Looking for conical sizing advice

[ThreeCedars]

I recently purchased a spare 1:48 Investarms barrel in 54 cal, and would like to try out some conicals. My main barrel is a slow twist PRB barrel, so this will be my first experience shooting conicals. I am using pure soft lead.

I have my eye on an Accurate mold, but have questions about the band diameter in relation to the bore. It is an “I” bullet design with multiple grease grooves. For a snug fit, how many thousandths larger should I go with the OD of the driving bands? I’m sure there is a convention for balancing keeping the bullet secure on the powder, while keeping leading down, but still being accurate.

I know this is a can of worms, and I’ve read a good bit, but wanted to ask this question specifically.

I have some go/no go pin gauges on the way to help me get a precise measurement, but I think I’m right at 0.542” bore diameter.

Also, is it necessary to get a bullet sizing setup? I would love to cast my bullets and use them if possible, but I am open to sizing if it’s required. If that’s the case, I imagine I will start with a larger diameter mold and size down.

Not trying to make things too complicated, but definitely interested in having my ducks in a row prior to dropping the money on a nice mold.

Thanks I’m advance! I really appreciate the time and advice!

 

[Grenadier1758]

Does your conical bullet have a flat bottom or is there a cavity as is used in a Minie' ball?

If it is a flat bottom, this may be something like a T/C Maxi-Ball. If it is a Maxi-Ball, then there will be three diameters of the bands along the conical bullet. Tha band closest to the base should be slightly less than the land-to-land diameter of your barrel. The middle band should be 1 to two thousandths larger than the land-to-diameter of the barrel. These bands being very close to the land-to-land diameter will aid in aligning the conical bullet to the bore. Being soft lead, these bands will easily pass along as the bullet is started. The final band at the top should be nearly the groove diameter to provide a sort of stop to the gas cutting. Sizing such a conical bullet removes the advantages of the soft lead conforming to the lands and grooves of the barrel. The flat-bottomed conical bullets can perform well with fairly stout powder charges. The base band should be no greater than 0.541". The second band should be no greater than 0.544" and the top band should be no greater than 0.550" or the groove diameter.

If the conical bullet has a Minie' Ball type cavity in the base, then you will be relying on the skirt around the cavity to expand into the rifling to seal the bore and get the desired stabilization from the spin imparted by the twist. This type of bullet can be sized to 0.001 to 0.002" under the land-to-land diameter. The skirt will need less powder to expand the skirt into the grooves. Too much powder will destroy the skirt and accuracy.

Can we see a picture of the cavity in your Ideal mold?

 

[ThreeCedars]

Interesting - the one I’m looking at is a flat bottom mold, from what I understand the replacement people have been using since the Lyman plains in 54 has become scarce. The picture is attached.

Are muzzleloading conicals typically set up with the tapered diameter driving bands? I get the concept of the bullet being engraved upon loading, and I like the thought that it kind of forms to your barrel as long as it’s cast the right amount larger.

I think Accurate does let you define the diameters of each band too.

 

[ThreeCedars]

So I guess the real question is if the diameter of all of the contact points of the bullet are the same, what should the diameter be if the bore is 0.542”?

Is 0.002” oversized enough to keep the bullet firmly in place, or would you suggest more since I’m using soft lead?

 

[stikshooter]

I recently purchased a spare 1:48 Investarms barrel in 54 cal, and would like to try out some conicals. My main barrel is a slow twist PRB barrel, so this will be my first experience shooting conicals. I am using pure soft lead.

I have my eye on an Accurate mold, but have questions about the band diameter in relation to the bore. It is an “I” bullet design with multiple grease grooves. For a snug fit, how many thousandths larger should I go with the OD of the driving bands? I’m sure there is a convention for balancing keeping the bullet secure on the powder, while keeping leading down, but still being accurate.

I know this is a can of worms, and I’ve read a good bit, but wanted to ask this question specifically.

I have some go/no go pin gauges on the way to help me get a precise measurement, but I think I’m right at 0.542” bore diameter.

Also, is it necessary to get a bullet sizing setup? I would love to cast my bullets and use them if possible, but I am open to sizing if it’s required. If that’s the case, I imagine I will start with a larger diameter mold and size down.

Not trying to make things too complicated, but definitely interested in having my ducks in a row prior to dropping the money on a nice mold.

Thanks I’m advance! I really appreciate the time and advice!

I have the Eye bullet in 50 cal , mold is specified for pure and drops as cast .506 for me ,the 54 you could ask Tom at Accura in lead what it would be/Ed

 

[user 34300]

If the bore is .542 ask fo the base to be 0.542 +/- 0.001. Middle band 0.547? Top band a hair over groove. IF they are 0.012" deep, then 0.566" I'd be looking for a shorter bullet. I would make it a REAL or wadcutter type of profile. Streaming is not going to help trajectory enough to matter.

I made a super maxi mold once, it was to long and just keyholed.

Ask for advice from the mold maker. I had him make me a 41 cal real-maxi kind of mold for a 40 cal CF barrel on a ml pistol. The specs were mine. It came out to small. Accuracy was poor. He might have been able to give good advice.

Doesn't Lee make a REAL mold in 54 already? Lee Precision, Inc.. Black Powder REAL Bullet & Combo Molds

 

[ThreeCedars]

Okay I will call and talk to Tom - that’s a great idea. I also have questions about stabilization since it’s not super fast at 1:48.

This would be an elk bullet, so I really like the extra weight and big flat meplat over a REAL, but I’m also planning on testing out some TC Maxi balls to see how they do.

I suppose in my next post I should ask about people’s favorite heavy conicals in the 1:48 Investarms barrels.

Thanks guys! I really appreciate the input!

 

[harleysboss]

That "I" bullet shoots great in 1-48 twist. When you order it specify the pure lead. If you are sure about the .542 bore measurement, Order it at .542 and select the + tolerance. That way it will be cut to drop a bullet at .542 or just slightly (.543-44) larger. Should not need a sizer that way. If you want that bullet to really hug the bore then use 40-1 lead and size it to .543 for a .542 bore. It wont move off the powder. To save you a whole bunch of time, 80 grains of FFG (Swiss if you have it) 1 58 cal wool wad over the powder and finally the "I" bullet. A soft lube that still stays in the lube grooves and you should come back from the range with a big smile. You chose the right bullet! Many shooters on the modern muzzy forum shoot that exact bullet (mostly in 50 cal version) and the results are solid.

 

[ThreeCedars]

That’s excellent news - thank you! This is all
sounding really positive. And I’ve got the 58 cal wads ready to go!

 

[Relic shooter]

Your getting some good advice from forum members.
A few years ago I was having a mold made for an original percussion English big game sporting rifle with fast twist rifling with shallower depth rifling that would be ideal for a slug.
Utah had at the time I believe three mold makers listed online at that time & one had a chart with formulas to determine the recommended bullet design & length for your particular barrel specifications.
Maybe you can find them or one of the forum members can help you out.
Relic shooter

 

[stikshooter]

That "I" bullet shoots great in 1-48 twist. When you order it specify the pure lead. If you are sure about the .542 bore measurement, Order it at .542 and select the + tolerance. That way it will be cut to drop a bullet at .542 or just slightly (.543-44) larger. Should not need a sizer that way. If you want that bullet to really hug the bore then use 40-1 lead and size it to .543 for a .542 bore. It wont move off the powder. To save you a whole bunch of time, 80 grains of FFG (Swiss if you have it) 1 58 cal wool wad over the powder and finally the "I" bullet. A soft lube that still stays in the lube grooves and you should come back from the range with a big smile. You chose the right bullet! Many shooters on the modern muzzy forum shoot that exact bullet (mostly in 50 cal version) and the results are solid.

Worked so well I sold both the 50/54 Lyman Plains and got The eye bullet ,also grease them with Idaho Lewis
(secret lube)/Ed