radny97 Posted November 17, 2022 Share Posted November 17, 2022 17 hours ago, varminter22 said: I understand that! But if that is true (and I saw your SAAMI ref), why aren't ammo manufactures (and us handloaders) loading all .38 Spec/.357 Mag/etc ammo with .355"/.356" bullets? I also understand that barrels can and do vary, but they should be with the .0004" or .0005" tolerance, correct? And barrels can vary a little in bullet preference. But a .358" bullet in a .3546" barrel?? Interesting. Said another way: Since you said "SAAMI defines the standards, and companies build their products around them" why wouldn't the standard bullet diameter for both calibers be .355"/.356"? 16 hours ago, superdude said: There is no such thing as a 38/357 barrel and a separate 9mm barrel. They both have the exact same specs. If you buy a 38/357 revolver and the barrel groove diameter measures .355", does that mean it has a 9mm barrel? No, it doesn't. That's because .355 is within the SAAMI specs for a 38/357 barrel. It's still a 38/357 barrel. Not true. 357 mag barrels have 1/18 twist while 9mm barrels have 1/10 twist. Link to comment Share on other sites More sharing options...
superdude Posted November 17, 2022 Share Posted November 17, 2022 The twist rate is different (though optional), but the groove diameter specs are the same. The groove diameter being the same is what people go nuts over. Link to comment Share on other sites More sharing options...
MWP Posted November 17, 2022 Share Posted November 17, 2022 4 hours ago, Toolguy said: The main thing to remember is you always want to go from bigger to smaller. For example, if you have .358 bullets, you can go to .357 throats and .355 barrel and be OK. If you have .355 bullets and .357 throats and barrel, it may not work as well. If the barrel has a tight spot where it threads into the frame, it will swage the bullets down and they will rattle down the rest of the barrel causing leading and large groups. I think this is exactly why I’ve had really good luck with my aftermarket barrels and 358 coated bullets of all weights. 358 bullet, most likely a 356-357 cylinder throat from a factory 929 cylinder, and a true 355 barrel. Link to comment Share on other sites More sharing options...
MWP Posted November 17, 2022 Share Posted November 17, 2022 (edited) 4 hours ago, Toolguy said: The main thing to remember is you always want to go from bigger to smaller. For example, if you have .358 bullets, you can go to .357 throats and .355 barrel and be OK. If you have .355 bullets and .357 throats and barrel, it may not work as well. If the barrel has a tight spot where it threads into the frame, it will swage the bullets down and they will rattle down the rest of the barrel causing leading and large groups. Short stroke. Edited November 17, 2022 by MWP Link to comment Share on other sites More sharing options...
MikeBurgess Posted November 17, 2022 Share Posted November 17, 2022 2 hours ago, mchapman said: Kirby G, Vic M and Billy S all had them, built by the guy in Phoenix , so I think that there were at least 4 of them, but I could be wrong, I've seen 3 of them. Cool, I only ever saw pictures of one on here Link to comment Share on other sites More sharing options...
gargoil66 Posted November 18, 2022 Share Posted November 18, 2022 21 hours ago, testosterone said: Not a machinist, you need a vblock to do this measurement properly anyways, no? TT: I am not a machinist either. What's a 'V' block? GG Link to comment Share on other sites More sharing options...
gargoil66 Posted November 18, 2022 Share Posted November 18, 2022 21 hours ago, testosterone said: Not a machinist, you need a vblock to do this measurement properly anyways, no? TT: I am not a machinist either. What's a 'V' block? GG Link to comment Share on other sites More sharing options...
ysrracer Posted November 18, 2022 Share Posted November 18, 2022 41 minutes ago, gargoil66 said: TT: I am not a machinist either. What's a 'V' block? GG A block in the shape of a V ? Link to comment Share on other sites More sharing options...
Toolguy Posted November 18, 2022 Share Posted November 18, 2022 You need a micrometer to measure the bullet diameter after it's been pushed through the barrel. For an even number of lands and grooves, a regular micrometer works. Six lands and grooves is common, there are many others. For an odd number of lands and grooves, you need a V anvil micrometer made for that number. Five lands and grooves is common, there are others. Most of the current S&W revos have 5 lands and grooves, which makes measuring the bullet problematic unless you have a V anvil micrometer (mike) made to measure 5. These are most often used to measure cutting tools with 5 flutes, like an end mill, reamer, special drill bit, etc. Link to comment Share on other sites More sharing options...
testosterone Posted November 18, 2022 Share Posted November 18, 2022 (edited) 2 hours ago, Toolguy said: You need a micrometer to measure the bullet diameter after it's been pushed through the barrel. For an even number of lands and grooves, a regular micrometer works. Six lands and grooves is common, there are many others. For an odd number of lands and grooves, you need a V anvil micrometer made for that number. Five lands and grooves is common, there are others. Most of the current S&W revos have 5 lands and grooves, which makes measuring the bullet problematic unless you have a V anvil micrometer (mike) made to measure 5. These are most often used to measure cutting tools with 5 flutes, like an end mill, reamer, special drill bit, etc. as defined by an actual machinist This is why, mostly, when someone says they slugged a barrel I have considerable doubt regarding the measurements accuracy. Edited November 18, 2022 by testosterone Link to comment Share on other sites More sharing options...
gargoil66 Posted November 18, 2022 Share Posted November 18, 2022 Warren: Thanks for that info. I have slugged a number of barrels to find most of them five groove. Impossible to measure with a standard calipers. Don't even want to think of how much a v block micrometer costs. Link to comment Share on other sites More sharing options...
Toolguy Posted November 18, 2022 Share Posted November 18, 2022 Under $200 if you know where to look. Much more otherwise. https://www.shars.com/products/measuring/micrometers/0-2-1-108-degree-5-flutes-measured-v-anvil-micrometer Link to comment Share on other sites More sharing options...
ysrracer Posted November 18, 2022 Share Posted November 18, 2022 33 minutes ago, Toolguy said: Under $200 if you know where to look. Much more otherwise. https://www.shars.com/products/measuring/micrometers/0-2-1-108-degree-5-flutes-measured-v-anvil-micrometer So you're saying a v-block micrometer has a block shaped like a V ? Interesting. Link to comment Share on other sites More sharing options...
Toolguy Posted November 18, 2022 Share Posted November 18, 2022 Click on the link and look at the picture. Link to comment Share on other sites More sharing options...
ysrracer Posted November 19, 2022 Share Posted November 19, 2022 1 hour ago, Toolguy said: Click on the link and look at the picture. Make me Link to comment Share on other sites More sharing options...
Toolguy Posted November 21, 2022 Share Posted November 21, 2022 I don't make anyone do anything. Everyone is free to do as they wish. That was a suggestion, not an order. Link to comment Share on other sites More sharing options...
BHBret Posted November 21, 2022 Share Posted November 21, 2022 OK, the v-block hurts my head. As the diameter of any object gets bigger the position in the V gets further from the corner of the V. Does the reading of the caliper takes that into account so you directly read the outside diameter? Link to comment Share on other sites More sharing options...
testosterone Posted November 21, 2022 Share Posted November 21, 2022 1 hour ago, BHBret said: Does the reading of the caliper takes that into account so you directly read the outside diameter? you are thinking to hard Link to comment Share on other sites More sharing options...
Toolguy Posted November 21, 2022 Share Posted November 21, 2022 Yes, you read it like a normal mike. That's why the angle of the anvil only works for one number of flutes. For example, a V anvil mike for 3 flutes is very different to a V anvil mike for 5 flutes, etc. Even numbers can be measured with a regular mike because there will always be 2 that are directly opposite. Link to comment Share on other sites More sharing options...
gargoil66 Posted November 21, 2022 Share Posted November 21, 2022 3 hours ago, Toolguy said: Yes, you read it like a normal mike. That's why the angle of the anvil only works for one number of flutes. For example, a V anvil mike for 3 flutes is very different to a V anvil mike for 5 flutes, etc. Even numbers can be measured with a regular mike because there will always be 2 that are directly opposite. Warren: Yes, I have seen them before but never used one. Makes sense that they would be shaped differently for different number of flutes. Am past the stage of slugging barrels so leave all that to you guys who know what you are doing. Thanks for the info once again. GG Link to comment Share on other sites More sharing options...
ysrracer Posted November 21, 2022 Share Posted November 21, 2022 6 hours ago, testosterone said: you are thinking to hard Agreed, just load up some bullets and see how they shoot. I did a side by side test with four different brands. No difference at 25 yards. Link to comment Share on other sites More sharing options...
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