Bullet weight and pressure

palabman · April 15, 2010, 08:42 PM

While digging through my reloading manuals searching for data on 102 gr Golden Sabers for my .380 Auto I found a load data for a 100 gr JHP. The max was 3.5 gr of Win 231. In the same manual the load data for a 90 gr JHP was a max of 3.2 gr. I thought that pressure increased as bullet weight increased. The data was out of Lyman 47.

brickeyee · April 15, 2010, 08:47 PM

Differences in bullet design can also affect pressure.

JHPs can have more differences than just weight.

palabman · April 15, 2010, 09:00 PM

If the bullet representation in the book is accurate, it does look like the bearing surface is a bit larger on the 90 gr.

dlb435 · April 16, 2010, 09:10 PM

I just did a check on your load data. It didn't check out. Go back and look at the max loads again. With 100 gain fmj the max load was 3.2 grain. The max load for 90 grain jhp was 3.5 grains. The max load for a 102 grain jhp should be 3.2 grains or less. I never did like reloading for small handgun caliblers. There just isn't much fudge factor in there.

palabman · April 16, 2010, 09:22 PM

The bullets I was comparing in Lyman 47 were the 90 gr JHC and the 100 gr JHP.
The 90 gr is a Sierra and the 100 gr is a Speer. I'm assuming the different bullet description (Jacketed HC and Jacketed HP) is just a difference in company terminology. Lyman 47 doesn't list a 100 gr FMJ but Lyman 48 does.

You are right about these small caliber loads. Enough to make you pull your hair out.

IllinoisCoyoteHunter · April 16, 2010, 09:28 PM

It is very important to understand how bullet weight, bearing surface, seating depth, and construction (jacketed, plated, lead, etc) can affect pressure.

TXGunNut · April 16, 2010, 09:30 PM

No 100gr loads in the 49th. There are few centerfire calibers I shoot that I don't have dies for, 380 is one of them. If the factory ammo doesn't start showing up soon I'll be looking for a set. What's so bad about loadin them?

April 15, 2010, 08:42 PM	#1
palabman Member Join Date: January 24, 2010 Location: SW PA Posts: 80	Bullet weight and pressure While digging through my reloading manuals searching for data on 102 gr Golden Sabers for my .380 Auto I found a load data for a 100 gr JHP. The max was 3.5 gr of Win 231. In the same manual the load data for a 90 gr JHP was a max of 3.2 gr. I thought that pressure increased as bullet weight increased. The data was out of Lyman 47.

April 16, 2010, 09:28 PM	#6
IllinoisCoyoteHunter Senior Member Join Date: December 23, 2008 Location: Southern Illinois Posts: 1,527	It is very important to understand how bullet weight, bearing surface, seating depth, and construction (jacketed, plated, lead, etc) can affect pressure. __________________ ~~IllinoisCoyoteHunter~~ ~NRA LIFE MEMBER~ ~NRA CERTIFIED INSTRUCTOR~

April 16, 2010, 09:30 PM	#7
TXGunNut Senior Member Join Date: January 16, 2010 Location: If you have to ask... Posts: 2,860	No 100gr loads in the 49th. There are few centerfire calibers I shoot that I don't have dies for, 380 is one of them. If the factory ammo doesn't start showing up soon I'll be looking for a set. What's so bad about loadin them? __________________ Life Member NRA, TSRA Smokeless powder is a passing fad! -Steve Garbe I hate rude behavior in a man. I won't tolerate it. -Woodrow F. Call Lonesome Dove My favorite recipes start out with a handful of used wheelweights.

April 15, 2010, 08:47 PM	#2
brickeyee Senior Member Join Date: December 29, 2004 Posts: 3,351	Differences in bullet design can also affect pressure. JHPs can have more differences than just weight.

April 15, 2010, 09:00 PM	#3
palabman Member Join Date: January 24, 2010 Location: SW PA Posts: 80	If the bullet representation in the book is accurate, it does look like the bearing surface is a bit larger on the 90 gr.

April 16, 2010, 09:10 PM	#4
dlb435 Senior Member Join Date: January 26, 2009 Posts: 654	I just did a check on your load data. It didn't check out. Go back and look at the max loads again. With 100 gain fmj the max load was 3.2 grain. The max load for 90 grain jhp was 3.5 grains. The max load for a 102 grain jhp should be 3.2 grains or less. I never did like reloading for small handgun caliblers. There just isn't much fudge factor in there.

April 16, 2010, 09:22 PM	#5
palabman Member Join Date: January 24, 2010 Location: SW PA Posts: 80	The bullets I was comparing in Lyman 47 were the 90 gr JHC and the 100 gr JHP. The 90 gr is a Sierra and the 100 gr is a Speer. I'm assuming the different bullet description (Jacketed HC and Jacketed HP) is just a difference in company terminology. Lyman 47 doesn't list a 100 gr FMJ but Lyman 48 does. You are right about these small caliber loads. Enough to make you pull your hair out.