I want to measure the barrel diameter in my Smith and Wesson .44 Magnum PC, 7.5". I want to do this because .44 cal bullets are made in .429", .430", and .431" diameters and I need to know which projectile to use. What is the typical precision apparatus to use here? Thanks for any replies.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
how do I measure my actual barrel diameter?
- Thread starter Sig_Dude
- Start date
If it has an even number of lands and grooves (and it probably does), the best way is to slug the bore.
Get a soft lead fishing weight that's a little larger than the bore diameter. Oil the bore and drive the sinker through. You can then measure it with good calipers or a micrometer.
The cylinder throat diameter is probably even more important. They should be 0.0005" or so larger than bore diameter.
Or just go the easy way and get .429 jacketed or .430 lead bullets and load them up.
Get a soft lead fishing weight that's a little larger than the bore diameter. Oil the bore and drive the sinker through. You can then measure it with good calipers or a micrometer.
The cylinder throat diameter is probably even more important. They should be 0.0005" or so larger than bore diameter.
Or just go the easy way and get .429 jacketed or .430 lead bullets and load them up.
Sheikyourbootie
New member
A pure lead egg sinker, a brass rod and a HEAVY (5# hammer) because the quick impulse of a small hammer blow can stick the sinker into the barrel. The brass rod needs a point at the end to sink into the sinker thus centering it.
The S&W barels are 5 grooves and are a bit more difficult to get an accurate measurement from. Also, you should remove your cylinder and slug each chamber...I have a Ruger that had one chamber that was tighter than the barrel. It would swage down ALL diameter lead bullets to the point it always leaded the barrel...until I had it reamed out.
An easier way to do this is order bullets of each diameter and see if any one diameter fires best and leads the least. Any commercially cast bullet, I give them a quick tumble lube in a mix of lee liquid alox/johnsons paste wax and just a bit of mineral oil....this has helped a lot in virtually eliminating leading at all pistol velocities...right up to gas checked bullets pushed to 1400fps.
The S&W barels are 5 grooves and are a bit more difficult to get an accurate measurement from. Also, you should remove your cylinder and slug each chamber...I have a Ruger that had one chamber that was tighter than the barrel. It would swage down ALL diameter lead bullets to the point it always leaded the barrel...until I had it reamed out.
An easier way to do this is order bullets of each diameter and see if any one diameter fires best and leads the least. Any commercially cast bullet, I give them a quick tumble lube in a mix of lee liquid alox/johnsons paste wax and just a bit of mineral oil....this has helped a lot in virtually eliminating leading at all pistol velocities...right up to gas checked bullets pushed to 1400fps.
Sheikyourbootie
New member
If you do that, the bullet standing the best chance at working would be a gas check hard cast. You might be surprised to see that the impact with water may actually cause a bit of expansion...even in solid design bullet that isn't hard cast.
Jim Watson
New member
The chamber throats in the cylinder are the critical fit in a revolver. If the groove diameter is just a little under that, great, but that is not what to pick bullets by.