How much sizing does the cylinder do?

[BBQJOE]

I finally got around to slugging my S&W .44 (629)
The barrel comes out right at .429, the cylinder throats are .427.

This just doesn't seem right.
Are they counting on some bullet spring back after they leave the cylinder?

My bullets are sized to .429 after dropping at .430-431.
I'm having slight leading in the form of dust, not chunks or ribbons using Hi-tek.

So I'm guessing I should quit sizing, but how about the cylinder? It seems to me no matter what size a bullet over .427 is it's going to get sized to that, and sending a .427 bullet down a .429 barrel goes against everything written here.

[chboats]

You are correct it is backwards. For best accuracy and the least leading the cylinder throats should be .001-2 larger than the barrel. They sell reamers to correct this or you could send the cylinder to a smith to ream it

Carl

[Wayne Smith]

I agree. This gun is backwards. CylinderSmith will ream it for you or, if you have the mechanical ability you can get a reamer and do it yourself.

[Mal Paso]

S&W has been cutting late model revolver throats tight to improve jacketed bullet performance. I reamed my cylinder throats to .4313" with a Manson Reamer. Cylindersmith no longer does 44 cal. You may be able to find a Gunsmith that would do it.

SAAMI Spec is .4325".

I use .431+ boolits that just push through the throats and are 1-2 thousandths over groove. Lead boolits will bump up under enough pressure and the lands displace lead making the fit tighter but it's hard to beat having good gun geometry.

[geargnasher]

Yup, made for jaxketed and will work fine for such. For boolits, not so good, expect leading in the barrel and poor accuracy. Ream the throats.

Gear

[williamwaco]

How did you measure the throats?

Be aware that you cannot measure them accurately with a caliper with flat blades.

You need to either slug them, cast them, or use an inside micrometer.

[uaskme]

629-4 is when they reduced the throats. I have 2 686s. 1 is a no dash and it has .356 throats. I had 3 cylinders reamed for $75. Measured mine with a pin gauge.

[bbqncigars]

You can DIY with a Flex hone, although .002" may take some time.