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Discussion Starter · #1 ·
I recently installed a Kart easy-fit bbl on my Colt 1911. Accuracy is outstanding. I do have an intermittent problem with f-t-f.

The 230 gr. RN factory round will jam between the top of the chamber and the back of the breech face. Some suggested that the bottom lip on the chamber needs to be radiused and polished more.

Any suggestions.



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517 Posts
Here is one possible, on M1911.org, by "1911Tuner". Read the whole article, but this is the digest version:


3-Point Jam (courtesy of 1911Tuner) [sorry, direct link won't work.]

"Feed stoppages... ...and most often these are a failure to go to full battery. Rather than go into the standard advice to adjust the extractor...polish the breechface...get good magazines... polish the ramp and throat...ad nauseum...I'll assume that the reader has already addressed these areas, and is at a loss to determine the cause of his woes.

Stem bind is usually the culprit in a failure to return to battery. Actually,.. Excessive stem bind is more accurate...or what is technically known as the "Three-Point Jam"

Three points...binding between the breechface, the barrel throat, and the underside of the barrel chamber. ...

There are a couple of approaches that will usually work. If the barrel is standing on the link in vertical lock, you can try a shorter link. You're limited to about .003 inch shorter here. ...

If the barrel is correctly locking via the bottom of the lug and the slidestop pin...and the lower lug is dimensioned so that the link is holding the pin away from tha frontt radius, you can't use a shorter link unless you modify the bottom of the lug...which will undermine your vertical lockup.

You can, however, modify the link a little by elongating the slidestop pin hole at the top to get the barrel off the link and onto the lug where it belongs. The barrel rise will be delayed, so that the slide will be a little further forward and the round a little deeper into the chamber...and at a shallower angle. The unlocking and linkdown timing will be unchanged, since the BOTTOM of the link's hole determines where and when the barrel will begin to unlock...and your stem bind will be substantially reduced.

On this modification, you are limited to about .005 to .006 inch of elongation, and even if it doesn't put the radius on the crosspin, it will put it much closer...relatively speaking. The probability of correcting the three-point jam with this is high...about 95%. If the lug rides on the pin, the chances of success are even higher. Elongating the hole even as little as .002 inch will usually produce a dramatic difference...so take it a little at a time. No more than necessary. This will make it a trial and error exercise.

To do this, ...." [instructions follow.]

Once again...credit to "1911Tuner."
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