Revolver boolit size

[Catpop]

This is how I find it after extensive testing with 357 RUGER Blackhawk and 44 mag RUGER Super Blackhawk. Notice I said I because this is from MY actual range result.

FIRST Groove fit
-Barrel leading disappears when boolit is .003 over groove diameter.
-Barrel leading is minimal and quickly removed with bore brush or same wrapped in chore boy bronze wool when boolit is .002 over groove diameter
-Barrel leading is a BEAR requiring many applications of chore boy with .001 or less over groove diameter.

SECOND throat fit
That said, we get to cylinder throat diameter
-throat diameter should be same size as boolit diameter. Or at most a hair over, say .0001 over. Finger push through is excellent.

THIRD cartridge fit
-cartridge must reliably fit all chambers of revolver!!!!! The last thing you need is the most accurate load in the world that you can't chamber!!!!!

All that said, boolit hardness and lubes come into play as lead boolit fps increase but basically not at target load velocity.

And that how I find it!

Additional info
I have 1973 357 bh that came with a .359 groove diameter and .358 throats- so every lead round fired swagged the boolit to under groove diameter. You see the leading that was causing!!!!
It now has .361 throats and shoots .361 with very minimal leading. It shoots .362 with no leading, but won't chamber 50% of rounds. So that's the end of that quest and I have a bh that's good only for jacketed bullets or a trip to choreboy town.

I have also been testing my new in box 2016 RUGER superblackhawk and found it came with .429 groove (they got that right) and .4315 throats (which I thought was good). Testing reveals .430 Missouri leads very badly, .431 Montana also leads but less badly, but hm .433 sized down to .432 offer only minimal leading.
Remember the .4315 throat it came with? So every boolit even though sized to .432 is actually being resized to .4315 on firing. So thats a brick wall on a factory new unmodified and still in warranty revolver.
I called RUGER yesterday and to make a long story short, was told in was in spec at Rugers tolerances of .4315 to .432. So NO help there! Yea I tired to get him to commit to bringing it up to .432, but to no avail. They were nice, but firm!

All this is actual hands on and may it will help you if you too experience lead boolit l adding issues with factory or hmm boolits

 

[Archie]

I've never trusted a revolver with barrels larger than throats. Can't be as accurate as might be, either.

I have to admit, if a revolver shoots well (within the criteria I need) I don't bother checking all that. I don't way to know, sometimes.

 

[Vern Humphrey]

The general rule is a revolver should get smaller as it goes forward. Start with a bullet between .001 to .002 over grove diameter, shoot it through a throat about .001 over groove diameter, and let the bore swage it down a bit more. Another point is, most cast bullets are too hard, and will often lead because of that.

 

[Jim K]

Vern, I wonder about your comment above. In my limited experience, it is soft cast bullets that lead,not hard ones, so the above puzzles me.

Jim

 

[Catpop]

All of my home cast boolits were brn 12 or less, made from only clip on ww and air cooled.
Yes I know some cast boolits like Oregon trail are 18 or higher. Missouri on the other hand makes 12 and 18. But neither makes the sizes I need.

 

[Vern Humphrey]

Vern, I wonder about your comment above. In my limited experience, it is soft cast bullets that lead,not hard ones, so the above puzzles me.

Jim

Bullets that are too hard will fail to obdurate. Gas can squirt past them, resulting in "gas cutting" of the bullet, which results in bad leading. A softer bullet will often solve the problem by upsetting and sealing the bore.

 

[Varminterror]

The general rule is a revolver should get smaller as it goes forward.

This.

I want a bullet which is 2-3thou larger than my bore, then cut my forcing cone to be slightly larger at the inlet than this bullet diameter (and I cut 11deg cones on almost all of my revolvers), and cut my throat to offer a slip fit to the bullet, with only the slightest finger pressure required to press them through the throat.

 

[Vern Humphrey]

The purpose of the throat is to capture the bullet as it emerges from the case -- the major diameter of the chamber is quite large, since it must be a slip fit for the loaded cartridge. If a slip fit for the bullet in the throat will keep the bullet controlled, so much the better. My experience is that about .001" constriction is about right for all my revolvers.

Question, are you shooting cast or jacketed bullets?

 

[Sunray]

"...Barrel leading disappears when boolit(SIC) is .003 over..." Leading has nothing to do with the bullet diameter. It's caused by trying to drive a cast bullet too fast.
Cleaning leading out has nothing to do with the bullet diameter either.
The hardness of a cast bullet doesn't affect leading either.

 

[Varminterror]

"...Barrel leading disappears when boolit(SIC) is .003 over..." Leading has nothing to do with the bullet diameter. It's caused by trying to drive a cast bullet too fast.
Cleaning leading out has nothing to do with the bullet diameter either.
The hardness of a cast bullet doesn't affect leading either.

First - "Boolit" is a common use term for lead bullets, to differentiate them from jacketed more easily. Hope you washed your feet today, so it doesn't leave a bad taste in your mouth.

Second - Fix your statement "it's caused by trying to drive a cast bullet too fast" by adding "for its hardness."

You're out of your depth.

 

[Varminterror]

Question, are you shooting cast or jacketed bullets?

Gilding & copper mono-metals, jacketed, plated, hardcast, and soft...

As usual, I've noted less advantage to the forcing cone when copper is involved, but I've yet to ever see it be a disadvantage. In general, when something has potential upside and no potential downside, I'll go after it.

I want just enough throat tension on a fresh bullet to require finger pressure. If I need to tap the bullet as when slugging the throat, it's too tight, if the bullet falls freely through the throat of its own weight, it's too large.

 

[Vern Humphrey]

I shoot cast bullets exclusively, mostly from wheel weights, and "lube" them with Powder Coating. Usually, I size them about .001 over throat diameter.

 

[Walkalong]

Leading has nothing to do with the bullet diameter. It's caused by trying to drive a cast bullet too fast.

Please stop posting that nonsense.

 

[243winxb]

357 RUGER Blackhawk and 44 mag RUGER Super Blackhawk.

What diameter are both bullets, after sizing and when ready to load?

Glad you found what works for your revolvers.

 

[Catpop]

243,
I can take one problem and spread it over months trying to solve it the hard way by trial and error. That's the fun part of the quest to me- doing it. I average about 4 quest per year!

The .429 groove 44 mag, although not 100% finished with that quest, is .432 now, but may end up at .433. No chamber size problems yet.

The .359 groove 357 mag is a .361, but that is only because .362 won't reliably chamber 100 % of time. Boolit too fat!
I'm finished with this quest------ unless I can open the chambers .0005---- hum???? Another quest? So many quest, so little time!

Thanks guys!