Depth of rifling

[Jon Powell]

Can anyone tell me the depth of the rifling on the Super Blackhawk and old Vaquero?

Thanks for any info you can provide.

 

[contender]

Welcome to the Forum!
True actual rifling depth can vary SLIGHTLY between guns & it isn't easy to measure the gun. The best way to get a true measurement of your gun is to slug the barrel. Take a soft, pure lead slug,, say from a fishing sinker,,, and drive it through your barrel. Then using a blade micrometer,,, that measures to the .0000 dimension,,, you can get actual dimensions for your gun.

If I may ask,, why are you needing info on these two guns?

 

[s4s4u]

FWIW the slug from my NM 45 Colt SBH Bisley shows about .004" to .0045"

 

[Jon Powell]

Thank you for responding.
The reason for wanting the info on these two guns is simply because I use them the most often. When I slugged the bores the Vaquero was .430 and the SBH was .4295. I also slid pin gauges down the barrel and the .416 gauge is the largest that will fit. As s4s4u stated above, I've read rifling is usually around .004 or near that anyway. Maybe I'm missing something here, but it looks to me like the rifling in the SBH is about .0135 and the Vaquero is .014 going by the difference in measuring the barrel slug and the pin gauge.

It really doesn't matter, I just got curious and thought I check with the people who know these things. Can you tell it's been kind of cold around here lately? I really need to get out for a while.

 

[s4s4u]

You need to divide those numbers by 2.

 

[Jon Powell]

I guess that's what they call a "senior moment". Thanks s4s4u, suddenly it's becoming clear.lol

 

[David Bradshaw]

Jon Powell..... depth of rifle groove, or height of the land, is determined in part by method of rifling. Unbutton rifling, a carbide button is pushed or pulled through the bore, swaging grooves. Often, buttoned grooves are shallower than grooves which are broached or cut. Lands must have enough bite for the bullet.

Dimensions critical to accuracy include:
* uniformity of bore----no compression spots or loose spots.
* uniformity of groove.
* groove diameter----firm is better than loose.

Many factors which stretch beyond your question affect accuracy. A rough bore or groove may not hurt accuracy----providing it is uniform and not oversize. A rough bore which is uniform and of firm diameter may be lapped, with a fine improvement in accuracy and reduced lead and jacket fouling.

The accuracy potential of a great barrel is ruined by:
* excessively deep, rough, or tilted forcing cone.
* excessive force applied to or area of rollmark or stamping. (For this reason in contemporary manufacturing I prefer barrel markings to be etched.)
* over-tightening of barrel to frame (premature thread timing).

Exact depth of rifling doesn’t by itself mean much, unless it is much too shallow, as seen on some revolvers meant to interchange .410 shotshells and .45 Colt bullets.
David Bradshaw

 

[mohavesam]

Only know the SAAMI standard is .417 bore (lands) and .429 groove by reference materials. Nominal lead bullet diameter is 0.432.
http://www.saami.org/specifications_and_information/index.cfm

Don't get hung up on measurements to the ten-thousandths, as they usually require climate controls and calibrated mics. Remember, Rugers are built to manufacturing tolerances.

 

[Jon Powell]

Thank you Gentlemen. I appreciate all the information.