Next steps to increase accuracy ?

[Distant Thunder]

"Every mold will have a sweet spot - once you find it forget everything else and just cast till you tired of it"

Absolutely agree with that. Once I'm casting good bullets I don't like to stop until I just can't go anymore!

[Lead pot]

I'm a messy caster

Getting the mould temp up is the first step getting consistent bullet weight.
When the mould is up to proper temperature it will take about a 3 or 4 slow count for the sprue to gray out but the bullet in the mould is still the consistency of hard butter and when the sprue is cut you will get a build up of alloy between the plate and the top of the mould.
If you get frosting under the sprue puddle your alloy is getting to hot, if the bullet shows frosting your way over on the temp.

Now that you have a good Lyman Ladle and your mould is up to proper temp twist your mould with the plate on it's side and mate the ladle spigot to the hole tight enough that the alloy won't leak out and start the pour and slowly rotate the mould so the plate is now on top. When you see the alloy level stop dropping or a little alloy seep out under the spigot the cavity is full.
Now raise the ladle off the plate a couple inches with the mould over the lead pot and let it empty on the hole. What this does is vibrate the alloy compacting it filling all voids and give you a sharp base edge. Sort of like the cement workers do running a vibrator down the cement forms when they pour a foundation or hit the side of the forms with a hammer filling voids.

Starting the pour with the plate on it's side and a slow pour gives the air a chance to escape and it also stops a swirl that makes a gray blemish on one side of the ogive. You will get a clean bright bullet drop from the mould doing this.

I cast with a snug sprue plate, one that will not swing on it's own it needs me to push it open. The air will still bleed out and it will cast a more consistent bullet weight. A loose plate will raise when filling the mould and also raise the bullet weight and let some flash over on the base when the alloy and mould gets to hot.

After a few casting sessions you will see great consistency in your bullets and you will see 3/10 gr variance from the light to heaviest bullet. Not more then 5/10 differences in weight.

Another point casting a grooved bullet, or a slick for that matter. If you open the mould blocks to soon, before the alloy sets, you will pull the bullet out of round no matter how perfect the mould cavity is. This gets amplified with the harder the alloy is the longer it takes for the bullet to set.
Also the more tin or tin/antimony the lower the casting temperature needs to be. If you see frosting show up turn the temp down. A little under the cut sprue is ok, you just don't want it to look like galvanizing...........Kurt

[Distant Thunder]

Kurt,

That's some good info and really explains some things I've wondered about but never thought all the way thru myself. Thanks for posting it.

DT

[kokomokid]

Kurt, how long are you waiting after the puddle freezes before you cut the sprue?

[Lead pot]

In actual time I can't say, maybe three- four seconds sometimes longer. Depends on the alloy I'm using. If I'm casting with 1/20 it will take a little longer then when I cast using tin/antimony/lead it gets to be a feeling. I don't make loading or casting a speed thing, I cast 50 or so and walk away from the pot and do something else for a while and return later. When I cut a sprue I pay attention to what the base of the bullet looks like. If it is shiny and turns gray I slow down. Some mould makers use a very large hole in the plate and when you cut the sprue to soon your also pulling the base away from the side of the mould because of the extra amount you are cutting so with that you have to give it more time to set. The Brooks moulds are just about right at .130" and even them I like the smaller hole plate of .100" if I can get the mould maker to make it.
My go to alloy I cast at around 700 degrees and the lead/tin 1/16 I cast around 720. like I said I watch the frosting and adjust the heat to that.
If you pay attention to the way the sprue sets you can tell right away if the bullet drops out light by seeing how deep the dimple shrinks. The way I cast I barely see a dimple form and if I do that bullet will drop out light and it will go back into the pot.

[Road_Clam]

Thanks Lead Pot for your casting tips, I copied them to a word doc for reference. I'll absolutely try your suggested method and let you know how things work out.

[flatsguide]

Lot of good info here. When I cast I count in my head. When I insert the dipper into the mold and roll the mold and dipper to the vertical I start the five second count in my head. At five I remove the dipper and make sure it leaves a puddle and not a starved sprue. Then when the sprue Metal so.idifies I do another five count and then open the mold with my gloved hand. I cast at 815 F and 99% are plus or minus .4 tenths grain.
Regards, Richard

[varsity07840]

I also agree with much of what has been said. Jack up that powder charge to fill the case. A very clean/dry bore between shots is super important when shooting PP if you want top accuracy.

Are you seating it very shallow, like 0.1" in the case?

How snugly (is that a word ?) does the patched bullet fit the bore? There should be some resistance upon chambering the round, i.e. you want to feel the bullet engaging the lands as it slides in. I've never had decent accuracy with poor fitting bullets. If necessary use a sizing die on the patched bullets. I run mine through a 0.451" Lee push through sizer.

Don I have shot 540gr ( 1.51" long ) Money bullets through a 1:18 twist .45-70 at 500m and although I don't think it's ideal, they did shoot quite well, definitely under 1.5 minutes of vertical dispersion so I don't think that will make for a 5-6 minute group at close range. But you are right of course that for serious work it wants to be shortened.

I have also own a rifle ( C. Sharps .45-2-7/8" ) that just doesn't shoot bore diameter patched bullets very well unless a lube cookie is used.

Chris.

.451 will not chamber in my Pedersoli.