Cast boolits and cylinder throats

[Gundogblue]

I’ve read that a boolit that fits a little tight in the cylinder throats is just as, if not more important than the revolvers bore diameter. The reason I ask is because I size my .44’s to .433 for my 1894 Marlin, well I also have a Colt 3rd gen SAA IN .44 special. While i’ve Only shot it once, I’d like to cast some boolits and shoot it more often. This morning I took out the cylinder and with a wood doll rod I pushed them through the Colt’s cylinder, it took a slight bit of pressure to push the boolits through the cylinder. I measured the boolits and they measured .4335, so I’m thinking that .433 should work pretty well in the Colt, or am I missing something.
Thanks,
Paul

[Outpost75]

Slight resistance in which you can push bullets through with hand pressure only is fine. Tighter is too big. About 0.0005-0.001" less than throat size is correct. This permits slight clearance to allow for recrystallization growth of ternary PB-Sb-Sn bullets as they age. Not an issue with binary Pb-Sn alloys.

[mdi]

I have always found it best to size my bullets to the same diameter as the cylinder throats. "Push through", "drop through", "snug fit" aren't measurements, and can mean anything. You "slugged" your cylinders and got .4335" and your bullets measure .433", that's just .00025" difference in engagement (1/2 of the .0005" difference per side). so, yep that should work...

In my experience if a bullet is larger than the throats it will get sized down as it passes through, which is OK, but I got lead spray on the cylinder face and frame. If sized small enough to not obturate leading will most likely occur.

[Larry Gibson]

Your .433 sized bullets will work fine.

[DougGuy]

Sounds about right to me too! If it is a light drag fit in the throats, and they are ALL real even, it's good!

[rockrat]

I once had a 3rd gen NF in 44spcl. Cylinder throats on that one were also .433" and a bore of .428". I tried .430, .431, .432 and then .433. Groups got smaller as the boolits went larger. I settled on the .433" and it shot well, then I traded it off!!!

[Law.man]

One thing to consider - If the bullet si larger than the throat diameter, then it gets sized down alright, but the force of the bullet squeezing through the tight cylinder throat will accelerate wear on the gun, and will result in earlier loosening of the cylinder lockup (endshake will increase quicker).

So for my revolvers, I keep the bullet size at throat diemeter, or about 0,0005 under. In lay terms, If I drop the bullet down the cylinder bore, it must not fall through, but if pushed with a rod, it will pass through without excessive force (finger pressure).

But I never shoot bulets sized larger than the throats. This applies universally, but more so in high pressure magnum cartridges.

[Outpost75]

^^^^^^^^^
Law.man knows of what he speaks!

[BeemerMark]

You're going to have to shoot a million or two lead bullets to wear that heat treated cylinder throat.

[Walks]

Am I the only one who has COLT SAA's with proper size cylinder throats and bore's.
Both my .44SPL's have cylinder throats that measure .427-.428 & both bore's measure .427 , both my .44WCF
Extra COLT cylinders for these Revolvers were cut from .357Mag cylinders, so measure at .427 for all 12 holes.
They are 3rd GEN guns made in 1983-4.
On the other hand my NF in .44SPL has a .427 bore die & .428-.429-.430 Chamber mouths. I use a .429dia RN load just for that revolver.

[Green Frog]

When I had a K-22 cylinder modified to recreate my Model 16-3 homage, the ‘smith suggested .313” throats for its match chambers and I agreed. So far it seems like a good idea, but I have to remember to keep my .314” bullets out of it since in the 32 S&W L chamber they stop about 1/8” out... one of my next projects is making up a good tight cartridge gauge similar to the ones Dillon makes (but doesn’t furnish in 32 S&W L. )

Froggie