S&W model 64 question

[seabat0603]

I have a S&W model 64. It's the stainless version of the model 10 military and police. I slugged the barrel to see what they were. In fact I slugged it twice and came up with this,: .346-.347. Now that seems a bit tight to me. I have ordered 2 lyman molds # 358432 ( 160 grain wad cutter) to use with this gun. If the molds cast a .357 to .358 I'm over by 10,000. That seems like way too much. Please tell me if I'm going to have to size my bullets to say .348-.349.
Just to make sure I wasn't loosing my mind I slugged the barrel on my 1911. It came out at .450 both times. Any and all input would be great, thanks-seabat0603

[dubber123]

Are you sure the slugs you used on the 64 were big enough to begin with? That is a way tight measurement.

[seabat0603]

I used a 50 caliber round ball.

[9.3X62AL]

S&W revolvers typically have 5-groove rifling patterns, so a V-block measuring fixture is needed to get a precise measurement. Your results are about right for a "mic" of a land and groove! :)

Give the cylinder throats a try, likely they will be somewhere between .357" and .358". Just about all S&W 38 Specials thrive on a diet of .358" castings.

[dubber123]

I used a 50 caliber round ball.

Well, that should have done it![smilie=1: I think Al's got your answer. I have quite a few S&W 38's/357's, and they all seem to do well with .358" slugs.

[Bret4207]

S&W revolvers typically have 5-groove rifling patterns, so a V-block measuring fixture is needed to get a precise measurement. Your results are about right for a "mic" of a land and groove! :)

Give the cylinder throats a try, likely they will be somewhere between .357" and .358". Just about all S&W 38 Specials thrive on a diet of .358" castings.

Agreed. My Smiffs all take .359 or .360, usually .360 in PB.

[44man]

Yep, the guys are right. Those S&W bores are hard to measure. Some guys wrap thin shim stock tight around a slug and measure, subtract double the shim thickness to get a closer measurement. Still not perfect. They are like trying to measure a five point star, point to point. :mrgreen:

[seabat0603]

I measured the cylinder throats on all 6 cylinders. Everyone of them was ( .355 )
I even measured twice to make sure. So, should I just shoot the boolets as cast or should I size them to .356-.357? I think .358 might give me leading problems. What do you guys think?

[Bret4207]

.355?! I suggest you check your measuring instrument against a standard. That's seems awfully tight for a Smith, that's smaller than some 9mm's.

[seabat0603]

I measured several bullets of known size with the same calipers. Over and over I get the same diameter. It's not the calipers. So whats your suggestion, cast and size to .356-357? Should I call S&W to see what they say.

[fourarmed]

Seabat, the holes could be that small - stranger things have happened. On the other hand, there are more accurate ways to measure small holes. (I am assuming you didn't pull the caliper out of the hole before reading it.) If you know somebody with a set of pin gauges, they will give you a much more sensitive measure.

Edited to add: If you are measuring a slug pushed through the holes, you are probably OK, but if you are using the ID jaws, they aren't necessarily as accurate as the OD jaws.

[seabat0603]

I think I have the right answer. I called S&W and spoke to a weapons specialist. The ball end of the cylinder should measure .356-.357. Mine is .355. He said that is a bit tight and I should size my bullets to .356-.357. If the gun doesn't shoot well , send it in and for $150.00 I can have the cylinder reworked. I'll try the as cast, sized to .356, and the .357 to see whats transpires. If you guys have any other ideas that I haven't thought of please let me know.-seaba0603

[lathesmith]

Calipers? I know I'll probably get flamed for saying this, but that's not the best tool for this kind of measuring work. Lacking a set of pin gauges, you need to drive (gently) a slightly oversize slug thru each chamber, and then measure with a micrometer. I know that Redgreen believes that "any tool can be the right tool", but when trying to do precision work it don't really work out that way (except on TV.)

If your slugs are STILL small, say .355", I would still try 358's at least before getting too worked up about this. See how the gun shoots first, before worrying about changing anything. .355 bullets won't have much neck tension in 38 brass, and will probably give many more problems than loading and shooting .358's will. So, try the gun first, and see how it shoots.
lathesmith

[lathesmith]

Calipers? I know I'll probably get flamed for saying this, but that's not the best tool for this kind of measuring work. Lacking a set of pin gauges, you need to drive (gently) a slightly oversize slug thru each chamber, and then measure with a micrometer. I know that Redgreen believes that "any tool can be the right tool", but when trying to do precision work it don't really work out that way (except on TV.)

If your chambers really do measure that small, say .355", I would still try 358's at least before getting too worked up about this. See how the gun shoots first, before worrying about changing anything. .355 bullets won't have much neck tension in 38 brass, and will probably give many more problems than loading and shooting .358's will. So, try the gun first, and see how it shoots.
lathesmith

[seabat0603]

SO you don't think .358 dia. bullets will lead? That's 3 thousands over. I've always thought that sizing a bullet 1 to 2 thousands is enough. I have shot all kinds of factory rounds through this gun and every one of them gives poor groups. 10 feet away the groups are a 1 hole. Twenty-five yards and they are within a paper plate. I'm not looking for a tack driver, although it would be nice. I have never owned a firearm that grouped this poorly. Please gimmie all thoughts and suggestions. How about water dropping my bullets and heat treating them in the oven to make them harder. I'm all ears.-seabat0603

[lathesmith]

seabat, I see that you HAVE tried the gun a bit, that's a good place to start. Poor groups could be an indicator that your cylinder throats are undersize in relation to the barrel. If this is the case your gun will shoot poorly no matter what kind of ammo you feed it, with the possible exception of Hollow base wadcutters. That $150 price tag seems a mite steep to me--there is a guy on line called cylindersmith.com I believe that comes highly recommended. I think he will ream a cylinder for $30 or so. All you would need to do would be to remove your cylinder and send it to him, which is a very simple job.

As a note of reference, I have a couple of S&W model 10's, and they measure .357 and shoot as well as I can hold. So, it looks like you are on the right track here.
lathesmith

[Maven]

seabat, Several things to say about your dilemma. First, you'd be surprised how much a CB can be sized without destroying accuracy. If it is sized concentrically and the lube grooves are filled with lube, they can be sized much more than .003", particularly if you use a Lee push-through sizing die. Second, clean all the Cu jacket fouling from the bore before you try your new CB's, but then try something like this: Using #358432 + 2.5grs. - 2.8grs. Bullseye, load 30 rounds with -432 sized to .356"; 30 with -432 sized to .357" and 30 sized to .358". From a steady rest, fire five 6-shot groups @ 25 yds. at each target, having marked them appropriately beforehand. One of those should show tighter and better grouping than the others. Btw, I'd be inclined to retest the best of the three loads with -432 seated base first.* If the groups are equally poor, I think I'd seriously consider returning the gun to S & W or possibly to Cylindersmith:

www.cylindersmith.com



*I've had several button nosed wadcutters, e.g, RCBS' for my .38Spl./.357mag. and a Lee for my .44Mag., that shot poorly when seated with the button nose forward. Figuring that I had nothing to lose by seating them backwards, I tried it and got the accuracy I was looking for.

[sundog]

$150 is way too much. You can probably buy a reamer and bushings for less than that and do it yourself. Then you have a reamer for future jobs, rent, or be a hero with your buds. You might even ask here if anyone has one to rent. Or like Lathesmith suggested, cylindersmith.com.

[Bret4207]

SO you don't think .358 dia. bullets will lead? That's 3 thousands over. I've always thought that sizing a bullet 1 to 2 thousands is enough. I have shot all kinds of factory rounds through this gun and every one of them gives poor groups. 10 feet away the groups are a 1 hole. Twenty-five yards and they are within a paper plate. I'm not looking for a tack driver, although it would be nice. I have never owned a firearm that grouped this poorly. Please gimmie all thoughts and suggestions. How about water dropping my bullets and heat treating them in the oven to make them harder. I'm all ears.-seabat0603

In general the smaller a boolit the more likely it is to lead. IOW- if you shoot a .356 boolit though a .356 barrel it's more likely to lead than a .357 or .358 boolit. It seems to be a matter of boolit fit. IME until you get into the grossly over size area, say a .362 boolit through a .356 barrel I don't worry much about pressure and less about leading. The reverse case would almost certainly lead, especially if it's at all a warm load.

Now some here will disagree, but in my limited experience a harder boolit will be more likely to lead IF it's the slightest bit small. The commercial "hard cast" boolits I've used have been horrid in this respect, and some were pretty darn expensive and allegedly had "silver" in them or so the ad stated. A properly fitted "hard" boolit isn't anymore likely to lead than a softer one in many cases. I believe it's a matter of finding a balanced load- one that finds the boolit alloy and size responding positively to the powder used in that particular gun. How do you find it? Use the largest boolit that will chamber in your gun, WW or WW/Lead alloy and a proven design boolit driven at moderate for the cartridge speed with an appropriate powder/primer.

You can size a boolit down an unbelievable amount, if done properly, and still get great accuracy. As another poster stated, it's all in knowing how and using the right equipment.

In your particular case, with your seemingly undersize cylinder throats, I'll make a couple suggestions. First- Take that cylinder and really clean the snot right out of it. I mean CLEAN IT! I'd go so far a suggesting you take some Chore Boy scub pad or 4/0 steel wool on a worn brush and dose it good with a cleaner like Hoppes or PB Blaster or whatever and go after any fouling in those throats. I'd want to see bare, blued metal when I was done. Then take some measurements. If you still get slightly undersize throats, then do like Paul said and try a variety of sizes and see if that helps. If all this yields no good results and you want to keep the gun I'd send it out to Cylindersmith or another 'smith to have the work done. S+W's $150.00 is robbery!

[seabat0603]

Well I did what you suggested and guess what? I went from a .355 to a .356 after I cleaned the crap out of it. Now don't get me wrong, I have always cleaned my firearms so as you could eat off of them. I just didn't realize that I still had that much residue in the throats. After I cleaned them, bore brush in my drill, I used jb bore bright. They are now clean as w whistle and I'm happy with that. So thanks for that BRET. Now I'm gonna try what MAVEN suggested. Thanks guys and I'll yell if it don't work. Thanks-seabat0603

[Bret4207]

HOLY CRAP!!! It WORKED!!!! I had no idea....I was just joking!!!! :shock:

HAR!!!!! :kidding: :mrgreen:Hey, glad it worked out. Now follow Pauls (Mavens) idea and see what happens. You may be surprised. I'm betting the fatter you go, the better it shoots. Stick with a softer alloy, even straight WW might be a little hard. If you can try 50/50 WW/pure lead, in addition to straight WW or any harder alloy you might try. And stop worrying about leading. A little scrubbing with Chore Boy or 4/0 steel wool will wipe it right out.