Adding a .460 oversot card to pan lubed 45-70 405 HB boolit affect pressure?

[bassin57]

Hi,
After shooting my trapdoor with SR4769 and 5744 I saw what looked like unburnt powder. Since I pan lube my hollow base boolit I try to clean out the bottom with a q tip and mineral spirits. I purchased .460 overshot wads (wad -460-b) from Track of the Wolf in hope of getting a more efficient burn and consistency. Will adding this wad cause a increase chamber pressure? Also whats a good method to insert the card without compressing the powder?
Bassin57

[Calamity Jake]

Do not use that card wad pressed down on the powder that creates an air space under the boolet when
the powder goes off the card wad will act like a piston and compress the air and could ring a chamber, use some kind of filler,
dacron or cream of wheat, something that fills the air space.
Do a search for fillers on this sight there is a lot of info.

[bhn22]

And yes, anything that decreases case volume will increase chamber pressure by an unpredictable amount. At best, you need to restart your load development from the beginning, or develop a new load with a different powder.

[runfiverun]

if nothing else is taken from this thread it should be NOT to put a card or wad of anything on top of the powder column that isn't also touching the base of the boolit.

I second the addition of Dacron, it will hold the powder in place and trick the powder into thinking it is in a slightly smaller case size.
in effect it's like adding more powder, so to keep your pressure and velocity the same, you need to reduce the load.

[bassin57]

Hi,
Thank you for the replies. I have only started shooting my TD with my cast 405 grn HB boolit using suggested starting powder loads with 5744 and SR 4759 which I understand is position sensitive. I will like to make loads with and without dacron filler to see if there is a difference in accuracy. Since I am loading at starting load powder specs; 5744 26,0 grn -( range is 26-29)grns and and SR 4759 24.0grn (24-26.5 grains) in my lyman manual would a 10% decrease in powder charge for the dacron filled case be enough? From what I have read on this web site dacron seems to be the most used filler. Thank you for you help and recommendations,
Bassin57

[John Allen]

Bassin, why not go to blackpowder instead. It is what the gun originally used and a hoot more fun.

[Larry Gibson]

I use the dacron filler extensively with both those powders under that same bullet and others in my own 45-70 TDs. Start 1 gr lower with each powder.

I also suggest a read of the sticky on the use of fillers paying particular attention to post #4.

Larry Gibson

[bassin57]

Hi,
Thank you for your replies. Now I have a starting point and what to use as a proper filler. I chose 5744 and 4759 since I can use these powders in my other rifles, I also use RX7 and 4198 for jacket loads that I have been making for some time. But making your own cast boolits for your loads is a lot of fun. There is a lot of material to learn vs loading jacketed bullets. I have recently purchased cast molds for most of the firearms I shoot. I have loaded commercial cast bullets for my hand guns for sometime but that will change once I get my alloy data completed. I realize that will take some time, but in the end it will be worth it.

bassin57

[44man]

On top of all that, with a HB, even if the wad touches the boolit and powder, it will be driven into the base hollow.