Hornady HAP .356 and hodgdon load data conundrum

[Guitarmageddon]

Hello all,

In the pursuit of optimizing bullet choice for my cz p07 barrel, which slugged out at .356, I decided to try a couple .356 FMJ choices. I got some zero 125gr fmj and also the hornady action pistol .356 125gr. The hodgon site shows an extremely conservative velocity and charge weight for the HAPs. Just so happens that my ideal OAL for plunking is what they have chosen for their OAL. 

 

But when I run the numbers inside GRT, I just dont see why they have chosen to be so conservative. I have attached what GRT shows for the listed hodgdon ladder. Yes a power factor of 118 for their "action pistol" bullet....odd. 

Im thinking I can comfortably take this to 3.6 and just about 1000fps. Has anyone else played with this powder/bullet? Ive seen forum posts here and there and seems hornady/hodgdon give the run around about it and dont comment as to why.

But when I sit down to plan out my n320 testing, its not much different from any of their other FMJ listings to be honest. At least not as stark of a contrast as hodgdon shows.  

The peak charge of 3.3 on the hodgdon ladder is only a 57% case fill at that. something doesnt add up. Id love to hear your thoughts, thanks all. 

[OnePivot]

Wow, thats messy data. Sierra 125's at a weird short 1.090 and 4.8 grains of 231 show 28kpsi and over 1000fps! 

 

I know haps run short, but that's really really short. Even with that profile I'd want them closer to 1.090. That's basically an uncut xtp, and 147 xtp's show a higher 3.4gr max at 1.100. 

 

I think you can safely extrapolate some data if you run those haps way longer. Even for a cz, that seems unreasonably short. 

[superdude]

Hodgdon's 'conservative' velocity is because of the short OAL. That raises pressure. The pressure is 33,600 psi which is getting close to the max 9mm limit of 35,000. 

[Guitarmageddon]

Yea after running lots of loads through GRT and comparing simulated numbers vs actual, this one doesn't seem to come close to reality. In the end, this just may be a bullet for n320. Even the VV reloading today doesn't show such a stark disparity in HAP vs regular more conventional fmj loadings at a shorter OAL.

Edited July 19, 2021 by Guitarmageddon

[Farmer]

I’ve even wondered about the 230g Hornady FMJ FP for the 45 acp. Loadings for that are pretty anemic compared to others. Always thought that maybe their jacket material was more “draggy” and raised psi. I have some but never pushed them to see what they would do. Using their loadings they never shot very good. 

[Tunachaser]

One issue with the 125 HAP's is that the dia. is .356 instead of the usual .355 for jacketed bullets.  This increased dia. COULD cause an increase in pressure in a barrel that slugs out at .354-.355.  When I asked Hornady about this they said it was because the 124 was intended for 38 super.  They said the 115 HAP was intended for 9 MM.  However they do market the 124's for 9 MM.  Their XTP and FMJ-RN are .355, the only .356 bullets they offer (that I know of) is the 124 HAP.

[Sarge]

11 minutes ago, Tunachaser said:

One issue with the 125 HAP's is that the dia. is .356 instead of the usual .355 for jacketed bullets.  This increased dia. COULD cause an increase in pressure in a barrel that slugs out at .354-.355.  

It is quite typical to run .356 and some even use .358’s in their 9’s. 
Pressure increase with .356 will be negligible 

[Guitarmageddon]

So I did run the HAPs through the Chrono today. Again, .356 projo in my .356 barrel. I first did 3.5, 3.6, 3.7. grains I was unable to hit 1000 fps. I am going to do 3.8gr  tomorrow to see what the results are. This is with n320 at 1.064 OAL. I didn't bother messing with hp38 like I planned. After 3.8 grains I start to get pretty darn close to 100% fill and I like to leave myself some wiggle room in there. 

[Sarge]

For good function and reliable power factor you’ll need to get 125’s to about 1050fps. 
 You are running almost a full grain light with some of your loads. You are going to be 4.2ish before even getting close.

[Tunachaser]

21 hours ago, Sarge said:

It is quite typical to run .356 and some even use .358’s in their 9’s. 
Pressure increase with .356 will be negligible 

With lead coated or plated bullets not jacketed.

[Sarge]

52 minutes ago, Tunachaser said:

With lead coated or plated bullets not jacketed.

.356 jacketed won’t hurt anything.

[Tunachaser]

On 7/21/2021 at 8:43 AM, Sarge said:

 some even use .358’s in their 9’s. 
 

 

.356 yes but not .358

[Steve RA]

I use some .358 jacketed in my 9mm.  it has a 9mm Kart NM barrel.  Mostly I shoot 130 LSWCs in it.