how to measure slug from S&W 629

[mebe007]

Ok so I slugged the barrel of my 629 today and it only has 5 grooves so how do I measure it? Saloon what's the best way to measure my throats

[tinsnips]

Frist wrap the the slug with shime stock. Then deduct the thickness of the shime[don't forget to deduct both shime thicknesses] . Use a micrometer not a caliper it is more accurate. It has worked for me .

[mebe007]

Sorry not trying to sound dumb but what is shime stock. I'm a but confused

[Doc Highwall]

Shim stock can be any metal made in specific thickness's, usually stainless steel or brass. A piece of .005" feeler stock will work just subtract .010" from your measurement. You need something flexible to bend around the bullet tightly with out much effort to measure.

[mebe007]

Now what us the best way to measure the throats

[Doc Highwall]

The best way is with a pin plug gage. The second best way is tap a bullet through and measure it. If your bullet just falls through you can smash it a little with a hammer or a press just enough so it will not fall through and needs to be tapped through, try to use a soft alloy. You can also use the larger fishing sinkers.

[WARD O]

If you have a set of feeler gauges - the smaller ones will work for the bullet wrap.

Ward

[Catshooter]

So will some card stock. Not a corragated box wall, but actual card board. It's just thicker paper.


Cat

[Edubya]

Make a soft slug. Slug the first inch of the muzzle. Extract the slug. Use it to measure the cylinders. If it goes through only with force then you have to enlarge the cylinders. It should require little or no force. The cylinder will be the final sizer of your boolit. Measure the cylinder.

EW

[fecmech]

I've found if you rotate the slug in the mic you can catch the leading edge of one groove and the trailing edge of another on the other side of the bullet to get a good reading.

[midnight]

Somebody I read about made special V-blocks. You measured from the bottom of the block to the top of the bullet lying in the Vee. A number was stamped in the block and you subtracted that # from your measurement to get groove dia. It might have been an article in the Single Shot Exchange. The guy who made the blocks would measure them fo nothing if you sent him 3 slugs. Maybe comeone here can remember where to get those V- blocks. Their were even instructions to make your own.

Bob

[Larry Gibson]

Strip of beer/soda can .3 - .5" wide by 3-4" long will work very well. Measure the thickness of the strip, wrap around the "slug" and pinch the ends up against the "slug" reasonably tight with finger and thumb of one hand and measure the outside diameter of the strip/slug with micrometer/caliper with the other hand. Subtract twice the thickness of the strip from that outside measurement and you then have the groove depth of the barrel.

Larry Gibson

[MtGun44]

I always do what fecmech says, never had any issues.

Bill

[462]

I'm with fecmech and MtGun44. Close the micrometer gently and slowly, as you rotate the bullet.

[Pepe Ray]

I'm befuddled why no one remembers that 45Nut has the "V" blocks for sale.

Some guys like dedicated tools, And besides that, you youngsters with the nimble fingers may be able to negotiate boolet + shimstock + michrometer with only 2 hands but many of us find it an exasperating chore.

Nimble fingers, good eyesight and shim stock are a great solution when motivated by MT pockets.

Support the site.
Pepe Ray

[mebe007]

Ok so I used the roll in calipers method and I'm getting .429-.429 1/2 for the barrel. Plugging the cylinders in getting .429, and I checked myself like 6 times and git .430 on 2 occasions. I think there is some personal error in there. So what size mold do I want to get and size die?

[mebe007]

i want a good all around mold to start with and needs to be great for hunting. deer - black bear sized game

[S.R.Custom]

I've found if you rotate the slug in the mic you can catch the leading edge of one groove and the trailing edge of another on the other side of the bullet to get a good reading.

What he said. You come up a few ten thousandths on the small side --especially if the grooves are rounded in their corners-- but good enough for the purposes of sizing throats & boolits.



Ok so I used the roll in calipers method and I'm getting .429-.429 1/2 for the barrel. Plugging the cylinders in getting .429, and I checked myself like 6 times and git .430 on 2 occasions. I think there is some personal error in there. So what size mold do I want to get and size die?

Using calipers is tricky. If you pull or push too much on the knob in your effort to get a good reading, you'll bend/rack/stretch the mechanism and get a distorted reading*... when measuring the outside diameter of something, use your largest average reading. When pulling the knife edges to an inside measurement, use the small reading.


*to get a good illustration of this, play around with measuring a pin gage of known diameter. If you want a real eye opener w/r/t using the knife edges of a caliper, try playing around with a check ring of known diameter...

[Frank]

Lee 310-430 RF