So as promised, I played with this a bit. Not shot any. But wanted to play with the 'concept.' And, again, I doubt that a pig (short of Hogzilla's) offers enough density to allow a .50 to expand. It would zip right through, but the hydrostatic shock would completely destroy internals... So thinking of this as a way to create a hollow point that would open up in a hog? IMHO, not a chance.
That said... the hollow point concept is a bit of a path to accuracy. And .50 pulls aren't known for their accuracy. So as a concept, this might may be a way to improve the accuracy of cheap 'plinking' ball ammo in some of the better BMG's.
So started with API. I don't recommend doing this to API or APIT as these have some incendiary compounds in them that are not compatible with heat, friction, sparks... the things that occur during machining. So when I did this, it was with lots of oil and tiny cuts to keep things cool. For Ball ammo (which I didn't have handy) you can do some cool stuff, I think. But don't do it with the Incendiary, Tracer, API or APIT. Please.
So here is what I started with. Note these are cheap surplus pulls. Not pretty. Big marks on them. Fine to load for beltfed or plinker. But not accuracy-oriented. The tip is silver, for API. Nose is... rounded and not even. Not the kind of thing that is going to give you good 1000-2000 repeatability. Started by carefully filing off the raised edges from the puller so it would seat cleanly in a lathe collet.
So after spinning it in the collet front and rear, used Scotchbrite to clean the crud off it and overall 'clean it up.' Note that the pull marks are still there, but the raised areas are gone. The bright spots near the pull marks are the 'smoothed' area. This was put in the collet again and trued. The truing was the most time-consuming part of the operation. None of these were nicely round so that they would spin true in a collet. FYI, I took a .338 from Badlands and put it in a collet and it spun dead nuts. These, either becaues they are just bulk produced or pulls... did not spin true. So had to tap the tip around until it spun true.
Once it spun true, I used a carbide tool and cut .025" off the OAL to create a Meplat. I actually cut just to the point where I was exposing the core. That seemed to be .025. Your mileage on ball may vary. But as soon as I could see the little 'core' dot, I'd stop. PS. I 'did' measure the OAL after cutting and to 'just' expose the core was .025".
Once the little core was exposed, I used a centering drill. This is a very rigid drill used to create the taper in the end of a piece of stock so that it could go in a live center/tailstock center. This one is 1/4" diameter shank and about a 1/16" drill.
With the centering drill, cut a small hollow point, stopping before reaching the shoulder of the drill. Probably about 1/8" deep. This removed a very tiny amount of material, leaving a nice hollow point and definitely extending into the core. I believe that against a thick enough target, it would expand. By thick enough target, I mean an elephant, rhino or blue whale. Sorry Greenpeace. Against a pig, this would probably not even begin to expand before it passes through. I could be wrong, though. This is just what I 'Think' based on experience with the .50.
Last, I cleaned the bullet up with some 800 grit paper and some Brasso... just make a nice photo.
So... how will these perform? Honestly, I don't know. Here is what I 'think:'
I 'think' that if done with ball bullet pulls (and I need to order a can of them... or get someone here to send me some), we would get a round that 'might' expand in a deep enough target. That said, Ball has a steel core (even though it's not technically AP). But you may get the bullet to fold back and possibly release the core. Maybe. If I had to shoot the shark from Jaws... I'd possibly be happy with this.
More likely, I think these would give some much better accuracy/repeatability results than regular pulls (with rounded nose and nasty puller marks.) Somewhere between turned copper solid match rounds... and straight pulls. I think this improvement will come from two areas.. first, cleaning up the high spots and the like that will affect the bullet as it goes in the case and then engages the rifling. The second is that the hollow point will provide much better external ballisttics, acting like a match hollow point and creating that 'pad' of air that is much better than the dome of the standard ammo.
IF I am right (big IF)... this could make such a 'conversion' worthwhile given the cost of copper solids. I figure that once I get 'in the groove' I could probably do about 40 - 50 of these conversions per hour. And if I could get good results out of them, that would be worth doing for some 'better than plinking but not quite match' rounds. Something I am going to pursue more of... or maybe someone else wants to give it a try.
Again, for the OP... don't bother with hogs. But for those who want to shoot a BMG 'cheaper and better,' it's worth a try. I am definitely going to get some Ball and make 50 rounds up... and try an accuracy test!
Hope this is interesting to someone. The 'machining' was not hard. The big question is whether it's a waste of time or gives a noticeable improvement in performence.
And again... DO THIS WITH BALL ONLY. Don't fuck around with pyrotechnics... I did it for expedience and with much care. BALL ONLY!
Cheers,
Sirhr
