Lead alloy effects in swaging

[Metroxfi]

You did try the same bullet, just with a different alloyed core, in gel and there was no measurable difference? So there seemed to be no difference between pure lead, Pb-sn, and Pb-Sn alloys when swaged even though there are big differences when the same alloys are cast? That would almost imply that something happens to them as the material is worked...

I sort my clip-on and stick-on weights and keep them separate, even pour them into different ingot molds for visual reference. They only mix when I want them to, so when I say I use clip-on alloy I mean it's not diluted with anything softer. Most references note clip-on weight with 2.5-3% antimony, 0.5-1% tin, and a trace of arsenic, 10-12BHN depending on the tester and age and so on. If I'm using such a hard lead in my swaging why am I not just poking holes in stuff? I do understand I'm using an abnormally thin jacket but would it shed the jacket and just punch a pinhole through the other side? Why doesn't a much harder lead affect the expansion of such a bullet? If I were to use linotype, which is very brittle, how would that allow the bullet to hold together? I've read stories of guys dropping a bullet cast of linotype on a concrete floor and it splintering, I've also seen pictures of linotype bullets recovered from animals where the bullet is just pieces. On the other hand, I shot some 230gr conical SWC's cast from clip-on and oven heat treated at some 3/4" thick mild steel from my 454cas. The bullets left a crater 3/8" deep and almost one inch wide, the crater was packed with a hemispherical plug of lead that was about a third of the bullet's original weight. Now why didn't that just splatter? was it because of the shape of the crater containing the energy? Was it because of a low antimony content being significantly hardened, therefore being more tough than brittle? So if the exact same alloy would be used in swaging why does it want to splatter when hitting a soft target? I mentioned earlier that sometimes we weren't getting exits on prairie dogs, ground squirrels, gophers, bubonic plague carrying rats, whatever you want to call them. That's less than 4" of penetration with a rifle bullet. Don't get me wrong they work fantastic for what I use them for, all I'm saying is that I get those results using a hard alloy, what changes if the alloy changes?

I completely agree with the whole rimfire jacket bullets being a hook to get people into this, I've actually run into many older shooters whole either have or had and sold a 22LR to .224 kit and only used it a handful of times before putting it on a shelf for a couple decades. Seems like some guys either don't have the patience for it or don't get the results they want and just give up. On the other hand, how many commercial bullet manufacturers started out with the very same kits? I've been able to secure more lead than I could ever use by using them as trade for wheel weights, same with most calibers of pistol brass. I don't think they're superior at all, except for cost and availability. I seriously asked if I could sweep the floors at the indoor range after a competition, so for a total of two hours of my time I got more jackets than I'll ever need. I could have bought commercially available jackets but they're what, $.05ea? Considering I'm in the middle of a batch of 4,000+ .224" bullets for my lead friend, I think the money on jackets could be better spent elsewhere. But what does this have to do with the alloy of bullet cores?

[Valornor]

I'm trying to answer your question, but I think you aren't understanding what I am saying, and I'm probably not doing a good job breaking it down.

Everything is velocity dependent. Bullets have a function window, this window is defined by a min and a max velocity. Manufacturers look at the intended use of the product, I.E, Medium game, varmint, big game ect. and then look at the caliber and determine at what distances the hunter is likely to take the shot. Based on this they establish that velocity window. If you exceed the window, I.E your target ends up being 50 yards in front of you instead of 300 yards. The bullet will over expand and be "explosive". We see this all the time with people shooting super duper 300 magnums and taking white tails at 50 yards. The bullet wasn't optimize for that distance and thus it doesn't perform well. Sure it kill the deer but no one gets a pretty mushroomed bullet, all they get is fragments. Then they complain that the bullet didn't perform well, when in reality they we pushing it well beyond it's designed function window.

When swaging hunting bullets you need to approach it from the same angle. You likely have an intended caliber, and an intended velocity. The jacket you are using are thin walled which already lends it's self to easy expansion. You might try soft lead, you would try very hard lead, but you might get the same results as the bullet is impacting at a velocity well above that which the bullet can expand and retain its jacket. The hardness or alloy of lead is irrelevant. You might be shooting bullets with Linotype cores and all you recover is pulverized lead and jacket fragments.

There are so many variables when it comes to terminal ballistics. The shape of the bullet, the material being fired into, the velocity, the angle of impact, caliber of projectile to name a few. You are focused on one of many.

Here's what I would suggest:

1-Lower your velocity and slowly work it up. I strongly suspect that if you start slow, say 850fps, and work up it up shooting a soft alloy and a 10BHN alloy side by side, you will get to a point where you start seeing differences. It might be 1500fps, it might be 2000fps. Honestly I don't know. Any I don't think anyone here can give you the correct answer as it's very dependent on your specific loads. You can continue to work up your load until you get the performance you want. Maybe you don't get the velocity you want, and that's where you can start trying different things, heat treating, chilling, vary alloy to get what you are looking for. But until you find the failure point of your bullets, and your comments would suggest you are well beyond that now, you are not going to see a difference.

2- Splurge just a little and get some Berger or Corbin .22 cal jackets. Repeat the above steps, and I will suspect you'll see jacket construction is much more important then lead alloy hardness. However it would be interesting to see the results and I suspect you will learn a lot.

We can banter all day long about what pure lead does compared to 10bhn or linotype but in the end the only way to know is to set up controlled tests and gather the data.

[Zbench]

Valornor,

Excellent reply and my thoughts exactly. Especially the part about the jacket. I'm sure what the core is made of matter "a little", but not enough to overcome the huge deficits of the jacket. Like most things in life, there is no free lunch. Want free jackets made out of 22 shells? Then prepare for the fact that your bullets are going to blow apart when they hit anything. What you just described is what I found. After not getting the results I wanted, I bought some real 22 cal jackets and the difference was night and day. So much so that I put the 22 shells stuff in a box and labelled it "end of the world jacket maker" A bullet that blows apart on impact is better than no bullet at all.

[uncle dino]

What Val said....test, test, test.. D

[runfiverun]

Z-has a handle on how it works.
the short list he gave above should also include a tip. [exposed lead expands the jacket faster]
exposed lead will affect how a bullet expands.
think about it in terms of time.
making it take longer or less longer to expand will affect penetration.
[terminal performance]

adding tin will add penetration because of how I explained earlier.
you have to break the tin and it takes linear stress very well [think of turning a board on the flat versus on the edge] tin is the edge, antimony is the flat.
up and down holds a ton of weight because of the grain and that's how tin acts in a lead alloy.

combining both tin and antimony forms a different matrix within the lead than either one alone.

back tot he cast boolit thing.
speed and meplat diameter both influence how they work too.
a soft alloy [50/50] with a 65% meplat driven over 2100 fps is too destructive.
drop the meplat diameter to about 15% and bring the alloy up to water dropped ww alloy and 2300 fps will mimic the performance of the 65% meplat at 1900 fps.
your once again trading time, time for the nose to upset.

[Metroxfi]

Thanks for the great response!

Again I'm only using the 22LR jacketed bullets as a base example for comparison. I'm not trying to turn a bullet made of garbage into the most perfect big game hunting bullet, I'm just saying that generally if you want less expansion you use a harder alloy. I'm using a harder alloy and I don't see how I could have any more expansion. I do understand that bullets are built for a specific situation and just because a bullet will take down an angry grizzly doesn't mean it's right for deer.

Scrap the 22Lr jacket idea, let's say I bought a box of corbin's jackets and made three batches of bullets.
Batch #1 Pure lead core, bonded to a corbin benchrest jacket, formed with a 6S ogive and a .95" meplat.
Batch #2 Pure lead alloyed with 3% antimony core, bonded to a corbin benchrest jacket, formed with a 6S ogive and a .95" meplat.
Batch #3 Pure lead alloyed with 3% tin core, bonded to a corbin benchrest jacket, formed with a 6S ogive and a .95" meplat.

All bullets weighing the same, all constructed exactly the same except for the core alloy, all fired at the same velocity into the same calibrated medium. Would there be any difference?

I understand there are many variables that decide what happens upon impact, I only want to focus on one right now. If you made cast bullets out of those same alloys they would act very different upon impact, would it be the same for swaging?

I have nothing against buying commercial jackets and if I were trying to make a hunting bullet I absolutely would, it's just that it's not worth it to buy enough jackets for 500 bullets when I shoot less than 10 of them a year at edible game but I shoot thousands of rounds at varmints. Right now I do want a bullet that will explode, I'm just trying to think outside of the box and I can't find any info on the effects of alloys other than the "use soft for more expansion, hard for less expansion. Not too hard, you'll ruin your dies." argument which doesn't really tell me a whole lot.

I would absolutely love to test all this for myself but I wouldn't be able to do it properly, with proper ballistics gel, virgin gel for each round, multiple samples of each bullet at the same velocity for consistent samples. The best I'd be able to do right now would be either wetpack or water which is great for recovering a bullet and getting it to expand it would tell you nothing about wound channels or proper penetration. If the wetpack isn't the exact same type of material with the exact same amount of water, squeezed out the exact same amount, supported the exact same way, and all at the exact same temperature then your shot to shot variances are so much that your test is almost meaningless. It'd be like shooting different bullets into completely different mediums, say one water and the other dirt, and saying the bullet fired into dirt is no good because it didn't expand as much compared to the one fired in water. Well, it did but it's not a fair comparison. To do a proper test would require a level of consistency that I can't provide at this time. Also, before doing tests aren't you suppose to do, oh what's it called... research? Shouldn't you obtain a certain level of knowledge so you know what to expect from your tests? I've done testing with hollow points cast out of different alloys at different velocities and the differences in alloys is amazing, especially when you can crank up the velocity to fragmentation in some alloys. It just doesn't seem like that translates over to swaging. About the best test I could do right now is fill a five gallon bucket up with water, put a lid on it, lay it on its side and shoot through the lid. I could then strain the water and recover the pieces, that would give me a recovered bullet but no idea on penetration or wound channel, assuming the bucket would even hold together.

There are drawbacks to the bullets made of 22 shells but in my opinion they sure beat the hell out of FMJ's. I'd take no penetration with a full energy transfer over a pinhole any day. They are great for super cheap plinking and varmint bullets if you have the time to make them. I have a friend that shoots an insane amount and he only buys 55gr FMJ's, he buys them in the bulk 6,000 boxes for like $450. Even those turn out to be $.07-.08 a piece, about the same cost as the powder in a 223. By making bullets from 22LR shells and scrap lead I can take that $.07-.08 off of each round, which adds up. Hell, that's enough to pay for the powder on the next batch, plus I have a bullet that will actually do something. The Jackets from Corbins are $.10-.12 a piece depending on the quantity you buy, that's a significant increase from free especially in any sort of large quantity. I'm not saying they're not worth it, I'm saying for my use it's not worth the extra cost when the 22LR shells do just fine.

There are obvious things I can do to make my personal bullets less frangible, like changing the jacket or bonding, but forget about my personal bullets for now and try to think about the bullet that you yourself use. Think of your own go-to bullet and how it would act if you changed only the composition of the core alloy. Would the core gain the attributes of the added metals or would there be essentially no change due to the lead being worked? Like Valornor mentioned when suggesting I do tests starting very slow, the differences may be much more noticeable on something slow, say a 30-30win, versus something much faster like a 300wm. Maybe there's just too much impact energy that it completely overwhelms any alloy you could use.

[Valornor]

There are a few things to remember about testing.

1. It is expensive. Collecting data, setting up tests and doing it right, takes time and money.
2. To minimize item #1, companies and individuals apply statistics. Using small test samples and applying even a basic understanding of stats can tell you 90% of what you want to know with 10% of the effort.
3. There will always be noise in the test, velocity will vary from one shot to another but for the most part we accept that. (unless its way low like a squib) Part of doing research is identifying the factors that you will control and the ones that are beyond your control. You try to control ones you can, and you live with the ones you can't. Again how do you get 90% of the answer with 10% of the work?

For what you are doing, wet newspaper or phone books would be ideal. There's a dirty little secret in the industry about ballistics gel. It's a poor simulation of flesh, its expensive to use, and you can get the vast majority of the info from shooting into water at a simulated downrange velocity. However it's the best we have. You'll get the majority of the answer with wet newspaper. You'll mainly looking for expansion and weight retention. You will miss out on the cool visuals, but you'll have reasonable confidence on how your bullet is functioning. In terms of controlling the consistency of the news paper stack, that may be some of the noise you'll need to live with. I will say that as long as you are reasonably consistent with the news paper your results will shine through the statistical noise.

A velocity difference of 25-50fps that you might expect from reasonably decent ammo is meaningless unless you are on the verge of expanding...this is from experience.

Muzzle velocity is not the velocity bullets are designed to expand at. If you don't have a range long enough for what your intended use is, you can download the load and simulated it there. It's not perfect but it will give you a very good idea of what the bullet does in terms of expansion. Shooting into a bucket is the worse way of testing unless you have calibrate your ammo to shoot at a simulated velocity then it's a pretty reasonable test. Like you said cut a hole in the lid, but I would suggest a larger bucket depending on caliber 55 gallon drums aren't enough to prevent the bullet from exiting the bottom and screwing up your test. I've seen monolithic bullets penetrate a 40ft column of water and still have enough energy to dent the 4in ball value at the bottom of the tank. Obviously it failed to expand, but when you're testing something new these things happen.

You're right in that you need to go into a project with some basic thoughts on what you think is going to happen. Usually you want a defined result. In this case you'd say a "X" Muzzle velocity I want my expansion to be "Y" my retained weight to be "Z" perhaps you'll have other goals such as depth of penetration. You'll also enter in with a thought as to what your controlling factors are. In this case your hypothesis is differing lead alloys equate to different terminal ballistics. So you will isolate all other variables, and do what you have done. Personally I'd test five to ten rounds each. That will give you enough info to make sense of things. I'd also load and test at what you think the expansion window is, so you know where your bullets perform the best.

Here's my predictions on the tests you outlined.

Tin, will have little effect to on expansion. Least not at the level's you're talking. It will perform similar to the pure lead core.

Antimony will increase the function window of the bullet. So if you hold velocity constant with the pure lead and tin bullets, you wouldn't see as much expansion. However I predict the difference would be slight if any at modern muzzle velocities greater than (2500fps). At lower velocities like 1800fps or below there would be a much more noticeable difference.

[Metroxfi]

There are a few things to remember about testing.

1. It is expensive. Collecting data, setting up tests and doing it right, takes time and money.
2. To minimize item #1, companies and individuals apply statistics. Using small test samples and applying even a basic understanding of stats can tell you 90% of what you want to know with 10% of the effort.
3. There will always be noise in the test, velocity will vary from one shot to another but for the most part we accept that. (unless its way low like a squib) Part of doing research is identifying the factors that you will control and the ones that are beyond your control. You try to control ones you can, and you live with the ones you can't. Again how do you get 90% of the answer with 10% of the work?

For what you are doing, wet newspaper or phone books would be ideal. There's a dirty little secret in the industry about ballistics gel. It's a poor simulation of flesh, its expensive to use, and you can get the vast majority of the info from shooting into water at a simulated downrange velocity. However it's the best we have. You'll get the majority of the answer with wet newspaper. You'll mainly looking for expansion and weight retention. You will miss out on the cool visuals, but you'll have reasonable confidence on how your bullet is functioning. In terms of controlling the consistency of the news paper stack, that may be some of the noise you'll need to live with. I will say that as long as you are reasonably consistent with the news paper your results will shine through the statistical noise.

A velocity difference of 25-50fps that you might expect from reasonably decent ammo is meaningless unless you are on the verge of expanding...this is from experience.

Muzzle velocity is not the velocity bullets are designed to expand at. If you don't have a range long enough for what your intended use is, you can download the load and simulated it there. It's not perfect but it will give you a very good idea of what the bullet does in terms of expansion. Shooting into a bucket is the worse way of testing unless you have calibrate your ammo to shoot at a simulated velocity then it's a pretty reasonable test. Like you said cut a hole in the lid, but I would suggest a larger bucket depending on caliber 55 gallon drums aren't enough to prevent the bullet from exiting the bottom and screwing up your test. I've seen monolithic bullets penetrate a 40ft column of water and still have enough energy to dent the 4in ball value at the bottom of the tank. Obviously it failed to expand, but when you're testing something new these things happen.

You're right in that you need to go into a project with some basic thoughts on what you think is going to happen. Usually you want a defined result. In this case you'd say a "X" Muzzle velocity I want my expansion to be "Y" my retained weight to be "Z" perhaps you'll have other goals such as depth of penetration. You'll also enter in with a thought as to what your controlling factors are. In this case your hypothesis is differing lead alloys equate to different terminal ballistics. So you will isolate all other variables, and do what you have done. Personally I'd test five to ten rounds each. That will give you enough info to make sense of things. I'd also load and test at what you think the expansion window is, so you know where your bullets perform the best.

Here's my predictions on the tests you outlined.

Tin, will have little effect to on expansion. Least not at the level's you're talking. It will perform similar to the pure lead core.

Antimony will increase the function window of the bullet. So if you hold velocity constant with the pure lead and tin bullets, you wouldn't see as much expansion. However I predict the difference would be slight if any at modern muzzle velocities greater than (2500fps). At lower velocities like 1800fps or below there would be a much more noticeable difference.

Awesome write up!

If water or wetpack will give decent results I may just try that. I don't think I could get my hands on enough of the same kind of paper for a proper wetpack so I'll probably just do the water, I was hoping for as much consistency as possible. I have access to a range that goes to 325yds and there just happens to be a small creek running alongside the range so I wouldn't have to lug water around. I could set the target from 200-300yds, typical varmint distances, and use standard 223 loads. I was thinking of a sealed 5gal bucket laid on its side, and shooting through the lid but I'm almost certain that it would rupture the bucket. I'd probably be better off cutting a section of the side of the bucket out, making a trough type container. That way it has a way to vent off all the pressure without rupturing the bucket, shoot through the plastic lid and just patch with duct tape after each shot. On the lasc website they have a water test of 45 200gr SWC's cast of pure lead shot into a plastic drum from above at 800fps and it goes through three feet of water and 'thunks' the bottom of the drum. Using enough water is a must but with such short penetration to the bullets I'll be using I think the length of a five gallon bucket would be sufficient. I would really like to see what kind of wound channel these would make, especially the temporary cavity but it's not really important at this point.

I'll probably try three different alloys:
#1: straight clip-on alloy
#2: Hospital lead or cable sheathing (Xray shield, not isotope canisters. Cable sheathing with joints cut off)
#3: stick-on weights with 2-3% tin added

I'll try a small batch of each, maybe 30-40 bullets each. All my lead is salvaged scrap or wheel weights but I'll try use as close to pure as possible and keep things as true as possible to their respective alloys. After I finish my current run I'll put them together, maybe a couple weeks. By then the creek by the range will be thawed enough so I can use that as a source for water. I'll shoot one round then strain the water in a paint strainer to recover the pieces, set them aside and label them, patch the bucket lid and shoot another round. Starting with a load that produces 3,100fps with a 55gr bullet at the muzzle, at 200yds I should be down to about 2,300fps, just over 1,900 at 300yds. I think a few shots at 200 and 300 yards should tell me a decent amount. I'll keep everything the same except what type of lead I use and I'll keep them clearly marked. I have a couple other things I've wanted to try too, if I get around to it I'll make some other types to test and recover. I just have to finish this batch for my friend, he got me 20+ buckets of wheel weight last year and I really owe him.

When you said you think antimony would increase the function window of the bullet, do you mean it might expand at a lower velocity and hold together at a higher velocity than compared to pure lead? That would be a really interesting factor.

I guess I'll just have to suck it up and go do some shooting.

[Valornor]

Sorry it probably won't increase the size of the function window just the Max and min velocities. So if its at min 1300 and a max of 2200 in pure lead, you might see an increase of 100 or 200 fps over min and the same for max. Least that would be my theory.

I've done what you have done to an extent. Here's what I have found. Rifle bullets create hydro static shock where as pistol bullets do not. Hydro static shock is very, very rough on containers. Your bucket might not survive more then a couple shots if the first shot doesn't do it. Even with an open or vented top. Shooting through a lid will mess with your results. Polypropylene is a very different material than water, you're going to deform or break up the bullet before it hits the water. That's why the wet news paper method usually is a good one. It's a better (slightly) analog for tissue, if you have it all packed in a cardboard box the transition from cardboard to paper is pretty mild, and will give you better results. Down side is you have to dig through the mass to find it, and its fragments.


Most companies used temporary wound cavity and permanent wound cavity as marketing gimmicks. Really cool to see, especially on high speed video, but the truth is as long as the bullet holds together, and penetrates all the wound cavities look pretty similar. As long as it's an conventional expanding bullet...FMJ's look ike you shove pencil through the block. Fragmenting bullets are a different story they go in aways and looks like a mini grenade went off. Gel testing is mandatory for something like that.

[runfiverun]

you can always simulate velocity drops at shorter distances by lowering your initial velocity.
it sucks to walk to 200 yds and back and to 200 yds and back.
you can just drop the speed in the 223 and shoot at 25 yds.

[Metroxfi]

Ok got it, it wouldn't make the window bigger just move it on the velocity scale.

It would suck to walk back and forth every single time, lucky for me the range I have in mind has a designated driving trail on the side opposite the creek and there's hardly ever anyone there. It'll still be a pain going back and forth but I think it's worth doing. I think driving back and forth would be less of a pain and take less time than finding a load for a jacketed bullet at the toned down speeds and loading special batches, plus the chrono and maybe some adjusting for consistency. Good idea though, slow your bullets down to impact speeds with powder charges instead of distances.


Instead of shooting through the lid what if found a way to contain a garbage bag full of water? The only barrier I'd have to shoot through would be the bag, still use a bucket or a trough type container to catch the water and bullet after the shot. Maybe use a bucket like I originally thought and cut a 4" hole in the lid as a window to shoot though.I could possibly construct a wooden trough with the proper width to hold plastic bags of water and staple a strainer bag to the front of the trough and shoot through it, punch a hole in it a bit higher up and allow the lower half of the strainer to catch the bullet/pieces.

I would do a wetpack but I don't think I could get my hands on enough material for 5-10 shots each of 3 different bullets and two different distances. I may have enough for a couple shots of each but not enough to get a solid average per bullet. After each shot into wetpack I'm sure the first 5-6" would be trashed so the sheer volume of material I would have to take to the range would be a truck load. When I did a wetpack for the pistol bullets I tested I didn't bring enough with and tried to reuse it, even trying to repack it all the bullets still zipped right through instead of being stopped.

I'm just trying to think of a way to do it as practically as possible and still have a certain level of consistency, you can't really screw up water. Any ideas on anything else I should test since I'll be going through the trouble? I have a few hornady 55gr soft points and some barnes varmint grenades, recover a couple of those for comparison?

[Valornor]

Having some commercial ammo to bench mark against is always a good idea. The Hornady soft points will probably give you the best comparison to what you'd want from a lead core bullet. I velieve the varmint grades are compressed tin/copper core, but I might have those confused with the vaminators.


I was going to suggest hanging plastic bags, I think that would be a good idea, but I don't know how labor intensive it would be. Punching a hole through duct tape probably isn't a bad idea either. There's probably a few ways to skin this cat and get consistent results. I like the gallon bag idea, if you hung several up in a line and had a container around them, you should get the expansion and catch the pieces without destroying your container each shot. I couldn't tell you how many bags you'd need to line up to slow everything down to where the slug doesn't punch a hole on the back side. If it was me I would try and get a water column that was in the 30 to 36in range.

[runfiverun]

I don't know.
water is real hard on bullets.
wet paper is too.

if I was going to try something repeatable I would probably build a box out of ply wood and place cardboard every 6 inches then put something in the front [water balloon] and use oiled saw dust behind it to slow and catch the fragments.
if your just looking for varmint type stuff the balloon and a couple of newspapers [one in front one in back] would replicate a P-dog fairly well.
the cardboard would give you a pattern to judge what's happening.
coyotes are not heavily boned animals and depending on the performance you wanted slight adjustments could be made and based against store bought performance.
this gives you a portable, flexible and repeatable catch basin.

the cardboard box sections could be had at the grocery store.
some saw horses from 2x4's.
news papers easily gotten.
the big expense would be the plywood and a couple of 1x2's to hold the cardboard.
even saw dust is easily had at the lumber store for just the asking.

you could use it for bigger gun testing too by placing the cardboard every foot and using more paper and water bags.

[Zbench]

If you devoted the time to building a wooden box like 18" square and 3 feet long with an open top and lined it with poly, couldn't you make the end out of hdpe or some other hard plastic that is 1/8" thick? Sure you will get holes in it and the water will leak out, but you could put duct tape on the holes on the inside in between shots to keep it from leaking out too fast. Even just put the hose in it and keep it full, and not worry about how much leaks out. I'd think that would work for multiple shots and not cause hassles finding the bullet. Has anyone tried anything like that? The trick would be to find something thin enough that would hold that amount of water back. Maybe just make a 6 x 6 window in the end so it's supported enough to hold the water back.

[Zbench]

Maybe use a thick piece of yoga mat...that should be self healing to a certain degree as long as you don't shoot in the same place time after time...would be easy on the bullet nose too

[runfiverun]

I'm sure you could get creative.
HDPE or even a chunk of rubber conveyor belt could be used as a backer of sorts [but would maybe influence the bullets negatively]
I just figured water balloon or milk jug and smaller amounts of paper to simulate smaller targets.
the cardboard is just there to hold the oiled saw dust and to look for the last hole so you can find the fragments.

[R.Ph. 380]

Keep seeing on TV that you can use that new Flex Tape to stop any leak..........................................hehe he

[runfiverun]

maybe we can get that guy to stand there and slap some tape over the hole to prove how good it works.

[Zbench]

Phil Swift is the man! The only question is, should you use black or white?

[Sasquatch-1]

depends on how old your pot is. if it's shiny new use the white, if it's old and soot colored use the black.