How do you break a slide?

[OPinOKC]

MY AO1911 PKZ, bought new in September 04, is back at Kahr for the second time. When I called recently to check up on it, they told me they were waiting for a new slide to put on it. I've never heard of broken slides. Anyone know what might be wrong?

Both times it quit it jammed with the slide half back. According to the work report after its first trip to Worcester, they polished the feed ramp, barrel hood, slide stop, extractor bore, and replaced the extractor.

Kahr customer service is pleasant enough, although their excuses are not especially confidence building (it was taking a long time because their gunsmith who does 1911's took an unexpected vacation to Bulgaria), and I (naively) assume they're telling me the truth about the slide.

O.P.

[ranburr]

It is probably out of spec. If it is really broken, it is a cast part and it was probably a bad casting from the start. Either way, it is disturbing.

ranburr

[stans]

Auto Ordnance pistols are usually made up of cast parts, including the slide. Slides take a real beating, especially the back end of the recoil spring plug tunnel as it hits the head of the recoil spring guide rod every time the gun is fired. Castings tend to be very hard, perhaps a bit too hard for a slide. Hard parts tend to be a bit more brittle and prone to cracking. So a cast slide will usually crack at the point of highest stress, and that is usually where the back of the recoil spring plug tunnel meets the body of the slide. Cast frames, on the other hand, if properly made are nearly as durable as forgings or bar stock. It's just the slides that don't seem to last nearly as long.

[1911Tuner]

I feel yer pain! I've busted 3 slides and one barrel in the past 18 months or so. One was an old Thompson Auto Ordnance...a casting that had about 30,000 rounds through it...and two Colt USGI slides...machined barstock... that were rough enough to forego preservin'em for restoration projects, so I used'em up. :p

The barrel was original to one of the Colt slides...1942 production... and it broke in two just forward of the first locking lug. It went downrange with the bullet stickin' out of the muzzle. I thought the bushing let go and spit the recoil spring and plug downrange at first. Good thing I saw it, because the gun fed and chambered another round...and went into battery. If I'd tickled the trigger, it would have fired.

About 25,000 rounds after installing a new barrel in the gun, the slide let go. The AO slide broke clean through to air, while the Colts cracked and stopped about halfway. Both Colts continued to function, and I discovered the breaks at home.

All slides broke adjacent to the ejection port. The two Colts broke in the upper left-hand corner. The AO broke in the middle of the port on the right side. The gun suddenly started shooting a foot to the left, but otherwise functioned perfectly for the rest of the mag...4 rounds...and locked on empty.

Yeh. Defecation Occurs... :rolleyes:

[stans]

The port wall crack totally escaped me, but that is a bit of a thin area and subject to tensile stresses.

[1911Tuner]

The port wall crack totally escaped me, but that is a bit of a thin area and subject to tensile stresses.

Heh. That thing would almost shoot around a corner, stans... :D

The thing about a crack in a casting as opposed to a machined barstock part is that most of the time, a crack will progress slowly and only go so far in steel and stop, or it can be check-drilled to keep it from continuing. When it starts in a casting, it moves fast, and will usually break clear through...and check-drilling only slows it down. The crack will start again on the other side of the hole fairly quickly.

Sharp edges and corners are the most likely places for cracks to start.

[stans]

Agreed! I have one cast slide, and Essex casting for my home built Commander. I keep a real close eye on it.

[RitaR]

MY AO1911 PKZ, bought new in September 04, is back at Kahr for the second time. When I called recently to check up on it, they told me they were waiting for a new slide to put on it. I've never heard of broken slides. Anyone know what might be wrong?

Both times it quit it jammed with the slide half back. According to the work report after its first trip to Worcester, they polished the feed ramp, barrel hood, slide stop, extractor bore, and replaced the extractor.

Kahr customer service is pleasant enough, although their excuses are not especially confidence building (it was taking a long time because their gunsmith who does 1911's took an unexpected vacation to Bulgaria), and I (naively) assume they're telling me the truth about the slide.

O.P.
Go to the AO web site (you can get there trough the Kahr web site). Then go to the articles that they have reviewing the new 1911's. The Aug. 2002 Guns & Ammo Handgun magazine review talks about the slide on the test new AO gun being frozen in a partially opened condition. The article says a small sliver of steel atop the locking lugs on the barrel had sheared off the lug recess in the slide. Kahr says they are awere of the problem and have fixed it on current (what's current?) production.

[savent]

Just to set the record straight, AO states that their frames are 4140 steel investment-cast, but the slides are machined from bar stock (4140 billet CNC-machined). Other high-stress parts (slide stop,for instance) that were cast are now also machined from bar stock.

I'm sure many of you have heard of well-known gunsmith Bill Laughridge (chosen as 2005 Pistolsmith of the Year by the American Pistolsmithing Guild) from Cylinder & Slide.
He only customizes & repairs quality-built 1911's, and lists only these on his website: 1911 Colt , 1911 Springfield, 1911 Kimber, 1911 Kahr Auto Ordnance, 1911 Smith & Wesson. At the request of Gunweek Magazine, he tested the AO 1911 for hardness,
and here is their report:

"Laughridge had taken some guns from Auto-Ordnance and tested them for hardness on a Rockwell machine. Having similarly tested other 1911 clones of various pedigree and origin, and finding what he felt was soft steel, he was happy to report that the new stuff from Auto-Ordnance features good heat treating.

"Obviously," he said about the Auto-Ordnance pistols, "they are a price point gun. This gun that's coming through Kahr Arms is damn near on the money. . . . I think the Kahr Arms gun, the way it is heat treated, I would think you'll get 40,000 to 50,000 rounds."

[OPinOKC]

Thanks for all the helpful replies, guys, you're the best. My PKZ came back from Kahr, and looks like it has the same old slide. The gunsmith's notes only say that he polished the barrel. I took it to the range this afternoon, and put 40 rounds through it, Federal AE ball, only 40 because it's an outdoor range and it's hot here in central Oklahoma. It basically ran fine.

RitaR, I especially found the G&A Hanguns (2002) article helpful: both times the gun jammed (the cause of its trips to Kahr) the slide was stuck half open and would not move, just like in the article, which makes me think my problem is the one mentioned in the article. Maybe "polishing the barrel" means undoming the lugs. No telling when my gun, or its slide, was made, of course, but the fired shell case envelope is dated 9/14/04, which is about 2 weeks before I got it.

O.P.

[John]

I am not sure if the Rockwell test is the only thing that identifies a good slide (or whatever). It shows you how hard the metal is, but nothing more than that. The metal can be hard, but brittle, in which case it will crack.

[Ric4509]

Broken slide and/or slide keeps jammin'. My friend owns a shooting range and is planning on getting an AO 1911 for his rental gun wall. If this is the case, then an AO 1911 will not last. Our existing SS 1991A1 rental gun goes through 3,000 rds per week. It's been in the wall since for 4 years now. The barrel will soon to be replaced. It has a minute line of crack just below where the rail starts in the frame, about 1/16 of an inch.