I have a Colt Series 80 that appears to be un-modified, Colt barrel, which I have owned 3 years. After recent target practice, 200rds, no issues, it was time to deep clean the pistol. I ultrasonic cleaned, inspected parts for cracks and/or battery and found some issues/questions.
When in battery the barrel tang falls short of contact with the frame breach face by .012". Instead the rear edge of the barrel chamber impacts the breach face between 10-11 and between 2-4 when looking at the frame from the front. The barrel chamber rim itself shows only minor impact in these 2 areas. Since the tang is short when the barrel cycles into battery the barrel rides up the sides of the breach not on the barrel tang.
Additionally, the barrel hood tang width seems undersized. The tang measures .418" and the slide slot measures .440". Since the barrel rides the link (not the lugs) this allows the barrel to roll counter clockwise causing the firing pin to strike the primer about .030" off center, to the lower right.
The pistol operates fine but these issues seem problematic. Should I replace the barrel or is this slop acceptable for an unmodified factory pistol?
You'll find a set of Army Ordnance blueprints for the M1911A1 in our Tech Issues section, 14th link down. Assuming Colt uses those same blueprints to make your gun, the gap between the hood and breechface should be 0.002" to 0.010". But the fact that yours is 0.012" is of absolutely no consequence. Note that for a M1911A1 that is within specifications, the hood never comes into contact with the breechface.
As for the width of the hood and it's slot in the slide, your hood is 0.003" above the maximum spec and the slot is right at the maximum spec.
Such is the nature of the Gov't Issue M1911A1 and commercial versions such as yours. It's not a Swiss watch!
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Additionally, the barrel hood tang width seems undersized.
You have me confused. What are you referring to as the barrel "tang," and what is the frame breech face you think it falls short of contacting? The breech face in a 1911 is entirely part of the slide, not the receiver.
I misspoke; I intended to refer to the slide not the frame. The barrel tang is the rear of the barrel hood which protrudes beyond the chamber rim at the top. Clearly I need to bone up on 1911 component terminology…
Based on niemi24s feedback it seems the pistol is near enough to spec to not require a rebarrel.
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I misspoke; I intended to refer to the slide not the frame. The barrel tang
is the rear of the barrel hood which protrudes beyond the chamber rim at the
top
Based on niemi24s' feedback it seems the pistol is near enough to spec to not require a rebarrel.
And the aft end of the barrel hood is the only part that contacts (or nearly contacts) the breech face. The cartridge headspaces on the chamber mouth such that the head of the case is (approximately) flush with the back of the barrel hood. Below the barrel hood, the case rim is exposed behind the chamber portion of the barrel and there is nothing on the chamber mouth below the hood that can or should be contacting the breech face.
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...the rear edge of the barrel chamber impacts the breach face between 10-
11 and between 2-4 when looking at the frame from the front. The barrel
chamber rim itself shows only minor impact in these 2 areas.
I'm pretty sure what you're referring to is the contact between the chamber face and the breechface guide blocks (shown here):
Yeah, what to call all that stuff can be pretty daunting for a newcomer to the 1911. Guess we need a terminology guide/photo for the barrel & slide too - sort of like the one we've got for the frame in the Stickies. Hmm-m-m.
Well, as long as I brought it up - here's a trial image:
Please let me know if there's anything else that should be included.
Thank you both for your feedback. The drawings are a big help. I inserted a sized cartridge in the chamber and reviewed the chamber face to breech face relationship. The seated cartridge head looks to be .010+-from the breech face and as Hawkmoon indicates is ~ even with the back of the barrel hood. In my series 80 it is the chamber face which contacts the breech face guide blocks during a cycle into battery, the chamber extension (barrel hood) contacts nothing even though it passes within (.005") of the breech face. Is this a problem which needs to be corrected?
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Is this a problem which needs to be corrected?
This from Post #2 holds the answer.
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Assuming Colt uses those same blueprints to make your gun, the gap between
the hood and breechface should be 0.002" to 0.010". But the fact that yours is
0.012" is of absolutely no consequence. Note that for a M1911A1 that is within
specifications, the hood never comes into contact with the breechface.