New model Blackhawk throats

[shovelwrench]

I was under the impression that a .453 bore in a .45 LC was pretty commmon. Thats what I measured my NEW Blackhawk stainless at, with a good dial caliper. Now a good smith is tellin me to recheck my numbers, cause he only reams cylinders to .452.
What gives, anyone willing to lend me a .454 reamer?

 

[shovelwrench]

I was under the impression that a .453 bore in a .45 LC was pretty commmon. Thats what I measured my NEW Blackhawk stainless at, with a good dial caliper. Now a good smith is tellin me to recheck my numbers, cause he only reams cylinders to .452.
What gives, anyone willing to lend me a .454 reamer?

 

[45x4]

Hey shovel:

Carefully push or tap a lead slug sized .454-.455 through your barrel, then measure that. Also do the same with your cylinder throats.

Ideal sitution is, your throats should be .0005 to .001 larger than the barrel grooves. (the high ridges on the slug.)

If this exsists, your gun will shoot well if not, then ream the throats to cause this sitution.

 

[tomcatt51]

New 45LC Blackhawks are meant for 451/452 bullets. They got away from 454 years ago. A dial caliper is inadequate for measuring throats. Telescoping gauge and .0001"'s micrometer or slug the throats and use a mic. Ruger Blackhawks are notorious for undersize throats and barrels installed with too much crush so there's a constriction in the barrel where it's threaded in the frame.

 

[john traveler]

That's correct. Dial calipers are no where near accurate enough to measure chamber throats. Your best bet is to use a pin gage set, or, lacking that, to push a soft lead slug through and measure it for the throat diameter.

 

[Tom C]

I use pin gages and check all my revos. My NMBH from 7 or 8 yrs. ago measured .449 to .451", very tight to only slightly tight. They all worked better reamed to a consistent .4525". .453" isn't big enough to hurt much, but the dial caliper isn't good enough to give a true picture of your throats.