Links
Howdy valor,
The standard link is .278 inch center to center, and that length will
work out well in about 90% of the production guns that you'll run across, regardless of caliber. Occasionally, tolerance stacking will make that length
something less than optimum, but it will generally work.
The problem with deciding on a plus or minus length is that there are a few
factors to consider. The vertical dimension of the lug, and the forward radius to name a couple. It's possible to have a perfect fit when the barrel is vertically locked, but still allow the barrel to ride the link as the pin swings
around the forward radius. Using a short link to address this can put the
pin and link in a hard bind when the pistol is in battery.
Likewise, you can have a barrel that's locking ON the link, and use a shorter one to get it on the pin, and wind up with the pin in a bind on the forward radius. If the lug's location is a little off in either direction, it gets even more complicated.
When there's a stem bind condition that affects the reliability...and the
link is letting the barrel ride on it, it's generally better to simply elongate
the top of the hole a little if a .003 shorter link doesn't work out well.
More than .003, and you can wind up with the barrel's linkdown being stopped by the link instead of the frame...and that's not good. Sometimes
even .003 will cause it. Another fairly simple thing to check for, by the way.
That doesn't affect the linkdown timing because the bottom of the hole is
what works with the pin to unlock the barrel. That dimension stays the same. Only the area that contributes to the stem bind is altered.
Hope this helps
Tuner