Let me preface this with, I am just now getting into reloading. According to the Lyman Pistol and Revolver handbook, i need to slug the barrel on my Colt RHKP pistol to determine the bore size. Then i can determine what size cast bullet i need. I have heard of people using muzzleloader balls to slug a bore and of people casting a cylindrical slug for this purpose. I have 36 cal muzzleloader balls, .375”. The Saami spec for 38 s&w is .361” Could i safely drive one of these balls down the barrel to slug it? I was wondering if anyone that has some experience with slugging a bore could offer some guidance.
Think Brownells or someone has a kit for doing that . not very costly at that.
I’ve used lead sinkers. Clean the bore well and then grease it it up before you put your lead ball down the bore.
If you don't want to slug it, you can also just experiment with different diameter bullets going up or down a thousandth of an inch at a time. It won't be as efficient as slugging the barrel, but you can get there.
If you have soft lead sinker or bullet that is too fat you can lay it on a hard surface and tap on it with a hammer and make the diameter smaller.
Or you can roll it while pressing down on it with a steel plate.
You can make a skinny bullet fatter by standing it on it's base and hammer the tip of it.
I lube the bore very well and the bullet also.
When you do slug that pistol barrel pay attention on how much force it takes through the entire barrel.
Then remove the slug and stick it in again and send it down the barrel and again notice the force applied.
I found my Ruger and my S&W revolvers have a tight spot where the barrel meets the frame.
I ended up fire lapping the barrels and accuracy improved greatly.
Very hard (impossible for me) to get a cast bullet to shoot accurate with a pinch in the barrel near the frame.
I know some guys that jacketed bullets are the only accurate ones in their revolvers.
Or you can roll it while pressing down on it with a steel plate.
You can make a skinny bullet fatter by standing it on it's base and hammer the tip of it.
I lube the bore very well and the bullet also.
When you do slug that pistol barrel pay attention on how much force it takes through the entire barrel.
Then remove the slug and stick it in again and send it down the barrel and again notice the force applied.
I found my Ruger and my S&W revolvers have a tight spot where the barrel meets the frame.
I ended up fire lapping the barrels and accuracy improved greatly.
Very hard (impossible for me) to get a cast bullet to shoot accurate with a pinch in the barrel near the frame.
I know some guys that jacketed bullets are the only accurate ones in their revolvers.
Swampratt had a good idea about shaping a fishing sinker to fit. The fire lapping is a whole other thread though! I think it’s been discussed a couple times. I’ll see if I can find the threads and revive them. There are some interesting ideas and techniques out there.
I must ask what you measured the OD of this with.
I know many barrels are larger at the beginning than at the muzzle end.
Push that ball back through the bore as is and see if it is tight at the muzzle Harder to push for the first 1" or so.
See if it gets easier the farther down you go.
And lastly see if it gets hard to push once you are at the frame junction last 1.5" of barrel towards the cylinder.
I know many barrels are larger at the beginning than at the muzzle end.
Push that ball back through the bore as is and see if it is tight at the muzzle Harder to push for the first 1" or so.
See if it gets easier the farther down you go.
And lastly see if it gets hard to push once you are at the frame junction last 1.5" of barrel towards the cylinder.
I measured the diameter with digital calipers. It has a bit of resistance entering the barrel, but as soon as it is in, it moves freely till the last 3/4” near the chamber. At that point it takes some effort to push it the rest of the way through. About as much force as pulling a trigger.
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