+p question

Dre_sa · June 4, 2010, 10:05 PM

I figured this would be the best place to put this question since hand loading requires such attention to detail.

my question is this;

at what velocity does +p pressure level start when using a 230gr. projectile in 45 auto?

so basically how fast does a 230gr have to be going to be considered +p, when fired out of a .45 ACP?

reason I ask is I see on midway, that federal hydrashock 230gr. is listed at 900fps, and in the comments / reviews section, someone states that this load is not +p.

Sevens · June 4, 2010, 10:30 PM

Plus-P isn't a speed, it's a state of mind!

Actually, it's a pressure. .45 Auto has a peak pressure of 21,000 PSI and when a cartridge is built to a max of 23,000 PSI, then it becomes a .45 Auto +P.

The truth is, you could see a bullet move even slower and still produce a +P pressure if you used the wrong powder.

Plus-P is a SAAMI standard and it's all about peak pressure to earn that designation. If you reach 28,500 PSI, that's a .45 Super.

Dre_sa · June 5, 2010, 02:51 PM

I understand +p is a pressure level, but I was thinking that the combination of bullet weight and velocity could give an indication of pressure.

A certain weight bullet driven at a particular velocity gives a specific pressure. at least that was my impression.

so a 230gr at 900fps isn't +p, but its well above the "standard" vleocity of 830 fps, so i figured that the pressure level would be at least close to +p.

Am I thinking wrong? is it all dependent on powder type and how fast it burns? are weight and velocity no indication of pressure?

ScottRiqui · June 5, 2010, 03:11 PM

Weight and velocity aren't a reliable indication of pressure. I just ran a correlation analysis on 23 loads from Lee's "Modern Reloading", using the recipes for 230 gr lead bullets. The correlation between pressure and speed was 0.58, which is a very poor correlation (1.00 would mean that they're perfectly correlated, while 0.00 would mean that one has no effect on the other.)

All that a value of 0.58 tells you is that the two variables are "positively correlated", meaning that in general, larger pressures are associated with higher velocities, but it's such a poor fit that you can't reliably use one to predict the other.

Jim243 · June 5, 2010, 08:01 PM

Quote:

is it all dependent on powder type and how fast it burns

That is almost correct. It also depends on the amount of space the powder has to burn in.

Jim

ForneyRider · June 8, 2010, 03:46 PM

WARNING THESE ARE ALL MAX LOADS.

I do 5.3gr of W231 for ~850fps, but went up to 5.8gr W231 but SD and accuracy was bad.

I do 7.5gr PP for +P 230gr 45 ACP load and it is very consistent. I get about 950 fps. I've gone 1000fps through the chrony, but the slide slammed hard when cycled in my 1911.

June 4, 2010, 10:05 PM	#1
Dre_sa Senior Member Join Date: April 19, 2005 Location: Left coast Posts: 610	+p question I figured this would be the best place to put this question since hand loading requires such attention to detail. my question is this; at what velocity does +p pressure level start when using a 230gr. projectile in 45 auto? so basically how fast does a 230gr have to be going to be considered +p, when fired out of a .45 ACP? reason I ask is I see on midway, that federal hydrashock 230gr. is listed at 900fps, and in the comments / reviews section, someone states that this load is not +p. __________________ Imagine what I would do, if I could do all I can.

June 4, 2010, 10:30 PM	#2
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	Plus-P isn't a speed, it's a state of mind! Actually, it's a pressure. .45 Auto has a peak pressure of 21,000 PSI and when a cartridge is built to a max of 23,000 PSI, then it becomes a .45 Auto +P. The truth is, you could see a bullet move even slower and still produce a +P pressure if you used the wrong powder. Plus-P is a SAAMI standard and it's all about peak pressure to earn that designation. If you reach 28,500 PSI, that's a .45 Super. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

June 5, 2010, 02:51 PM	#3
Dre_sa Senior Member Join Date: April 19, 2005 Location: Left coast Posts: 610	I understand +p is a pressure level, but I was thinking that the combination of bullet weight and velocity could give an indication of pressure. A certain weight bullet driven at a particular velocity gives a specific pressure. at least that was my impression. so a 230gr at 900fps isn't +p, but its well above the "standard" vleocity of 830 fps, so i figured that the pressure level would be at least close to +p. Am I thinking wrong? is it all dependent on powder type and how fast it burns? are weight and velocity no indication of pressure? __________________ Imagine what I would do, if I could do all I can.

June 8, 2010, 03:46 PM	#6
ForneyRider Senior Member Join Date: December 4, 2007 Location: Forney, TX Posts: 725	WARNING THESE ARE ALL MAX LOADS. I do 5.3gr of W231 for ~850fps, but went up to 5.8gr W231 but SD and accuracy was bad. I do 7.5gr PP for +P 230gr 45 ACP load and it is very consistent. I get about 950 fps. I've gone 1000fps through the chrony, but the slide slammed hard when cycled in my 1911. __________________ When all is said and done, there is a lot more said than done.

June 5, 2010, 03:11 PM	#4
ScottRiqui Senior Member Join Date: January 27, 2010 Location: Norfolk, VA Posts: 2,905	Weight and velocity aren't a reliable indication of pressure. I just ran a correlation analysis on 23 loads from Lee's "Modern Reloading", using the recipes for 230 gr lead bullets. The correlation between pressure and speed was 0.58, which is a very poor correlation (1.00 would mean that they're perfectly correlated, while 0.00 would mean that one has no effect on the other.) All that a value of 0.58 tells you is that the two variables are "positively correlated", meaning that in general, larger pressures are associated with higher velocities, but it's such a poor fit that you can't reliably use one to predict the other.