Plastic jacketed swaged slugs

[uncle dino]

I've been tinkering a bit.. I have noticed with full bore slugs that they have a tendency to engrave the rifling unevenly... It seems to me, the more plastic I add to the engraving surface of the slug, the better it centers in the bore rifling.. I'm not sure why that is. But scores of recovered slugs tell the tale.. So I hope to test this theory within the next few days.. Here are a few of my test subjects.. The solid orange slugs are 530 grains and the attached base wad slugs are 450 grains.. Hopefully we will have a winner..d
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[Hogtamer]

Dennis you are a wizard! Those may be the best yet and the originals are terrific. You know I'm pulling for the 450s.

[longbow]

You know what? I found that my straight ribbed Brenneke clones suffered badly from cocking in the bore (or in the forcing cone) flattening the front edge of ribs at the nose and opposite side ribs at the tail (diagonal like if that makes sense). The were long slugs with a substantial attached wad and quite beefy ribs. I was more than a little surprised especially since slug length would bridge the majority of the jump through the forcing cone.

I have to think that there is some tipping as the slug leaves the hull thee impacting the forcing cone flattening the ribs which of course do not bounce back.

That is another reason I have stuck with wad slugs for the last while. The wads seem to either absorb that damaging impact or guide the slug into the bore better.

Interesting that you have had similar experience. Are you slugs tipping or engraving off center?

Good looking slugs by the way and as usual great work!

Longbow

[uncle dino]

Lb, I am not seeing any evidence of tipping. I have made long solid slugs that will start into rifling while the base is still in hull...same issue...Slugs will be engraved all the way around. But deeper on one side than the other.. Hard slugs are worse than soft. Hopefully the plastic jacket will survive impact into media so I can study them. My theory is too large of a surface area for slug to engrave. Causing slug to actually ride up on the rifling.. D

[tomme boy]

Goodsteel did a good deal of experimenting when they were designing the 30xb. He was trying to figure out what was happening when the bullet was entering the throat. He down loaded the rounds to just barely get out the barrel so the slugs were not damaged.

Load up some bloopers and see what you get. My guess is if you did a load with 5grs of bullseye it would get out the barrel.

[BigMagShooter]

what's the plastic?

has anyone tried to powder coat them?

[KrakenFan69]

Man those are sweet! I believe the white bit is HDPE (High Density Polyethelene, think cutting board)

Kraken Fan #69

[longbow]

Okay, just curious. So your slugs are engraving off center which to me is even weirder than tipping.

Mine were definitely tipping. I have no idea why but so they were. Possibly poor roll crimps? I hadn't thought of that before but maybe. These slugs were also long so even if crimp wasn't real good they should bridge through or almost through the forcing cone.

Just another shotgun slug loading mystery!

Hmmm, I wonder if your off center engraving could be starting as tipping so the nose hits off center and starts engraving deeper then the rest of the slug lines up? And yet another shotgun slug loading mystery!

I wish I was smarter!

[megasupermagnum]

how about a slug with 3 driving bands, and the first is bore size, while the bottom two are groove size?

[uncle dino]

Yes. Plastic is high density polyethylene.. With long jacketed slugs I have actually seen where the slug started to engrave as it entered the rifling.. Then the rifling on the slug disappeared in the mid section and rode up over the rifling and re appeared at the base.. I think the pressure needed to engrave so much area is too high, so the slug either tips or rides up over the rifling. Right or wrong.. That's my theory... D

[William Yanda]

Thinking about this, the pressure on the base is even, right? Something must be influencing the projectile to make it uneven.

[bikerbeans]

Dennis you are a wizard! Those may be the best yet and the originals are terrific. You know I'm pulling for the 450s.

HT,

I think Dennis plans to make a 1,000 grain slug just for you!

BB

[uncle dino]

Yes the base is stiff on a jacketed slug so it will engrave..sometimes even sometimes not.. I believe the rifling is determining where the slug ends up in the bore..d

[bikerbeans]

Others have reported that the mouth of a loaded slug should fit the chamber very snuggly to help align the slug with the bore. I do this by aggressively roll crimping the slug to flair the case mouth. Works okay with a bolt action or breech loader, not so much with a pump or semi-auto.

FWIW, the now defunct remington buckhammers were the most accurate FB slug I have ever shot. Buckhammers had a front lead ban that engraved the rifling but about 90% of the bearing surface was a plastic one piece wad. Buckhammers were not a short slug. I can dissect one and send you the slug/wad if you like.

I think MDNR will love the safety factor of the blaze orange slugs.:bigsmyl2:

BB

[Cap'n Morgan]

What kind of leade does the barrel have? A long taper will probably help centering the slug, whereas a more abrupt angle could result in an offset start - especially with a rather soft wad.

I hope you don't mind, but I have actually stolen your slug design to use for a hybrid between a Brenneke and your plastic-jacketed slug - using injection molded wads with helical fins for use in smooth bore barrels. The wad mold are finished and the first batch looks fine. More to come...

[longbow]

Hmmmm, I am leaning in the opposite direction Cap'n Morgan. I am thinking that the long forcing cone allows tipping of the slug then uneven engraving. Slugs have a lot of mass so inertia and repositioning takes place in milliseconds so if the slug can yield and take a set as lead does then the damage is done. Plastic is much more forgiving in that regard.

Speculation on my part but this may lead to some testing as BB says to ensure loaded hulls are as concentric as possible and slug centered in the hull. I am thinking a ribbed slug that is large enough to make the hull a tight fit when chambered. The ribs should collapse to bore diameter reasonably easily. That or brass hulls so there is no question the hull and slug are centered. If tipping damage still occurs then it is lack of support during the jump through the forcing cone.

Something else that I really hadn't thought about much before is crimp quality not so much for ensuring good burn but more in that if the crimp unrolls a bit unevenly that could cause tipping of the slug as it leaves the hull. I am thinking that maybe some uncrimped hulls could be loaded and tested for comparison. Some form of binder will likely be needed to provide some resistance at ignition... maybe wax/beeswax. Again, maybe brass hulls are the way to go and use a crimp with bore size slug. Or maybe use fold crimps. As long as the crimp is consistent and opens evenly life should be good.

Just kinda thinking out load here. I see an issue that I think needs solving... or at least I want an answer.

Cap'n Morgan ~ it sounds like you are thinking something like the old AQ slugs. They were more like a bore diameter round ball with flat bottom attached to a helically finned plastic wad. I bought a box for testing and was very impressed with the accuracy. BPI says the new Thug Slugs are the AQ replacement but I haven't tried those yet. They are quite different design and do not have helical ribs on the plastic wad.

I'll be interested to see your latest development, it sounds interesting and very doable. Are you thinking commercial sales or just another challenge for you? I like the idea for sure.

Longbow

[uncle dino]

I am very curious to see what you are working on cap'n. D

[uncle dino]

Well I got a chance to test .. Plain plastic jacket did ok, but not as well as plastic jacketed base wad slug.. Shot these out of my ush.. 2 3/4 cheddite hull. 34 gr. Longshot, bpgs seal, brush wad topped of with a 1/8 felt, slug, roll crimp..was kind of nasty out so I didn't dig out the chrono..
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My media was frozen so I was unable to recover the slugs, going to have to wait for a good thaw..d