Cyclinder throat size,

[Gundogblue]

Hi all.
I’m going to cast some boolits for light target loads for my son, he has a Taurus Raging Bull. I cast .44 boolits for my 1894 Marlin to .433 and they work perfectly, but are far to big for my sons Taurus. The only thing I had to measure the cylinder throats on the Taurus was some Hornaday XTP’s, (.430) I tapped one through the cylinder and it measured .4285. So I’m thinking if I get a boolit sizer in .430 that should work, am I right?
Thanks,
Paul

[Mal Paso]

I had a S&W with .428" throats. .430 bullets will work but I had leading. If the throats are really .4285" you may want to send the cylinder to Doug Guy on this forum.

[Bazoo]

Likely the bore diameter is larger than the throats. So the bullet gets swaged down in the throats and is undersized in the bore=severe leading. With jacketed bullets, they are more forgiving and work anyways. Having the cylinder throats opened up will be desired, and very reasonable priced. You need to slug both the bore and throats with soft lead. Egg sinkers will suffice.

[mdi]

I would think .4285" is too small. My 44 Magnum revolvers all have .431" throats and groove diameters to .429"-.430. I would remeasure the throats either slugging or, pin/plug gauges (measure all). Also slugging the barrel so you will know for sure the throat diameter is larger than the groove diameter...

[DougGuy]

If you keep going down in size, so that it fits the throats, it will be too small for the barrel. If you shoot a .430" through .4285" throats it won't be .430" when it exits the cylinder on the front, it will be throat diameter.

Throats need honed to a minimum of .4305" for use with .430" boolits but I would suggest .4315" and size to .431" you could have them honed to .4335" if you want to use .433" and not have to size differently and keep ammo separate for each gun but I wouldn't if it was me.

The other thing you can do is load fairly soft alloy, soft enough that you can easily scratch it with a thumbnail, this will go through tight throats and still have enough pressure behind it to bump up and fill the barrel, this is what jacketed bullets do b/c they have a dead soft lead core that will resize quite easily and adapt to changing diameters easily.

[Bazoo]

Doug, on jacketed bullets, the jacket gets swaged down with the lead core. Does the jacket spring back or get bumped up? I would think that how soft the core is would matter as the jacket would resist bumping up with anything but full power loads.

[DougGuy]

Doug, on jacketed bullets, the jacket gets swaged down with the lead core. Does the jacket spring back or get bumped up? I would think that how soft the core is would matter as the jacket would resist bumping up with anything but full power loads.

Strip the jacket off one and see how thin it is, or better yet pull pieces of it out of a deer that got hit with one and you will see it's not much more than gilding metal foil.

As proof of this, my own Vaquero 45 shot to one point of impact with 300gr J words over 22gr W296, and it shot 320gr TC higher, throats were .450" at best. Thread choke was SEVERE, at .449" after reaming cylinder throats to .4525" then Taylor throating the choke out the big J words shot to the SAME point of impact as before, while the 320gr TC shot considerably lower almost joining the J words group. It occurred to me that the J words were filling the bore after exiting the front of the cylinder before reaming, and secondly, dwell time was not changed after reaming throats, because the J words weren't creating the same amount of resistance as the TCs were, so that did not slow them down enough to notice any difference in point of impact.

While the 320s were creating quite a bit of resistance being they were mostly linotype, they were likely increasing dwell time giving the muzzle more rise before exiting, and after reaming, there was no more resistance, allowing the boolits to exit the muzzle before it attained the same azimuth as it did before reaming and Taylor throating.

[mehavey]

I’m going to cast some boolits for light target loads

Before the OP does anything else....
- Size .430+
- Use very soft alloy (even pure lead)
- Lube either thin-film ALOX or PC.
- Fast powder

`Betcha mirror finish bore upon dry patch after shooting.

[Gundogblue]

Thanks for all the info I really appreciate it. But seeing that it’s my sons gun and he doesn’t want to go through all that he just bought a 500 pack of Berrys plated boolits size to .429-.430 and asked me to load those for him. I’m really glad all my guns don’t have undersized cylinder throats, they’re easy to cast for, same with my leeever rifles.

[mehavey]

If they're Berry's they're soft.
Load/shoot them as-is.