Finally slugged the 629's barrel.

[ScottJ]

First of all give me my moron card for using a WW cast boolit to slug. Man, that took some pounding.

Went muzzle back which I know isn't optimum but it was the easiest.

Lead actually shaved off as it went in.

I know S&W's are hard to measure because of the 6 grooves. Here's my method.

I'm using a dial caliper and I've verified its accuracy with a feeler gauge. Then using the same pressure as got me the correct reading on the feeler I put the boolit between the jaws and rotate it to get all the measurements.

Got .429 at the largest.

Picked a really good looking boolit from my last casting session. It's also .429. I might have a lement my mold.

[35remington]

It's great that you slugged the barrel, but you missed the most important measurements - the cylinder throats and the forcing cone of the barrel, and also checking for thread choke under the frame.

Get those three items attended to, and you'll have something. You don't have anything to base a "best" bullet sizing diameter on yet.

Generally, you size to fit the cylinder throats, not the barrel. Usually, the cylinder throats may run somewhat larger than barrel groove diameter, and if you must fit one or the other, the cylinder's the thing to pay attention to.

[ScottJ]

Did the throats awhile back. They are also .429.

Also since resistance didn't increase back toward the forcing cone I'd assume there is no restriction at the threads either.

[Edubya]

Do you shoot "as cast"? It would be much easier to size the bullets to your load specs then do the slugging. Also, consider using the tape-on WW.
Many people say that we should be able to push the slug through the cylinder with a solid amount of pressure on the pusher dowel. Mine takes a little more than that. Might be a good thing to mark each slug (easily etched with a knife point) the roman numeral I-VI then with a pointed magic marker on the back of the cylinder, so that you can compare all cylinder bores accurately and idetify any that need reaming.
EW

[Edubya]

OOPs, didn't see your reply.
Cylinders should measure 0.001, at least, larger than barrel. Might check again and if the same is coming out, you might contact S&W.
EW

[geargnasher]

My FIL's Model 29 has a .429" groove diameter, too, but the cylinder throats measure .4322" or less so I have to size to .4325" to get this otherwise dimensionally and mechanically sound revolver to shoot straight. My preference would be to get a cylinder that had .430" throats, but I would also prefer reasonable prices and noble politicians!!

If your gun is new and the cylinder is undersized you have 2 choices: Get S&W to "fix" it (yeah, right! First you would have to convince them their gun isn't dimensioned correctly, and then get them to ream the throats to the correct size. Keep in mind that manufacturers aren't gunsmiths and only have "tolerances", not dimensions) or ream the cylinder throats to a nice even and consistent .430". If you do that, the gun ought to shoot very, very well.

You can either rent a reamer through the mail or buy one from Brownell's with the appropriate guides, or buy a chucking reamer from an industial tool supply house and do it yourself. If you go with the latter, (I did after someone here recommended it as being MUCH cheaper) you can make a pilot out of good old masking tape carefully wrapped aroung the shank to ride in the cylinder as you bore it. No matter what you use use a quality tap oil.

Just a suggestion.

Gear

[Rico1950]

ScottJ
Just send it (the cylinder) to Cylindersmith, very reasonable and fast turnaround.

[ScottJ]

Maybe I need to re-check the throats. I bought this gun the year the 629 Classic was introduced (1993 I think).

It has always been very accurate. I used to could do offhand groups a 7 yards that were almost a single, bullet-sized hole.

At 25 I could make all shots touch.

At 50 I could could make groups you could cover with your hand.

I have sent many hundreds of j-word downrange out of it over the years. I've never had a reason to question its accuracy.