barrel in the frame just this tiny amount usually results in a dramatic difference in the
"feel" of the slide going to battery. Allowing the bullet nose to impact the throat at a higher point also reduces the tendency to bullet setback and hollowpoint deformation. It also creates a little more clearance for the slide to get past the locking lugs.
If the pistol could use a bit more barrel lowering, it's time to look at the frame bed itself. Approach this with caution. Here's where it gets dicey, and a little too much can ruin the frame.
Use the sanding drum on medium speed. As a happy coincidence, the drum fits the curved portion almost perfectly, and a straight cut is generally all that's needed. Again, the limit is about .003 inch. Since the feed ramp is angled, lowering the bed will lengthen the top of the ramp. This may require that you set the bottom of the throat forward to regain the gap at the junction of the ramp and throat.
Don't lay the drum straight down in the bed. It will grab and send the drum over the top and mar the frame rails...and it will cut too too quickly to limit the depth even if you can control it. Instead, angle the drum at about 15 degrees or so, and use only the front edge to make the cut. Point the front of the frame toward you, and cut by pulling the Dremel toward you in one smooth motion. Don't allow the drum to stand still for even a split second. Keep it moving until it comes off the forward part of the bed, and don't let it dip as it comes off. Bring it straight off. Use very light pressure on the drum, and check the barrel radius in the bed after each pass.
Be aware also, that if the lower lug is correctly fitted in the bottom of the frame, it may not let the barrel come down. Use a strong light to see if the sides of the lug are making contact in the frame. If they are, the bottom of the barrel won't lay in the bed, and the barrel will stand on the sides of the lug. Dress the sides of the lower lug feet with a smooth mill file LIGHTLY...and recheck. Use the felt tip marker to color the sides of the feet, and press the barrel firmly into the bed. dress the area of contact a little and recheck. Ideally, the barrel should hit the bed AND the impact surface in the frame at the same time. Stopping on the back of the lug instead of the bed is preferred to stopping on the bed if the ideal is beyond reach. It will fall to the bed unless the feet are holding it off. In an ideal fit...the feet SHOULD support the barrel in linkdown
just a fractional amount...about .001 inch or less...but this is time consuming, and most production pistols aren't fitted this way...It doesn't seem to have an adverse effect.
It would also be a good idea to assemble the gun and do a feeding test after each pass with the sanding drum. You want to remove the absolute minimum of material...just enough to feel a difference...to a maximum of about .003 inch. Depending on how light a touch you have with the Dremel, this can be done in one pass. As a rule, if you see more than just a tiny amount of sparking, you're cutting too fast.
It's important to use even pressure. You don't want to angle the bed. All you want to do is lower it a tiny amount. Just a little goes a long way. Lightly polish the bed with a piece of 600-grit paper on your fingertip. Check the .032 gap between the top of the ramp and the bottom of the barrel throat and adjust if necessary.
Usually, reducing the bottom of the barrel will produce the desired results, or at least strike a functional balance between smooth feeding and keeping the lower lug stresses at a minimum. It's what I call a "Street and Strip" job. The gun is more feed reliable for carry AND suited to medium range use. The full Monty often makes the gun feed so smooth and fast that it should be limited to carry and the occasional run for the purpose
of function testing and familiarization.
Again...This work should be approached with caution and with the full understanding that the feeding charactistics of the gun will be altered
to a large degree.
Luck!
Tuner
Success or failure with this exercise depends solely on the reader's
care and patience. Understand that if overdone, can result in expensive
damage to the frame of the pistol, and must be performed with that in
mind. I can assume no responsibility for any damage on the part of the reader.
Tuner
-----------------------------
Okay...Here's where the firestorm will likely begin. Several years ago, when I was goin' nuts in an attempt to get a Safari Arms-built 1911 to run, a neighbor stopped by to check out the exercise. I was in an open garage, and he heard the cussin'. This guy was a young adult that had been brain damaged after a car had hit him on his bike at age 12 or 13. He had a simple view of everything. He asked me what was wrong, and I explained to him that after trying everything that I was supposed to do, it still wouldn't work. He shrugged and said: "Then do something you're NOT supposed to do." In that suspended second, I learned something from a man with the mind of a child.
In the last thread, we saw that lowering the angle of entry into the chamber makes for a smoother feed. Virgil Tripp came up with a newly designed magazine that positions the round at a higher point in the grip, and the reason is to give the round a straighter shot at the chamber. I have to assume that Virgil also studied the round's impact on the
throat, and figured out that the higher it struck, the better. The drawback is that the mags are expensive at over 40 bucks a copy, and their function varies from gun to gun.
Enter the part that Kuhnhausen says that I'm not supposed to do...even though I've been doing it successfully for years. It involves first modifying the barrel...and finally the frame bed if necessary to get the desired results. With some frames, it's the ONLY thing that works. As I noted before, Kuhnhausen is probably going on the assumption that the frame on the bench is well within spec. When the frame is out of spec...the rules change. At least for those of us who can't afford to buy a new frame and start from square one.
To do this, you will need a smooth mill file and a Dremel with the large sanding drum. (They come in two sizes.) If you don't know how to follow a radius with a file, find a machine shop and have a machinist demonstrate, and then go practice it on some scrap round stock. It's simple to do, but hard to explain in writing.
The first approach is to radius-file the bottom of the barrel behind the lower lug. Go slow and follow the radius carefully. You should remove no more than .003 inch or so from the diameter. 20 bond typing paper averages about .004 inch thick, so you can see just how little is involved. When you go to the machine shop, it would be a good idea to take your file with you and have one of the guys remove the cutting surface off the edge of the file to prevent undercutting the back of the bottom lug. When you get through, clean up the corner at the junction of lug and barrel with a small round needle file. There shouldn't be a sharp corner there, but rather a smooth radius. Sharp corners lead to cracks.
Check the fit in the frame bed often to make sure it's mating up smoothly, and polish the filed area with a strip of emery cloth via the "Chattanooga Shoe Shine" method. Test-feed a round from a full magazine with the recoil spring removed. Lowering the barrel in the frame just this tiny amount usually results in a dramatic difference in the
"feel" of the slide going to battery. Allowing the bullet nose to impact the throat at a higher point also reduces the tendency to bullet setback and hollowpoint deformation. It also creates a little more clearance for the slide to get past the locking lugs.
If the pistol could use a bit more barrel lowering, it's time to look at the frame bed itself. Approach this with caution. Here's where it gets dicey, and a little too much can ruin the frame.
Use the sanding drum on medium speed. As a happy coincidence, the drum fits the curved portion almost perfectly, and a straight cut is generally all that's needed. Again, the limit is about .003 inch. Since the feed ramp is angled, lowering the bed will lengthen the top of the ramp. This may require that you set the bottom of the throat forward to regain the gap at the junction of the ramp and throat.
Don't lay the drum straight down in the bed. It will grab and send the drum over the top and mar the frame rails...and it will cut too too quickly to limit the depth even if you can control it. Instead, angle the drum at about 15 degrees or so, and use only the front edge to make the cut. Point the front of the frame toward you, and cut by pulling the Dremel toward you in one smooth motion. Don't allow the drum to stand still for even a split second. Keep it moving until it comes off the forward part of the bed, and don't let it dip as it comes off. Bring it straight off. Use very light pressure on the drum, and check the barrel radius in the bed after each pass.
Be aware also, that if the lower lug is correctly fitted in the bottom of the frame, it may not let the barrel come down. Use a strong light to see if the sides of the lug are making contact in the frame. If they are, the bottom of the barrel won't lay in the bed, and the barrel will stand on the sides of the lug. Dress the sides of the lower lug feet with a smooth mill file LIGHTLY...and recheck. Use the felt tip marker to color the sides of the feet, and press the barrel firmly into the bed. dress the area of contact a little and recheck. Ideally, the barrel should hit the bed AND the impact surface in the frame at the same time. Stopping on the back of the lug instead of the bed is preferred to stopping on the bed if the ideal is beyond reach. It will fall to the bed unless the feet are holding it off. In an ideal fit...the feet SHOULD support the barrel in linkdown
just a fractional amount...about .001 inch or less...but this is time consuming, and most production pistols aren't fitted this way...It doesn't seem to have an adverse effect.
It would also be a good idea to assemble the gun and do a feeding test after each pass with the sanding drum. You want to remove the absolute minimum of material...just enough to feel a difference...to a maximum of about .003 inch. Depending on how light a touch you have with the Dremel, this can be done in one pass. As a rule, if you see more than just a tiny amount of sparking, you're cutting too fast.
It's important to use even pressure. You don't want to angle the bed. All you want to do is lower it a tiny amount. Just a little goes a long way. Lightly polish the bed with a piece of 600-grit paper on your fingertip. Check the .032 gap between the top of the ramp and the bottom of the barrel throat and adjust if necessary.
Usually, reducing the bottom of the barrel will produce the desired results, or at least strike a functional balance between smooth feeding and keeping the lower lug stresses at a minimum. It's what I call a "Street and Strip" job. The gun is more feed reliable for carry AND suited to medium range use. The full Monty often makes the gun feed so smooth and fast that it should be limited to carry and the occasional run for the purpose
of function testing and familiarization.
Again...This work should be approached with caution and with the full understanding that the feeding charactistics of the gun will be altered
to a large degree.
Luck!
Tuner
.