Calculation fail...

FrankenMauser · March 30, 2018, 05:50 PM

Last year, maybe even two years ago, I took two chamber casts of my .475 Tremor, measured a few angles for feeding, and modified some magazines to feed wide meplats.
Then I took my measurements, calculated the most (of everything) that I could get away with for a 400 gr bullet with a long nose in a short throat, and had Mountain Molds cut it.

I finally got around to casting some a while back, and got around to putting together some dummies last week.

Yea, um...

I got the nose diameter / ogive wrong, and they won't chamber without excessive force.

(I checked dimensions. The bullets drop within tolerances, as ordered.)

To rub salt in the wound, it fits and (otherwise) feeds as intended; and is too long for the .480 Ruger unless the ogive is 1/4" inside the case.

At least it wasn't a terribly expensive mold...

Perhaps I can find a caster shooting .475 Linebaugh in a TC, or a caster with another .470 / .475 cartridge that wants a 'plinking' bullet.

Time to pick out the MM 477-400s and melt them back down.

I'll have to dig out my chamber and bullet drawings again, to see how I screwed up and address that nose diameter/ogive.

Rangerrich99 · March 30, 2018, 06:40 PM

I know it probably stings a bit to have miscalculated so badly, but it gives me a little chuckle just to see how much of that bullet is sticking out of that cylinder. At least you know now what not to do.

FrankenMauser · March 30, 2018, 10:38 PM

I understand. No hard feelings from me.
It's a comical sight, and not your fault.
It was entirely my screw-up.

Every custom mold is a learning experience. Most go well. This one.... We'll call it a speed bump.

Beagle333 · April 1, 2018, 03:15 AM

Man, that's a big ol' whompin bullet. I wish I had something that would shoot it, but all I have is a .480 pistol too.

March 30, 2018, 05:50 PM	#1
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	Calculation fail... Last year, maybe even two years ago, I took two chamber casts of my .475 Tremor, measured a few angles for feeding, and modified some magazines to feed wide meplats. Then I took my measurements, calculated the most (of everything) that I could get away with for a 400 gr bullet with a long nose in a short throat, and had Mountain Molds cut it. I finally got around to casting some a while back, and got around to putting together some dummies last week. Yea, um... I got the nose diameter / ogive wrong, and they won't chamber without excessive force. (I checked dimensions. The bullets drop within tolerances, as ordered.) To rub salt in the wound, it fits and (otherwise) feeds as intended; and is too long for the .480 Ruger unless the ogive is 1/4" inside the case. At least it wasn't a terribly expensive mold... Perhaps I can find a caster shooting .475 Linebaugh in a TC, or a caster with another .470 / .475 cartridge that wants a 'plinking' bullet. Time to pick out the MM 477-400s and melt them back down. I'll have to dig out my chamber and bullet drawings again, to see how I screwed up and address that nose diameter/ogive. __________________ Don't even try it. It's even worse than the internet would lead you to believe.

March 30, 2018, 10:38 PM	#3
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	I understand. No hard feelings from me. It's a comical sight, and not your fault. It was entirely my screw-up. Every custom mold is a learning experience. Most go well. This one.... We'll call it a speed bump. __________________ Don't even try it. It's even worse than the internet would lead you to believe.

April 1, 2018, 03:15 AM	#4
Beagle333 Senior Member Join Date: January 7, 2012 Location: Auburn, AL. Posts: 2,332	Man, that's a big ol' whompin bullet. I wish I had something that would shoot it, but all I have is a .480 pistol too. __________________ . . . Have a Colt and a smile.

March 30, 2018, 06:40 PM	#2
Rangerrich99 Senior Member Join Date: March 20, 2014 Location: Kinda near Phoenix, AZ Posts: 1,254	I know it probably stings a bit to have miscalculated so badly, but it gives me a little chuckle just to see how much of that bullet is sticking out of that cylinder. At least you know now what not to do.