Lyman 525 slugs

[megasupermagnum]

I'm starting this as a continuing notebook for my work with the Lyman 525 slug. I already posted a chunk of it in another thread, so I'll copy and paste that later.

Today I was testing a single thing, and that was how does the alloy effect these slugs. All of my slugs were cast on the same day, with the same mold, and prepared with a hot glue filled base in the same manner. The only thing was I cast a bunch of range scrap alloy, around 10-11 BHN, and another bunch with pure lead. I then loaded each the same in a working up ladder. I chose a load from the Lyman shotshell manual using 800x. I'll list the load below. I worked up to that in 1 grain increments. I loaded 2 rounds of each slug, two soft, two hard. 27.5gr, 28.5gr, 29.5gr, 30.5gr. and finally 31.5gr. I did not have any real Winchester AA wads. Instead I used the Windjammer AA clone, because it is bright blue, and I figured it would be easier to see.

12ga Federal Gold medal 2 3/4"
Federal 209A
31.5gr 800x
Winchester AA wad
Lyman 525 slug
fold crimp

All shots were with my H&R Ultra Slug Hunter with 24" barrel. I did record the velocity incase anyone is interested. Chrono was about 12' from the muzzle, seemed to read good with no wad interference. Velocity spreads were decent. Keep in mind these were only 4 shots per load.

27.5gr-1312 fps
28.5gr-1329 fps
29.5gr-1373 fps
30.5gr-1411 fps
31.5gr-1437 fps

Now the real interesting results are from the reason I did this test. I wanted to see how alloy effected the wads. An old Buckbuster slug recommended this test with their slug, and the best load was when you saw the petals start to shear off. In the picture below is the wads I recovered. I did miss a few; even bright blue they are hard to see going down range at 1400 fps. I only picked up the ones I saw for certain where they landed. I fired 2 rounds, went and got them, fired 2 rounds, got them, and so on. On the left is the wads from slugs cast of pure lead. On the right is wads from slugs cast of range scrap. Bottom/closest to you is 27.5gr, and top/farthest is 31.5gr.

My reaction is that first of all, the powder load made little difference in the wads. There's only just over 100fps from the slowest to the fastest load, so not as big a range as I had hoped for. It could also be that these Downrange wads just can't handle this level of loading. The petals on these are thin. If I measure at the top band of the slug, they are only about .722" with these wads. The same slug in a Federal 12S4 for example is around .736". The more interesting thing to me is that the pure lead slugs left most wads with at least a couple petals intact. All but 1 wad from the hard slugs sheared clean off. This is exactly what I wanted to find out, but it is the opposite of what I predicted.

After thinking about it, it reminded me of something Longbow has said. The way these slugs work is that the hollow base expands to fit the barrel. I don't think expansion is the best word for it. What I believe happens is they actually set back. There isn't an expansion in the sense of most cast bullets. The wad is what takes the brunt of the pressure. What I think happens is that the solid head of these slugs does not deform. The hollow base on the other hand is weak by comparison, and the acceleration from being fired, with the weight of that solid head, the only way is for the slug to compress, and what you end up with is the skirt both collapsing, and expanding outward. Since there is a wad and barrel, they can only go so far. From previous testing I'm not finding any correlation between chamber pressure, and this expansion. I think it is because acceleration is the driving factor, and the higher the velocity, the higher that acceleration is going to be. What is interesting to me in this test is that the harder slug, which should resist this setback more, is showing that it is actually expanded more than the pure lead... or is it? I'm going to theorize that this setback actually occurs inside the shell itself, possibly in the chamber/forcing cone just past the shell, can't know for sure. The reason why the hard lead is shearing the petals is because it is harder, and thus resists being squeezed down through the forcing cone, and into the barrel. The pure lead is softer, and squeezed down easier. I'll have to figure out a way to recover a couple of each to see how they look, see if one is expanded more than the other.

Same as always, this leaves as many, if not more questions than when I started. I think all that is left to do is to fire groups at 100 yards and see what happens. I have a bunch of Federal wad cut for this, more on that next time. I actually have the highest hope for pure lead now. It should in theory expand/set back more readily at lower velocities, and at the same time appears to be better for higher velocities too.

[megasupermagnum]

I have not had any problems with glue falling out of the bases. I even recovered one from a black bear, and the glue was still in there, and it took some grunt with a screwdriver to get it out. Considering how much these slugs expand during firing, it is amazing. So maybe my process will allow you to try something different.

It may sound too simple, but this is how I'm having success filling slugs with hot glue. I first prepare a pan, anything works. I use an old cookie sheet. I lightly spray it with lube. Last time I used PB blaster since it was closest. I've only tried this at room temperature slugs, it stands to reason that the warmer they are, the better it will bond. I then take the glue gun when it is up to temp, and squirt glue into the base, being as smooth as I can to keep air out. The fill is what I find makes or breaks it. Leave a real big heap over the top. Not so much that you spill and burn yourself, but enough that a good ring squishes out in the next step. I then take that slug, usually it is in my fingers a few seconds as I orientate it, plus it allows any bubble to come to the surface, and generally gets warm indicating a good bond, then in one motion I push it base down onto that cookie sheet, and push and twist slightly. Repeat with all slugs. The key to the next step is to let them fully cool. Resist the temptation to check them early. Once cool, peel the slug off, and you will see the ring of glue. Grab it, and it tears clean off if the glue is cold. This leaves a perfectly flat glue filled base of the slug that will not fall out.

Filled bases are the only way I have got accuracy from hollow based slugs. Hot glue is by far the most user friendly way I have found to do it. The next part of the equation is getting them to expand in the bore to the right amount. While using regular lead shot wads is convenient, they are highly variable. What I'm finding is that these variables are not so detrimental with hollow based slugs because they all expand to fit. No expansion = no accuracy. For this reason you want to cast hollow based slugs as a softer alloy. Even pure lead can be a great choice. Clip on wheel weights is getting to be on the side of too hard.

Here is todays surprise, the wad fit did not matter that terribly much. I was shooting the Lyman 525, and I used a range of wads I'll get to later. I was trying out a couple Downrange wads, which I found to have phenominal consistency, but too thin. My Lyman 525 slugs were casting with the top band at about .682". In both the Downrange WAA and 12S3 clones, OD at that top band was only about .723", far smaller than my guns .731" groove diameter. On the other end was the Federal 12S4, which was the thickest, bringing the diameter to .736", depending. I found the Federal 12S4 variable, and all of them were out of round by about .005". What I found is that all of them shot pretty much the same if the slug expanded to fill the bore, kind of.

Today I was experimenting specifically on chamber pressure. I tried three powders, American Select, 800x, and bluedot, which pretty well covers the spectrum of shotgun powders from fast to slow. I went off of Lyman load data manual, picking loads that were all about the same chamber pressure, but velocities were different. I think the American Select was around 1275 fps, 800X about 1400 fps, and Bluedot 1500 fps. One would think that because chamber pressures were about the same, American Select would expand the slug the most since it had the most abrupt launch (fastest powder). What I found instead was a direct connection to velocity, not pressure. It seems it is the acceleration that matters most, not the chamber pressure. How I determined this was by recovered wads. Those fired with American Select looked almost unused only slightly sooty. They shot horribly, about 12" groups at 100 yards. The 800x looked heavily used, sometimes a petal or two had sheared off. The Bluedot loads looked a little worse yet, all of them had at least one petal missing. Despite that, both the 800x and Bluedot loads shot about the same, around 5" at 100 yards. All testing today was using my H&R Ultra Slug Hunter.

I then tried a couple other wads. One such setup I used was to remove the cushion of the wad, not something I recommend unless you know what you are doing. I cut the cup from a 12S4, and trimmed the petals to fit the slug. I then used an X12X gas seal, and a stack of hard cards under this sabot. This load shot the best of the day. Heck, it's up there as one of the better groups I've ever shot, measuring 3 1/4" at 100 yards. The difference was that this sabot came out intact. The same load with the normal 12S4 was shearing petals. With a solid card stack underneath it did not. None of the recovered wads have ever shown any indication of pushing into the base of the slug. Despite that, I know that the hot glue is not as strong as the lead skirt. With a normal lead shot wad it is going to cause the skirt to expand more than if you have a solid stack of wads. What all this means is that you have to read the wads. It seems Buckbuster got this right all those years ago. Determine your safe max load, then start low, and increase by 1 grain increments until the petals begin to shear off. Your most accurate load should be around there. You are causing that skirt to expand more and more, until the plastic of the wad can not hold it anymore.

Below is a few pictures. First is a Lyman 525, cast of 96/2/2 alloy, fired from a 16 gauge, recovered from a black bear. Note the hot glue still in the base. Next is todays best group. I don't know what the small holes are, I took this target from the garbage. That's one good thing about shotgun slugs, there's no mistaking who's holes are who's. Last but not least is a couple wads recovered from the day. The left brown wad is a cut from a Federal 12S4. It is shorter because this particular one is from an ongoing project to make an extremely low recoil slug with a Lee 7/8 oz slug. I should have saved one from the Lyman 525, I must have been too impressed with the group they shot. Unlike the Lyman, this one from the Lee shot poor, even though it started off at a healthy .738" at the widest part. I'm trying for subsonic, but with no slug expansion, they just don't shoot. The right blue wad is a Downrange WAA12 clone wad. This is one which only measured .723" at the widest, yet shot acceptably. This was a book max load, right around 11,200 psi. You can see the slug expanded so much it sheared most of the petals off. If you look closer you will see a line about 3/16" from the top. This line is from the slugs top band, which started just under the top of the wad before firing. During firing, this slug is shortening considerably, and expanding the hollow base, which is shearing the petals. The petals are shearing at about the center point of the skirt. I did not recover any slugs today, but I would fully expect them to look just like the one fired from the 16 gauge. For the record, the 16 gauge is a smooth bore, and it shoots that goofy slug amazingly well.







Actually I'm going to add one more picture. This is a brand new cast Lyman 525 next to that fired and recovered one from a 16 gauge. That is how you want your slugs to look if shooting for accuracy.

[longbow]

msm... excellent info! Terrific write up and I know lots of work to do all that so thanks for sharing.

Yes, terminology... base expansion sounds more like Minie skirt expansion due to gas pressure which is not happening here. Set back seems like a good description of what is happening ~ squishing lengthwise so expanding radially.

It is interesting that you got best groups with the shotcup cut off and hard card wad column. That is exactly what Ranchdog found using Lee slugs.

As for petal shearing, I have had some very thick skirted slugs that "belled" at the bottom resulting in the sharp skirt edge slicing right through the wad petals. These were ACWW and I was surprised that the extremely thick skirts would flare that way but the wad pushed up and domed forcing the skirt to flare at the bottom. These were not filled. I suspect that is why Lyman has the reverse taper at the skirt bottom so during set back and skirt expansion that sharp edge is not the first thing to meet the wad petals.

I'll bet the height of the petal shearing matches the top edge of the skirt band of the unfired slugs.

To note, during set back the mass of the slug doesn't want to move due to inertia. The body at rest wants to stay at rest but it is being kicked in the butt by a large force (chamber pressure acting on the base) and the skirt supports the rest of the slug mass so the skirt bottom sees the highest stress forcing the lead to yield which occurs less and less up to the nose due to less mass ahead so less stress. For the Lyman slug design with solid nose the high stress would end at the top of the skirt/end of cavity which is evident in your pic of the expanded slug where the skirt has deformed pretty dramatically.

I would have expected that chamber pressure would be the deciding factor on set back and velocity due to higher chamber pressure = greater acceleration but that seems not to be the case from your results which is also very interesting... as is the fact that petals didn't shear when the cushion leg was cut off the wad. I would have expected there to be more set back with the solid wad column than with a cushion leg.

Again, a very informative and interesting post. Thank you!

Longbow

[megasupermagnum]

Now we are getting into theory which I can't prove. Here's my thoughts. I believe that with a normal lead shot wad, such as a Winchester AA, even with a filled base, the wad is still being forced upward, and the hot glue is the weak point. Even though most wads show no doming at all, I know that wad is pushing upwards. If the base is not filled, I do see domed wads. This is depending on the load of course. I plan to test non-filled slugs too. What all this means is that the hot glue is pushing outward, adding to that setback. Without the glue, the wad is being forced into the hollow base, and is even more dramatic. Maybe this is a good thing if you are trying to make lighter loads. The only reason I can think of on why the solid card wad column doesn't seem to shear petals is because that stack is evenly distributing the load. It's not just a thin gas seal and thin wad, it's a substantial chunk of wad. I see the same thing with some buckshot loads. Too little wadding, and it will wrap itself around the buckshot.

Why chamber pressure doesn't seem to matter I can only speculate. Peak chamber pressure happens inside of the shotgun shell, and I'm pretty sure it happens before the payload has barely moved, possibly before the crimp opens. After that, pressure only drops. So the entire time that slug is accelerating, pressure is dropping. Pressure effects bullets because that pressure is acting directly on that bullet. In this case, the pressure is acting on the wad. Even the hardest cards have a ton of give in them. My guess on why hard cards shoot so good is because the wads remain consistent. I'm getting decent accuracy with lead shot wads no doubt, but look at those recovered wads. There's no way something so mangled can be consistent. On the other hand, if you back off that load so it doesn't do that, then the slug is no longer setting back enough to be a tight fit. With card wads, we can get that setback, and the wads aren't shearing because the wad isn't expanding the base of the slug from pushing into it.

[Cap'n Morgan]

The glue filling works pretty much like 'rubber pad forming' where rubbers ability to expand in all directions is used to form simple parts.



Drywall filler is probably better if you want to prevent the skirt from expanding and still have some set-back expansion.

[W.R.Buchanan]

Captain: It called Hydro Forming?

Randy

[longbow]

Hot melt glue is pretty flexible under bore pressure. My extended glue tailwad wad slugs show considerable outward pressure against wad petals from the glue tailwad. And yes, it is a hydraulic type action in that as compressed axially so it expands radially.

Longbow

[megasupermagnum]

I'm assuming by drywall filler, you mean mud, maybe spackle. I'm guessing that is far too dense. You may as well cast the slugs as a solid at that point. Maybe bondo would do ok as a base filler. I'm quite impressed by hot glue. It's the lead shot wads I'm not impressed with, and the #1 reason I've not done much work with wad slugs to this point. I have to wonder, is this Lyman 525 simply this well thought out and designed, or is it just an air rifle pellet that happens to work good? While once in a blue moon someone has decent luck with the Lee's, most people never get beyond mediocre results. .680" round balls aren't that good in a wad. Really nothing is that good in a wad. The Buckbuster slug was the only other slug I've been impressed with, and at this point I think the Lyman 525 is actually better. The main downfall I'm finding is that wad slugs do not shoot good at low velocities, and such I don't think there is any replacing a .735" ball for low recoil loads. Maybe I'll find a way to improve on that.

[longbow]

msm... there is always the Mihec full bore Lyman sabot slug clone. No wad to mess with for that one but same design. Having said that, It really doesn't have to set back to fill out the bore if it is groove diameter + a bit. I haven't seen any reports on the full bore version, or don't recall any at least. I'd think they should shoot pretty well unless there are differences in CG or other details.

Then there are the solid slugs but at "normal" 1 to 1 1/4 oz. they are pretty short and stubby. Accurate has quite a few solid slug designs but I am sure you know that already. One you may not know is that I sent the Dixie Tusker drawing to Tom so he added it to his catalogue but it has a hollow base and he doesn't do core pins so that has to be outsourced. I always liked that design but no rifled shotgun so I didn't buy a mould. It is Accurate 73-740TN and with hollow base is 600 grs. for the Dixie design.

https://www.accuratemolds.com/bullet...ullet=73-740TN

I guess I am drifting off topic here since this thread is about 525 gr. wad slugs. Oops! I'll leave it there.

Longbow

[megasupermagnum]

No worries. I'm shooting the Lyman 525 as a full bore slug... in 16 gauge. That's what is really interesting to me is this one has multi use potential that nothing else I've used so far has. A .735" ball is phenomenal in 12 gauge with the right load, in certain guns. In 16 gauge, nope. In 10 gauge, nope. A .680" ball is pretty good in 16 gauge, not very good in 12 gauge, useless in 10 gauge. A Lee 7/8 oz slug is acceptable in 12 gauge, useless in 16 gauge, not even going to bother in 10 gauge. Now we get to this Lyman 525 slug, and I'm seeing some of the best accuracy I've ever got in 12 gauge, the best I've ever got in 16 gauge. I have yet to shoot it in 10 gauge, but by putting one of my cut 12 gauge sabots inside a 10 gauge SP10 wad, fit is perfection. I think there is a real good chance this works in 10 gauge too. It isn't the end all, be all, but this one checks a whole bunch of boxes. I would not shoot this slug through any real choke. IC would be fine. Modified probably won't hurt, but I wouldn't. Full choke I think it has a good chance of damaging. Along with that, this slug design requires that setback to be accurate, and so far nothing sub 1250 fps-ish has been good. Much more testing to come, but if I was looking for low recoil, I really doubt these will ever compete with a .735" ball at 900-1000 fps. For full bore slugs, I still have an Accurate 73-770S mold, and accuracy is fantastic, but it eats lead like crazy, and you can't drive them very fast without insane recoil.

[longbow]

Isn't the 12 gs. Lyman sabot slug a little large for 16 ga. at 0.680" at the nose? That is solid lead and has to squeeze down by 0.018" to fit 16 ga. bore. Not a big bearing surface but still quite a bit of squeeze down.

I'm wondering now if my attached hot melt glue skirt tailwad might work for your subsonic loads. As mentioned above it does expand and press the wad petals tightly against the bore.



These are Lee 7/8 oz. slugs modified with center post and screw to ensure the tailwad stays attached though that mod was done for screw on wads Brenneke like. Actually, just peening the drive key over works for cast on tailwads like these.

The three slugs on the left are as cast from the Lee mould. The three on the right are sized to 0.672" for paper patching to suit wad/bore requirements... which may not be necessary.

Anyway, point being that the attached wad compresses axially and expands radially to the point it squeezes wad petals pretty hard. I've been wondering if that would account for varying petal thickness issues in rifled gun. Your results indicate it might if there is enough pressure to cause the compression/expansion of the tailwad and that should be less than required to cause lead to set back.

Longbow

Longbow

[megasupermagnum]

My 16 gauge 11-48 "slug barrel" has a .673" bore. Even if it had a small bore, this slug would be a good candidate for a sizer. It takes very little force to size down that little top band to .673", and at that size, it would be fine in even tight bored 16's. The biggest problem is fit in the hull. At .680" you once in a while get one that a little too tight in a Federal hull. In most guns it would be fine, in a semi-auto, not as good. I plan to size these to .678" for 16 gauge purposes.

[megasupermagnum]

You got me curious, so I decided to ram a slug down my Stevens 530A 16 gauge. I used a Lyman 525 cast of pure lead, and they measure .682" on the top band as cast. Using a shotgun cleaning rod, a couple hard smacks with my hand put it in the bore. The bore on this apparently measures .667". You can see the top band is definitely sized down more than the earlier pictured slug fired from a .673" bore, but nothing crazy. The skirt is just barely touched. Honestly I don't see a huge deal. I have a PTII strain gauge on this gun, so at a later date I'll shoot some .678" sized slugs through it. The thing to remember with a smooth bore is that you don't have the rifling to engage. While say a .731" groove diameter 12 gauge sounds big, the rifling brings the bore down to say .722" (guessing). Shooting a .735" slug through a rifled 12 gauge with .722" bore is nothing. Look at that earlier 16 gauge picture. I think the skirt when expanded causes much more resistance than the head does.

[W.R.Buchanan]

If I can put in a few cents here. I have not seen anyone get Rifle like results from a Lyman Slug from a smooth bore anything.

However I have seen Hogtamer and Leon get really good results from Rifled Barrels.

I have some of these loaded up using Rem STS hulls, the Blue Claybuster wads with Mica on them, and 1/8' card in the wad and glue filled bases, fold crimped. The OD around the wad with the slug installed was .728-30. As soon as it warms up I will shoot these thru a Rifled Barrel and thru a Rifled Choke Tube and see what happens. I am expecting good results.

We'll see. I really want these to work because they are so cool looking and you've got to know anything getting hit by one is going to feel it. My Mihec mould makes perfect Slugs.

Randy

[longbow]

Well I guess there isn't a lot of lead to squeeze even though the nose is oversize.

I'd say that Lyman wouldn't be selling the moulds if they couldn't be shot through a full choke safely but that assumes they are in a shotcup and I am quite sure petals would squeeze down and shear easier than lead will squeeze down as in your naked slug in 16 ga.

Having said that I agree with your comments on rifled barrel squeeze down plus I have read that at least some Paradox guns or Paradox copies had rifled chokes down to 0.690" so really tight squeeze for a solid slug... narrowish driving bands but still a tight squeeze.

I also know a guy who accidentally shot a 0.735" RB through a full choke barrel with no damage to the gun.

Of course in that case pressure has dropped a great deal but the impact and swaging stresses must be considerable with the squeeze occurring in milliseconds.

Longbow

[centershot]

You know, I wonder if we're worrying about that "squeeze" needlessly. Think about it: The Paradox guns of yesteryear were sometimes choked quite tightly, as Longbow has stated. Now consider the state of metallurgy at that time. I'm not saying that they were cavemen but surely the barrels we have today are far superior to what was available then. Even the processes of heat-treating have grown mega-fold since then. Maybe we worry too much about that "squeeze"............

[longbow]

I have been wondering that myself. I doubt pressure testing would indicate a problem at the choke due to the squeeze... but that is speculation on my part. Someone with a pressure trace system could check pretty easily by shooting a bore sized slug with solid nose (like the Lyman sabot slug or a bore diameter round ball) through both cylinder bore and choked barrels.

Also, best to check with soft lead, ACWW and heat treated alloy all same weight and same load recipe.

If all are bore diameter I'd expect pressures to be very close unless there is obturation... which would be good to know.

Through choked barrel my suspicion is that pressure will have dropped enough that over pressure is unlikely but the impact and squeeze may cause significant hoop stress in the choke. Harder lead should result in higher hoop stress.

A solid slug isn't likely to obturate but also isn't as easy to squeeze down.

I suppose a strain gauge on the choke would indicate choke expansion just as it does on the chamber but not sure how the pressure trace systems would interpret that as the expansion due to swaging could be much greater then chamber expansion due to pressure... at least depending on wall thickness.

But all speculation on my part.

I have an old junker side by 12 ga. I was given so am thinking I might cast some solid soft lead slugs and some solid ACWW slugs then shoot those through the choked barrels to see what happens. Gun tied to a tire and long cord to trigger of course.

If a hard slug doesn't split the choke I'd repeat a few times to see if the choked is opening up or if it splits after a few shots.

Another project on my list! It's a long list!

Longbow

[centershot]

If a hard slug doesn't split the choke I'd repeat a few times to see if the choked is opening up or if it splits after a few shots.

Another project on my list! It's a long list!

Longbow

And that brings another question to my mind. A couple years ago I acquired a nicely used but not abused Ithaca SxS Flues model in 12 gauge. The serial number dates it to 1917 manufacture. The barrels are choked 0.700" on the left and 0.714" on the right, probably full and modified when new. The right barrel undoubtedly saw more use, it's trigger being first in line (two triggers) and it being more openly choked. That barrel should have mike'd 0.710" ID when new, now it's worn 0.004". I've no idea what has been fired through it in it's lifetime but doesn't 4 thou' of wear seem like a lot? The barrels are marked Krupp Fluid Steel, so not Damascus. I know the family this gun was passed down through, conservative people, not known for being careless with firearms. So, my point relative to the topic, were guns of this era built from steels that were more prone to wear, "softer" steels that might yield to pressure without bursting the barrels? It impressed me that the barrel was that far off spec, but who knows, it might have been that way when new!

[longbow]

I'd be surprised if it wore that much. Most likely a light modified choke or simply made oversize.

But that is just my opinion.

Shotgun specs seem to vary quite a bit. I have a Browning BPS with buck and slug barrel marked I/C that mic's 0.710". Seems a bit tight for I/C... about 0.010" tight.

Longbow

[Cap'n Morgan]

Back in the day, I and a couple of friends used Spanish AYA s/s guns. The guns were bored for 3" with 30" barrels and with full and modified choke.
Unlike most double barreled shotguns, which has their barrels and ribs soft soldered together, the AYA's were brazed, and the barrels were definitely "softer" than most other shotguns.

Over time all three guns developed a slight bulge at the start of the choke. Nothing dramatic, and mostly just a cosmetic problem.
This was before steel shot, but we did put quite a few Winchester 1-7/8 ounce shot #4 and #2 through them.

If normal shotgun shells can expand a barrel, I'm sure a hard alloy slug could do some damage as well.