9x19 boat tail

[EMR]

I recently picked up a MP 358-147 mold (drops at 154gr per specs) from a recent GB here. After loading a few and pulling to check for swaging, the good news is that there’s no swaging using a Mr Bullet Feeder powder through on my Dillon 650 (which is fairly equivalent to a M-Die).

Using a Lee .357 push through sizer, they mic at .3562. So far this hasn’t caused any leading with my other 9mm molds. There is however noticeable boat tail in the boolits from the tapered 9mm cases.

I don’t have any time in the foreseeable future to actually try these out and actually shoot them, but is anyone willing to wager if this would cause any leading or accuracy issues?

Loaded and pulled on the left. Freshly sized and not loaded on the right.





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[nicholst55]

Correct me if I'm mistaken, but I would personally call your 'boat tail' swaging the bullet base. I would fully expect it to cause gas cutting and leading.

[EMR]

Correct me if I'm mistaken, but I would personally call your 'boat tail' swaging the bullet base. I would fully expect it to cause gas cutting and leading.

I’m fairly new to casting so this is why I brought this up. Indeed the base is swaged but the rest of the driving area measures the same as it did when it was sized. Which in all of my pistols .3562 does not cause leading.

I’m curious to see what will happen.

Thanks for your input!


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[trapper9260]

Correct me if I'm mistaken, but I would personally call your 'boat tail' swaging the bullet base. I would fully expect it to cause gas cutting and leading.

When I see talk about boat tail it is like you stated the bullet base.I have very little of them for cast.But the ones I use dose not do any leading.I use the old NRA lube with ATF.I make it myself.

[tazman]

Some boolits in the heavier weights for 9mm have a noticeable taper at the base already as cast. The 356637 comes to mind. Other boolits have bevel bases which are similar if not a pronounced.
As long as the body of the boolit seals the bore, there should be no gas cutting and no leading.

[mdi]

Isn't the PC coating a protective coating to prevent gas cutting? Hasn't anyone retrieved a fired bullet and inspected the base? Those I found has no gas cutting/burning/melting apparent on the bases...

[EMR]

When I see talk about boat tail it is like you stated the bullet base.I have very little of them for cast.But the ones I use dose not do any leading.I use the old NRA lube with ATF.I make it myself.

The ones that you shoot, are they for pistol or rifle?

Some boolits in the heavier weights for 9mm have a noticeable taper at the base already as cast. The 356637 comes to mind. Other boolits have bevel bases which are similar if not a pronounced.
As long as the body of the boolit seals the bore, there should be no gas cutting and no leading.

This is what I was thinking myself. I hope you're right! I'll be pretty bummed if I have to search for a different mold. Not really sure how to get away from swaging the base.

Isn't the PC coating a protective coating to prevent gas cutting? Hasn't anyone retrieved a fired bullet and inspected the base? Those I found has no gas cutting/burning/melting apparent on the bases...

I believe you're confusing gas checks with powder coating. PC only acts as a lube.

[mdi]

The ones that you shoot, are they for pistol or rifle?


This is what I was thinking myself. I hope you're right! I'll be pretty bummed if I have to search for a different mold. Not really sure how to get away from swaging the base.


I believe you're confusing gas checks with powder coating. PC only acts as a lube.

Not for any of my PCed bullets; 9mm, 38 Special, 357 Magnum (at magnum velocities), 44 Magnum (at magnum velocities), 30-06 (in a Garand), and 7.62x54r (at low jacketed velocities)...

[country gent]

Section a case in half you may be getting into where the case starts to taper into the head portion causing the "boat tail" This heavy of a bullet ( think length) may greatly reduce powder capacity in a 9mm case when loaded to OAL required. Be careful with the starting loads.

[wmitty]

I think country gent has nailed it.

[EMR]

Not for any of my PCed bullets; 9mm, 38 Special, 357 Magnum (at magnum velocities), 44 Magnum (at magnum velocities), 30-06 (in a Garand), and 7.62x54r (at low jacketed velocities)...

Sounds like you’ve had quite a bit of success! Hopefully that’s good new for me then.

Section a case in half you may be getting into where the case starts to taper into the head portion causing the "boat tail" This heavy of a bullet ( think length) may greatly reduce powder capacity in a 9mm case when loaded to OAL required. Be careful with the starting loads.

This sounds like solid advice. Thanks!


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