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

[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:



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-