Cracked barrel bushing??

[kayakersteve]

I was cleaning my Sig 1911 last night after a shooting session and noticed a fine crack through the bushing. I've not seen this before and was wondering if other 1911 folks have?? I called Sig and they are sending a me a replacement and didn't seem to think it was a big deal?? Anyone else experienced this?? Could it possibly lead to injury to me or the gun if I hadn't noticed it??

 

[IanS]

Its very very rare but any part can fail due to poor QC or bad manufacturing techniques. That goes for tool steel, MIM, or cast parts. The good news is that most defective parts give up after the first few hundred rounds. That's why its important to really test and push any gun before relying on it.

Most likely the recoil plug, spring, and bushing would have flung downrange and you'd probably just have been shocked and embarrased at the range. If you were using it at that moment to defend yourself well, that would not have been good to say the least.

Did SIGArms (SIG Sauer) say the busing can literally be dropped in and not fitted?

 

[kayakersteve]

Yes, they did

Did SIGArms (SIG Sauer) say the busing can literally be dropped in and not fitted?

They did and I was a little suprised as I thought they needed to be honed to fit just right...But I am relatively new to 1911's. I even offered to send the barrel and bushing in for them to look at and they stated that would not be needed.

 

[IanS]

Some bushing are literally so loose that no fitting is needed. SW1911, Colt, and I guess SIG's as well. It shouldn't be a problem. Drop it in and drive on.

 

[wjkuleck]

I thought they needed to be honed to fit just right

Yep, but "good enough" is, well, "good enough."

Regards,

Walt

 

[WESHOOT2]

just me?

I myself would be wondering how that bushing cracked......oh yes I would.......

(SEE, because usually they crack for a reason).

 

[kayakersteve]

Me too!

Any thoughts??? I have wondered that and was concerned about the attitude from Sig that they would just send me a new one and didn't even want to see the old one for evaluation???

 

[ranburr]

Take this opportunity and put a good bushing on the pistol. King's or EGW's oversized. It will do wonders to improve the accuracy of the pistol. And, they won't break.

 

[OneClownDown]

The wonders of CNC machining will never cease. Modern methodes of machining make it possible that each part is as near identical as the previous one. Gone are the days of each machinist setting up the lathe and hand dialing in rougher and finisher for each part. Multiple tool holders in a turret head and electronic eye sensors along with a bar stock feeder will spit out identical pieces. Sans custom fit hand finished firearms, you're not really gonna see or lose much in receiving another "drop in" bushing from SIG. Yes modern maching has made it cheaper, but once set up, the cnc will put out more quality with consistantcy.

 

[fastbolt]

A King's bushing cracked in a friend's Officers Model ... after he'd fired more than 10,000 rounds through it. Another one was fitted and more than another 10,000 rounds was fired without issue before he retired that .45 for other off-duty weapons. He still takes it out and shoots it from time to time, though.

A couple of his other replacement choices have racked up more than 50,000+ rounds each since he started using them.

He's hard on his handguns.

 

[wjkuleck]

Modern methodes of machining make it possible that each part is as near identical as the previous one

CNC is only as good as the tooling/gauging. Tools wear. There will always be a manufacturing tolerance. If you're CNC'ing a bushing/barrel pair, the tolerance is set so that the largest barrel OD permitted (before changing to a new tool) will fit into the smallest bushing ID permitted (ditto). This means that you'll have a tight fit with the CNC parts if both are at their tolerance limit in the converging directions. You'll have a looser fit otherwise, and the loosest fit when the barrel OD is at min and the bushing ID at max.

CNC does not affect tolerance bands. CNC allows machine programming directly from solid model CAD, makes numerous setups unnecessary, and, with autogauging, can change worn tools for fresh ones. All this makes staying within the tolerance bands more practical. CNC does not, however, make identical parts; properly programmed, it keeps the parts within tolerance.

"Gunsmith-fit" bushings have an ID smaller than the tolerance for "production" or "drop-in" fit. However, you do need to open the ID up enough so that the barrel will fit into it.

Regards,

Walt

 

[OneClownDown]

Walt,

I'm aware of that, this is where QC plays its role in inspecting the parts assuring they conform within the tolerances of the blue prints. Tooling gets changed out, a part is run to assure tolerances, and the line continues until the next tool change. I beg to differ in the area of tolerances and CNC reliability. All CNC machines are different from one another, thats why say in a conversational or G code(FANUC) program, there are offsets placed directly into the program prior to running through the operator/programmers experience and can be adjusted mid runs to compensate for tooling wear. The intial set up is the key to repeatability. Tooling does wear eventually, but there again thats what offsets and inspections are for.

 

[wjkuleck]

Tooling does wear eventually, but there again thats what offsets and inspections are for.

We are in violent agreement.

My point, unclear as it was, is that CNC does not a perfect part make, much less every part being perfect, or even the same. Even with CNC, you will find one set of mating parts that fits much more closely than another set, yet all the parts will be within the tolerance that was set down.

That's the nature of manufacturing. That 1911 bushing, when it arrives, may be quite snug on the barrel, or noticeably loose, depending on how the tolerances stack. That's irrespective of whether the parts were made on a Haas CNC machining center or a Warner & Swasey #2 lathe.

Respectfully,

Walt

 

[brickeyee]

The only cracked bushings I have ever seen were caused by inadequate relief for barrel tip down during cycling.
A bushing needs enough clearance to allow the barrel to tip down.
Many newer barrels have a reduced diameter back from the muzzle to provide the clearance, but a bad tolerance stack can still occur.
Older straight barrels require relief of the bushing to allow tip down.

 

[wjkuleck]

Older straight barrels require relief of the bushing to allow tip down

[Sincere question] So, how did all those pistols with straight barrels work for the last 90 years or so?

Regards,

Walt

 

[Master Blaster]

Sig uses a considerable number of MIM parts in their guns, the hammer and trigger (for sure), and the worthless internal extractor (probably) in my P220ST are MIM, Not sure about the barrel bushing in your SIG 1911.

That may have nothing to do with the problem. If you want to do it right, measure the largest outside diameter of your barrel, and the smallest indoe diameter of your slide opening, Check with Ed Brown, Wilson and other manufaturers for the dimensions of their drop in bushings (assuming its a standard barrel bushing for a 1911) and pick one with a .001 bigger inside .01 smaller outside diameter than your gun and you will have a national match fit that will improve accuracy. I used and ED Brown to replace the collett bushing on my 1975 series 70 colt and its still going strong after thousands of rounds.

You may also want to look at a briley spherical bushing as a replacement.

Meanwhile get the free one from SIG just in case.

 

[kayakersteve]

Hmm, I'm not sure about last post???

MIM parts - Here's a quote from Sig:

Each new model Revolution™ features a stainless steel slide, stainless steel frame with 25-line per inch checkering, match grade barrel, hammer/sear set and trigger. The de-horned slides and frames are machined to exacting tolerances and hand-fitted to insure reliability and performance. SIG SAUER uses only premium internal parts which means no plastic and no MIM parts.

Internal extractor /// Mine has an external extractor???


Food for thought??

 

[IanS]

kayakersteve,

When SIG Sauer says "premium internal parts" I think they meant it in a general way. I dont' see anywhere in the quote where they say "internal extractor". Don't let whats "on paper" necessarily influence you regarding performance. Generally certain things are more desireable for 1911 aficionado's but that doesn't mean it applies to every individual gun. Some people have issue with MIM parts and won't hesitate to spend the money to swap them right away. I don't. I've got over 10,000 rounds through my SA Pro and it has 3 MIM parts. It is the most tested and vetted semi-custom 1911 on the market and I've yet to hear of issues with MIM parts with the Professional Model. But I have seen tool steel parts prematurely breaking in other similarly priced 1911's. What does that mean? Not all MIM parts are equal. Not all tool steel parts are equal. Not all parts whatever the manufacture are equal. Get at least 1000 rounds of ammo and really wring your 1911 out once you've replaced the bushing. Only then will you get an idea whether the gun is good as is, new parts are needed, or whether you should go with something else.

 

[kayakersteve]

That's my plan! Thanks

 

[kayakersteve]

Update

I received the new bushing and I think I wasn't the only one that had this problem because the new one is much thicker - 100 rounds today wit no problems and accuracy is still great.

I was unhappy with the break, but happy with the service and fix!