Proper Way to Polish Throat on 1911


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Smeg
August 28, 2007, 10:44 AM
I have a 1911 that has a sharp lip at the point where the barrel ramp makes the transition into the chamber, and it causes some rounds to get hung up when the slide returns to battery.

I think it's this lip is because the mouth of the brass is buggered up a bit on the bottom when the jam occurs.

I had annoyingly frequent jams when I first purchased it, and after a 600 rd break-in period and replacing the factory magazines with Chip McCormick mags, they were reduced by a large amount. However, I still have about 1 jam every 16 rounds or so, and it's always in the manner I previously described.

I've read enough to know that using any kind of power tool would be a bad idea, but I haven't found much in the way of describing how to do it with your finger and a very fine grit sandpaper. Do you rub side to side? In and out? About how long does it take? Should I use some sort of polishing rouge? Any other tricks in the technique?

Thanks in advance!

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Mad Magyar
August 28, 2007, 01:14 PM
I recommend a competent gunsmith...It will not cost that much...The problem with do-it-yourselfers is taking too much off & weakening the underside....
After it's finished, should handle your ammo needs other than FMJ....

BigG
August 28, 2007, 01:25 PM
The case could also be hanging up on the breech face or extractor so don't go to work without knowing that you are correcting the problem.

Smeg
August 28, 2007, 01:55 PM
The extractor isn't the problem, I've already verified that. Bringing it to a competent gunsmith costs money, and I'm confident I can do this myself.

Can anyone answer the questions in my original post?

Spartacus451
August 28, 2007, 02:13 PM
You rub in and and out in the direction of cartridge travel. If you look in Kuhnhausen he points out how it is essential that you not move the location of the bottom of the lip left or right (looking into the chamber). I am pretty sure my terminology is incorrect. It is also important that you not round the edge as it is supposed to act as a tip over point for the cartridge. It should not be sharp, but neither should it be soft/round/melted. I would err on the side of less round and more sharp. You could start with 600 grit sand paper.

What make/model 1911 is this? Most barrels come pretty clean from the factory. Have you tried to test feeding with the extractor out of the gun?

There are factors besides the barrel ramp that can cause ammo to hang up on the lip so I would not assume that it is the whole problem. Can you show us a photo of the gun with the slide locked back look down at the barrel and frame ramp?

Smeg
August 28, 2007, 02:28 PM
Thanks, adweisbe.

I have 2 1911's, both full size Springfield Loaded models: one is the newer black stainless model, the other an earlier production model from 1999 (before they went to ambi-safeties and the ILS gizmo). The newer black stainless one is the one causing trouble.

I removed its extractor and replaced it with the extractor from the 1999 one, and it still did the same thing. Slide failed to completely return to battery, approximately half the length of the cartridge extended out of the chamber, and the rim of the cartridge was secured underneath the extractor. I did not try it totally without an extractor, though.

Further, the sharp lip I describe on the barrel of the black stainless version is no where to be found on the barrel of the one from 1999, which has a smooth transition from the ramp into the barrel and no sharp edge to speak of.

Thoughts?

JoeHatley
August 28, 2007, 02:33 PM
I used a cloth and some Flitz on mine.

http://www.iowatelecom.net/~hatley/sw1911_ramp.jpg

I'm not sure I accomplished much, it's always feed fine, but it sure cleans up easier.

Joe

Spartacus451
August 28, 2007, 02:49 PM
My thoughts are always to wait and see what 1911Tuner has to say, but if I had to give it a go...

http://newforum.m1911.org/showpost.php?p=248480&postcount=2
Second in the series of most common malfunctions is the Failure to Go To...or Failure to Return to Battery. Actually more common then the true failure to feed, and sometimes a little more difficult to cure...though still not beyond the reach of the average tweaker. Most often due to excessive stem bind, it can also be a light 3-Point Jam. The 3-Point often mimics excessive stem bind, and is sometimes difficult to tell whether it's a light 3-Point, or excessive stem bind.

Due to the feeding angles and other areas of the design, Browning-based tilt barrel designs operate under a certain amount of stem bind. Nature of the beast, and there's a purpose for it. It serves as a sort of brake that keeps the slide from slamming into battery so hard that it damages the lower lug feet...the slidestop crosspin...the slidestop pin's hole in the frame...or even the frame itself. Additionally, a proper measure of stem bind contributes to the overall control part of "Controlled Feed" that helps to make the 1911 and other similar designs so reliable. Excessive stem binding is another matter, and usually produces the failure to go to/return to battery sooner rather than later. All may be well until the gun gets a little too dirty, or a little too dry...or the recoil spring starts to fatigue a bit. Again, here is where many people decide to do a little reliability work...and reach for the ever-present and dreaded Dremel tool. Notice a trend here? Lay the Dremel on the table and leave it there!

While the full-blown 3-Point Jam comes as a result of a wedging action, caused by hard interference brought on by barrel engagement timing...the stem bind problem is more of a friction and/or clearance issue. The most common being a simple matter of excessive extractor tension, and...almost evenly divided...extractor geometry. Trailing the possibilities in a distant third place is the magazine itself, though the magazine-related problem is seldom alone in the game...and when it is...it's generally our old friend, insufficient spring strength.

Part of the magazine's function is in pushing the case rim under the extractor. In some magazine designs, it's ALL that performs this function, except for the final dab of pickup just as the round completes its breakover and enters the chamber. In others...notably the gradual, late release designs...the round breaking over to horizontal by way of the slide's forward movement utilizes the top of the barrel ramp to help cam it into the extractor. Although these magazines are timed for a later release...the release actually starts earlier, with the final release occurring later.

Both functions are important...but with some magazines, the spring is THE deciding factor. In these, the ability of the case rim to smoothly cam the extractor open and allow access is critical. Not only is a light bevel at the bottom of the tensioning wall needed, but the positioning of the wall itself relative to the breechface can make or break reliable feeding. Here is where aftermarket extractors with oversized front pads...aka "Fitting Pad" comes into the picture. It allows the installer to set the extractor at the optimum depth...closer to or further away from the breechface center. This has two distinct advantages. It allows the use of abrupt/early release magazine timing and it allows the extractor to have a little heavier bend...and more tension for reliable extraction with less risk of the claw slipping off the case rim. Of course, the depth and added tension can also be used with gradual/late release magazines. So...There is a distinct advantage to a good aftermarket extractor, as long as the installer understands that they are NOT drop-in parts that only require tensioning in order to fundtion. They may...but probably not, and in any case, very unlikely to perform at optimum unless fitted and carefully tuned. Certain modifications are also often required.

The distance between the two small, parallel blocks at the underside of the breechface are next on the list of probably causes. This distance should be no less than .484 inch, with .488 being the other end of the spectrum, though there are many smiths who will open'em up to .490 and beyond. But, for all but the most stubborn...this range will work. I like to see it about in the middle at .486 inch, with a light bevel on the lower corners to effect a funnel or camming effect. Seems to work well, and it's a lot easier than opening up the whole block.

Next is roughness...either in the chamber...on the barrel ramp's top corner...or the breechface itself. Breechface finish problems are most often around the firing pin port, but can come in other ways and in other areas. There's no need to mirror polish the breechface...and like overpolishing the feed ramp...can be detrimental in some pistols. Most notably those that don't have the correct 89 degree/8 minute angle. If the breechface is closer to 90 degrees than specified, overpolishing of the breechface often results in loss of control of the feeding round, and most often near the bottom two rounds in the magazine...and most often on the last round.
That angle is there to act as a soft brake that prevents the rim from jumping out of the magazine too quickly. If the angle is too close to dead vertical, it makes this little trick more likely to happen. So...If roughness of the breechface is noticed, the key word is "Smooth" rather than "Mirror." There is correctly and properly a small amount of friction offered to the upward moving rim. If it jumps, it's out of control. Loss of full control...even for a fraction of a second...is enough to make a malfunction more likely. Not guaranteed, and certainly not every time...but a matter of "Sooner or Later." A smooth, controlled transition from magazine to extractor pickup to breakover to seated in the chamber is the desideratum.

Last on the list is the recoil spring itself. Technically and more correctly referred to as the "Action Spring" rather than the recoil spring...an overly-weak spring can be a contributor to a failure to go to battery...though seldom the only cause. In a pistol that is functioning correctly...even a half-strength spring should strip and chamber the round, and put the slide into full battery...provided that the spring is full-length and not cut too short. This isn't to suggest that the proper cure for an occasional failure to go to battery is to install a stronger than specified recoil spring...but rather that new, standard-strength spring should be included in an overall reliability tune-up. Changing the spring at regular intervals is the accepted practice that keeps the gun running smoothly, but isn't a cure-all for feed and RTB issues.

The definitive test to determine if the extractor is the primary or sole cause of a failure to go to battery is simply to remove it and see if the gun functions more smoothly without it. If it does...the main problem is with the extractor. If not...it's elsewhere. One final point is that...although the extractor is the primary cause...there may also be other factors at work along with the extractor issues. A stacking of sorts where no single problem will cause the problem by itself...work together to throw everythig oput of whack. While dddressing any one of these problems may allow the gun to work...seeing to all of them provides a higher degree of reliability than addressing only one or two. The quintessential "Reliability Job" that is usually done, but sometimes overdone. Not always to the point of producing diminishing returns...but unnecessary work to no real or practical end. i.e. If it functions at or near 100%...what can really be done to make it more reliable? Since it's statistically impossible to improve on 100%, and since 100% is a statistical impossibility...what can be done to increase the odds of near-perfect function than simply seeing to simple details? The answer is, of course...Nothing.

The more that you alter the basic dimensions beyond a certain point...the greater the liklihood of taking it too far. Simply put...While a little is good...a lot isn't necessarily gooder. Know when to stop.

Since you have two barrel ramps to compare and you can see a difference (where I think there should be no remarkable difference) then you have probably located a problem spot.

When you say the rim of the brass are you talking about the mouth of the case where it meets the bullet? Are you using wadcutter or hollow points or plain old ball?

Detachment Charlie
August 28, 2007, 02:57 PM
DREMEL -- Full Speed, 80 grit abrasive wheel or stone, press really hard. Ramp should turn blue just before you grind all the way through. Then, go to the gunsmith & have him install new barrel and polish the feed ramp.
Hey, everybody else here has done it.:neener:

Smeg
August 28, 2007, 03:04 PM
Plain old ball is all I shoot, sometimes reloads in my older one, but not in the black stainless since it can't even feed ball reliably at the moment.

When I say the rim of the brass, I'm referring to the part that the extractor grips against the breech face.

As far as trying it without the extractor as you and BigG have mentioned, will that yield a different result from trying it with an extractor I know to be functioning properly? If so, I could give that a shot. I assume this would be done by locking the slide back then dropping the slide stop to feed a round rather than shooting it without the extractor, right?

It may bear mentioning that when a failure to return to battery occurs, it is easily rectified by partially pulling the slide back and letting it slam forward again to give the round a second tap to enter the chamber. Would this be more indicative of a possible problem with the breech face or a possible problem with the throat?

Smeg
August 28, 2007, 03:05 PM
DREMEL -- Full Speed, 80 grit abrasive wheel or stone, press really hard. Ramp should turn blue just before you grind all the way through. Then, go to the gunsmith & have him install new barrel and polish the feed ramp.
Hey, everybody else here has done it.
My mother once told me to be avoid people like you :).

Mark whiz
August 28, 2007, 03:05 PM
It might be in your best interest to call Springfield, explain the situation to them. They really seem to go out of their way to take care of issues and would probably fix it at no charge, maybe even polish up things real nice for you too.

Smeg
August 28, 2007, 03:09 PM
I want to learn to do this myself, though. I don't think this is a problem beyond my abilities. I just need a little advice getting started.

Spartacus451
August 28, 2007, 03:12 PM
The extractor is a fitted part so there is no performance guarantee when dropping in an extractor from another gun.

I am having trouble understanding how the top of the barrel ramp could bugger up the rim of the case.When do the two come in contact?

If you can recreate the jam hand cycling with the extractor then it is worth checking if you can recreate the jam by hand cycling without the extractor. It is possible that it won't show up with hand cycling. As for shooting without the extractor, I am not sure if that is what 1911Tuner meant. You should be able to hear and feel the difference between rough feeding (overcoming a lot of sudden sharp stem bind ka-chunk) and smooth feeding.

Smeg
August 28, 2007, 03:26 PM
I'm sorry, I meant mouth when I said rim in my original post. It has been edited accordingly.

I will try hand cycling again without the extractor.

1911Tuner
August 28, 2007, 04:06 PM
If the top corner of the barrel ramp...throat...is sharp, then a little rounding and polishing will help...but that doesn't sound like what's causing your problem. The mark just below the case mouth indicates a 3-Point Jam, and that's caused by the bullet nose impacting the barrel ramp too low, and pushing the barrel forward. If it has a distinctive "Ka-Chunk" sound and feel as it feeds...more pronounced on the top two rounds...that's your problem.

Be very careful if you polish the top corner of the barrel ramp. Remove VERY little material.

You may be able to cure it with a different magazine design...and maybe not. It depends on how far out of spec that your feed ramp is. Switching to a gradual, late release point may do the trick. See if you can borrow a factory Colt 7-round magazine. 7...round. Pictured below is the difference.
The two outer magazines have the lip design that you want to try. The center mag is like the McCormick.

http://i40.photobucket.com/albums/e243/1911Tuner/Lips.jpg

Hoppy590
August 28, 2007, 04:16 PM
proper way to Polish your throat?
http://www.thehighroad.org/attachment.php?attachmentid=63054&stc=1&d=1188332010

+

http://www.thehighroad.org/attachment.php?attachmentid=63055&stc=1&d=1188332126

:neener:

Whats one word in the english language that changes its meaning when capitalized.... Polish ( as in ethnicity/nationality) and polish ( as in to make shiney!)

Smeg
August 28, 2007, 04:30 PM
Whats one word in the english language that changes its meaning when capitalized.... Polish ( as in ethnicity/nationality) and polish ( as in to make shiney!)
Har har :p. You're supposed to capitalize significant words in a title, goober.

Thanks for the info, Tuner. I didn't realize there was that much of a difference between McCormick and Colt magazines. I know you specified 7 round, but do you think a Colt 8 round might do the trick as well?

The "Ka-Chunk" you described was most certainly present when I was using the Springfield OEM 7 round magazines, and switching to the McCormick afforded an immediate improvement. I don't have access to a Colt magazine, so would it be wise for me to go ahead and pony up the dough for a couple, or would it hurt to try and round off the top corner of the barrel ramp first?

What about bending the feed lips on my McCormick magazines to the shape of the Colt feed lips?

1911Tuner
August 28, 2007, 06:03 PM
I know you specified 7 round, but do you think a Colt 8 round might do the trick as well?

No.

What about bending the feed lips on my McCormick magazines to the shape of the Colt feed lips?

Won't work.

Hoppy590
August 29, 2007, 12:11 AM
just having my own personal laugh. i walked into almost the same situation about polishing a car

Smeg
August 29, 2007, 08:56 AM
OK, here's the deal...

I was able to acquire a mil-spec 7 round magazine with the little tit on the follower and the feed lips as you described. I used new cartridges this time instead of the same ones I have been using that were all chewed up. The gun still jammed in the manner I described, but the mouth of the casing was not damaged in any way.

Thoughts?

I just realized I completely forgot to try cycling it without the extractor. I'll give that a shot when I get off of work.

1911Tuner
August 29, 2007, 09:09 AM
I was able to acquire a mil-spec 7 round magazine

Mil-spec or actual USGI magazine? The term "Mil-Spec" has become a catch phrase, and doesn't guarantee that it's the genuine article.

The full-tapered GI magazines sometimes require a little adjustment for the release timing. Easy to do if you've done it enough...but tough to get right if you're not experienced.

The "hybrid" type magazine combines the gradual release of the GI magazine and the timed release of the wadcutter-type mag...but slightly later.

The gun still jammed in the manner I described, but the mouth of the casing was not damaged in any way.

The undamaged case indicates that the magazine did away with the hard 3-Point Jam...which solves the main problem. If you can push the slide into battery with the stoppage, it's probably a matter of extractor tension, or a weak mag spring. Remove the extractor and see if the gun feeds smoother.
If it does...tweak the extractor.

Smeg
August 29, 2007, 10:04 AM
Would you mind elaborating on tweaking the extractor? I know I've read somewhere that this can be done by hand by placing part of the extractor in the extractor slot and bending it one way or another to loosen/tighten it. Is there a better way to do it without a tool specifically designed for adjusting extractor tension? Should the fulcrum for the bend be closer to the hook, middle, or base of the extractor?

When I'm function testing without the extractor, should I release the slide by hand, or drop the slide stop?

*I took some pics of the jam last night, I will post them after I get out of a meeting in about an hour.

Smeg
August 29, 2007, 11:53 AM
Pics:

http://i231.photobucket.com/albums/ee64/tjellzey/1911Jam004.jpg

http://i231.photobucket.com/albums/ee64/tjellzey/1911Jam003.jpg

http://i231.photobucket.com/albums/ee64/tjellzey/1911Jam002.jpg

Smeg
September 1, 2007, 06:52 PM
Thought y'all might like to know, problem solved.

I took out the extractor, banged it a bit with a hammer to reduce the tension, and it works wonders now.

I never did try cycling it without the extractor, but I did notice that the rims of the jammed cartridges were chewed up pretty good.

Thanks for the help.

1911Tuner
September 1, 2007, 07:01 PM
In the middle picture, it looks like the extractor is contacting the forward bevel of the case extractor groove...and maybe the hook is a bit too long, too. That may be part of the problem, but as long as it's up and runnin' shoot it and see how the extractor tension holds out.

Smeg
September 2, 2007, 02:17 PM
Yeah, I polished the bottom bevel per a recommendation I saw in one of your other posts as well.

Couldn't have done it without the info you've already provided.

1911Tuner
September 2, 2007, 05:02 PM
Not the bottom bevel of the extractor...The nose of the extractor is bearing against the forward angle of the case extractor groove.

wally
September 2, 2007, 05:37 PM
The nose of the extractor is bearing against the forward angle of the case extractor groove.

Which is likely the reason reducing the extractor tension may have solved the issue at least for these ammo brands. If the hook really is too long you might find the problem re-occur with different ammo unless these current brands are at max dimension.

--wally.

Smeg
September 2, 2007, 11:50 PM
Oooooh, I see what you're saying. I'll keep that in mind if problems should happen to return.

Hacker15E
September 3, 2007, 01:43 AM
Let the record show...another 1911 feed-ramp-polishing-train-wreck averted.

Tuner, you're the man.

I can't wait to go shooting with you again when I get back from England!!

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