First off let me cuss you for even bringin up the 410 slug reloading.
I have been for a long long time been lookin testing assembling combonations for the 410 slug myself.
I have seen where others have sucessfully shot a 385 gr cast slug BUT IT WASNT IN OUR NORMAL 410 SHOTGUN BUT RATHER IN A SPECIAL 500 DOLLAR PLUS BARREL FOR AN ENCORE OR TC.
So its not safe in todays modern guns we are more than likely refering to here.
Ok that said i too have done some UNPROFESIONAL TESTING MYSELF and ran into some interesting facts that all should be aware of and check out with there loadings ect.
Ok ill post the factory specs of the 410 shotgun for a non back bored chamber but will also inform you that if you have a back bored chamber the choke specs again change but bigger change not smaller so if anyone wanted to use this info they can as ill be talking about a older style H&R Topper Model 158 with a 410 full choke NON BACK BORED CHAMBER and it has tighter tolerances so a back bored chamber would be ok just a tad more sloppy per the tighter choke of a NON back Bored Chamber.
Ok i wouldnt at this point worry about if you had a bored or non bored chamber as really the ACTUAL CHOKES DIAMETER MEASURED WILL BE THE IMPORTANT ITEM HERE.
Ok the link posted below shows bored and non bored chamber specs for all shotgun gauges so others could follow this post and use the other specs as a quide.
When you click on the link take notice of the non back bored chamber specs for a 410 modified and the 410 full and the 410 extra full choke measurements.
Ok now heres an issue everyone needs to know if reloading the 410 with slugs.
I have in my possesion a H&R 410 barrel marked modified choke which should measure .402 diameter but IT IN FACT MEASURES .390 WHICH IS EXTRA FULL.
So check your chokes to be sure as we are now loading a solid slug which WILL NOT flow through a choke sorta like fluid as shot can move rearward ect to pass through a choke much easier than a solid slug can.
So now we can load per the chokes tolerance for a safer load knowing the choke being involved now.
Ok the link i promised.
Sorry members daughters after me bout going somewhere but ill be back and edit this post with more info that should help .
Ok im back the girls here wanted to go to the flea markets at the lakes and boy im glad i did.
Found a 7ft fishin rod for 5 bucks and got a box of 50ct 38 super auto remington factory loads for 10 dollars and berkley strike walleye fish attractant for 1 dollar so im happy.
Alright so lets pickup where i left off.
I disassembled a factory 2.5 inch remington deer slug and heres the info on the slug i found.
The slug weighed 96.4 grains and measured .480 inches long and was exaclty .400 inches in diameter. (Remington lists it on the 410 slug box as 1/5 ounce)
The remington slug is soft lead and is the forester slug design with hollow base to the nose almost and does have the rifling on it.
Now if anyone here knows what the federal 1 ounce slug looks like being hollow base that federal called the F127 load then you know what the remington 410 slug looks like just in 410 size = cute little rascal ill tell you that.
Next under that slug was shot buffering that filled the base of the slug down to the wadding and the buffering weighed 16.5 grains as an amount.
Any one here seen or used the BPI shot buffering will know what it looks like for the buffering.
Then the card bd wad disc was measuring at .402 inch diameter and .147 inches thick.
This card was not the flet type wad but actualy a cery hard card bd card that is many times called the nitro card.
Under that was the UNKNOWN POWDER TYPE that weighed 12.8 grains.
Powder was flake design and is a bit larger in size and lighter gray colored than unique as an example - So unique was black colored and smaller than the UNKNOWN light gray and larger flake
powder chg found in the rem factory load.
POINT BEING I DONT KNOW WHAT THE ACTUAL POWDER IS IN THE REM SLUG LOADING.
Overall length of the factory roll crimped 410 2.5 inch slug load measures 2.275 inches long roll crimped and unfired which after firing the roll crimp would now be most likely around 2.5 inches but didnt measure a fired case.
Ok so i figured this much info to most likely be safe to use in attempting to load a safe round for measurement specs per the slug and case length.
Keep in mind that the .400 soft lead foster style rem slug would smush down safely through a fixed choke per being thin wall hollow and soft where as a coppr pistol or even rifle slug WILL NOT AND THIS APPLIES TO CAST SOLID SLUGS AS WELL.
Dont need anyone blowing up guns gettin hurt ect. SO read that line again and make it stick in the grey matter in yer skull.
Now some here might want to avoid using the plastic type granulated buffering and it might be possible but consider these benefits first.
The buffering in rems factory load being what it is actualy would not only make any safe powder chg fit without trying to add cards which will just add to chamber pressures possibly going into outer orbit by stacking up say 1 inch of hard cards which i dont even have to try it to know your askin for troubles and your gonna get it in flesh and blood injuries SO DONT GET TOO CRAZY WITH USING CARDS TO TAKE UP THE EXTRA ROOM.
If you dont have buffering use cotton balls stuffed in place of it then.
Well the slug info comes into the recipe .
I used the normal remington 410 shotcup youd normaly use for lead shot rem SP410 wad but i cut the wad petals all the way to the bottom of the shot cup but not through into the powder piston cup on the wads bottom if it isnt already.
Rem wads i believe were already slit all the way but winchester 410 wads needed cut as i recall.
The reason is you do want the shot cup wad to act as a sabot for the slug and if the slug fits into the wad tightly and not slit all the way then the wad wont fall off soon enough and itll screw with the accuracy so slit them and let the wind catch the wad petals and pull the wad off the slug for best accuracy.
The slug that fits inside the 410 shotcup wad should measure .313 diameter and be 100 grains max or no less than 84 grains in wt.
Now you people casting your own slugs can get any of the following lyman molds and cast your own 410 slugs.
Lyman mold number 31355 makes a 85 grain round nose.
Lyman mold number 31357 makes a 100 grain flat point nose slug.
Lyman mold number 313226 makes a 93 grain round nose and in my opinion the second best slug for above due to the slugs longer diameter and not tapering off so fast .
Lyman mold number 313249 makes a 84 grain round nose slug and in my opinion would be third but still acceptable option .
Lyman mold number 313445 makes a 95 grain wad cutter but still a domed flat point that is in my opinion number one per slug design that would match up close in rems slug length ideas.
Now im going to tell you how i came to making a decision on the powder type and chg.
I chose Winchesterrs ww296 powder.
BUT WW296 POWDER CAN BE TOUCHY ON LOADING PER CRIMP TIGHTNESS AND LOOSENESS OF POWDER IF NOT WADDED CORECTLY WITH ENOUGH COMPRESSED LOAD PRESSURE ON THE LOADING AFTER ROLL CRIMPED AND CAN BE A REAL PROBLEM BOTH SQUIB LOADS AND DANGEROUS OVER PRESSURES BOTH .
However properly loaded ww296 per my books and computer load balistics program says ww296 will give me best speed versus lower lead unit pressure in the barrel upon firing thus increasing the safety factor of the loading.
So if you look in your reloading book at the 410 1/2 ounce powder chg and wad used youd see the chg i went with.
Now 1/2 ounce is equal to right at 215 to 220 grains and im loading under half that weight in a cast slug or copper jacketed slug of 100gr down to 84 gr so pay load will not be near the half ounce load for the power chg you decide to use per your reloading books info.
OK HERES WHAT YOUR PROBABLY WAITING FOR + THE LOAD BUT FIRST THE DISCLAIMER>
YOU READ RESEARCH ALL THIS INFO AND DECIDE FOR YOURSELF IF ITS SAFE PER YOUR MIND AS IM NOT A PROFESSIONAL BY ANY MEANS ON THE LOAD .
Just that i load it and works for me in my guns choke.
Im doing the plastic wad sabot type loading to be able to fire the load through any 410 choke up to the normal full choke diameter measured of .395 inches diameter to ensure safe slug pass through without the exposure of bursting a barrel due to choke restrictions but still be adeqaute for a modified choke even though a tad looser fit but youll still have a barrel if its a full choke.
Now i havent mentioned that i have and lyman makes them a .410 roll crimper that you simply put in a drill i use a drill press that will roll a 410 case down just like the factory rolled crimps.
They work great and the secret is warm up the roll crimp just a bit with a flame as after warming the steel crimper it softens the plastic case and really does a nice n neat roll crimp.
Or very slowly roll your first 3 cases very slowly and let the crimper heat up from friction on the case works good too.
Look on ebay and search 12ga 20ga 16ga 410 Lyman roll crimpers and you should find one id think so you know what it looks like or google search lymam roll crimper but be aware there was a clamp on the bench hand crank style thats usualy pretty high priced that DOES NOT WORK WELL WITH PLASTIC CASES AS IT WAS MADE FOR WAXED PAPER CASES WITH A SHOT CARD.
The drill style crimper works for plastic cases and should be around 20 dollars or so.
Winchester 2.5 inch case - This spent case was the folded crimp rather tha roll crimped but still roll crimps just fine.
CCI 109 primer - drops barrel pressure to 8,500 lup. = Or you can use WW209 primer but barrel pressure increases to 9,100 lup - But still well under the 12,000 lup for max pressure.
Be aware that if you use the 209 primer that even though a higher pressure curve that my balsitics program says the velocity in feet per second does not change much even worth mentioning.
Also my ballistics computer program is dated back to the late 80s when DOS 6.22 computers were the norm rather than todays windows - But i still trust it and it hasnt let me down yet.
Powder chg is Winchester 296 powder at 13.5 grains.
2ct .125 thick 410 nitro cards over powder chg and compressed at 20 foot pounds min to ensure tight pack on powder as its sensitive to loose squibs loads if not kept tightly compressed which later your roll crimp will help add and keep this tight pressure fit on the powder chg.
Add buffering till you fill the case just aprox a little over 1/2 inch from case being full - Or compressed cotton balls till same just dont get crazy of packing the crap out of it just tight enough that itll still compress a bit but not a bunch for slugs travel down bbl later.
Know a win wa410 wad with slits cut to bottom of wad but not through the wads flat inside of the shotcup.
Now i use the lyman cast slug mold number 313445 with soft lead but since its under sized per chokes needs it can be pure wheel wt lead but wont expand as well as soft lead.
This is my number one choice for loading as its 95 grains right at rems slug wt of 96. grains and is a wad cutter design which is a straight wall slug with a domed flat top which also comes as close as you can to rems foster slug in diameter but still not a hollow base.
Drop this slug into the now slit cut winchester waa410 shotcup and press firmly into the wad ensuring its seated flatly in the wad and trim the excess plastid wad petals off just to the slugs top most still 313 diameter mark leaving the domed flat point of the slug proturding above the now cut to length petals.
press this into the winchester case hull on top of the buffering or cotton ball stuffing and press down till you get enough case to roll down over the slug to get it to compress and hold the slug and internals tight for proper ignition of the powder as again powder needs to be tight packed at at least 20 foot pounds of pressure and thats for example tested after roll crimping that if you cant press the slug and wad further into the finished roll crimped round _ YOU GOT IT and thats all you need but dont go over bd buy using the drill press to over pressure the load while roll crimping eigther so roll crimp n check then if nore needed further roll crimp till you get it.
Now this sounds tricky but its not after you do it and experiment youll see its not and exact roll crimp legth by any means.
Im only trying to drive it into your mind what needs to be done and why and my explanation while in depth is only to get you to understand why ect.
So roll crimp till crimper wont easily roll crimp anymore and just check slugs tight in wad column with no movement down into case.
Now i didnt chrony the load but my once again old DOS 6.22 ballistics program says itll shoot the load right at aprox 1900 feet per second.
Now trajectory wise if this load is sighted in at 1/2 inch high at 50 yards the slug should by my program be minus 2 inches low at 100 yards or there abouts.
I didnt write down the foot pounds of energy at muzzle or 50yds or 100yards per my notes.
And i think its due to the cast slug that was used and if copper jacketed it might have given energy specs.
Now tht was with a winchester 410 case above.
With a remington 2.5 inch case same as above per info but with the fllowing components.
Winchester 209 primer only ! Or any 209 primer - NO 109 PRIMERS
Winchester 296 powder at 15.0 grains which will be aprox 9500 lead unit pressure and a bit faster at 1950 feet per second.
This one uses a Remington SP410 wadd slits cut if not already to bottom of cup with above cast slug lyman number 313445 as a 95gr wad cutter style slug wad petals trimmed as above and finished as above.
I didnt test load any federal cases as winchester 296 powder wasnt listed any where i could find info.
But if i was to want to do the federal 410 plastic case my info says IMR4227 at 15.5 grains using eigther a rem sp410 wad or a federal 410sc wad and a 209 primer would produce just a tad over 11000 lead unit pressure at the 1900 fps velocity = BUT TAKE NOTICE AS I DID = 12000 lead unit pressure is considered the safe max per my ballistics program for a 410 shotgun with full choke and your ALREADY AT 11000 lup.
NOW IN MY OPINION WE ARE SITTING TOO CLOSE TO THE CAMP FIRE HERE LEAVING US WIDE OPEN TO DISASTER.
Remember crimp pressures ect so id stay away from the federal case per the much higher pressure curves.
Its just not worth gettin hurt over .
PLEASE PEOPLE DO NOT USE THIS INFO AS A QUIDE PER CHANGES ECT FOR YOUR TESTING BUT RATHER INFO.