1911 dust cover crack

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45auto

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Opinions on dust cover cracks:

I have a 1/4" "hair line" crack on a 5" steel Colt 1911. It has about 30,000 rounds and it's the main shooting gun. I'll take it to a gunsmith in town just to make sure it's a crack, but it looks like it.

Is this something that will continue to crack, i.e. wait till it's worse, take care of it right away, etc? I'm the orginal owner so I suspect Colt will replace it no charge...I'm assuming.

However, I doubt they will fit a new beavertail, extended ejector, smooth the edges, high grip the frame, etc, etc. Perhaps it might be cheaper for me to send it out and have the crack repaired!

This is a situation where the warranty is nice, but rather not use it...maybe
;)

Your thoughts.
 
What are you calling a dust cover ? There are some military guns that have a 'dust cover' which is a sheet metal piece that covers the ejection port and keeps out dust and dirt.
 
I may be calling it the wrong name. It's "covers" the recoil spring and rod on the frame. It's cracked at the rear, nearest the slide stop hole in the frame.
 
Whoa. Sounds like someones been pushing the edge of the envelope with it. I read about a guy who cracked his similarly from running 260g bullets in it. Supposedly he had it welded up and just uses it for a range gun now with softball loads.

I'd replace the frame if it was me.
 
By "dust cover" do you mean the "bushing" at the muzzle? If that's the case, replace the bushing.
 
However, I doubt they will fit a new beavertail, extended ejector, smooth the edges, high grip the frame, etc, etc. Perhaps it might be cheaper for me to send it out and have the crack repaired!
Click to expand...
You are probably right there - might be cheaper to just get the crack fixed. I would think that would be do-able...

Tuner...? Old Fuff?
 
Cracked

Yep...They'll crack at that point. Nope...It ain't likely to crack all the way through. Most stress cracks are self-terminating, but just to be sure,
when one of my beaters crack there, I center-punch the end of the crack and check-drill it. Three of my regular beaters are cracked there...all were check-drilled 10-15 years ago and the guns have done fine. They look a little funky, and if it's an issue, it can be tigged and refinished. You'll have to judge whether or not the gun is worth it.

What usually causes it is insufficient clearance between the top of the spring tunnel and the bottom of the slide when the slide is fully rearward.
When the slide smacks the guide rod head in recoil, the frame flexes slightly, and the end of the tunnel pushes against the slide. The sharp corner formed at the junction of the tunnel and the frame rail is a good place for a stress riser to form, and a crack is sure to follow. Clearance should be .007-.010 inch between the slide and the tunnel with the slide all the way back. I like a little more...about .012, but .010 should be enough as long as you keep a fresh recoil spring in the gun about every 2,000 rounds and you don't shoot a lot of high-pressure ammo or heavy-bullet handloads...over 240 grains/velocity over 750 fps.

Shock buffs will help to delay the onset of those cracks, but probably won't prevent them altogether. I use buffs in my own design recoil system in my beaters, but not in a carry gun. Some pistols do okay with buffs...Some don't. Heavier than standard recoil springs may help a little too...but will often start a crack at the slidestop crosspin hole if the gun is a really slick feeder, and heavy recoil springs can bring on a whole 'nother set of reliability problems.

In any event, the crack will probably stop when it reaches the thicker area of the spring tunnel/dust cover.

Luck!

Tuner
 
I think that Tuner is on the right track. I have seen at least a dozen Colt lower ends cracked right where you say yours is. I always drilled the end of the crack and told the owner to keep on shooting. A shok-buff would have prevented that but it's too late now. I have seen more Commanders crack that Government models. A really good welder can fix it but I would not put the heat on it if it were me. Colt will not replace it. They also will not sell a lower end to anyone. That is the area where the slide smacks the frame hard every time you fire the gun. I have never seen a Caspian frame crack in 20 years.
 
Thanks for the replies.

This gun has always been shot with moderate loads and a shock buff...always!
14lb to 15 lb recoil spring.

Is this a "Colt" problem or a 1911 problem?
 
Who's Gotta Problem?

Howdy .45 Auto,

It's a..."Ain't got enough clearance between the top of the cover and the bottom of the slide"....problem, but they'll all usually do it, given enough use. The sharp corner left at the junction of the frame rails and the end of the spring tunnel left by the machining step is a perfect place for a crack to start. As the metal fatigues from the repeated impact...aided by the repeated flexing/relaxing of the tunnel...the internal stress riser formed by the machining step turns into a crack. Certain other areas on the gun are susceptible to it, as well...which is why it's a good idea to lightly break sharp corners wherever possible.

Luck!

Tuner
 
Cracked

WA said:

Im no expert but the only two I have ever seen were on a lightweight Commander and a full size Caspian....
_____________________

I've seen a BUNCHA lightweight Commanders crack there. Also a whole slew of GI pistols, and a few Commercial guns that had high round counts.

Besides my old GI beaters, I've got an early 1991-A1 with a crack started on the left side of the gun. Estimated at about 40,000 rounds...split about half and half, with/without buffer, and all hardball or hardball equivalent
reloads. Also seen three Caspians crack...All three with high round counts,
estimated somewhere in the 50,000 + range.
 
Interesting thread, I just wish my gun wasn't the "subject" of it. :)

It seems to me, in my simple mind, that if this type of cracking is not unusual that "they" would change how they produce them.

Round the corners, thicker dust cover, more clearance...isn't that possible?

Any thoughts on Kimber or Springfield frames...any difference or all the same?

Hi Tuner,

Do you think a 16lb spring would have made a difference, even on moderate loads? Power factor of @170. I think hardball is @190.
The 14lb spring feels the best with a shock buff. They do sell a FLGR with a buff on both sides of the recoil spring head, perhaps that would have helped also??

Also, this gun has a fair amount of vertical play between the slide and frame. Perhaps the slide is pounding the dust cover more because of this excessive movement?

I'm asking these questions not to "whine" about Colt or the 1911, rather to prevent it from happening again.
 
Preventable

Howdy 45Auto,

The answer to your questions...Probably, but maybe not.
It depends...(Gawd! I sound like Senator Kerry)

A heavier spring would soften the shock a little and delay the onset of a crack there by about the same percentage that its rate is above a 16-pound spring...or roughly 12%. Adding a shock buff would bring that figure up tp about 20% more rounds before it starts. Not really substantial,
but st least something. Going up to a 25-pound mainspring would help
another 10% or so...and a firing pin stop with a radius on the bottom on the order of .075-.080 inch would help even more. Going too far on the spring rate...even if you don't wind up with other issues related to slide timing and speed...imposes more impact stress on the slidestop crosspin, and can bring on a crack adjacent to the hole in the frame.

Prevent it completely? Not likely without a change in the shape of the end mill used to cut the spring tunnel. Redesigning the tool by dubbing the corners so that it would leave a small fillet instead of a sharp corner would do more to prevent the cracks, but would require a tooling change. That costs money and jacks the price of the guns up. Just dubbing the corners of the tool isn't so much a problem as getting the corners of each flute
exactly the same keeping them sharp enough to make a clean cut. I made that very suggestion to Colt several years ago, but never got a response. Ditto for Springfield.

It also depends on the clearance that I mentioned before. Under impact, the frame flexes slightly, and the tunnel springs upward. Since the front
of the tunnel moves the greatest distance, that's the part that makes contact, and applies leverage on the junction based on the amount of force applied multiplied by the length of the tunnel. Just creating a slight bevel
at the front corners would negate a little of that. Increasing the clearance to .020 inch would probably eliminate it...but you'd have a visible gap between frame and slide...and most people find that unacceptable.

Look over the gun and find the square, sharp corners. Everywhere that you see one is a prime place for a crack to start. Some you can get to and break the corners...some you can't. Another good reason to keep a long, thin, tapered scrape around the workbench. You can get those into places that a stone or file won't go.

Hope this helps...even though I flip-flopped a little.:D
 
I have a plan for this! Ugh.................................................darn, I misplaced it. I did not know you were using a light spring which means that your slide was smacking that area of the lower end harder than normal. It is a 1911 problem. I know that changing springs is in fashion now more than ever now. The New SIG 1911 uses an 18 lb recoil spring. I also did not know you were using a shok-buff. I still don't know if you installed a guide rod in this 1911. One of the problems here is that we rarely have enough information to make a good diagnosis of these problems. I use 16 1/2 Variable Power Wolff recoil springs in every 1911 that goes through here. Anything else can affect the balance of the gun. Both light and heavy recoil springs cause various problems in different areas of the gun. I do not use light loads even in my Cowboy guns. I do not use heavy loads in anything but my .454 Casull Raging Bull. When you stray away from a balanced 1911, you can expect these kind of problems to occur. Tuner has seen alot more guns than I have because I have only used a couple of hundred Caspian Lower ends and to this day, have never had one crack. Of course, I address these areas in the ones I built so they are not off center and are getting the right kind of smack. I use a Blue Felt Tip Marks-a-lot and cycle the gun to see what is what in these. When you fire a 1911, you exert brutal forces on every part in that gun. The slide slams back, cocks the hammer, slams forward to strip a round out of the magazine and shove it in the chamber, and then does that again and again. It is a wonder to me that they seem to last as long as they do. Well, back to my plan for this..................................................................................................
 
What Happened?

I dunno dave...bad spring maybe? Very old spring...probably. Spring
was too long and stacked into a solid before the frame stopped the slide?
Very possible. Seen that cause it a time or two.

If ya imagine a pistol with a clear plastic frame and slide...and watch, in your mind's eye as the slide starts to move and the spring compresses,
you can see that the spring stacks up on both ends...on the stub guide rod and inside the plug. At full slide travel, the spring is captured both on its od by the plug...and its ID by the guide rod. It can't deflect sidewaya very much before that point because it's in the spring tunnel...at least not enough to cause a kink like that one. In fact...if you'll drill out the end of a standard-length plug, slip it over a FLGR and compress the spring, the plug will touch the guide rod head with the spring completely captured...so I vote bad spring on that one.

Cheers, old sport!
 
Last edited:
Okay, thanks for all the info.

I vote the manufacturers correct this potential "situation" with a design change as detailed by Tuner...imagine, they may even have to "think" instead of copying a design. :cool:

This gun has used a FLGR for half it's life to help what I thought was a sloppy slide/frame fit. Way too much vertical movement IMHO. I understand Colt is doing a better job now with their slide/frame fit now. This gun, by the way, has been very, very reliable and accurate. I'm keepin it.

I have used various springs during it's life, but I never thought 14-15lbs was too too light for a load 10% lighter than hardball. Many competitors use lighter springs than that and shoot much more than me without problems, but mine cracked...oh well!

Life is short, don't sweat the small things. :)
 
Thanks, Tuner and Dave,

I have seen that situation, and had it figured out that way. I am glad to have you guys confirm my thinking. Those threads are always great for learning something.

Jim
 
Confirmation

Hey Jim! Sorry I was so long gattin' back on this one.

I sorta stumbled on that theory after noticing that on several frames that were cracked in that area, that there was evidence of harder contact about an inch back from the end of the spring tunnel. I started using feeler gauges to check and found that the clearance was tighter near that point when the slide was in full recoil position. I started checking all the new or nearly new pistols that I set up for hard range use, and on the ones with less than .010 clearance, I draw-filed the tops of the tunnel rails to get the clearance...and I haven't cracked one since.

Got another theory to run by ya...

You've seen the cracks that run adjacent to the slidestop pin hole...The one that runs from right at the bottom radius downward. I've found that
about 80% of the ones that do that either feed and go to battery so fast and hard that the slide goes home with a "WHOP" instead of a smooth "ka-chunk" sound... or the owners have used high-rate recoil springs in the guns for hard use. Just as a sidebar, in nearly all the pistols that have cracked there...the magazines that were used exclusively were
the ones with the wadcutter-type feed lips...the ones that release the round early and abruptly as opposed to magazines that have tapered lips and release more gradually.

I'm pretty well convinced that there's a connection, though I'm not sure yet
how much the magazines' abrupt release contribute to the cracks.

What think?
 
Is it possible that with a shock buff, if it fits tight in the cover, that when it expands from impact it could crack the dust cover?

How tight should the guide rod head and buffer be in that area?
 
Anything is possible, but I really doubt that a shok-buff would case that frame to crack. I think it cracked because it was not built right.
 
I think it cracked because it was not built right.
Click to expand...

One thing that is ignored is that a gun is a just a metal mechanical device. Like any other mechanical device it can break.

Some break faster than others. Millions of reasons why....

WildmetalfatigueAlaska
 
Okay, thanks for the info. I'll stop "whinning" about my gun now. ;)
 
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