JHP vs HP/XTP

Lackwell · April 14, 2009, 12:02 PM

I am trying to load a 357 mag. gun with Hornady XTP 38 Caliber 158 gr jacketed Hollow points. I would like to use Bullseye powder with cci sp primers.
I have a load off the internet of 6.5 gr Bullseye with a win sp primer. The load
is for a JHP listing only. Does the JHP/XTP make any difference or is the weight and the JHP all that matters? If anyone has a bullsleye load for this bullet
it would be great. Thank you all for your help.

SL1 · April 14, 2009, 12:57 PM

I suspect that you already know that Bullseye is not the best powder for full-power loads in the .357 Magnum. So I'm not going to give you a lecture about better powders that you are probably having a hard time buying right now. Hopefully, others won't either.

To answer your question, yes, there is some difference between the XTPs and some other JHPs that lead to slight differences in max charge weights. This has to do with the shapes of the bullets and how deep they end-up being seated when crimped in their canelures.

I did not find any data for Bullseye with the 158 grain XTP/HP bullet in the .357 Magnum, either. I have a 4th edition Hornady Manual, and they don't list that powder for that bullet. I did find a 6.8 grain max load for the generic 158 grain JHP listing in Lee's 2nd edition manual, and I checked the 6.5 grain load you cited using the 158 grain XTP/HP in QuickLOAD, where it seems to be near max, but OK. QuickLOAD seemed to slightly underpredict the Hornady .38 Special data for this bullet with Bullseye powder, so the 6.5 grain load in the .357 Magnum may be a little under-predicted, too. The 6.8 grain JSP max load was slightly over the SAAMI pressure limit in my QuickLOAD calc using the XTP bullet, so I wouldn't recommend that for you.

I suggest that you treat the 6.5 grain JSP load you found as max for your XTP load. You should work-up toward that limit with caution. Bullseye may get a little spiky at these high pressures with so much space left in the case. Hopefully, you don't need a maximum load and can be satisfied with a charge that leaves pressures well below max. A +P load in the .38 Special case is only a little over 4 grains of Bullseye, so you can get almost that much performance with the same charge in the .357 Magnum case.

And, be VERY careful not to double charge with Bullseye. A double charge fits the case with some room to spare, but the pressure calculates out to nearly 140,000 psi! That is enough to blow-up any gun that takes the .357 cartridge.

SL1

kcbrown · April 14, 2009, 09:06 PM

Quote:

And, be VERY careful not to double charge with Bullseye. A double charge fits the case with some room to spare, but the pressure calculates out to nearly 140,000 psi! That is enough to blow-up any gun that takes the .357 cartridge.

Yeah, but if the gun survives it, what's the resulting muzzle velocity?

apr1775 · April 15, 2009, 09:23 AM

I just checked my Hornady load manual for loads with this bullet; no Bullseye for 357mag loads listed, only slower powders. They do list a mild 38spec load with this bullet and powder. If at all possible, get a more suitable powder for magnum loads.

April 14, 2009, 12:02 PM	#1
Lackwell Junior Member Join Date: March 27, 2009 Posts: 4	JHP vs HP/XTP I am trying to load a 357 mag. gun with Hornady XTP 38 Caliber 158 gr jacketed Hollow points. I would like to use Bullseye powder with cci sp primers. I have a load off the internet of 6.5 gr Bullseye with a win sp primer. The load is for a JHP listing only. Does the JHP/XTP make any difference or is the weight and the JHP all that matters? If anyone has a bullsleye load for this bullet it would be great. Thank you all for your help.

April 14, 2009, 12:57 PM	#2
SL1 Senior Member Join Date: November 8, 2007 Posts: 2,001	I suspect that you already know that Bullseye is not the best powder for full-power loads in the .357 Magnum. So I'm not going to give you a lecture about better powders that you are probably having a hard time buying right now. Hopefully, others won't either. To answer your question, yes, there is some difference between the XTPs and some other JHPs that lead to slight differences in max charge weights. This has to do with the shapes of the bullets and how deep they end-up being seated when crimped in their canelures. I did not find any data for Bullseye with the 158 grain XTP/HP bullet in the .357 Magnum, either. I have a 4th edition Hornady Manual, and they don't list that powder for that bullet. I did find a 6.8 grain max load for the generic 158 grain JHP listing in Lee's 2nd edition manual, and I checked the 6.5 grain load you cited using the 158 grain XTP/HP in QuickLOAD, where it seems to be near max, but OK. QuickLOAD seemed to slightly underpredict the Hornady .38 Special data for this bullet with Bullseye powder, so the 6.5 grain load in the .357 Magnum may be a little under-predicted, too. The 6.8 grain JSP max load was slightly over the SAAMI pressure limit in my QuickLOAD calc using the XTP bullet, so I wouldn't recommend that for you. I suggest that you treat the 6.5 grain JSP load you found as max for your XTP load. You should work-up toward that limit with caution. Bullseye may get a little spiky at these high pressures with so much space left in the case. Hopefully, you don't need a maximum load and can be satisfied with a charge that leaves pressures well below max. A +P load in the .38 Special case is only a little over 4 grains of Bullseye, so you can get almost that much performance with the same charge in the .357 Magnum case. And, be VERY careful not to double charge with Bullseye. A double charge fits the case with some room to spare, but the pressure calculates out to nearly 140,000 psi! That is enough to blow-up any gun that takes the .357 cartridge. SL1

April 15, 2009, 09:23 AM	#4
apr1775 Senior Member Join Date: May 3, 2007 Location: Virginia Posts: 425	I just checked my Hornady load manual for loads with this bullet; no Bullseye for 357mag loads listed, only slower powders. They do list a mild 38spec load with this bullet and powder. If at all possible, get a more suitable powder for magnum loads.