The science (or lack thereof) of wad column building???

[cpileri]

Is there any science behind the building of a wad column? I figure there are a few knowns: the gas seal goes over the powder. OK.
The slug gets a hard card to have a firm base. OK.
But after that, does the order of cork or felt or fiber or hard card/ nitro card matter?
Example: see the wad column in the picture
82679

i need all this for proper height in the shell, that much is a given.
But would it matter if they were all cork beyond the x12x over powder and nitrocard under slug?
With steel powder, cork and felt are recommended to avoid pressure spikes. Does it matter where in the wad column they are?
I am thinking about the wave front of the expanding and burning powder/ gas first shoving then slamming into the various resistances that wavefront would encounter.
Does the whole wad column begin to move as a unit quickly enough that wad component order really doesnt matter?
It doesnt make sense that that would be so, or else the felt/ corks couldnt attemuate the pressure spike.
Anyway, any help appreciated.
C-

[Cerberus62]

My Lyman 3rd Edition has a number of built up loads, I will look to see if there's any pattern to the order they go in.

Ballistic Products has a tech sheet on card and fiber loads. If you don't have it I can send a copy, just PM your email address.

[cpileri]

82689Actually, I do have that pamphlet. Thanks though, very kind of you.

As i was reading it, I noticed that they mostly use similar wads; i.e. alot of card wads stacked to required height. No real, "science" to it, except to mention that the fiber wads dont significantly change pressure.

OK, so i can use that. Put a 3" load into a 3.5" hull and add 1/2-inch of fiber wads and pressure should be OK.

But reading carefully alot of their other load data, (see this post:
http://castboolits.gunloads.com/showthread.php?212513-Load-development-analysis-and-question-progressive-increases-of-Longshot ),
I noticed that their use of multiple X12X or X20X wads DEFINITELY increased pressure and decreased velocity. Seems liek the best bang-for-buck is to use only 1 XnX obturator. Ok, i can use that too.

Trying to compile a list of guidelines for the reasoned approach to wad column building.

Considering the "wave theory of burning propellant gasses", we knwo that a bore obstruction is a bad thing- unless you want to blow up your gun. So somewhere between the chamber and the muzzle, its bad to encounter an area of increased resistance. I imagine that the faster the burn rate of the powder, and shotgun powders are all pretty fast, the closer to the chamber is the peak of the pressure curve; and thus having an area of increased resistance in that spot would be most deleterious. Of course, closer to the chamber, the metal is thicker; so maybe its no problem even if it occurs.

So i am imagining a wave of pressure building up rapidly from zero before ignition to maximum...where? still in the hull? down the bore somewhat? I guess it depends. Then I imaging that my wad column starts to move as the initial portion of the powder is consumed, and as progressive burning continues, the subsequent areas of the wad column move and finally the projectile. So...

If i give the column some felt ro cork wads, this presents a relatively lower resistance to being moved then , and here is where the main question lies, if I put a hard card wad or something does that equate to an obstruction of some kind?

Then again, the biggest object to get moving is the PROJECTILE; which virtually always is the last thing that the wave has to push against. SO maybe my ultra-complicaed wad column building is not necessary as long as a few basic guidelines are followed. So far, this guidelines include:
1. use one obturator over the powder
2. give the slug a hard base underneath it, and
3. use cushions (cork,felt, etc) for slower powders to avoid pressure spikes (but so far, the question remains as to where to put them in the stack, if that matters at all)

Just as an example, consider this wad column (picture up top). All this is the correct height, but does it matter if I put a HCW in between the felt wads, or should i put the felt near the obturator? or can Ijust dump them in there any old way?

Still learning!
C-

[SuperBlazingSabots]

Good morning Elite Musketeer Cpileri, I just checked that I still have 2 cents left so you being a Elite I do not mind sharing it with you.

1. Tight fitting OP wad, if loose fitting add a 1 inch square of plain paper on powder first.
2. .170" stronger, harder, dark nitro card.
3. You can use your 1/2 felt here.
4. .125 nitro card.
5. 1/2" cork wad tho I do not touch them personally.
6..125 nitro card.
7. 1/4 white felt wad.
8. .170" stronger, harder, dark nitro card.
9. Your slug.

Its like making a sandwich, using nitro cards like bread on the outside and every thing else in between!
If you make your sandwich too thick its hard to manage, similarly its better not to let things get out of hands and stick with 3 inch for extra hull space, I'm already out of my last 2 cents.

Best regards,
Ajay
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-Elite Group of Slug Shooter's
We all, who take slug loading seriously are a dedicated family, who have taken it upon ourselves to perfect our tech. We experiment to find better techniques and share our knowledge.
Location: New Jersey. USA / Frankfort, W.Germany / London, UK
-Elite Group of Slug Shooter's
We all, who take slug loading seriously are a dedicated family, who have taken it upon ourselves to perfect our tech. We experiment to find better techniques and share our knowledge.

[hubel458]

Which is why I like to use more of the slower powders, less wads needed.
Keep it simple like the accutip and our sabot loads, Just a seal, white felt,
and our sabot. The sabot has tough enough bottom it, don't need a card
under it. Cards are a help under hollowbase slugs.

As far as being a science, it is more art than science it seems at times.
Many like to use less of a faster powder to save money and use extra wads
of some kind to take up space ..So lets compare, my slow powder loads, say we get 80 loads per
pound that is about 30 cents of powder. Fast powder loads get twice as many per pound
so that is 15 cents for powder. With fast powder you add couple extra wads and card
cost 2-4 cents each. so what is really gained for saving a dime. More problems
and less velocity in comparison......Ed

[longbow]

This isn't very scientific but so far I have found that a hard card wad column works best for me:

- gas seal over powder
- hard card wads and/or nitro card wads to take up space
- nitro card wad under slug
- slug

If loading for round ball, I find that a scoop of COW on top of the last nitro card wad provides a nice seat for the ball. Not necessary with a flat based slug.

I've tried a variety of fiber wads, cushion leg wads, fillers of various types and got best accuracy using bore size balls and slugs with a solid wad column under the slug/ball. The more solid the wad column the better accuracy I got.

YMMV but that's what works for me.

Longbow

[cpileri]

Thats all good info! I also got from a guy on sgw to use the thicker wads closer to the bottom. General consensus so far seems to be consistent w my few posted rules above, and that all the cards and especially the fiber wads dont change pressure much.
If one wants to simplify the wad column, then space needs to be taken up by something else: use bulkier powders.
Caveat: although during development the 'middle' of the wad column may not matter much from a pressure standpoint, be ready to switch to different components, harder cards per longbow) to maximize accuracy.
C-

[cpileri]

Here's a tidbit i found on handload forum, by Turbo in april 2012, specifically referring to substituting slug for shot in 410 bore, but mentions the wad/airspace so i thought it belonged here:

"Since the 410-bore doesn't normally have hardly any "crush" in its wad set-up with most loads you can use a very simple wad-column consisting of just hard nitro cards stacked between the powder and the base of the slug. If you load without any wad column at all and leave all that extra air space that the plastic shell lead shot loads that you "borrowed" the load data from don't have then it will change the dynamics of the load and the load data won't be right and you will have to futz with it and adjust the charge to get it to work right (which can be done of course) but using some kind of a wadding column or filler to take up the space such that everything is compressed and held tight and there isn't any extra powder space in the resulting cartridge makes loading by weight with "donor" load data from lead shot loads applicable with a minimal amount of adjustment."



C-

[littlejack]

For may own information.
Is the "felt" wad used for the cushioning effect, the same as the crush section of a plastic wad? This would be to prevent deformation of the shot upon firing, and also as a secondary effect, promote "less" felt recoil?
I am going to use the plastic seal "opw" from a plastic wad, remove the cushion/crush section of the wad, and replace it with a fiber wad, to bring the shot cup & slug up to the proper height to crimp.
I do not have any felt wads, and need to know if these are necessary for reducing pressure in the load, or is it safe to build a sabot/slug load without the felt wad?
The reason I am doing this, is that the plastic wad/sabot/slug combination was poorly inaccurate.
Ed said to try this combination to give the slug a more solid base, and to where the slug would leave the muzzle straight, not cocked.

All help is very much appreciated.
Regards
Jack

[cpileri]

Jack,
I got info from Mr. Hubel as well, so maybe this is something either you've considered and rejected, or else cant use for whatever reason (crimp height, etc). But,
The felt and cork do act as shock absorbers and reduce somewhat the perceived recoil, but mainly act to avoid pressure spikes from faster burning powders.
Depending on the details of your load, it may well be perfectly safe to build a slug load without any cusion. And you do want a nice solid base (hard card wad or wad cup base) placed right under the slug to give a solid platform for its launch.

I was in fact reading your 750gr/69-cal slug thread, and I really hoped it would work. i was going to suggest paper patching it up to bore (groove, if rifled) diameter. See this thread:

http://castboolits.gunloads.com/showthread.php?214295-Can-you-get-in-troubel-over-patching

I'm still learnign as well. But if you can come up w another way to load heavy slugs, it will help us all.

C-

[hubel458]

Any cushioning is helpful to moderate peak pressures with
all powders, moreso with faster powders, and slower like 4759 needs
less cushioning for that purpose. It is easier just to buy BPI
seals and you get better quality seals, than ones cut off of wadcups
and the white felt cushions BPI has crushes down perfectly straight..
If base of whatever cup your using is weak, not our sabot though,
use hard card under it and then felts under that then
the over powder seal.Ed

[cpileri]

Guess I got THAT backwards!
Thanks,Ed.
C-

[dverna]

Perceived recoil - be really careful with throwing these terms around. Everyone "knows" that some slower powders shoot "softer" than some of the "faster" powders - right????? Well maybe not.

A few years ago a man named Neil Winston (he was president of the ATA and has done a lot of "debunking" of old wives tales surrounding shotgun shooting and loads) challenged a number of shooters to determine which loads were loaded with a "soft" recoiling powder and loads with a fast powder. These were "blind" tests and loads were intermixed so shooters could not tell what load they were testing.

Using these different powders, the loads were tailored to provide the same velocity with the same components.

A number of shooters did the test and not one could tell the difference in recoil within statistical tolerances.

There is a "placebo" effect that enters into our perception of how things are. If you believe recoil will be less - you will convince yourself that is true. The worst thing you can use to "justify" an opinion is "common sense". Bear in mind that the firing event (from ignition to exit from the barrel) lasts for microseconds. What happens over the 1/2" in a wad column is inconsequential.

Recoil pads work because the rearward travel of the gun takes place over tenths of second and the human body can discern differences that take tenths of a second. The human body cannot sense the difference between 2 or 6 microseconds.

Build your wad column to give the load performance and/or crimp you desire. If you want less recoil from your loads there are only two ways to to that. Reduce velocity and/or reduce payload.

Don Verna

[littlejack]

Thank you all for your input.
I DO believe that the main reason for the cushion/crush section of the plastic wad and/or the felt wad, is to cushion the abrupt forward thrust of the payload of shot. The shot would be deformed "more" without this cushion, and cause the shot pattern to spread more quickly, and have voids IN the pattern.

I also believe that this cushion effect does not have any positive effect on the slug base, but, will have a definite negative effect if the cup base is pushed into the hollow base of a slug. This does, and has happened to my slug loads without the use of the appropriate nitro card wads between the bottom of the cup, and the base of the slug. Also, if the cushion section of the plastic wad compresses off center upon firing, will push the slug cocked as it leaves the muzzle. I have picked up fired plastic wads that have the seal section NOT in line with the cup, which in my opinion WOULD most definitely cock the slug as it leaves the muzzle.
Regards
Jack

[cpileri]

.
not one could tell the difference in recoil within statistical tolerances.


You know, that's true. i once did my own little experiment like that. Calculated loads, no chronograph so make of this whatever you will, but calculated to be same shot weight and velocity w different powders in same gun. I coudlnt tell one bit of difference. My single example isn't statistically significant, but I am a believer nonetheless.

C-

[bikerbeans]

cp,

FWIW, another member and myself have been loading fullbore slugs exclusively with gas seals, 1/8" nitro cards and a slug. We are currently roll crimping but have also used a fold crimp. In the 12ga, I am using Turbos 600 grain .73" hollow base slugs and the gun (H&R Ultra Slug - LITE) will shoot 4" or better 3 shot groups @ 100 yards. My best load is with 44g of Blue Dot and the recoil is stiff. The other member is using a 700 grain fullbore solid base slug (custom Accurate mold) with 40g of Blue Dot. His accuracy out of his H&R Ultra Slug Hunter is better than mine.

We have both loaded fullbore 1oz slugs for the 20ga using only a gas seal, 1/8" nitro cards and a fullbore slug. Once again roll crimping and fold crimps have been used. Load development for my 20ga (H&R 20ga Tracker II, cutdown to 18.5") is still on going. Wasted a lot of slugs and time with first a bad scope and then a stripped scope rail screw hole.


BB

[OnHoPr]

Also, if the cushion section of the plastic wad compresses off center upon firing, will push the slug cocked as it leaves the muzzle. I have picked up fired plastic wads that have the seal section NOT in line with the cup, which in my opinion WOULD most definitely cock the slug as it leaves the muzzle.
Regards
Jack

I agree with that theory. I believe the powder that is put in first can sometimes/most of the time if just dumped into the hull to start the load will be non-level which theoretically could cause or enhance this problem. I did a test with Rex III, H6, Longshot, 4756, 800x, herco, steel, and green dot just dumping into one of the clear hulls from the scale pan and all the powders lay canted in the hull. Herco laid the most even. If you were to use the x12x GS with its ringed construction, this would trap powder unevenly in the hull possibly helping to create the canted wad column with more powder on one side of the charge than the other to create a cant in the wad column all the way to the exit of the barrel. Taking a dowel rod and patting down the powder level is one of my steps to help prevent this phenomenon, in theory anyways. I also tried to start using dome style gas seals to hopefully keep the ignition pressure centered to help prevent this.

[hubel458]

I always tamp powder level when loading slugs.
And a lot of wadcups used for slugs need cards to strengthen
bottom as they aren't as thick and tough as most
discarding sabots. Now the CSD 20ga ones worked ok without cards with minie bullets in them for me with slower powder..Ed

[cpileri]

See, this thread is more interesting than I first thought.

Bikerbeans, where are you getting the full bore 20ga slugs? Im interested! would eliminate this wad-fitting prob i've had.

of course, the wad column will still be important. ;)

C-

[bikerbeans]

C-

Two sources for the 20ga fullbores, Turbo has them and my friend has a 20ga mold, from Accurate. These are for rifled barrels only, I am sure your know that but I like to repeat it for others. PM me your address and I will mail you some to play with.

BB

[littlejack]

OK fellas, I changed my mode of attack.
I have some 3/8" Alcan fiber filler wads to work with.
Rather than use the standard shotcup (in my case, BPI's HCD 18) I dissected it in to two parts. I removed the gas/powder seal from the base of the wad, trimming away all that held it onto the cushion section of the wad. Then I removed the cup portion from the cushion. The cup has a .065 thick base section.
Now to load.
I use my Mec loader to drop the powder charge (38 grains of BlueDot). I jiggle the hull side to side to level the powder. I then push one of the gas/powder seals down to the powder charge. On top of the seal, I seated the Alcan 3/8" fiber filler wad. I then seated the HCD 18 cup with a .070 nitro wad in the bottom, and the .677 slug on top of the nitro wad. The seal, fiber wad, cup and .070 nitro wad are the same height as the HCD 18 wad with the nitro wad I originally used in my first loads. The big difference will be that the new loads will have no
cushion section to push the slug cocked when leaving the muzzle. These loads should have a good solid base to push the slug down the bore and out the muzzle. After all were pushed into the hull, I compressed everything with the mec, and then fold crimped.
I did notice when using the 3/8" fiber filler, that there was a small amount of compression provided with this wad.
I am wanting to get to the range to try these new loads out. It will be a few days though, there is a big storm coming through.
If these loads look promising (accurate) I will call BPI, and order some of there gas seals.
Jack

[longbow]

Not sure if I missed it or not but regardless of perceived recoil which I won't bother with, there is the issue of increased pressure due to reduced volume if a cushion leg wad is replaced with a solid wad column. That cushion leg collapses as soon as pressure starts to rise so increases combustion chamber volume and reducing pressure.

I do not have pressure test equipment so cannot cite details or pressures but from what I have read and observed, this can have a significant effect with fast powders and less effect with slow powders.

Maybe someone with pressure testing equipment can prove or disprove that but I would be careful about replacing a cushion leg wad with a solid wad column if you are using fast powders at same powder charge as with cushion leg wad.

Longbow

[littlejack]

Longbow:
I just read your post after posting mine. This makes very good sense to me. My loads are a little under max for a heavier slug than I am shooting.
I may load a couple of rounds with a lighter powder charge to shoot first, and check for pressure signs.
Jack

[cpileri]

PM sent.


C-

Two sources for the 20ga fullbores, Turbo has them and my friend has a 20ga mold, from Accurate. These are for rifled barrels only, I am sure your know that but I like to repeat it for others. PM me your address and I will mail you some to play with.

BB

[cpileri]

Speaking of wads, i was looking at the wads attached to a bunch of BPI slugs, including the new Thug slug line. Pic:

83034

Right in front is an 880gr truncated cone. Forget that one, it just photobombed the pic.

Left (red) is a 1&3/8oz Thunderbolt DGS (guilandi) slug, then one on its side so you can see the concavity in the base of the wad, then the slug which has a hollow base and a little nubbin of lead protruding a bit, then the wad alone. Not alot of cushion effect on these attached wads.

Middle (dark blue) is the 1&1/8oz 12ga THUG Slug, a new one from BPI. Much cheaper than the DGS at abt 50Cents each. again, one on side and wad alone, then slug w hollow base and essentially no protrusion within the hollow slug base. Notice the thin nubbin at the slug-end of the wad. Its very thin. Will see how it looks after slug is fired. I suspect it will deform when fired though it may be hard to tell since the projectile will hit a dirt/rock berm before I can collect it.

Right (light blue) is the 7/8oz 20ga THUG as assembled, then on side for base displaying purposes, then the wad alone (no nub), then the hollow base of the slug itself.

The THUGS have more cushion/crush allowable in the wad design, seems to me.

Will see how they shoot.

C-

[hubel458]

Even though removing collapsible plastic cushion will raise peak
pressures,if comparing same weight of fast powder, it
is still better to have a more solid wag column of wads and cards
and go with more of a slower powder. Good advice to go with slower
powders. Saving dime per load on powders trying to do little amounts of fast
powders don't mean much if stuff is tore up, and you can't hit
broad side of a hog/deer...Ed

[cpileri]

Thanks, Ed.
I typed some load data, here:

http://castboolits.gunloads.com/showthread.php?212873-Preparation-for-next-SuperBlazing-Hubel-etc-test-having-issues&p=2408265&viewfull=1#post2408265

and none of these powders look very slow, shotgun-speaking; but I am not the best at determining burn rate (i know, there are charts). but I was wondering if "we" would do something with the slugs, using slower powders and different wad columns.
Would there be any benefit to filling the cavity in the slug w epoxy, then hard cards under it- to prevent pushing thru the slug base?
Or even using the factory wad but supporting the base w a smaller card like Ajay does?
C-

[hubel458]

When I mention slow powders I mean 4759, Steel and on down
to Blue Dot, in the chart, in relation to 20-16-12ga loading.
A thin card in wadcup would work if cup isn't strong enough
like Ajay does, but there is possibility that right slower powder
it may not need it.Ed

[cpileri]

Found some old info from James ad Dixie regarding wads:\

Let's talk about filler wads in general. Those that have studied original works by W.W. Greener, and others, have to be impressed with some of the patterns of those days...and with no plastic wads, sleeves. or whatever.
Also if one studies chamber specs, you will find the European gun makers were very slow to make longer forcing cones indeed. This is becuse other parts of the world were/are still using cut wad columns indeed! In order for cut wads to seal well. there needs to be a short forcing cone. This allows the shot to be entire in the barrel before the seal in the hull is broken and makes for a short distance before the wads enter the shotgun's bore.
Now...there was word put out then (as well as now) that either the overshot wad or the filler wads were blowing do-nut patterns...indeed?
What was happening was cheap hard/heavy waxed wads were blowing into the base of the shot. Even Greener found that! The use of lightweight pure cork wads stopped that. And..it still works today! A good rule of thumb is...for shot charges you must use a soft light wad column and for a slug load you should use a hard wad column...period! The use of flour, grits, buffer, or what ever as afiller can cause a lots of sidewall pressure (create a packed plug) and run pressure right through the ceiling!
Another problem is the use of too thin nitro cards...we have found that the .250" (1/4") nitro we have Circle Fly to cut for Dixie are ideal indeed. Recovered .250" nitros show no evidence of blowby/burnout and when used in rifled barrels...show the rifling marks.
On another hand...the use of pure cork as a filler in large volume straight centerfire hulls...do not show any oressure problems. And..do not tell me that they burn up...they just do not!
Today...some of the finest custom long range shotshells..are loaded with a BPI X12X overpowder wads, .250" niteos, and pure cork filler wads along with a Teflon sleeve/buffer....fact, not speculation.
However...cut wads just do not work well in extra long forcing cones...where one piece plastic wads are best.

[Carryacolt]

Cpileri,
Excellent info on the wads. I grew up loading the Alcan wads and the hard waxed filler wads.

Forcing cone?? I understand the reason for them in the SHOT gun, but why are they in the dedicated SLUG gun? Would it not reduce the variables that effects accuracy if it was not there, just the chamber to the bore without any force cone at all?

[cpileri]

Opinions seem to be split, from what i have read. but alot of well-respected slug shooters seem to think that NO forcing cone, just a chamber shoulder like a rifle, would be best for a dedicated slug gun.
C-

[Carryacolt]

That is my thoughts and the #1 item on my fun "bucket list" - a new barrel without the cone

[cpileri]

More from old posts by James Gates (Dixie SLugs):

"There is no doubt in my mind that the BPI X12X may be the best over-powder wad for sealing, both regular and over-bore barrels, on the market today. I have recovered other OP wads shot in the Browning BPS's .740" barrel that had the sealing ends turned forward, but never an X12X. In regular barrels the "Obtutator" wads work well also, but my favorite in 12 ga is still the X12X. The sizes are as followed: X12X @ .272"x.734" and the "Obturator"@ .247"x .725"
Since we test our loads in the .740" barrels as well as the standard .729"/.730" barrels, we use nothing except the X12X wads. The variation shot to shot shows a reduction when using the X12X.....which means the seal is tight and no blowby "

and

" 6) And last.....tests prove that a stacked wad column using over powder wads like Ballistic Products "X12X" and "Obturator", light wool or Styro filler wads, and a shot sleeve (teflon or sprayed with Ms Moly), plus a rolled crimp.....gave better patterns and uniform velocity than one piece wads!
"

[hubel458]

I built my first 12ga FH with long brass case with a rifle type
freebore. had to do it with lathe tools. Pain in the neck.
Getting those big reamers built that way costs almost300 bucks.
To much money and I used regular 9 degree forcing cone 12ga reamers
for the rest. In shooting I couldn't see much difference
A 9 degree cone is about .900" long, and tapers into rifling fine.
and sabots/slugs with wads, etc are longer than that so that
isn't the source of any great leakage.. With plastic cases and 12ga
chambers being built loose fit the cases expanding are the source
of leakage. So use biggest and tightest seal and white felt
which squishes out to minimize leaks.Hard cards only if sabot
needs protecting. These are what works fot slower powder loads
where case has more powder and you don't need
a huge wad column.Ed

[cpileri]

all great info!

[Greg5278]

Carl, can you post a few pics of my slugs on the 760 minie ball Thread. Preferably the 770TC design, perhaps whatever else you might have pics of. I don't know how to post pics right now.
Thanks,
Greg

[cpileri]

Sure. i'll do it tomorrow if I can't do it tonight.
I can point to some links though, and then tomorrow I will line up one of each and snap a pic and post it.
C-