Infinity Tri Loc II®Barrel Bushing -
Congratulations for purchasing the most technically
advanced components in the world!
All persons in the room must always wear eye protection when disassembling
or re-assembling a firearm. Even if you don't plan on working on
a portion of the firearm with a compressed spring, proper eyewear
provides an extra margin of safety in the event you unintentionally
release a compressed spring.
- The outside diameter has three lobes that are equispaced for lockup.
- The inside diameter has three lobes that are equispaced for lockup
and barrel control.
- The SV Infinity Interchangeable Breechface slide has a very slight
(.003 deep) relief on the inside of the muzzle end at the 9:00 o'clock
and at the 3:00 o'clock positions. This allows the bushing to be "dropped"
in with a "loose" fit of several thousands and then rotated (with a
plastic wrench) for a "cam" lock interference fit. This system eliminates
the tolerance stackup of conventional slides and bushings.
Infinity Tri-Loc II® Bushings are available in several
different outside diameters.
Fitting the outside diameter of the Infinity Tri-Loc II® to a slide
other than an Infinity IBS will require polishing of the inside diameter
of the slide (at minimum to remove burrs) and or mounting of the bushing
to a mandrel and polishing the outside diameter with a narrow ribbon
cloth (320 grit or finer) carefully to ensure that you have reduced
the diameter between the locking lug and the face of the bushing the
same as the area above the locking lug.
- The Infinity Tri-Loc II® does not utilize a conventional narrow internal
band that is only one thousands ( .001") larger than the barrel diameter
for barrel lockup. Rather, The Infinity Tri-Loc II® incorporates two
cylinders - one parallel to the rails (unlocking position of the barrel)
and the other that is parallel to the barrel during lockup (approximately
The barrel locks up just like a bull barrel in that it touches on
the very muzzle end at the 4 and 8 o'clock positions and at the rear
of the bushing (3/4" from muzzle) at the 12 o'clock position. The
design thus allows for approximately a .005 larger internal diameter
than the barrel diameter for smooth operation and a vastly increased
bearing seat area when locked up. Yes! , the design eliminates the
ugly and damaging "bushing ring" on the outside diameter of the barrel.
The two lower internal lobes (4 and 6 o'clock) act as rails for
the barrel to be guided on when the slide is moving thus reducing
drag and also any possible binding from dirt etc.
- Testing for proper muzzle lockup is very simple. Pull the slide slightly
open and insert a one thousands (.001") feeler gage about .100 " wide
at the 12 o'clock position and in about 1" from the muzzle. Close the
slide (barrel now in battery) and pull gently on the feeler gage. A
slight resistance indicates a fit of less than .001. The slide may not
fully close with the feeler gage in place. As you pull the feeler gage
out the slide should close smoothly. If the slide does not close smoothly
move to step 6 and repeat step 5 until you have achieved smooth operation.
- Check for too tight a fit at the muzzle by testing the barrel bounce
or spring back at the radial lugs. The 1911 system is capable of "bending"
the barrel slightly. This is an elastic movement and the barrel will
return to its "as manufactured" straightness with the bending moment
After checking for the lockup mark at the 12 o'clock position on
the very rear of the bushing (lockup cylinder at .86 degrees) . Polish
the mark lightly with a Dremel type sanding drum (400 grit or finer)
and return to operation five (5) for retesting. Repeat operations
five (5) and six (6) as required.
Testing for and correcting barrel bounce is a
job for an experienced gunsmith only.
The purpose of these instructions is not to educate an inexperienced
person on the proper fitting of all aspects of barrel installation.