Interesting Ammo Design

So I got a message saying “Hey, check this out!” or something similar. It is a brand of ammo I’ve never heard of before…( 2 of them). So I look. Darned if it isn’t actually a new idea.


Underwood Ammo

Underwood Ammo

Note the flutes on the bullet. They are shaped to deflect material hydraulically into side channels. Supposedly gives the effect of a hollow point while not limiting penetration. Very interesting idea, and kind of novel.

Underwood Ammunition is a family owned business started by Kevin Underwood in Charleston, WV. A lifelong shooting enthusiast, Kevin began reloading in his spare time. Quickly, a small reloading press turned into an entire loading operation including presses and stations set up for over 40 calibers. With a rapidly growing business Underwood Ammo relocated and built a brand new facility in Sparta, IL so that we might better serve our customers.

$28.99 for a box of 9mm at this time. Didn’t find a cartridge count, but weight is about 1/2 pound, so about 20? as a guess? Saw one write-up on another site where they did a velocity test and they tested as “as advertised or faster” (some makers products are, er, not quite as fast as advertised…)

Lehigh Defense

Does something similar. Guess I’ve not been watching bullet development for a while… I found it interesting that they have applied their solid copper tech to some older lower power cartridges as a kind of ‘upgrade’. Since I’m fond of older and smaller as it makes for nice compact guns… the .32 ACP interests me. Well, that, and the Walther PPK was James Bond’s gun ;-)

There are many excellent older cartridges with performance constrained by the metallurgy available for the firearms at the time they were designed. Some are so good, as in the 45-70 Government, they have been updated for modern pressures and re-released as modern cartridges, others, like the 32 ACP will probably remain with low operating pressures, due to the number of guns in existence.

Is there a way to bring modern performance to the low pressure cartridges through advanced projectile design and manufacturing? At Lehigh, the world’s most innovative projectile and ammunition manufacturer, the answer is a bold YES.

We are pleased to announce the release of our Xtreme Cavitator family with the first cartridge being the venerable 32 ACP.

The Xtreme Cavitator uses a unique geometry to form a vapor pressure spike at the nose blanketing the flank of the bullet with a long envelope of air as it passes through media eliminating side drag and allowing deep penetration. The heck you say? No, it isn’t voodoo or marketing hype, it is physics. If you are bored, look up super cavitation torpedoes; the dang Russians where there first. The fact is, all bullets create cavitation; we just created a design with a unique nose and an air reservoir groove to accentuate the effect. How does 13.5” of penetration from a 32 ACP in 10% gel sound?

We were not satisfied with a deep penetrating solid, but then applied the science of our XP and XD technologies to use the nose to redirect the hydraulic energy radially, creating a larger permanent wound cavity than any expanding solid. We merged this concave surface into a square nose that defeats barriers by dividing the hoop strength of the contact media.

The end result is a conservation of energy from a square nose to breech entry barriers, to a concave surface directing hydraulic energy outward creating an enormous wound cavity, to a cavitation point that blankets the bullet with a boundary of air reducing flank drag and allowing deep penetration.

That is one mean looking bullet…

Lehigh Defense .32 ACP bullet

Lehigh Defense .32 ACP bullet

They put up gel photos for penetration and channel shape and include feed tests / reports:

Cartridge: 32 Auto
Bullet weight (gr): 50
FTM – Fluid Transfer Monolithic
Box qty: 20
Velocity (fps): 925
OAL (in): .945
Penetration (in): 13.5
Wound cavity (in): 1.5

*Patent Pending
Note: Feeding Capabilities
The list below will outline which 32 Auto’s we tested the XC’s in and which Guns we have been notified by our customers that there have been feeding concerns:

Tested / Verified
Berretta 32 Tomcat
Kel-Tec P-32

Noted Concerns
Walther PP Manurhn 7.62
Barrier Performance Chart per FBI Protocol

Nice, that! Finally an ammo maker who tests their product in several real guns (not just a test stand) and takes reports of any feed issues experienced. And gives you more than just wt/velocity info…

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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20 Responses to Interesting Ammo Design

  1. H.R. says:

    E.M. – I’ll have to check out the accuracy of the .32 ACP bullet at 12 feet. I’m concerned about the bullet tumbling beyond six feet or so. No concerns as a belly gun but many defensive shots are made at the 12-feet range on average.

    About 2010-2011 or so, you were having some some posts and comments regarding defensive weapons. I brought up that I had a .357 mag revolver and was looking for a .357 gate-loading lever action rifle to go with it. We discussed the ‘never out’ benefit of the lever action and the fact that both were dual ammo capable. Well I got the lever action in 2014. My son likes everything ultra-modern. His exception is now the lever action. He saw the beauty of the load on the fly capability from a pouch of loose ammo.

    I also added a Stoeger SxS 12ga Coach Gun for hallway defense. Yes, you’re limited to 2 shots, but I am leery of jams and I find the revolvers and side-by-sides much safer and more reliable in an amped-up situation.

  2. H.R. says:

    Here’s a another good review of the Lehigh Extreme Cavitator .32 ACP.

    At the bottom is a photo of a nice group at 7 yards. No bullet rotation evident and excellent accuracy.

    Only 2 negatives: failure to feed in the particular test gun (Beretta Tomcat) and a couple of odd over-feeds where the was fed out of the gun and down-range behind the fired round. I’ve never heard of such a thing so I think it is particular to the Tomcat.

  3. Larry Ledwick says:

    Interesting design for sure. Lots of new stuff coming out in all copper due to lead restrictions.

    I found another innovative design just the other day. The .40 S&W is almost always sold in a hollow point or square nose truncated cone bullet design. Some guns do not feed such bullet designs reliably so I went looking around and found some variations. The one I settled on was the 165 gr Hornedy Critical defense (actually has more muzzle energy than the 180 gr designs and is readily available locally). The other I found and need to find is the Glaser Power Ball ammo, it uses a polyethylene ball inserted in the nose of the hollow point to give a feeding friendly ball ammo nose shape and is also available in other calibers down to the old .32.

  4. H.R. says:

    Aaannnd… Here’s my carry gun (Remember, when cat-fishing, I’m in lonely places late at night where bodies have been found. When seconds count, help is only minutes away.) I also have a 9″ razor-sharp filet knife at hand. I don’t want to draw down on every yahoo that shows up at 1:00 am where I fish, which they sometimes do. Mostly, if they see that filet knife near me & my bait, it’s going to be a nice conversation about fishing. The key is to be alert, spot the approach early, and stand up and look confident and self-assured.
    My wife’s carry gun: I got her to carry because after her stroke, she looks like an easy mark.

    My wife is really good with that gun. I’m really good with that gun. Turns out, just about anyone is good with that gun. Must be the gun.

    Having a concealed carry license increases your responsibilities as a gun owner. By law, I must immediately identify myself as licensed to carry whenever I have contact with law enforcement, whether or not I am carrying. Then wait for instructions from the officer on how he’d like to proceed. We were trained that it’s even better to declare up front whether or not we were carrying and ask how the officer wished to proceed.

    In training, we were warned that we might be handcuffed briefly while the officer made sure there was no threat from a weapon, but that would probably only be done if there were recent incidents in the area that might have the local cops on high alert (usually not likely, and I’ve no reports of it actually being done to a CCW holder).

  5. Lynn Clark says:

    And in a pinch you could use the Lehigh bullet to drive deck screws. ;-)

  6. H.R. says:

    @Lynn – Just how would you know about that? ;o)

    (nice spot!)

  7. Graeme No.3 says:

    German soldiers in WW1 scored hollow tracks along (about half) the side of their bullets, with their bayonets. They were denounced as using illegal dum-dum bullets.
    I don’t know if it affected the accuracy or range.

  8. John Howard says:

    With the government purchase of millions of rounds of ammunition the advent of high velocity air rifles has arrived… 1400 fps and near dead level at 200 yds, and they are not toys by any stretch as they were when we were kids.

  9. E.M.Smith says:


    Nice one!


    Glad to hear the lever worked out for ya… addictive little sucker :-)

    Love the looks of that Sig! With good ammo, like Winchester Silvertips, the one shot stop is roughly the same as a military ball .45 ACP (which drops a charging horse per acceptance test in 1911…) With the solid copper hydraulics in it… hmmmmm…..

    Always wanted a coach gun… work better than a pump one handed. Put coach gun in one, pistol in the other, pretty much no worries… Though I’d likely get it in 20 Guage… easier to one hand and lighter…

    Where I grew up had lots of rattle snakes, the odd bear, an occasional mountain lion (mostly in the hills) and “enough” 2 legged snakes that “fishing gun” was more a “tackle item” than oxymoron. Usually a handgun so as to avoid Game Warden talking about hunting licences… The most common issue was “snake load first shot or deer sized animal capable round?”

    I was from the 2 guns camp :-)

    It was common to see farmers and fishers open carry in town, usually to the hardware store that sold guns and ammo…

    I stock some shot shells to this day. Old habits…


    Yup. Every attempt to ban by restrictions just results in improvements by inovation. People and their creativity are like that… That is what caused the creation of karate, nunchucks, side handle batton, etc etc. Control Freaks never learn.

    So someone had the idea of banning bullets by banning lead. Result? More lethal bullets made with better materials….

    Some years back I saw this moment coming, so bought a reloading kit with lead pot and bullet mold. I’m set as long as cars use wheel weights and pipes are soldered… Oh, and most anything works in shotguns with modest load pressures, even snips from big copper wires. Only have a mold for .357 9mm .38 Special, but that covers many of the inventory and all the SHTF ones. Even the lever gun. The .357 .38 ones have the big old straight side cases that are happy with black powder, if it comes to that. (Though I know how to make guncotton / cordite from battery acid, fertilizer, cotton, and vaseline… I did it about 12… yeah, a bit precocious. .. but it was legal to do then. The nitrocellulose is gelled a bit with the vasoline, shaped, then coated with graphite if easy handling or slower burn is needed..)

    Oh, but be careful not to use tin solder for pistol bullets (at least in California) as that is classed as “armor piercing”… yet curiosly OK in the lever gun as rifles have different rules… so make sure to store them with the rifle…

    I hope things never get that bad, but a linear projection from 1968 or so to now is “not good”.

    An interesting book on improvised munitions reported how the Pillipineos in W.W.II used match heads to refill primers (mostly in shotguns) and used most anything as projectiles. Their preferred gun? A short double bbl 12 guage… Worked a champ in jungle cover cutting through greens just fine all the way to the Japanese soldiers… ANY ammo or gun being banned by the occupying forces… like that was gonna work…

    Part of why I’ve always wanted a coach gun :-) Stories drive sales…

  10. E.M.Smith says:

    @John Howard:

    Classed as “firearms” (at least in Kalifornia)…

    Ever since reading the Lewis & Clark history, I’ve wanted one like they used for small game hunting. Larger caliber than we have now. Cast round lead ball, IIRC. Wonder if they will make a comeback? I’d buy one… or two… or…

    @Graeme no.3:

    Range ought not change detectably, but accuracy will depend on the balance and precision of the engraving. I wouldn’t do it to a sniper round, but to 100 yards, not much likely.

  11. Larry Ledwick says:

    I’m set as long as cars use wheel weights and pipes are soldered…

    Cough lead skin diving weights cough.

    I have had casting gear for 30+ years started with a .58 caliber hawken for black powder. (still have it)

    Memo on expedient bullet molds, you can cast lead in high temperature silastic rubber. We used to use that to make little medallions for our black powered matchs. I would sculpt the medallion for that years match out of wax, then use the wax original to make silastic female molds, to pour the lead into. We gave the neck medallions to the shooters when they paid their entry fee. I could throw 50 or so medallions on each mold before they began to break down.
    The rubber eventually breaks down from the heat but you can make expedient bullet molds out of other stuff too, like plaster of paris well cured and then baked at low heat in an oven to fully dry it out.

    Dip a good bullet in Vaseline or similar mold release and then cover with high temperature silastic rubber, let cure completely then make a hard jacket for the rubber out of anything rigid like plaster of paris, concrete, epoxy what ever. If the cast is a bit over size you can then swage it to exact diameter by pushing it through a polished hole of the right size in metal plate.

    Recently I started collecting casting molds for common calibers and can cast for just about everything I own right now.

  12. Larry Ledwick says:

    They were also feared by Napleon’s army due to the difficulty in locating the shooter, (low muzzle report, and no smoke) Napleon was said to have ordered the summary hanging of anyone found in possession of one of these air rifles.

    The modern high velocity air rifles make a good survival backup for small game and rat control etc. Very low cost per shot and if you have one in .177 caliber you can practice with reusable steel bb’s

  13. E.M.Smith says:

    Field Expedient bullet mold:

    Thick chunk of metal with about 1000 F melting point
    ( iron, brass, bronze, copper, aluminum, …)

    Drill press or vertical drill stand


    Similar metal cup or pot on handle. Don’t use Revere Ware, the spouse or your parents will get mad…

    9mm or 10mm or “whatever” diameter drill. (9mm works in .357 and the .38s too. 10mm=.40)

    Drill a bunch of holes in the plate, but not through it, the depth = desired bullet length.

    Melt lead, tin, solder, other low mp alloy in pot. pour over plate and clear excess from top (a bit of angle iron is good for that. Let cool. Use chisle to true bases, remove sprue. If extraction is hard, you can try drilling a small counter hole for a nail sized punch from the backside (Plug with weak plaster during molding) and / or spraying with mold release, waxing or smoking the mold before filling.

    I’ve not tried this method (figuring that if a few hundred rounds of 9mm .357 .38 in a half dozen guns wasn’t enough, I needed to change sides ;-) so I’d work out the bugs if it ever became necessary. I figured, worst case, drill the 10mm through, make 10mm plugs of bar stock, wax and load, leaving a bullet cavity above them.. Layed on a surface, they stay in place, then just press or punch out once set. For bulk production, I’d drill lots of holes in a plate of desired thickness / bullet length and clamp to a solid backing plate with release compound (so lead can’t make a thin glue layer between the plates). Then just pour and add a topping plate to close the tops and clear excess lead. Once cool, a punch gives you nice wad cutters…

    For extra credit, work out the lost wax and sand mold plus swage variations…

  14. Larry Ledwick says:

    Note from a black powder shooter, good way to keep the bullets from sticking to your mold is to “soot” the mold with carbon black from a candle flame (or acetylene lamp is better) before you make the pour. It makes a great release coating. Talcum powder or fine graphite for locks would probably also work but have not tried it.

    Using wax or grease as a release will often result in blemished casts (ie the sides of the bullets have wrinkles in them) Paraffin wax works good as a lead flux when melting the lead (so does bee’s wax ) but harder to come by and more valuable for other uses.

    Any cheap cast iron small sauce pan makes a terrific lead casting pot. These show up in thrift stores and surplus stores all the time. Any small steel ladle works for pouring the lead after you crimp a small spout in one side.

    (or you can just pick up one of these)

    I would mimic commercial molds, take two bars of steel or aluminum drill all the way through them with a suitable size drill to place roll pins to “key them” together with perfect register. Then drill down from the parting line as you described. That would make a two sided mold which can be knocked apart after you have cut the sprue and let them cool. Or you could put a gate hinge on one end and a dowel pin on the other. As you say expedient projectiles are very easy to make.

    In WWII the Japanese when being starved out in the south pacific made expedient bullets out of bamboo. They worked at close range and were very infection prone for they shattered into pieces when they struck. My Dad talked about them from his WWII PT boat days as they had abandoned stay behindJapanese soldiers to deal with after they set up bases.

    A penny is just slightly larger than the bore of a 12Ga, they could be glued or soldered together and then sized slightly to fit inside the shotgun hull. Super glue will stick two pennies together so strongly you cannot break them apart if you prep the surface with alcohol first.

  15. E.M.Smith says:


    I see we are coming from slightly different design points. Your methods are much better, but take more equipment / planning (though not much more… but pins, hinges…) while I’m visualizing “after the fall” in the middle of the ‘aw shit’ without prep and using “found materials” and as field expedient / minimal as I can imagine.

    Yes, if you plan to prepare, by all means, buy more and better gear and design bigger ;-)

    And equally yes, anyone who had machine shop or worked in a decent repair works can make things far better than any of this in less time than I’ll spend making the coffee and getting ready to start ;-)

    On my “someday” list would be just to buy a bullet swage and be done. Not very expensive, or hard to operate… but I’d have to clean out the garage to use it ;-)

    You can make jacketed rounds that way, too.

    Unfortunately, my “enthusiasm” for metal working has faded with the time suck of life in the modern age, and the garage has filled up with all sorts of crap. Only some of it mine… So before I can return to hobby bullet making, I need to spend a few months sorting out just “what is this, and who put it here?” for 25 years of kids and their friends and the spouse and… There is NO car in the garage, only shelves and what I set up as walkways, now filled with “somebodies stuff”… Sigh. Even the workbench is now buried… In a real SHTF, at this point, my “plan” has to be “check into the Motel 6″…

    (They were “chuckers”. When in doubt, “clean up” {something somewhere} and chuck it in the garage… Never found a way to get the concept of “Selves and walkways” across…)

    But, in theory, once de-junked, I can easily bolt a swage and dies to my workbench… it already has the press and vibratory cleaner and…

    So for now, I just get to imagine being on the back patio with the hand drill and some metal plates as I know where those are ;-)

    Yeah, as you point out, making bullets is darned easy. Hard core 1700s technology… Primers and cases take you all the way up to the 1800s… chemistry only slightly above alchemy…


    Honorable Mention to using a 3-D printer to print “Shot Capsules” and their snap in plug, then filling with whatever crap or lead pellets you have… Works as long as you have electricity… and a 3-D printer…

  16. Bill S. says:

    I collect action types.
    But it so happens my lever action is a Winchester 94 carbine in 44 magnum. Had a gunsmith add a recoil pad mostly to get rid of the slippery plastic butt plate but also to add some length because I have long arms. The Williams peep sight just happens to allow one to keep both eyes open in case someone were to want situational awareness and also turns the rifle into a solid hundred yard deer rifle.

  17. H.R. says:

    Now here’s a nice little 12ga hallway gun (Saiga-12 with 30 round drum)

  18. H.R. says:

    This is the link I was trying to find. (15 sec video clip of Saiga 12, 30-rounds @ full auto) Look at that grin!

  19. E.M.Smith says:


    Unfortunately, despite the 2nd amendment clearly stating “shall not be infringed”, in Kalifornia that is a banned weapon. I’d love to play with one, but must leave the State and go to a Free State to do it…

  20. Willem Smit says:

    The Lehigh Defense bullet is nothing new. SFM designed the THV in the sixties and this is just a bad copy with unscientific copy write babble as “proof” of how this is supposed to work.

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