Brenneke slugs - light at the end of the tunnel...

[Cap'n Morgan]

Cap'n, it looks like you're doing well in the accuracy department, but how are your two wad systems working for cleanliness?

I never had any problems, but then I don't use pure lead for my slugs - and the tight fitting wads probably help keeping any residue at bay.

I recall when I started shooting clay targets back in the seventies, when felt wads were still the norm - at least in the cheap ammo we could afford. A few rounds of skeet would leave a significant amount of lead in and after the forcing cone - you could actually feel recoil increase as the build-up increased (or so it seemed) Anyway, a lead scraper was a must. Nowadays I run a cleaning rod through my skeet gun once a year - if at all.

The idea of powder coating has crossed my mind. A lime green slug would go well with the pink wad I think I visited the 'Coating and Alternatives' forum, but the amount of threads and stickies made my head hurt. Someone in the know should sit down and write a 101 on the subject.

[Blammer]

very interesting project! Keep it up! I'm all ears.

[Ballistics in Scotland]

I never had any problems, but then I don't use pure lead for my slugs - and the tight fitting wads probably help keeping any residue at bay.

I recall when I started shooting clay targets back in the seventies, when felt wads were still the norm - at least in the cheap ammo we could afford. A few rounds of skeet would leave a significant amount of lead in and after the forcing cone - you could actually feel recoil increase as the build-up increased (or so it seemed) Anyway, a lead scraper was a must. Nowadays I run a cleaning rod through my skeet gun once a year - if at all.

The idea of powder coating has crossed my mind. A lime green slug would go well with the pink wad I think I visited the 'Coating and Alternatives' forum, but the amount of threads and stickies made my head hurt. Someone in the know should sit down and write a 101 on the subject.

Lead to bore contact is one reason why your sleeve wad struck me as the better of your two options. Something of the velocity of your attached-wad slug ought to be a good subject for powder coating. But here is a website on other forms of coating which work well at higher velocities.

http://www.6mmbr.com/bulletcoating.html

I've never done this, but a friend did it more cheaply than bullet coating kits, with commercial molybdenum disulphide powder and carnauba wax, and extremely hard wax which can be powdered with pestle and mortar or an old coffee-grinder.

Other than on the range, the slug user expects only to fire one or two on a very good day's hunting. Like the old African hunters with their "bore" rifles, leading from even a pure lead bullet was no big issue. There has been no doubt, though, that the shot sleeve wad has been a great step forward (as, in the past, a sleeve made of card could have been) for the user of birdshot. The folly of using a long 20 bore for a 12 bore load, or a long 12 bore for a 10 etc., isn't anything like as much folly any more. There isn't anything like the tendency for shot to clump together due to hot gas intrusion, either. Ironically if anybody wants felt wads nowadays, it would surely be more expensive than plastic.

[Cap'n Morgan]

I was getting sore fingers trying to hold the shells from rotating while crimping... something had to be done!

This gizmo is milled from a single piece of plastic. The top profile "hinges" on the left side and the shell snaps in place with a slight pressure - then it's only a matter of applying a slight thumb pressure on the lever to lock the shell firmly in place while the roll-crimping is done. Combined with a new and (hopefully) improved roll crimper it should produce a more defined and deeper crimp. Tomorrow will tell...

[Hogtamer]

I'm jealous! My skills extend to stretching rubber tape around each jaw of some channel lock pliers. But I did just use them to load up some zlugs to shoot tomorrow.

[elvas]

Some simple hull vises that could be easily done by anyone:
http://www.siarm.com/index.php?cPath...5421c96a9ea731

[Cap'n Morgan]

Some simple hull vises that could be easily done by anyone:
http://www.siarm.com/index.php?cPath...5421c96a9ea731

A lot of great stuff at siarm.com - that's were I get most of my material. I actually started making a shell holder like the one showed with a tapered hole, but then my incurable habit of over-engineering stuff got the better of me...

The new crimp tool didn't work quite as planned. The idea was that a smaller radius would produce a tighter crimp - and it does, but when I tried to do the crimp in one push, the shell wall would collapse from the friction heat. Some sort of lubricating would probably help, but I just did the crimp in two steps instead. I believe a strong crimp to be essential with these fairly light slugs and will probably go back to my old crimper and then apply a second bevel-only crimp to fold/form the rim inwards using the aforementioned friction heat.

I tested a few sleeve-slug loads over the chrono and the poor crimp would clearly show from the readings. The first load was 23 grains of Unique and the speed varied from 990 fps to 1050. These were with less-than-stellar crimps. Next was 32grains of Herco with a more uniform crimp and the speed varied between 1380 to 1410 fps. Accuracy was good with the Unique loads while the Herco loads had a flier, the imprint of which clearly showed that it had lost the sleeve before impact.
I'm still on the last batch of polypropylene wads and once I get some made from polyethylene instead the problem with collapsing wads should be gone for good. In the mean time I will try upping the Unique load a little and lower the Herco load a bit. A uniform speed somewhere around 1200 fps would be nice.

[elvas]

I have used a lot of factory made roll crimping tools and some I made myself.
IMHO there isn't a better roll crimping tool than the Cortini & Pezzotti T2. I use it at 900rpm with the help of some WD 40 on a cotton swab for lubricating one hull lips after 5 or 6 crimps. This crimper could also be used for ironing out the lips of a fold crimped hull making it to have the look of a factory one and sometimes even better.
http://www.siarm.com/product_info.ph...roducts_id=306

[Cap'n Morgan]

Last weekend I got to try a new batch of wads made from polyethylene. Unfortunately the guys in the molding department couldn't find any high-density polyethylene (HDPE) and used ordinary low-density (LDPE) instead - That was a mistake!



The two wads on the left sat directly on top of 30 grains Herco. The heat and blast stripped them from the slug and I could pick them up from the top of the sand berm.

The next two had a 5/16 felt wad between powder and wad and fared somewhat better. Still, they had both shed the slug and showed signs of excessive compression.

The last two was a test of the Brenneke clone. The wad is secured to the slug with a self drilling screw and both wads stayed firmly attached during the ordeal. but also showed permanent distortion from compression.

The PE wads are put on hold until the guys find some of the high-density stuff! Good thing I still have a large supply of those pink PP wads...

We have other types of plastic - some are glass filled and extremely strong (think Gloc handgun frames), but while they would be ideal for the Brenneke wad, I dare not use them for the sleeve-slug, as they are likely cause deformation in tight chokes.

Oh well...

While most of the testing so far has been made with paper cases (I picked up a couple of hundred old, primed 2-1/2" cases a few years ago) I'm now using mostly plastic due to the availability. It seems most European brands are tapered (skivered) on the inside of the mouth, probably to help forming a better star crimp. Try as I may, I can't get a decent roll crimp on those shells unless I trim off the skivered part.



Various shells, including some RP and a couple of paper cases. Notice the poor crimp on the two full length shells on the right. As you can see, I have made a new mold for the sleeve-slug with much larger meplat combined with a slightly shorter length. It makes for a shorter overall length of the loaded shell and removes any possibility of accidents in a tubular magazine.



Next step will be testing for accuracy with different length felt/plastic wads under the slug. The sleeve-slug has shown some promises so far, but now summer vacation is upon us and I won't get much done for the next three weeks. Don't panic, I'll be baaack

[popper]

Anything more than dove loads hurts me - I did shoot 3 of the Rem slugs in 20Ga. Enough for me, I just buy shells anyway. Powder coating will reduce any leading problems. IIRC some in the coating section are trying it for slugs and balls. Problem with the 'filled' plastics is not strength but homogeneity ( I've even used nickel filled - really tough). Adding Cu vs Sn makes a better alloy, takes much higher pressure. IMHO an improper crimp would give worse accuracy than a bad wad.

[Cap'n Morgan]

It's been a while since the last post, but here we go again.

I have been trying all kinds of loads to try to keep my sleeve-wads from deforming during launch, but to no avail: both the polypropylene and polyethylene wads would suffer quite a setback resulting in slug & wad separating after leaving the barrel. However, I learned a lot from the testing and have pretty much dropped the slower powders in favor of faster burning. Much more uniform velocity from the fast powders and no partial bloobers. Of course this also means I'll have to settle for a lower velocity - around 1100 fps , but this may also turn out to be an advance as the slug will not have to pass from super- to subsonic velocity.

One interesting thing I found was that replacing a 5/16" felt wad with a 5/16" plast seal (x12x) would increase the velocity with almost 70 fps. Clearly the lips of the plast seal works far better than a greased feltwad.

I'm still waiting to have some wads molded in High Density Polypropylene, but in the mean time I tried to improve the strength of the wads I already have by filling the internal hollow space with fiberglass resin. It actually worked alright (at least the wad and slug would not separate) and I decided to se how they would shoot.

As you can see from the pictures the "sleeve-slugs" shoots quite OK... well sort of OK.




This 3-1/2" group is shot at 40 yards. The two outsiders show clear signs of fishtailing, while the two center shot are perfectly round, but it could be a fluke. The remnants of the slugs shows remarkably little distortion. This slug would be a real bone crusher.



This five inch, five shot group is shot at 60 yards and shows an almost liniar dispersion from the 40 yards group.
However, when I moved to 90 yard (94 to be precise) things fell totally apart as can be seen in the pic below.
There should be 8 shot in the target, but I can only count 6 - and some of them are sideways! The sleeve-slug clearly
has its limitation after sixty yards. Still, it's more than enough precise for the intended use (driven wild boar at zero to fifty yards)
and a 520 grain slug with a .60 meplat at 1100 fps is bound to make an impression!



And now for a real uplifting test...

The original brenneke project has more or less been neglected while I was testing the sleeve-slug, but today I finally got around to try a few of the helical ribbed slugs with the new PE wad screwed on. I used the exact same load as with the sleeve-slug (16 grain AS - one x12x - one 5/16 felt wad in a 2-1/2" shell) and only swapped the slug. Shot at exactly 64 yards, this four shot group measure slightly over two inches! This is by far my best results ever and I hope and pray it isn't just a cruel fluke



I'm all out of my brenneke slugs at the moment, but will fire up under Old Drip and cast some more shortly. Then it's time for the hundred yard challenge.

[longbow]

Now that is looking good! Are those full bore Brenneke style slugs?

As for the felt gas seals leaking... YES! It is amazing how well plastic gas seals work compared to felt and nitro cards. I tried some sleeve slugs using old shotcups I had cut gas seal off for use under full bore Brenneke style slugs. These were loaded over a hard card wad column with two nitro cards underneath as a gas seal. Well, gas leakage shredded the petals of the shotcup! All recovered shotcups were burned and stretched badly and accuracy was correspondingly poor.

I will be looking forward to your 100 yard tests.

Lately I have been living vicariously through you guys on Cast Boolits as I have not managed to get out shooting for many months. I am hoping to change that shortly and I have some of Hogtamer's Zlugs all Brenneke'd up and ready to go. Not sure if you followed his Zlug thread but he has had a mould made up for zinc slugs and he sent me some to test but being solid and me having only smoothbores, I had to machine some plastic wads and screw them on. I doubt they are as precise as your moulded wads but it is the best I can do so we will see how Brenneke Zlugs work... soon I hope.

Anyway, I was just thinking about you and was wondering how your project was going. I always look forward to your posts so this was timely and interesting. You are forging ahead and making good progress.

Longbow

[Cap'n Morgan]

Longbow,

Yes, these are full bore size - .728 to be exact, for both wad and slug. Most European shotguns have a bore size of .724 and I designed the wad & slug for a tight squeeze fit.

When it comes to testing the next batch I will try to find a way to measure the rpm (if any) of the slug at fifty yards. Perhaps I can use two targets spaced, say, 10" apart and measure the difference a single rib has moved "around the clock". First problem is finding a target material which will show a clear imprint from the slug. Next some way of marking a single rib - perhaps with a grease crayon or with a file. But first things first; the 100 yards challenge is awaiting

[longbow]

Not sure how much your Brenneke slug ribs cut the paper but some of my larger rib straight ribbed slugs leave a hole like a gear went through the target.

I am still trying to figure out why your ribs don't collapse and mine have a tendency to. I wonder if your tight fit is helping in that regard. My ribbed slugs run about 0.001" under bore diameter following the Paradox idea of slide fit. Maybe not a good idea with ribbed slugs?

Anyway, good to see that you are still at it and making good headway.

Good luck on your 100 yard testing. I'm rooting for you! Looking forward to your next post.

Longbow

[elvas]

Cap'n Morgan,
Cut the petals of some Gualandi Scatterer wads, leaving the center cross post, and fit it at the base hole of an appropriate drilled full bore slug. Some people use this technique here to make nose heavy smoothbore slugs with fairly good accuracy results.
http://www.ballisticproducts.com/Bro...ctinfo/00BSUB/

[elvas]

Sorry, this is the correct link:
http://www.gualandi.it/en/tables.html

[Cap'n Morgan]

I finally got around to try the brenneke clone at 100 yards.

In the meantime my "plastic" colleague had made me a batch of high density polyethylene wads. At the same time he also ran a batch made from PB (polybutylene) which is the stuff used for those indestructible plastic wrap packages we all have cut our fingers on trying to open them.
Due to less shrinkage the PB wads were slightly larger than the HDPE wads, but fit perfectly with the slug and I decided to give them a try.



Even with only 2X magnification I could clearly see the holes in the target at hundred yards. The first four looked like something around five inches with the fifth opening the group to seven inches - still a great result.

I shot five more rounds at a new target. Same load, but with paper cases. This group was an even six inches! Given that I was shooting leaning over the roof of my car, and using a 2x long eye relief scope I'm sure I'm to blame for at least an inch, maybe two. Certainly this slug can shoot...




So here we are... more than two and a half year after starting on this project and several hundreds test rounds later, I don't think I can wring anymore precision out of a smoothbore shotgun. I was aiming at six inches - so to speak - and now have a load that will do just that - and at a price less than that of a cheap clay target shell. Now I'm just hoping for a chance to try the slugs on some wild boars the coming winter.

[jmort]

"So here we are... more than two and a half year after starting on this project"

That is an impressive accomplishment. Looks very much like the Brenneke, but a more aerodynamic version.

[dverna]

Good job Cap!!!

[Hogtamer]

Nice work Cap'n! Thanks for keeping us posted all along the way. Now tell me about that scope mount please! Fits on the ventilated rib?