I have some 140 grain Corbin FMJ bullets that I would like to load for my S&W 642 in P+ velocity. The bullets are round nose and have two cannelure grooves and are .634 in overall length.

Has anyone had any experience with these bullets? Any help will be greatly appreciated.

Well, in a revolver the OAL is only limited by the cylinder, so...

Since these are RN FMJ you can load them at the cannelure (of your choice?) with pretty much any of the powders listed on the Hodgdons website somewhere between the START and the MAX for a 140gr bullet.

i.e., 6.5 gr of #5, 4.5 gr WIN 231, etc. Then just work up... If you need to?

Don't expect (or try to attain) typical CORBIN high velocities, please!

Cheers!

Hornady's 140gr XTP is only slightly shorter in BOAL (.600") & it's cannelure is .310" from the base.

Seating your bullet to a corresponding depth, no reason you couldn't use Hornady's data to start working up a load with your bullet.

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Thank you all for the information. I am planning on reloading and testing some later in the week and will post my results.

When a .357" bullet has 2 crimp grooves it's usually for use in .38 Special brass and .357 Magnum brass.

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SWCA #3437

Ah... But which is for which...?

Cheers!

And in some bullets its "faux" cannelure is really for core retention &/or to facilitate the manufacturing process.

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Noticed that on the Sierra SIG V-Crown 9mm 124 & 125gr bullets the can is at different points as well as the differing profiles... Since they are for semi-automatic calibers I'd believe the concept stated above probably applies...?

Not terribly unlike the multiple grooves on many lead revolver bullets?

Cheers!

Back when .357 Magnum brass was scarce you would seat the bullet longer for the .357 Magnum and shorter for the .38 Special. Both were made in the more available .38 Special cases. I'm not sure why the bullets are still being made like that unless one of the cannelures could be for core retention like said above. Try asking the manufacturer, that will get you the correct reason.

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Yes, that's one that has a faux cannelure. Can't remember where I read it but it's for core retention & to control expansion.

Another is (was) Hornady's 45 caliber 200 & 225gr FTX bullets. Back in 2013 I bought a box of the 225gr FTX bullets specifically to try the "dual cannelures" and seat them to different depths but still be able to give them a roll crimp.

The Hornady literature at the time showed the "two cannelures" as did the picture on the box of bullets I purchased.

I was surprised to find the bullets in the box only had one cannelure so I emailed Hornady to get an answer on the difference.

They said, "This bullet actually has a single cannelure for loading. The small cannelure close to the base of the bullet is not intended for loading, it is there to aid in core retention and to put the top crimping cannelure on the bullet. We have recently developed a process to do this without the need for the bottom one."

You can see the different in their catalog pictures from 2013 & 2022 below.

Hornady's 45 caliber 300gr XTP does have two crimping cannelures to give you two different seating depths, & COAL", depending what cartridge & firearm you're loading it for.

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And, then there's the Federal HST Micro 130gr 38 Special +P JHP-WC (a.k.a. P38HST1S) bullets... Where it is clearly to help jacket retention.

Cheers!