duplex powder load w/ lyman 525 slug

[wmitty]

Long story short, this was not successful. I'd worked up a successful load using the 2-3/4" Federal clear plastic hull available from Ballistic Products using 40 gr. Blue Dot / Fed. 12S3 wad / Fed. primer/ Lyman 525 slug w/ knurled edges and hot glue in cavity. Decided to reduce the charge wt. of BD and replace the resulting decrease in volume with WC 860 purchased from Jeff Bartlett. A check of powder densities showed 40 grains of BD occupied the same volume as 60 grains of the 860. I reduced the charge of BD in 5 grain increments from 35 to 15 grains; loading 4 rounds at each reduction in charge wt.

Velocities in relation to charge wts as follows:

35.0 BD / 7.5 860 - 1387 f/s avg.

30.0 BD / 15.0 860 - 1293 f/s avg.

25.0 BD / 22.5 860 - 1185 f/s avg.

20.0 BD / 30.0 860 - 1069 f/s avg.

15.0 BD / 37.5 860 - 863 f/s avg. (two rounds only)

A small amount of unburned powder was found in the barrel after firing. The muzzle was bumped on a clean board and the unburned granules were a flake type powder; which puzzled me, as I had expected it to be the WC 860 which had not been consumed. No ball powder granules were found among the unburned powder particles. The reduction in velocities made me think the 860 was not igniting or was only partially igniting. I'd like to hear opinions from those who might enlighten me as to why the increase in overall powder charge didn't result in increased pressure/ velocity. The 40 gr load of BD was chrono'ed the previous weekend at 1507 fps. Again; I'd like to mention the firearn used was a Savage 212 bolt action with rifled tube. Accuracy decreased as overall charge weight increased; about 5" group at 50 yds with the 35/ 7.5 gr charge and two of the last four in the 15/ 37.5 missing the target completely; these being hangfires which the chrono did not pick up.

Any thoughts?

[runfiverun]

I'd look at the velocity's and the amount of blue-dot used.
they seem real linear.
and about the same as you'd expect from a faster powder without the filler. [860]
you might want to try putting a used/cheap sheet in front of the barrel and look for the unburned 860.
it might not be 'unburned' but was not able to burn quickly enough or with enough pressure to be effective to actually do any pushing of the projectile.

[wmitty]

rfr- I seen what you are saying; I guess I could repeat the test using a known inert filler of close to the same density as the 860 to see if velocity lines up with the reduced charge wt. I was hoping Ed Hubel might chime in on this.

[hubel458]

Did you check basecup expansion.

The reason the loads slowed down is because of increased amounts of a

really slow powder. Nothing bad is going on, what it did, is supposed to happen.

Now you need to use the 15 gr of starter and 40 gr of 860 and go up 5gr

at a time until basecups expand as much as what they did with 40gr of Blue dot.

and see what velocity is. We used 90 gr of 4759 in 3" plastic case and it is

way faster than 860, so I know the case can be packed full of 860 with 15gr

of blue dot starter under it. and get great speed. When case gets full

just use one seal, no filler wads.With slow powders cushion wads are

not needed to moderate peak pressuresl

In 3" RMC turned brass cases in NEFs , and Savage, with

15gr of Blue dot starter we have used 180 gr of those slower powders

like 860, 872, Hbmg, etc , work just fine. Ed

[wmitty]

Thanks for dropping in, Ed. I didn't check the basecups for expansion, but I will. I'll also get some gas seals from Ballistic Products to allow me to increase the powder charge; as the current 12S3 wad was at it's limit with the 40 grain charge of Blue Dot with this particular hull.

[Greg5278]

Why are You using Powder as Filler? Inert Fillers are much more predictable. Eventually Somebody is going to get Hurt with some of These Ideas. I'm all for pushing Limits, but using a Nitrocellulose substance as Filler is asking for trouble.

I'd try Hard Cards, Poly batting or a proper Wad. Federal Hulls have the most internal capacity in the .090" Version. Fiocchi Hulls are also good, but with a goo bit less Capacity.
Greg
AKA 12 Bore

[wmitty]

Greg5278

I am not trying to use the 860 as a filler. I have a large quantity of this powder which I'm interested in finding additional uses for besides duplex loads in rifle cartridges. When Ed mentioned increasing the quantity of 860 in order to obtain an increase in velocity; I decided to try and find the point where this takes place. The Savage 212 is a strong action and if I damage it, well, I'll let you guys know. I'm not recommending any of the loads I am using to anyone and I absolutely don't want anyone being injured. I understand that it's not possible to measure excessive chamber pressures in shotshells without lab equipment and I won't be using these loads in other shotguns.

[victorfox]

build a 4 winds and try this icspiriment from distance... i'd hate to learn a perfectly good gun was trashed....

[runfiverun]

he isn't using it as a filler he just doesn't have a good way to get enough resistance on top of it [the 860] for it to burn well just yet. [so it's acting more like a case filler than a powder]
using the blue-dot kicker should help get it going, but so far he hasn't hit the right combination.
I would think about maybe a faster powder for the kicker nothing radical but herco might be pretty good.
your moving the projectile away from the gas volume faster than the 860 is generating it.

[hubel458]

Do not use a faster powder for a starter, The starter is just that, and we
do not want any faster than what is necessary, as it will change the speed of
the regular load to fast, The Blue dot is just right.It also lays in best so powders
don't mix, as it is like a flake powder, stuff sets on it without mixing.
Can not use any starters that are ball powders, harder to ignite and may mix.

There is no way that he can blow up the gun with 860 and slower in a 3" case
with sabot and crimp shortening up the powder space.. We have used duplex loads
in plain old NEFs, other break actions. Those loads came about as guys went from our
BMG primed brass cases we built, to shotgun primed RMC brass cases and the 3.5' plastic and shotgun primers
needed help for all the slow rifle powders, Cases that held 2-3 times as much powder as 3" plastic, WE have used the slowest powders made with
blue dot starter just fine.Including super slow 20mm powders..Ed

[runfiverun]

herco is a flake powder it is a step ahead of blue-dot but isn't sensitive to temperature changes.
800-x is closer, steel closer yet.
the wad not being punched up is clearly an indication of too low a pressure rise, and that the blue-dot is not doing the job here.
it's either that or the crimp or projectile weight is not enough to hold things in place while the pressure is generated.

[hubel458]

Yes weight is a bit light, which is problem but you get the pressure up to burn the powder

cleaner by adding more powder, And if some of the starter doesn't burn

it is no harm. The object of these type of duplex loads

is higher speed while keeping PEAK pressures at magnum turkey load levels which is

what plastic cases can handle. In this process we get the extra speed by having larger amounts

of the slow powder do its work further down the barrel with a higher overall average

pressure level. But yet keep peak pressure at mag levels only, no more. And blue dot

did this the best with all the slow powders we tested. And both NEF and

Savage can operate a lot more pressure than what 12ga plastic cases hold,

The NEF nearly twice and Sav 3 times.

His last loads in the test with the 860 would be less than half the peak pressure

level of magnum 3.5" factory loads. If he has lots of that powder like I do, add it

in and burn it up. Maybe with relatively light slug he can get 16-1700 in 3" case .

We got 1800 with duplexing with 605gr in 3.5" plastic cases.In NEF.Ed

[runfiverun]

right,,, I understand what you got.
but his lighter weight is [I think] the problem here.
so initiating the timing event of the second powder might need to be tweaked to a sooner point in the sequence to get it to burn and help push the projectile.

this is something I have had to work out in higher velocity cast rifle loads before, so that's where I'm coming from.
it was look and see type load work-ups like you had to do with the heavier projectile.

[bikerbeans]

I found that unique wasn't fast enough to ignite RL26 in my diesel tractor starting shotshells. These are the ultimate light loads, no payload. I found that BP, pyrodex and triple 7 would ignite the RL26. I agree with r5r that a faster priming charge would help. I would also be very careful using a fast starting powder, you may cause the slow powder to burn too fast and create a overpressure "event" in your shotgun.

BB

[wmitty]

I'm reading the comments being made very carefully, and I was concerned the weight of the Lyman slug and wad wasn't enough to allow adequate pressure to properly burn the 860. The .735 roundball is roughly 10 % heavier, but I have no idea as to whether higher pressures would be generated by using it with a gas seal vs using the Lyman 525 inside the Fed. 12S3. I will continue to add 860 using the 15 grains of Blue Dot and post my results. I have found the Claybuster knockoff of the Win WAA12R has a shorter leg section than the 12S3 ( .5" vs .83") so I'll gain some powder volume while still using the Fed. 2-3/4" hull. I realize swapping components is a bad idea without working up from initial loadings; so I will have to ponder the best way to use the shorter leg wad with the reduced powder charges.

[elvas]

If slug weight is the problem, a new core pin could be made for the Lyman mold to produce a solid base slug of about 600-620grains depending on alloy used. Since the slug will be used in a fully rifled barrel there wouldn't be any stability problems I suppose.

[hubel458]

Are these FED hulls the ones where the inside riser the primer

goes in, is up from the filler around it.. If so some of the blue dot

starter will be below the path of the fire from the primer. May account

for unburnt powder. All duplex loads I tested were in REM hulls that have filler

around the primer riser, up level or little dish effect so that the starter powder is up

and more lays above the primer. Ed

[Greg5278]

W860 is way too slow for the 525 Lyman, unless you are really going to push it to 12GFH Levels.
Unkess You are going for super High velocities over 1600 FPS I'd stick with Powders no slower than IMR 4759, 4227, N110, or Lil Gun.

W860 was intended to burn well at higher than standard Shotgun Pressure. You'd probably be better suited with a Full Bore Slug. How do the Recovered Wads look? Are They dimpled with partially burnt or unburnt Powder?

Greg
AKA 12 Bore

[runfiverun]

something I didn't see mentioned but might be a big help is the primer.
I don't know what your using now but a hotter primer could swing the timing forward enough to help.

[wmitty]

Ed - the hull does have a recessed area around the outside of the primer. The hulls are the new Federal 2-3/4" primed hulls currently on sale at Ballistic Products. I do have the 2-3/4" Rem. hull which is basically flush across the bottom of the hull.

rfr - Which brand/ type of shotshell primer is considered to have the greatest brisance? I'll try to obtain some and see if it makes a noticeable difference.

Greg- I found one wad I'd picked up and could find no markings on the interior of the gas seal from impacting powder granules; is this a sign of pressures being too low?