I recently acquired a S&W 1911 with a Kart barrel installed.
It is wonderfully accurate but has an annoying quirk.
When shooting reloaded ammo, even the tiniest imperfection in the ammo
( slight bulge, off center bullet, OAL etc) will cause a failure to fully chamber that round even though it feeds smoothly up the ramp and "almost" fully chambers.
These very same reloads "plunk" and readily chamber in all of my other 45ACP autos.
Are Kart barrel/chamber dimensions tighter than usual?
Does anyone else have experience with Kart .45ACP barrels?

I haven’t had any issues with the one kart I have. You can always have yours opened up a little.


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I don't have 1st hand experience with Kart but I assume it's match grade with super tight dimensions.

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Jorge

A lot of times when that happens it's the bullet getting stuck in the rifling just ahead of the case mouth. Running a finishing chamber reamer with the proper "throat" will trim a smidge off the rifling to allow more different bullet contours and seating depths to function correctly. Many semi auto barrels have this problem, but it's a simple 5 minute fix.

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protocalldesign.com

You might also double check to see that the chamber depth itself is correct. Saami spec is .898" min.

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Ret. LE, FA Instr, S&W Armorer

Forget the plunk test, break down and buy an ammo gauge. Just because the loads plunk into your other barrels doesn't mean they're to SAAMI specs.

It's been decades, but back when I built 1911's I used a lot of Kart barrels. Their chambers are a wee bit tighter and at least then, had the leade (throat) cut for ball ammo. A wadcutter leade/throat would help some, and as noted above, fairly easy to do with the right tool and the right person holding the tool.

Kart does make a quality barrel and had the smoothest bores of any of the 1911 barrel makers I saw in use.

I'll agree and disagree with the above^ comment on an ammo gauge. These tend to fit max specs but at times bullet profile on the shoulders can cause issues in chambering. I have a S&W Shield that though my rounds safely drop into my ammo checker they are a wee bit too long to 'plunk' into my barrel and certain bullet profiles don't fit my barrel that do fit the ammo checker fine. These rounds do work fine in other guns I own.

I think you will need to reload rounds that 'plunk fit' your Kart barrel or see if there is a different bullet profile that works better and load for this Kart barrel. You may also invest if you don't have one a Lee Factory Crimp Die and see if that doesn't help you. It is likely that the rounds you make that fit the Kart will easily chamber in all the other guns you mention.
Karl

See Post #10 in the following Thread. Loading .45ACP with H&G 69 type SWC Forrest r's excellent discussion and photos should provide all the information you're seeking regarding Kart barrels. There's other good information in the thread as well; that's why I didn't just direct link to Post #10.

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Dave Brown
SWCA #3279

Kart barrels are my No. 1 choice for 1911s. But, I learned that they are not perfect. When I shot a lot of Bullseye, we tested Kart and other barrels in a Cominolli device. This is basically a cannon breach single shot action device that accepted a 1911 barrel. It was designed for accuracy testing. It bolted to our Ransom Rest fixture, which was itself a steel I beam set deep into a concrete foundation. Nothing short of an earthquake would affect accuracy tests.
The Nat'l Guard team would buy Kart barrels in a lot and test out the good from the bad.
We found that indeed they varied. The best ones would put 10 shots under an inch @ 50 yards. The mediocre ones would open up to 1.5" or so. Still OK, but when you saw the best ones, you get spoiled.
The chamber is a big part of that accuracy. Even the "bad" ones had good, tight chambers.
Fix the ammo issues first!

Jim

I second getting an ammo gauge and checking your ammo, especially if you're shooting handloads.
Years ago my best friend made his living building custom .45s. One of our friends came to him with his reloaded ammo and gun and asked the 'smith to work on his barrel so it would feed the reloads reliably. The 'smith gauged his ammo and said, "Load your ammo to spec and it'll work just fine. No need for me to redesign your gun to fit your ****** reloads."

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John

Sounds like as mentioned above it needs a finish reamer dropped in it. If you would like you can send me your barrel and slide so I can see how the hoods fit. From there I can ream to .904. That's my go to depth.

Before that though drop the depth part of a caliper in it and see where it's at.

If you'd still like it looked at shoot me an email at [email protected] or find me on the Facebook thing. Lol. Page is HS Custom, LLC

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Using Tapatalk

Seriously, I wouldn't touch that chamber before ruling everything else out of the equation.
Ammo is the first step.
Next, the fitting of the slide to frame.
After that, the fitting of the barrel lug and slide stop. This one is tremendously important. It affects lock-up, reliability, and even felt recoil. (When you hand cycle the gun empty, is there a slight snick or more pronounced hitch just as it goes into battery?)
Next, check the barrel bushing. Sometimes guys forget to allow for the angle of the barrel relative to the slide. The barrel can actually be torqued if the proper allowance is not there.
Last, check barrel hood to slide fit.

You might want to ask over on the Bulleye-L forum. They have some gunsmiths that really know about barrel fitting.

Best Regards,
Jim

PS: you do trim your brass and sort it by headstamp, right?

Buy a maximum cartridge gage! Don’t confuse crummy ammunition with a crummy barrel. Your Kart barrel is almost certainly not a problem. Learn to make good ammunition.

likely a little more crimp needed. a barrel capable of real accuracy will behave like this. I think Baer uses these barrels but not sure.

My P226 digest absolutely everything. On my 210 I need to really check the crimp and test every round in the case gauge. If it is sticky in the case gauge it won't chamber in the 210 but well made 9mm ammo shoots 2.5'' groups at 25 yards free hand in that gun. Ways better than any other 9mm I own. The barrel throats, chamber etc are way way tighter to the right tolerance apparently that a typical combat gun type setup.

For my wadgun with a Kart barrel when I use lead swc it really works better with a tighter crimp (.464-465). you did not say what bullets your using but if your using lead swc try a tighter crimp.

I have a Rock River with a Kart barrel. The test target that came with it has an 8 shot group that measures just under 11/2" at 50yds. They are good barrels. I've got 700 rounds loaded up that will not drop into the chamber. It's not a depth problem. They only drop in about 1/4". They need to be crimped tighter. Factory ammo always runs fine.

Yes! The SWISS MADE SIG P210 were designed, and made, right!
My personal choice for best service pistol, ever.
If the 1911 had been designed and built to that standard, there wouldn't be the cottage industry of 1911 parts and services that we know of today.

To the OP, the taper crimp recommendations are great. Troystat gives good numbers. Don't overdo it, or you'll get other problems.
By the way, you didn't mention if the Kart barrel you have is an E-Z fit, or the National Match gunsmith fit. The former have two rectangular patches in the lockup groove ahead of the chamber. These are nice barrels, but are often marketed for DIY installation which may be problematic in the wrong hands.
Do you know who did the work?

Jim

(PS: To Oysterer and fiveo, Baer and Rock River have indeed made some nice 1911s!)

I suspect the Kart barrel has a short throat. The throat may need to be recut to slightly lengthen it. It is also possible that the chamber is cut to minimum length or even minimum diameter. Again, a finish reaming of the chamber may be needed. But, before going to all that trouble and if you don't have the tools and knowledge of how to do it, taking it to a qualified gunsmith, take a close look at your reloads. Kart barrels are match barrels and they do require that the ammo meet the dimensional specifications of the caliber.

Back in the early 90's, I had a bullseye gun built with a Kart barrel. After fighting with problems like yours, I started shooting my H&G 200 gr swc bullets sized at .451". The .452" bullets caused the issues. I realize now that I should have something done to the barrel to fire the .452"s, but I just shot the smaller diameter lead slug.