1911 Slide To Frame Fit

[Aguila Blanca]

The barrel is in the slide, but the slide stop/cam is in the frame.

There is no cam in a 1911. There is a swinging toggle link.

If the slide to frame fit is such that the action of camming the barrel into lockup can actually move the slide upward, or pulling the trigger can move the slide upward (as in the BHP), accuracy will suffer.

Pulling the trigger of a 1911 does not and canno do anything to move the barrel. The barrel is moved up into lockup by the link, and as long as the barrel is moved into lockup consistently (the same each time), it really doesn't matter if there's some vertical play in the slide-to-frame fit or not.

In the 1911, the link fit is another complicating factor and the lockup can be affected if the link forces the slide upward relative to the frame when the barrel locks up.

See above. Consistency is what matters.

 

[polyphemus]

The barrel lug geometry functions as a cam and it is what locks the barrel up.
The link unlocks it as the slide reaches the separation point the link has no effect on barrel lockup,the barrel should sit square on the crosspin until the link
pulls it down.

 

[RickB]

That's the case in a "hard fit" gun, but not the case in the M1911/A1 specs.
The barrel is essentially "floating" between the slide and the slide stop pin.
The pin might be .199" in diameter, its hole in the frame .201" in diameter, similar tolerances in the fit of the link to the barrel, barrel to the slide, etc.
There will be some vertical movement between the frame and slide.
Best case scenario would be something like .005" of vertical movement of the barrel.
The barrel can also tilt slightly because the lower lungs are not in firm contact with the slide stop, like a bike on training wheels.

 

[James K]

In a 1911, the barrel foot should cam up on the slide stop, the link acting only to pull the barrel down in unlocking. Actually, the link is not needed at all to lock the barrel into the slide. Having the link support the barrel is called "riding the link" and is not conducive to accuracy as it can result in barrel wobble, though it works OK in a "sloppy" GI pistol.

Pulling the trigger on a 1911 does not involve the frame to slide fit, but in the case of the BHP and a few other guns, it does, and I said "as in the BHP". You can actually feel the slide move upward when pulling a BHP trigger.

Jim