45 70 Round ball and Bullseye

[Spokerider]

Ive been reading about using bullseye and round balls in a 45 70 until my head is spinning......

Seems most use Unique powder in this application........wondering why, and if unique holds advantages over bullseye.

I'm thinking of starting the load at 3.0gr of bullseye, no fillers, with the ball lightly roll crimped just below the equator.

How high can I go with the bullseye and still have a safe TD load in my contender? 7 or 8 grains?

Is there a risk of detonation doing this? Would it be better to push the ball [ a pure lead .490 sized to .459 lubed with LLA ] all of the way into the case right on the powder?

Thanks.

The prospect of detonation is spooky.

[Larry Gibson]

Bullseye works a lot better than Unique, no risk of "detonation" and no filler needed.

You can seat the ball down on the powder, or close to it in fire formed cases. I've tried it both ways and found little difference so I seat at the case mouth. Start at 2 gr and work up to 8 (if you want to but accuracy will go south before you get there) so I suggest to 6 gr. The psi in minimal and all even a double charge (of a normal load of 6 gr or less) will do is to deposit a bit of lead in the bore. My standard load for my TDs using a 275 gr cast bullet is 8 gr Bullseye for 1050 fps. A RB weighs a lot less.

Larry Gibson

[TCLouis]

If ya start with a 0.490" round ball it weighs 177 grains.

[Spokerider]

Thank you guys, that helps.

I'm not looking to max the velocity......just want to try to keep the POI close to what the sights are at now, whatever that velocity turns out to be.

[Spokerider]

Larry, did you notice any difference with the Bullseye / RB ballistics if the gun were tipped muzzle up, or muzzle down before firing?

[Larry Gibson]

Yes, there can be an induced difference in ballistics. However, in working up the load the key is to find that psi point where the very easily ignited Bulleye burns efficiently regardless of "powder positioning" during normal loading and gun handling. That point is where accuracy will be best with RBs. Bullseye does ignite quite easily, even in that big case, so it doesn't take much Bullseye to hit that point. Bullseye is really about the best powder for such loads.

At the ranges the RBs will be used shooting straight up or down induces more variables from a change in zero and the realationsship between the line of sight and angle of departure than will any change in velocities from powder positioning. The only way to really know what the zero change will be from shooting at extreme angles (+/- 75 degree angle) up or down will be to shoot up or down at those angles at a target placed at the expected or max distance to be shot at.

Larry Gibson

[Spokerider]

Thanks for the explanation Larry.
I'll keep the info in mind when choosing the load.