How to slug a .38 (or any non removeable barrel)

[ghh3rd]

I would like to slug my .38 spl snub. From what I gather this should be done from the chamber to the muzzle. Since it's not possible to do it in that direction with this gun, is it possible to start at the muzzle? Could it cause any 'trauma' to the end of the muzzle? How would I support the chamber to avoid damage to the gun?

I feel a bit self conscious about posting so many questions on this forum, but it's like I'm a kid in a candy store (that's full of knowledge).

Thanks,

Randy

[jack19512]

From what I gather this should be done from the chamber to the muzzle.

Who told you that? Myself I don't know how you would slug a revolver from the chamber end. All you have to do is use a wooden dowel or something like that to drive the slug from the muzzle end and use something like a wooden hammer handle to get the slug started in the muzzle. At least that is how I do it.

[mooman76]

I avoided doing small guns beause I thought they would be difficult but they were easy. I always slug from the muzzle by the way. It's best to use ball shaped pure lead to do the slugging. Tap it in, don't use a metal hammer. I use a plastic hammer. After it is started use a wooden dowel or piece of a cleaning rod. A pile of rags on the workbench can keep the gun from getting mared. I forgot to mention oil the bore first with some oil on a cleaning patch.

[ghh3rd]

Good! Then as soon as I get a caliper I'll slug away. I am casting .38 tumble lubed wadcutters but haven't loaded any yet. I'm told that they probably don't need to be sized, but I did purchase a sizing die in .358 for future bullet types, and would like to know if I got the correct size.

Thanks for the help.

Randy

[Whitespider]

Randy, I don't believe a caliper is gonna tell you what you need to know. You should measure the slug with a good micrometer, capable of reading to .0001-inch.

Calipers are pretty accurate to ..001-inch, but when determining proper bullet size that ain't close enough. You really need to know if your bore is (for example) .3567 or .3573-inch; most calipers are gonna read .357-inch in both cases. The .3567 bore would probably be just fine with a bullet sized to .3570, but the .3573 bore would require a bullet sized a bit over .3575-inch. As well, when using a sizing die the alloy will determine the final size; a .357 sizer will produce bullets of a somewhat larger size when using harder alloys. The only way to know, or learn, this information is with a micrometer that can read to .0001-inch.

[jack19512]

Randy, I don't believe a caliper is gonna tell you what you need to know. You should measure the slug with a good micrometer, capable of reading to .0001-inch.

The only way to know, or learn, this information is with a micrometer that can read to .0001-inch.

Just for everyone's info that don't know. They make calipers that will measure to 1/1000 and every bit as accurate as most micrometers. Not all micrometers are dead on either.

[Whitespider]

jack19512

.0001 is 1/10,000... not 1/1000.
That's not saying that calipers aren't made that will read to 1/10,000, but I've never seen one. Mine will read to the nearest .0005 (5/10,000), and it was damn expensive, I'd hate to even think what one that reads to .0001 (1/10,000) would cost.

[monadnock#5]

If each of us who have posted to this thread were given a standard and a certified mic, chances are very good that no two measurements would be the same. It's the nature of the beast. Part of what goes into the skill set of a gifted machinist is the ability to use his measuring tools to their fullest potential.

Both mics and calipers have their uses. Mics are easier to learn to use. If you're just starting out, get the mics with the ratchet on the thimble. The ratchet is like training wheels on a bicycle. It gives positive feedback to the user to know how much pressure is just enough for an accurate reading. Here's a free helpful hint: DO NOT look at the numbers on the mic while taking a reading. If you do, you will invariably come up with the exact reading you were looking for to begin with. And no, I would prefer you not ask me how I know this.

[Sven]

A couple of other thoughts:

From reading Veral Smith on this subject, you need to push a slug all the way through to find the smallest diameter and you need to slug just the muzzle and compare the two. That tells you if you have a tight spot (like under the barrel threads).

You also need to know the diameter of the chamber throats, or at least compare them to the barrel. On my Ruger Security Six and my S&W 629 MG, (both with 5 lands and grooves) the barrel slug will not fit into any of the cylinder throats, so when I fire a lead bullet, the cylinder throats are sizing the bullets undersize to the barrel. I just sent both cylinders to cylindersmith.com to have the throats opened up. The Ruger will be sized to .358 and the Smith to .4305 . I'm anxious to get them back and see how they shoot.

As long as I'm spending money on them, I'm going to spring for a trigger job on both, too! (I should have sent the Smith back to the factory when I bought it -- definetely wasn't to S&W standards!).

[GrizzLeeBear]

Randy, I don't believe a caliper is gonna tell you what you need to know. You should measure the slug with a good micrometer, capable of reading to .0001-inch.

Calipers are pretty accurate to ..001-inch, but when determining proper bullet size that ain't close enough. You really need to know if your bore is (for example) .3567 or .3573-inch; most calipers are gonna read .357-inch in both cases. The .3567 bore would probably be just fine with a bullet sized to .3570, but the .3573 bore would require a bullet sized a bit over .3575-inch. As well, when using a sizing die the alloy will determine the final size; a .357 sizer will produce bullets of a somewhat larger size when using harder alloys. The only way to know, or learn, this information is with a micrometer that can read to .0001-inch.

So, if my caliper reads .357 and I size to .358, whats the difference? As long as you size .001 to .002 over bore dia. I don't think it matters if you can't measure to .0001. For 99% of what reloaders and casters do, measuring to .0001 is really not needed IMHO.

[BD]

Maybe we should have a measuring devices "sticky". There is a very similar discussion going on in the cast boolits room under "cheap calipers".

While you can buy a caliper that will read to tenths, (1/10,000) , I'm not sure that you can buy one that will measure to tenths. At least I never found one.

Here's something I've tried which IMHO is well worth doing:

Take your favorite caliper and a well machined cylinder like a pin gauge, standard, end mill shank or even a good quality drill bit. Take ten readings in a row without putting either item down or changing your grip. You should set the caliper by feel with your eyes closed, then open your eyes and read the dimension obtained to someone else. Then take the list of dimensions generated and throw out all of the digits to the right which do not agree completely in every case. What you have left is your repeatable accuracy with that caliper, at that time, on that object. Do this once a day for 3 days. If the end result is the same each time, then you really do know the repeatable accuracy available from that instrument. If it's not the same each day you have to throw out digits to the right until you have a consistant result, which is then the true repeatable accuracy.

Doing this with a variety of calipers is what led me to buy a micrometer. Trying to accurately read different points on a cartridge case with the standard micrometer lead me to buy a blade micrometer.

BD

[Whitespider]

So, if my caliper reads .357 and I size to .358, whats the difference? As long as you size .001 to .002 over bore dia. I don't think it matters if you can't measure to .0001. For 99% of what reloaders and casters do, measuring to .0001 is really not needed IMHO.

Well, maybe it doesn’t matter, and than again maybe it does.

Let’s say you slug your bore and your measuring tool (that reads to the nearest .001”) says .357”, but in actuality it could be anywhere between .3565” and .3575”. Next you size a boolit in your .358” sizing die and measure it, which says .358”, but again it could be anywhere between .3575” and .3585”. Now what if the bore is really .3574” and the boolit is .3576”, wouldn’t you like to know that your boolits are only .0002 (or maybe a bit less than that) over groove diameter? I think I’d be moving up to a .359” sizing die.

Let’s say we’re checking cylinder throats. I slug the bore and cylinder throats of my revolver, and using your tool they all measure .357”. But if I use mine (that reads to .0001”) I learn that my groove diameter is .3567” and my cylinder throats run from .3571” to .3573”. I now know that my cylinder throats are .0004” to .0006” over groove diameter, I’m “good to go”. And my sized boolits, that are exiting my .358” sizing die at the above mentioned .3576”, should be about perfect for this revolver.

OK, what if it was the other way around? Say the groove diameter was .3572” and the cylinder throats were .3567” to .3569”, it wouldn’t matter if I sized the boolits to .360”, they’re still gonna hit the bore some .0003” to .0005” undersize. Only by measuring to the nearest .0001” would I know that I don’t need a .358” sizing die, I need to ream my cylinder mouths. Or I could just size the boolits to .357” and live with the associated problems of shooting undersized boolits.

I guess it’s a matter of precision. How precise do you want to be? How precise do you want the information you get from your measuring tools? When you enlarge a mold by lapping it, and your tool shows it enlarged from .357” to .358”, did it only go from .3574” to .3576”, just .0002” instead of the .001” that your tool reads? Or did it enlarge from .3566” to .3584”, which would be almost .002” (.0018”)? I want that information, especially when a tool can be had for around $50.00 (or even less) that can provide it.

Measuring to the nearest .001” is fine for trimming cases and seating boolits; but for most other things .0001 is the minimum needed precision IMHO.

[monadnock#5]

Randy, you should slug all your chamber mouths. It's part of the process. Remove the cylinder before slugging however, so as not to take a chance on springing the crane.

[jack19512]

jack19512

.0001 is 1/10,000... not 1/1000.
That's not saying that calipers aren't made that will read to 1/10,000, but I've never seen one. Mine will read to the nearest .0005 (5/10,000), and it was damn expensive, I'd hate to even think what one that reads to .0001 (1/10,000) would cost.

While I will be the first to admit I am a long way from being any kind of machinist my calipers say 1/1000 inch. Now what that means I'm sure others know more about it than me but the point I was trying to make is that you can buy calipers that measure closer than just .001.

[smlekid]

Jack your calipers are rated to 1/1000 or .001" of an inch
1/10000 or .0001" is really getting into Micrometer territory it must be stated that these tools are only as accurate as the user it is very easy to get different reading from different users it comes down to feel some like a firm drag others just a slight feel there could be a .0005 (1/2 thou) in feel
as long as the person is using the same feel with an inside and outside micrometer the reading should still be accurate
calipers can and do spring if you use to much thumb pressure so are harder for getting a good accurate measurement I use both every day and use calipers on thing that are not really critical when a measurment is crucial it is micrometers always
lets call it experienced fitters feel

[Echo]

I would agree with BD's comment that there may be calipers that read to the nearest tenth, they probably don't measure to the nearest tenth...

[Grampie not Grumpie]

When I slug my revolver I remove the cylinder and clamp a piece of 1x2 in the vice 1" side up with about 2-3" extending out. I slide the revolver over the wood and then drive the slug in from the barrel end. I wrap the revolver frame in a cloth to prevent any contact with the vise. When the slug reaches the forcing cone you can remove the revolver from the vise and the slug will fall out.

Grampie not Grumpie

[JIMinPHX]

When I slug a revolver, I put a piece of wood over the crown of the muzzle to protect it & then use a C-clamp to squeeze the slug in through the chamber end. I then re-rig with a short wooden dowel behind the slug to push the slug in deeper, etc. etc. etc. It's actually pretty easy.

[motorcycle_dan]

I would like to slug my .38 spl snub.

You want pure pb to do a proper slug. Find a cap and ball shooter. Use a .36 cal ball and push it through. If you can't find one you may need to buy a couple of .360 round balls. They will deform easily drive it through with a wood dowel as other have mentioned.

Measure how ever you like, Just be aware to measure your cast bullets with the same measuring device. Temperature of the device will change the indicated reading by up to 0.001 so it really doesn't matter the number it gives.

What you want to know is how it compares to the cast bullets you intend to run through it.

As other have mentioned you need two. One for the barrel and another for the cylinder. (actually would be best to have one for each chamber but that is a little too anal)

No matter what you do, the weakest link to any accuracy is the nut that operates the trigger.

[azrednek]

Good! Then as soon as I get a caliper I'll slug away. I am casting .38 tumble lubed wadcutters but haven't loaded any yet. I'm told that they probably don't need to be sized, but I did purchase a sizing die in .358 for future bullet types, and would like to know if I got the correct size.

Thanks for the help.

Randy

Randy I did some comparisons with the Lee 148 gr tumble lube wad cutter in a S&W 38, Ruger 357/9MM Convertible, Rossi 357 revolver and a Rossi 38/357 lever action rifle. With straight wheel weights they shot more accurately when I shot them un-sized lubed with Lee's Tumble lube. I tried 50/50 lube, Jake's Red and Jake's Moly, sized to .357 and .358. The flush seated wad cutter is a real pain to cycle through the lever action rifle but work just fine in revolvers.