Cylinder Throat Diameter,and bore Diameter

[Clay M]

So I check all my .41 mag and .44mag revolvers.What I found was interesting.My Ruger Blackhawk .41 mag has both a cylinder and bore diameter of .410.Many of my revolvers have cylinders and bores that match.All the guns shoot fairly well with cast bullets,but best with jacketed.I guess the question for those of you who know,would I improve the accuracy with cast bullets by opening the throat .001 over bore? The cost for gunsmithing seems to be about $75

[GP100man]

I had lead foulin in the throat of the barrel , just infront of the forcin cone.Opening the cyl stopped it, but no noticable gain in accuracy, but I`m not that good a shot since my eyes went & got old on me !! that`s my story & stikin to it LOL

[Clay M]

If I use gas check bullets,I don't seem to have any bad fouling.I think with a bore and cylinder that match a gas check bullet is better than the plain base,due to the fact that you can't size over bore dia. Plain base do seem to lead in front of the forcing cone.

[GP100man]

It sounds as if your over speeding the boolits alloy just a bit

[Clay M]

Just checked my Blackhawk .45 Colt stainless. Once again the cylinder and bore both match at .451

[Changeling]

For the .45Colt what is considered the "Absolute Best fit" in regard to bore (.451) and Cylinder throats (.452), that is what is considered the best fit. However a lot of guys on here will tell you to shoot it and see first witch has a lot of validity, since the above is not always a defacto standard that works!
Bottom line: Shoot it first from a rest so you are positive if you have a problem or not. Often times it is the shooter/load/bullet not the revolver.



Just checked my Blackhawk .45 Colt stainless. Once again the cylinder and bore both match at .451

[Clay M]

They all shoot pretty good,nothing terrible.I wouldn't call any of them tack drivers except my S&W 657 .It has a .410 bore,and a .411 cylinder.

[MtGun44]

"overspeeding your boolit alloy"? He is just asking about dimensions, where does this
come from?

Most guns shoot cast best with .001 to .002 larger boolit than groove diam. Your guns,
like pretty much all of them today, are very accurately made to work with the standard
bullet - jacketed. If you want to optimize them for cast, opening up the throats and making
your cast fit the throats - so a bit larger than groove diameter, it has a reasonable chance
of increasing accuracy with cast - but at the possible cost of reduced accuracy with jbullets.

Bill

[GP100man]

Well he started talkin plain based & switched to gas checks, I was at work & had to stop typin.

What I was leading to was a bit of gas cuttin from the riflin strippin just a bit at the beginnin of the lands.

I bet if he backs of the load by 1/2 gr. what leading that occurs will stop.

Having the throats .001" over makes a titer fit & will help this also, as the bigger boolit will grab the riflin titer .

Kinda think of shooting a boolit down a funnel from the big end not the little end , I was told this yrs. ago by an old caster.

[Larry Gibson]

My most accurate revolvers with cast and jacketed bullets all have throats that are the same as groove diameter or not more than .001 over. They are a Ruger Single Six .32 H&R, a Ruger Security Six, a Ruger .41 Bisley BH, a Ruger Vaquero 44-40 and a Colt .44 Anaconda. My other revolvers with .001 - .005 diameter throats over barrel groove diameters shoot well enough with jacketed and and some cast bullets but no as accurate as the tighter throated revolvers.

I wouldn't ream the throats unless you are absolutely sure you can and are shooting better than the revolver.

Larry Gibson

[Clay M]

Thanks for the replies. Good information.