Hollowpoint cavity designs

[theangrydangler]

That boolit should do just dandy for your application, though even with an expanded hole it won't guarantee DRT every time, from my experience. Deer can travel 50-60 yards with a heart that looks like lasagna from a 50 caliber projectile that opens up to, 75 upon impact. I've seen this many times. My state was a shotgun slug, handgun only state. Now straight wall cartridges allowed. My hunting buddies and I have killed many dozen Deer over the decades. A bang-flop is a bonus, but not necessarily the norm with basically what you plan to use. Thankfully, good blood trails are the norm, until a wad of fat clogged the hole on occasion. Be prepared to track. Be pleased when you don't have to.

Please keep us posted on your success and results. What you are doing is what makes this forum shine.

Thanks Chris Ill keep you guys updated on my development progress and results!

[Iwsbull]

Not exactly the same but close, here is a 8-9 BHN powder coated 420 grain hollow point that I recovered from a berm. The velocity at impact was in the 925+/- 25 FPS. It opened to .92”. 5” 500 Linebaugh.
IMG_6305.jpg

[theangrydangler]

Not exactly the same but close, here is a 8-9 BHN powder coated 420 grain hollow point that I recovered from a berm. The velocity at impact was in the 925+/- 25 FPS. It opened to .92”. 5” 500 Linebaugh.
IMG_6305.jpg

That's awesome. Do you have dimensions of the hp cavity?

[Iwsbull]

The mold is an MP 51-640. Without being at home to measure it is .4” deep and it is wide, I will try to get a measurement on the width this evening. It takes about 30 grains of weight off the with my lead. I see he has a 385 grain, a 440 Keith style and a 600 grain in stock. You might contact him and see what else he might have Mihec sometimes has a few not listed. I use the 640 design in 44, 45 and 48 and with my alloy they all like about the same velocity for impact 900-1000 FPS much faster and they shear the nose. Here is a 44 at 100 yards and 50 yards at 100 the impact velocity was estimated at about 970+/- and at 50 it was estimated at 1020+/-
[ATTACH=CONFIG]344023[/ATTACHIMG_6941.jpg

[GLynn41]

if the HP cavity you have is not quite what you want and this is about a want not a need-- I am the same way also-- a Philp's head screw driver can be used to change and experiment with the cavity. Also a 3 cornered file can be used to notch the outside of the HPC. Even lightly notching will affect performance ---you can turn them in to a very fast expander. Also there is a stickie about two-piece bullets from Bruce B? using any mold blocks similiar to the ones Lyman made for a bit. They never made them for the .41 ---nutz. Sally forth experiment and share.
Bruce B is under mold maintenance and deign. For whitetails I use large HPC as they are thin skinned.

[dverna]

Attachment 343955
Great expansion from the Lee 310 grain tested in water jugs. Notice how the sabot left a square shape on the fired boolit.

Barry,
Is that a pure lead bullet? What is the estimated velocity?

[Bigslug]

Another cool thread that I'm late to the party on. Sigh. . .

This is a great project you're on. Unfortunately, I'm in a lead-free state for hunting and am running high-velocity .30 cal copper for that task. Other guys are going to be able to give you more firsthand info on field performance of rounds like yours. I am however fairly deep into and nerdy on the terminal / expansion / penetration / gelatin / milk jug science side of things, so hopefully my $0.02 can be useful - even if they aren't making pennies anymore.

As for meplat size and maybe alloy choice, the gun has to feed your rounds reliably first and foremost, and shoot them accurately enough to do the job. If they choke on the ramp or smoosh themselves out of shape so badly on feeding that they don't fly, your mold is going to be a pretty paperweight. You need to work out the mechanics within the gun first, and then worry about the terminal side after you're reliably getting down the barrel and consistent on the target.

I've sat in on a number of L.E. duty ammo gel tests and killed a lot of lined up water jugs with the same. . .and then gone on to compare penetration of those with cast solids or FMJ's that DON'T expand. What I've found is that the stuff that expands to a monster mushroom is going to have only about 30%-40% of the penetration of hard alloy solids that retain their shape. In the L.E. world, it's evolved to a highly tuned science of being able to penetrate a little more than halfway through a human torso side-on with an arm in the way, or, if the bullet does exit, it'll be sufficiently depleted of velocity that it isn't a major threat to the surroundings.

Obviously, these aren't big concerns for hunting, and you're upscaling in mass to where getting sufficient penetration on a deer PROBABLY isn't going to be much of a challenge.

That said, 9mm's that expand to about .70" caliber while making the FBI's "ideal" spec of 12"-18" of gel penetration have been doing a GREAT job at ending arguments with 2-legged "game" quickly - deer are not so differently constructed. A similar, albeit deeper hole should work similarly.

My thought is that if you craft your 400-ish grain bullet to expand conservatively into the .80"-85" caliber range, it will create plenty of trauma, yet still reliably exit your deer from whatever angle you take your shot from (with the possible exception of a Texas heart shot). That will give you fast bleed out, good blood trails, and no question of your ability to break the larger, weight-bearing bone structures.

I would also think long and hard about giving the ability to do that at your slowest likely impact speed. This gets into the mind-bending problems of figuring out an alloy that will shoot well at your desired load intensity, yet will still expand when it arrives at its destination. You're already wisely onto a gas check design, but my feeling is that you probably want to tune your alloy and nose cavity to be able to expand at something between 1000 and 1200 fps.

My experience here is not vast, but I've found on several rifles with PLAIN BASE bullets that 10 BHN alloys start failing for accuracy around 1250-1300 fps of muzzle velocity at least in the .30-.35 caliber range. I'd listen to the gas check / lead-bullet / hunting experts on this.

The other school of thought is to say screw expansion, go for a harder alloy that shoots well at speed, and run the largest meplat your gun will run reliably on. The advantage here is that the bullet will perform about the same regardless of distance/impact speed. You're already starting at a "pre-expanded" diameter of .50", and that ain't bad.

At any rate, I'm very interested in what you come up with and in field reports of how it does.

[Barry54]

Barry,
Is that a pure lead bullet? What is the estimated velocity?

Don, It’s awfully close to pure lead. I was trying to master casting pure lead a few years back. Less than 2% tin and cable sheathing. I filled up the pot and cast a batch of bullets. Then after switching to a different mold, I refilled the pot with lead and didn’t add more tin. Did that a couple of times. I don’t remember where in the sequence of the day the 310 grain Lee were cast.

I never chronographed any loads from it but it’s the Vihtavuori recipe printed in the Savage owners manual for a 300 grain bullet. Scooped with the closest Lee dipper under the book max. Probably 2200 FPS? I can’t find the Savage owners manual online now, and I’m not home to look at the paper manual. Btw, That calculates to 3,200 foot pounds of energy. I don’t shoot it a lot…

[GLynn41]

from what I have learned when we powder coat and we can let them draw down, cooldown, i.e. anneal- the overall bullet will be softer, but with a jacket similar coating. this should help maybe with expansion also. Besides it looks great.

[theangrydangler]

20260718_172632.jpg

Here are the result of the .50 beowulf experiment. Ended up with a 465 grain shallow cup point with a narrow spike cavity in the center of it. Cast of pure +2.5% tin. Fired into ballistic gel at 1475 fps from 10 yards. Penetrated 2 feet of gel and 3" into a box full of dirt. Expansion is .938" diameter and weight 465 grains. 100%. Tried a deep hollowpoint but they just blow up and I didn't want to spend a bunch on antimony and tin hardening them to keep them together. These are cheap to cast "relatively" and are very close to my goal of 1" mushroom. It's gonna be a bad year to be a doe

[Balrog006]

Never been fond of hollow points, but they do have applications. About 30 years ago I purchased a Ruger 77/44 and fiddled with it looking for a good load. Wound up shooing 300 gr pure lead that was paper patched. It was put 8 shots into one ragged hole with a 3 MOA red dot sight. Not a single critter took a step after being shot. That included deer, hogs and a few varmints. The load I used was Lil Gun w/card wad. 1600 fps was the norm.

My Ruger 77/44 is probably by favorite medium game hunting rifle and favorite PC rifle plinker. You can load .44 cal down to powder puff or up to +P+ bear defense style. I had mine cut down to 16”+ and I run a suppressor on it so the heaviest are also quiet too!

I have an old brass HP mold from NOE that throws 300gr FP and a 278gr HP that’s my favorite.

[Balrog006]

20260718_172632.jpg

Here are the result of the .50 beowulf experiment. Ended up with a 465 grain shallow cup point with a narrow spike cavity in the center of it. Cast of pure +2.5% tin. Fired into ballistic gel at 1475 fps from 10 yards. Penetrated 2 feet of gel and 3" into a box full of dirt. Expansion is .938" diameter and weight 465 grains. 100%. Tried a deep hollowpoint but they just blow up and I didn't want to spend a bunch on antimony and tin hardening them to keep them together. These are cheap to cast "relatively" and are very close to my goal of 1" mushroom. It's gonna be a bad year to be a doe

That is a thing of beauty-seems like you accomplished your goal well with that-congrats and good luck in the woods this fall!

[ChristopherO]

You are on your way. Deer beware.

[theangrydangler]

20260802_131611.jpg
Here's some 214 grain bullets from my 350 legends and 357 magnum
2,2,96 alloy
Small pistol magnum primers (cci)
350 legend 23.5 grains shooters world blackout
16" 1825 fps
10" 1685 fps
357 magnum 11 grains lil gun
20" 1410fps
357 magnum 10 grains lil gun
20" 1290fps
Unfired bullet
Shot into ballistic gel at 10 feet
350 legend
Both bent through all 30" of gel i have and bounced off wood behind it.
357 magnum
Both went through about 24"