Smooth bores?

[W.R.Buchanan]

LB: after my gun is broken back in after this trip to FS,, I'll be shooting some home made stuff at home.

I will be bringing back a bunch of OF Roll Crimped factory hulls I'll pick up off the range there. I have found that the Federal Hulls Roll Crimp really nicely if you trim about 1/16" off the front end which gets rid of very end of the hull which get burned up or split during firing.

I reloaded 10 of them today to take with me with Lyman Slugs, blue wads, 18 gr of Green Dot, and a perfect roll crimp. I will use them for dedicated slug drills and hopefully they will shoot right. We'll see.

I'm gone til next Wednesday. See you guys when I get back and I'll have stories to tell!

Randy

[Bob9863]

I guess my question is .... why is there not more research done on smooth bores?

I've found the best smooth bore slugs to come from Europe, I have been using GB rifled slugs and getting 3 rounds touching at 59 yards and around or just under 3" at 100 yards, I've stoped casting slugs and only cast RB now as I can't get anywhere near that accuracy with anything I can make.
I've never considered rifled shotguns to be shotguns as you can't shoot shot in them so they are a 12 bore rifle in my book.
But there are some great smoothbore slugs out there and once you find one that your gun likes do what I did and buy every box they have on the shelf.

[longbow]

Okay then what are GB slugs and where do you get them?

The best I've shot to date, though I certainly haven't tried everything available, are AQ slugs... at least for home loading. Some factory loaded slugs have done very well for me too but... being a tinkerer, I want to cast and shoot. As you say though, I have as yet to manage to equal good factory made slugs or factory loads at ranges beyond 50m or so.

The quest continues!

Round ball to 50m can be quite accurate and can generally be depended on to maybe 70m. However, for me, 100m groups are fairly random. Sometimes good and sometimes not so good... and sometimes wild fliers. Certainly not dependable. That's why I want a good slug but... as above... the quest continues!

Longbow

[faustus]

My question would be .... how are rifled Foster slugs commercially manufactured? And how could we make our own in our hobby garage?

The TruBall Foster slug is the most accurate I have tried so far ....

[W.R.Buchanan]

The one thing that all of the High End Commercial Slugs have in common is that they are Swaged not cast. This insures an identical product from one round to the next and from one batch to the next. it also insures a perfect trailing edge which is the key to accuracy on any Lead Slug or Boolit.

It would be possible to swage slugs at home with a Corbin Press and the right dies but not cheap and certainly not worth doing unless you were going to fire literally thousands of them or going to sell them. You could also do it with a Hydraulic Arbor Press in your garage if you have one,(Harbor Freight?) and then it would just be the cost of the die.

All of the Italian slugs are swaged, Brenneke's, Lightfield's, Federal, Winchester, etc. same.

We have been studying this here for a long time and I myself have been immersed in the subject for about 9 months now.

The things I can tell you is that all of the "Rules of Boolit Casting" apply to Slugs, which are nothing more than large boolits. A perfect trailing edge being among the most critical. Weighing cast slugs and sorting around the highest weight for any given design is the key to consistency.

Balls should be perfectly round for best results. Recently saw a guy loading large ball bearings which are as close to perfect as is possible. Making sure they never touch the bore would be a good idea with those.

Next the slug (not ball) must be introduced into the bore perfectly square on two axis'and parallel to the center line of the bore.

The Slug cannot be distorted or deformed in any way during it's acceleration and release. This requires a firm base in the wad, or on top of the wad column, in the case of full bore slugs.

Every projectile has a Sweet Spot as far as velocity that allows it to fly at it's most stable, and undisturbed state during flight. You will have to hunt that speed down as it will vary from gun to gun.

I feel that these are the most significant considerations with regard to this subject. There may be more.

Feel free to add any other considerations to this list you feel I missed, as I doubt very seriously that I know everything about this,,, or any other subject.

Randy

Oh, the whole reason behind the Ball in Federal Tru-Ball Loads is that the Ball is forced into the rear cavity of the slug during acceleration and obturates the base of the slug to fit the bore, thus insuring a perfect fit to the bore every time. Pretty good idea I think.

Federal also has those nice "Flight-Control Wads" for their Buckshot loads which easily add another 10-20 yards to your shots. been working on duplicating those for a while now.

Randy

[bikerbeans]

Randy,

I would add rotation to your list. A slug is a big boolit and it needs to spin to achieve the best accuracy.

BB

[W.R.Buchanan]

I would add rotation to your list. BB

Probably a good idea!

Anything other than a ball must rotate to achieve stability. Even a ball needs to rotate some amount to get past the "Knuckle Ball" effect.

Randy

[Hogtamer]

You mean this is no good?
https://m.youtube.com/watch?v=vgYrT7AcTYI

[centershot]

Yes, unfortunately for us, the swaged rifled slug is beyond the capabilities of most of us D.I.Y.'ers! If here were a way to cast a slug with helical rifling then we could build a solid wad column beneath it and be on our way to success, buuuuuttt........

[longbow]

I am in agreement with most of the above.

Not sure a slug needs to spin though if it is properly drag stabilized. Spinning sure doesn't hurt though.

I still like the AQ and that is basically a Foster slug on a plastic pedestal... not a cushion leg. And that pedestal has helical fins. Now that is something we might be able to do at home especially now with 3D printers.

I still think the wad column is a key issue as well. if the wad column tilts at all then the gas seal could leave the muzzle unevenly just like an uneven/not flat boolit base. That can't be good. The factories can muck around testing and spec what they want to then order by the tens of thousands. I note that any Foster slug loads I've seen have a quite solid wad column whether gas seal and cards or plastic... it isn't a flimsy cushion leg.

If you want plastic balls for "Tru-Ball" like slugs Corbin sells plastic balls and they are, or were, available on that internet auction site in bulk. You'd want a tough plastic like urethane, nylon, Delrin or similar. You just need a ball that will just start into the skirt so as Randy says, it pushes into the slug and forces obturation to bore diameter. Not quite sure what an oversize slug swaging down would have the same effect...

Longbow

[Hogtamer]

I know nothing about machining, so is there a technical reason someone with the right equipment cannot cut grooves into a mold that would cast fins or "rifling" on fillout?

[Ozark mike]

Most molds are made with a spinning burr shaped to the size of the bullet a small bit on a mill could cut the slots into the mold but the chamber is round and getting it right could be a headache unless someone here has done it I don't know if it is feasible

[longbow]

Nope! I've made moulds that produce straight finned and ribbed slugs. I don't have the equipment or skill set to make helical ribs/vanes but Cap'n Morgan has made moulds with helical vanes just like Brenneke.

These have to be like swaging dies though and push out of a solid mould rather than a two piece opening mould as you are used to. Look up Ideal Cylindrical moulds and you will see what they did back in the 1800's. Okay, I'll do it:

Scroll down to page 6

http://www.castpics.net/subsite/Hist...eal_barlow.pdf

also:

second from the right at the top of the page

https://www.google.com/search?q=bull...w=1920&bih=937

I make a slotted hollow core that slides inside the mould so when I cast I push out a ribbed slug. They cast just fine but don't shoot any better than smooth slugs so...

Cap'n Morgan's mould produces a beautiful Brenneke clone that shot quite accurately for him. Not sure how he cut the helical grooves, whether CNC or EDM but he did a beautiful job of it and the injection moulded tail wads as well. He is a class act!

Now, in the past I admit to being a naysayer that Foster slugs rotate. However, Taofledermaus video shows that they do indeed rotate. Not nearly fast enough to give gyroscopic stabilization but enough to average out imperfect flight so maintain a smaller spiral course. Brenneke states that the helical vanes do not impart spin but if a rifled Foster spins a Brenneke must.

It would take some extensive testing to prove whether that slow rotation has any significant benefit but I have to say that I have shot several brands of factory loaded Foster slugs and all have shot quite well and better than home cast and loaded Foster slugs. I refer back to my comment on fit and wad column here though as I believe those are as important or more so than a slow spin.

More recently I watched the Taofledermaus videos of the Moose Minie .69 and Lyman .69 Minie and was blown away with the slo-mo video as both flew perfectly stable and accurately from smoothbore. Of course there are very limited number of shots fired but still it indicates if they are launched well they can fly well and more importantly accurately.

Longbow

[Ozark mike]

Yea I imagine you could take a rifled bbl and pour lead in it then push it out hydraulically then cut at the desired length. I'm just imagining things not to be taken seriously though

[Bob9863]

Okay then what are GB slugs and where do you get them?

I don't have all the groups I shot with them, I'm overseas ATM and will dig them up when I get home, but here are the slugs and a 3 round confirmatory group I put into a tree at 65m.
Nothing else shot as good as these, I've gust got to test them on some game now.

[Cap'n Morgan]

I have sometims wondered how the dies for the original Brenneke slugs were made. My best guess is that they were forged or perhaps cold-swaged using a hardened and polished punch. It must have taken several steps (and a lot of failed tries) before reaching the final result. Nowadays the mold would be made using EDM (eletric discharge machining) where an electrode shaped as the slug is burning the cavity directly in the hardened die. This process is rather slow, but by gradually reducing the current and voltage it can produce an almost mirror-like surface which needs no further processing.

I have contemplated making swaged slugs to speed up the process and to get a more uniform product. The plan was to make a swaging unit that could be mounted in one of our injection molding machines (of which the smallest has a closing pressure about 25 ton) The "base slugs" would still have to be cast, but this could be done in an ordinary multi-cavity mold.

The procedure would be quite simple: Place a slug in the die(s) and press a button. The die closes and forms the slug while any excess lead is bled out through a tiny venting hole in the die (this will guarantee an even weight even if the base slugs are of varying weight). The die opens after a second and the finished slug(s) is ejected. Wash, rinse, repeat...

[longbow]

Well Ozark Mike has an interesting idea! Using the push out type moulds I make one could indeed rifle a short piece of round bar then make the nose and HB plugs to suit. The ejector could be the HB cavity form so the entire base plug didn't have to match rifling.

I think the rifling would have to be considerably deeper than typical rifling to be effective as vanes but that is just time spent with the rifling machine. Mine would do it.

These are quite simple moulds and easy to make. Agreed that swaged slugs would be more consistent than cast but I think well cast slugs should be accurate enough for my needs... especially since I don't think I can fit a 20 tonne press in my basement!

Alternately the rifled choke tube is an option and my next project when I get time after the archery shoots. Again referring to Taofledermaus videos, I was convinced that rifled choke tubes can impart a good spin on slugs after watching their slo-mo video. Good enough to try myself and I would have done so long ago if I had a gun threaded for choke tubes. The benefit here if it works well enough is to keep one's smoothbore but have the option of the rifled choke tube for (hopefully) improved long range accuracy.

However, as the OP notes, factory slugs seem to do quite well in smoothbore and as he says, I'd be a happy camper if I could get that sort of accuracy from my home brewed slug loads. So far good accuracy much past 50/60m with my home cast slugs and balls is elusive. I think for round balls somewhere short of 100m and more like 60 to 70m is about as far as one can expect hunting level accuracy from an un-spun round ball. A good drag stabilized slug should hold up better though as Brenneke, Gualandi, Benco-Vitt, etc. have proved they can. How do we do it I ask? Consistency keeps coming back as the answer to me. If the slug is centered solidly in the bore and leaves the muzzle the same every time with no tipped wad columns, uneven base/gas seal... and of course maintains nose forward flight through drag stabilization then it should fly well. Obviously easier said than done!

Bob9863:

Those GB slugs look like what BPI sells as Thug Slugs... and likely are. AQ's have their origins in Europe too as do Brenneke, Gualandi and many others.

SIARM has a good selection of slugs for sale and many I have not seen on this side of the pond. Not sure why but so it is. I would have figured the marked in the States would have been very large when shotgun only areas were being formed but the solution seemed to go with rifled choke tubes, fully rifled barrels and sabot slugs.

I'll have to try contacting SIARM again. No response to my last e-mail. If they'll ship to Canada they have several slugs and wads I'd like to try.

Longbow

[W.R.Buchanan]

Those slugs are Thug Slugs made by Gualandi, I got some to load.

On the swaging dies with ribs, they would now be made with EDM. That is the only way to get the detail of the lettering on the face of the slugs.

However they were probably originally made by "Broaching" the groves into the die like the heads of socket head bolts are sometimes made. I have made screws in my shop that had a hex socket in both ends. They were not cold headed like the majority of screws are made since the quantities are not long enough to justify the set up of a cold heading machine. Broaching produces a chip for each groove cut which ends up in the bottom of the hole. Simply running the pilot drill (Minor Diameter of the Hex) back into the hole after broaching removes those chips and creates a smooth tapered bottom in the hole.

The Nose Detail with the raised bump in the middle of Brenneke Slugs has been there since the beginning. I suspect they drilled or bored a pilot hole then broached the ribs and then drilled the end detail which would remove the chips. The rear end of the swaging die would have been a simple punch which bottomed out at the correct depth and vent hole would bleed off the excess lead. The ejector pin could be either the whole front end detail or just the center bump, probably the former. The Germans have always been pretty good machinists, they obviously figured it out,,, over a hundred years ago! We are just Reverse Engineering it now? We are so behind!

Everybody should know by now that the ribs on those slugs are there to crush when ran thru a choke. They obviously will still "Bite" a little in the bore to impart some spin to the slug however that is not the primary reason for them. I suspect the Federal Tru Ball loads that obturate the slug to bore diameter have more of an effect on spin than just hitting the choke. Maybe that contributes to their accuracy.

I have a Brenneke Catalog which shows groups for some of their slugs. Most are shot with smooth bore barrels at 50 yards and are impressive. Some were shot at 75 yards as well and you can see how they open up into the 2.5-3" size. The 100 yard groups they show are all in the 3" range. When you consider that many hunting rifles can't even shoot that well, it is impressive, not to mention being so much more powerful!

Remember "Nothing Lives thru a Slug!"

One of the biggest problems with slugs is that generally they are about as Aerodynamic as a Refrigerator. Thus they don't fly all that well. Thus range will always be limited. But those poor aeros also detract somewhat from accuracy, and that is just something we have to live with, or find a way around.

So expecting one hole groups at 100 yards might be asking a bit much. Ranch Dog over at the Lee Loader website and here from time to time wants 3 MOA from his Marlin Slug Gun. He can get that from Lightfield Slugs however has not been able to get close to that with his handloads and he is about to abandon the project and sell everything and just buy them. I don't know if it is his ammo or his gun.

The Lightfield Slugs are the top of the heap when it comes to accuracy from Rifled Shotguns. We should all look there and try to extract as much information from their design as possible to apply to our slugs. STI also has some really accurate stuff and that is the road I am going down with my Brass Non Toxic Slugs. Lightfield sells STI slugs for reloading? Maybe that's a clue?

Don't forget that the gun also has something to do with this and if the gun won't shoot right nothing you put in it is going to make a difference. The last pic below is of the 3 shot group I shot with my A5 Smooth Bore Barrel with Federal Slugs. In this case it appears the gun is doing it's job. Hope the rifled barrel shoots too.

Randy

[faustus]

...

Everybody should know by now that the ribs on those slugs are there to crush when ran thru a choke. They obviously will still "Bite" a little in the bore to impart some spin to the slug however that is not the primary reason for them. I suspect the Federal Tru Ball loads that obturate the slug to bore diameter have more of an effect on spin than just hitting the choke. Maybe that contributes to their accuracy.

...

I can share another observation here. I have a Hastings cantilever barrel with straight rifling (Wadlock barrel). The straight rifling is supposed to keep the shotcup from rotating in the barrel when fired ... and this to improve the pattern.

Now, I have shot the Federal TruBall Foster slugs through that barrel (with a removable IC choke installed) ... and they were as accurate as out of my other 870P.

From this experiment .... it seems that rotation within the barrel does not really contribute to the accuracy ... or only marginally ... that is at least what it seems. If there is rotation, then it is after the slug left the barrel ....

[W.R.Buchanan]

Faustus: That is a pretty decent group at 50 yards !

There are Regular Slugs, which fly strait based on their weigh forward,
There are Sabot Slugs that discard the Sabot after it leaves the barrel but again must be weight forward or spin stabilized. There are Non Discarding Sabots that stay with the slug and can either work in a smoothbore as Drag Stabilized or in a Rifled Barrel as Spin Stabilized.
And there are Full Bore Slugs with either attached or non attached wads.

Beyond that the gun becomes the primary issue. Like all guns some shoot better than others, and some won't shoot at all.

Finding a combination of stuff that gives us the performance we want is what we are all doing here. Lots of variables.

Randy