Penta hp’s vs. large hp’s

[Wheelguns 1961]

I was wondering, I know that some of you guys have done alot of hp testing. Do pentas open at a lower velocity than a large hp? Do they expand more? What are the advantages and disadvantages of each? Any ideas? I just got an mp-mold with a set of penta pins, and plan on loading them in 9mm and .38spl. The 9mm will be run at a higher velocity. Thanks in advance for any insight anyone has on this subject.

[Messy bear]

I prefer penta for a couple reasons. The recovered ones I have show more tendency to hold the petals and not shed them completely with appropriate alloys. Some tend to mimic a Barnes X wereas most large hp just make a big mushroom. I believe penetration can be better with the petals vs large mushroom.
The other reason I like the penta is that in my molds the weight stays heavier with penta so not as much load and sighting difference. For example in the 308 Keith Mi-Hec the large hp is down to 288gr or so. The penta is 296 and the cup is 300. In an NOE 512 the penta and cup are same at 430. The large is 405.

[RobS]

I prefer the large HP and use a harder alloy so expansion is where I like it to be for penetration. Really is a preference I suppose and also dependent upon alloy that a person has on hand. Harder alloy also can take more RPM's or twist/velocity before skidding the lands which may or may not be an issue for your particular situation i.e. 9mm vs 38 special.

[Wheelguns 1961]

I cast one batch so far. I used 60/40 ww to lead. I figure the 9mm will run 950-1050fps, and the .38 should run 800-900fps. I am still experimenting with the 9mm. I have some loaded sized .357, and some loaded .358. The .38 will shoot .358. If I need to keep 2 different sizes, I figure I could make one size large hp, and the other size pentas. I appreciate your thoughts.

[Shuz]

FWIW-I have an MP-433-640 hollow point 4C brass mould that has only 2/ea round pins and 2/ea penta pins. That's the way I rec'd it used, from one of the members on this board. When I cast from it with my usual "handgun alloy" of 1/2 WW+1%tin and 1/2 pure Pb, there is absolutely no significant difference in weight between the two!

[Moonie]

I prefer penta for a couple reasons. The recovered ones I have show more tendency to hold the petals and not shed them completely with appropriate alloys. Some tend to mimic a Barnes X wereas most large hp just make a big mushroom. I believe penetration can be better with the petals vs large mushroom.
The other reason I like the penta is that in my molds the weight stays heavier with penta so not as much load and sighting difference. For example in the 308 Keith Mi-Hec the large hp is down to 288gr or so. The penta is 296 and the cup is 300. In an NOE 512 the penta and cup are same at 430. The large is 405.

When did Al start making pentagonal pins for his molds?

[Messy bear]

I made some for it.
If I find someone to post for me, maybe I could show some pix of recovered lead sheds.

[Chad5005]

FWIW-I have an MP-433-640 hollow point 4C brass mould that has only 2/ea round pins and 2/ea penta pins. That's the way I rec'd it used, from one of the members on this board. When I cast from it with my usual "handgun alloy" of 1/2 WW+1%tin and 1/2 pure Pb, there is absolutely no significant difference in weight between the two!

I have this same mold but in 2cav,i got 2 large hp,2 small hp and 2 solids when I bought mine used but no pentas

[Forrest r]

Sounds like you have to do a little testing.

Generalizations:
I've always started with alloys that were 1 bhn for every 100fps, meaning
8bhn ='s 800fps
9bhn ='s 900fps
12bhn ='s 1200fps
Penta -points ='s 800fps to 1000fps
large hp's ='s 1000fps to 1200fps

A lot depends on the size/depth of the hp as does the alloy. Those things above are nothing more that a place to start. There's nothing that says you can't use a large hp @ 800fps. The mechanics of a hp are 1 thing. How they function is another.

Penta-points do better at lower velocities. It has nothing to do with how they open. It has to do with resistance and depth of penetration. Do a search on federal hst 38spl p+ ammo and their hst line in general. The pedals open just as big as their large hp counterparts. They have deeper penetration then their large hp counterparts due to less resistance/space between the pedals.

If you're getting limited penetration then use the penta-points for that load/firearm combo.

In the snubnosed 38spl (2" bbl) I use the penta hp's for standard loads and either the 158gr penta or large hp's for the 950fps p+ loads .
https://i.imgur.com/7iOwgin.jpg

In the short bbl'd 9mm (3.2") I use both the penta & large 124gr hp's with a 1050fps load.
https://i.imgur.com/ZxGtzF4.jpg

200grn hp's for the 45acp loaded to 1050fps, at 1050fps I use either 1.
https://i.imgur.com/7QWMZbM.jpg?1

44spl's, don't have a light weight bullet mold that casts a penta-point hp. I do have the Mihec 245gr "keith" 503 clone and the 432-640 molds that cast penta-points. I just find them too heavy/slow to use in the snubnosed 44spl's. So it's large/deep/round hp's in the +/- 200gr range for the 44spl.
https://i.imgur.com/fo57jjU.jpg

Anyway short bbl's/low velocity calibers/firearms tend to do better with the penta-points. There's 4 different calibers/firearms above & they all have the 950fps to 1050fps velocity in common.

Sometimes it isn't about the perfect hp mushrooming, staying intact and having good penetration. When you have a hp bullet that has enough momentum/penetration, it does more damage when it frags. A home swaged 225gr hp tested in wetpack @ 50ft.
https://i.imgur.com/N0fGdoA.jpg

3 of those recovered bullets were recovered starting @ the 7 1/2" mark. 2 of them blew out the back of the bundle of wetpack.
https://i.imgur.com/2DQcarO.jpg

wetpack ='s taking bundles of newpaper 9" to 12" thick and taping them together. Put them in a cooler and filling the cooler with water. Take the whole thing to the range the next day, pull bundles out of the cooler and test away. I like wetpack better than water. You can put targets on the bundles, clothing, bones in the middle of them, glass/wood/drywall in front of them, etc. The wetpack absorbs a lot of hits and the bullets are easy to recover.

[Wheelguns 1961]

Excellent post Forrest R. Thank you for addressing the velocity issue. I was thinking that if I need to size different for the 9mm and the 38, that I would make one penta and large hp for the other. I need to get out and start shooting, but with back surgery looming in the near future, who knows when I will be up to it.

[Lloyd Smale]

make mine big and round if reliable expansion is your goal. Ive don't a lot of penetration testing and what I found with penta tips is two will expand well and one will do just the opposite and collapse inward and close the nose off. In all reality one of the best I tested was a plain old wfn casted soft and drove hard. they expand well and about allways stay together.

[Forrest r]

Excellent post Forrest R. Thank you for addressing the velocity issue. I was thinking that if I need to size different for the 9mm and the 38, that I would make one penta and large hp for the other. I need to get out and start shooting, but with back surgery looming in the near future, who knows when I will be up to it.

Thank you for that.

My post was nothing more then a place to start with your testing. FWIW, I size everything to .358" for the 9mm/38spl/357 & use those .358" bullets in 9 different firearms made by 5 different mfg's.

[LazyTCross]

I am Going to Post some Pictures for Messy Bear, he has lots of info (He is just an IDIOT when it comes to Techy things!!!)
I have some cridder pictures and Recovered boolit picts, not sure what he will comment on but here they are.

[LazyTCross]

https://uploads.tapatalk-cdn.com/20181015/4e7c5a19426cd8d632bf56c118b8336a.jpg


Sent from my iPhone using Tapatalkhttps://uploads.tapatalk-cdn.com/20181015/4e8ce9bb9d5a1ea2a8863a0e88b590e8.jpghttps://uploads.tapatalk-cdn.com/20181015/23c5fb46ed52aa0a82a5e3069af69c08.jpg

[LazyTCross]

https://uploads.tapatalk-cdn.com/20181015/230e36ae36e451f9eab2070b7a8e8e04.jpg
This is my 308 mp penta moving around 1450 I believe. Straight ww.

Target was not moved or manipulated.


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[LazyTCross]

https://uploads.tapatalk-cdn.com/20181015/1a5ff915f38d5394e632dd27b0d7c832.jpghttps://uploads.tapatalk-cdn.com/20181015/bb98d346b4147e6a105532c0dca158dd.jpghttps://uploads.tapatalk-cdn.com/20181015/6d0861818be0c3503de037ecad127f6b.jpghttps://uploads.tapatalk-cdn.com/20181015/ae7a12398dc669411c88f19a2212bcce.jpg
Jeff’s antelope.

I am sure this was MP Ruger only 325 penta.


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[LazyTCross]

https://uploads.tapatalk-cdn.com/20181015/46857a62577457ab0e23cc449c5ab1bf.jpghttps://uploads.tapatalk-cdn.com/20181015/8b76c25ff45ab14bf93070a1b3913ac0.jpghttps://uploads.tapatalk-cdn.com/20181015/5156ae42fee4099f79b026b655f17dc1.jpghttps://uploads.tapatalk-cdn.com/20181015/595d57eb5b0649b39cb1166faa99b590.jpg
Last years deer


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[fredj338]

I think both can work well, depending on the actual HP shape.
http://img.photobucket.com/albums/v703/fredj338/45-215gr.jpg (http://smg.photobucket.com/user/fredj338/media/45-215gr.jpg.html) http://img.photobucket.com/albums/v703/fredj338/452-251.jpg (http://smg.photobucket.com/user/fredj338/media/452-251.jpg.html)

[Messy bear]

Ok lazy. First one in post 14 was hit with 430 gr. 511 penta at 1000 fps out of 500 Linebaugh.

[Messy bear]

Second two pix in post 14 are 430 gr penta 500. I need to check for sure but I think it came out of a mature buffalo cow. Broke ribs and lodged on off side under skin. Impact velocity of 1150 or a bit more.

[Messy bear]

Post 16 pix are of the 325 penta you mentioned. 80 yd in the tail pipe. Muzzle vel of 1150 out of 45 Colt. COWW with 1 % tin added.

[Messy bear]

Post 17 has pix of bullet from last yr deer shot lenghtways with 500 and 430 penta made of 1/1.5/97.5 going 1220 fps muzzle. Range approx 55 yd. Broke 2 ribs and femur.