Speer Gold Dot - shallow vs. deep HP?

[hawk_sixsix]

I just purchased Speer 357 SIG GD 125 gr., DoubleTap/GD 147 gr., and Speer 9mm +P 124gr.

All have 6 serrations.

The 125gr. Speer are shallow HP; the Doubletap 147gr. and the 9mm are both deep. The 147gr. 357 is really deep.

What's the story here?

 

[hawk_sixsix]

 

[I AM]

Well, the heavier bullet is longer and can have a deeper cavity than the lighter/ shorter bullet.

 

[Walkalong]

The different bullets are designed to work at whatever velocities they are anticipated to be shot at.

They can control expansion with jacket thickness, lead hardness, cavity size/shape/depth, etc.

 

[RidgwayCO]

As I understand it, the wider and deeper cavities are there on some GDHP bullets to enable them to expand at lower velocities. I know that the hollow points on my Speer 200gr GDHPs (meant for the .44 Special) are huge!

For the bullets that can expect to be pushed faster (the 125gr for the .357 Magnum, the 240gr for the .44 Magnum, etc), the GDHPs have a much shallower cavity. For the .44 Magnum, the 270gr Gold Dot is a soft point (no cavity).

At least, that's the reason I've been told...

 

[Steve H]

if you get a chance look at the 45 cal Barnes XPB hollow point.......you have the grand canyon in that one.

 

[Ben Shepherd]

Yep-

If you look, most bullet manufacturers list velocity ranges for their slugs. The cavities in HP projectiles are tuned for correct performance in a specific velocity range. Generally, the bigger or wider the cavity, the lower the velocities it was designed for.

 

[Hungry Seagull]

My Speer Gold Dot HP's in the 230 grain are worthy caverns. You can almost walk into one of these. These are the 45 ACP rounds.

 

[hawk_sixsix]

Thanks for all the great replies, everyone. The velocity-tuning explanation makes sense.

Now, by all observations and with considerations to the above replies, the DoubleTap 357 SIG 147gr. is using a bullet intended for a 9mm, at velocities below 1000fps. It's a deep cavity. DoubleTap is loading this into a 357 SIG cartridge, pushing it 300fps faster than intended (DT rated at 1255fps). What's the consequence here?

 

[Hungry Seagull]

I dont know.

Ever get swatted by a thin hickory limb? It would sting pretty painfully if not leave a big mark that will burn for hours.

Ever get hit by a Louisville Bat? It might be days before you come up, if you live. However you would have seen it coming I think.

 

[Ben Shepherd]

It'll most likely act like most of cor-bons stuff, right on the ragged edge of explosive rather than expansive. Testing required......

Hey, looky there!! I just gave you an excuse, er, reason to go shooting.

 

[climbnjump]

Now, by all observations and with considerations to the above replies, the DoubleTap 357 SIG 147gr. is using a bullet intended for a 9mm, at velocities below 1000fps. It's a deep cavity. DoubleTap is loading this into a 357 SIG cartridge, pushing it 300fps faster than intended (DT rated at 1255fps). What's the consequence here?

Your concern is, of course, valid. That's why there is a difference in cavity depths between the 124gr. 9mm load and the 125 gr. .357 SIG load. The 125gr. bullet was specifically designed for the higher velocities of the .357 SIG - hence the shallower cavity.

However, I think you'll probably be ok at 1255 fps with the 147gr. bullets. My Speer Reloading Manual #14 shows .357 SIG loads for that bullet at velocities up to 1218 fps.

And a direct quote from the .357 SIG load data in the manual: "The 147gr. Gold Dot allows deeper penetration. The heavy bullets gave impressive velocities and are significantly more potent than when loaded in a 9mm Luger or 38 Super."