Cast Boolit Designs and Theory Questions

[Uncle Grinch]

Although I have been reloading for close to 35 years and casting for almost 20, I feel more and more ignorant after reading some of the posts that this forum offers up. We obviously have some very intelligent and experienced users here.

I would like for someone to give me a basic primer in cast bullet design, ie... , what do you look for in a cast boolit that makes it accurate, other than the mechanics of casting, that is. I see terms like Loverin, Postell, bore-riding and others, but I don't really know the difference in them.

I have Lyman's Cast Bullet Manual and can see the physical differences, but what are the dynamics that makes one different or better than the other?

[sundog]

Mike, while I do not espouse to all the theories that Veral Smith puts forward in his book, it is a good read, and provides alot upon which to ponder. Might be worth getting or borrowing a copy. Maybe someone on here can help with exact address.

Here's a neat reference in case you have not seen it before:
http://www.lasc.us/CastBulletNotes.htm

btw, thanks for supporting the NRA. I am a Patron Member, life since mid 70s. They may not be everything everyone wants, but they are the best game in town! sundog

[Bass Ackward]

Although I have been reloading for close to 35 years and casting for almost 20, I feel more and more ignorant after reading some of the posts that this forum offers up. We obviously have some very intelligent and experienced users here.

I would like for someone to give me a basic primer in cast bullet design, ie... , what do you look for in a cast boolit that makes it accurate, other than the mechanics of casting, that is. I see terms like Loverin, Postell, bore-riding and others, but I don't really know the difference in them.

I have Lyman's Cast Bullet Manual and can see the physical differences, but what are the dynamics that makes one different or better than the other?


Bls,

It depends on whether you are talking handgun or rifle. The rules of flight are pretty fixed. Small meplats result in more aerodynamic bullets. It is easier to stabilize a bullet where the weight is shifted to the rear. So a semi wadcutter for a handgun, allows a longer bearing area for the same weight bullet as comparred to other designs. Because pistol bullets have more coincidence to encounter the sound barrier, a bullet that can be aerodynamic and survive the transition through this barrier, means a more successful and accurate bullet design, unless you increase pistol bullet weights.

The negatives are that a semiwadcutter with it's sharp shoulder cleans the bore ahead of the bullet. This removes any blackbore or lube left from the previous bullet. Thus a smi wadcutter design must carry enough lube not to lead a bore. An olgival design will use this same lube that is already in the bore and thus requires less lube to prevent leading.

In rifles, a semi wadcutter is called a bore ride. Because of the longer nose, it (the nose) is sized to be supported by the lands and thus a bore ride. A Loverin was designed by a man named Loverin that is usually tapered and has multiple grease grooves required when lubes were of lesser quality. LBT has it's own charactistics which is mainly an olgival design with a wide front drive band to produce more contact with rifling.

Make this simple, If a cast bullet fits, it will shoot. How aerodynamically you make it will determine how FAR it shoots accurately. This goes for both handgun or rifle.

[Buckshot]

..............IMHO there are 2 cast boolit rifle designs. The bore rider and the Loverin. Each has peculiarities. The bore rider 'may' be harder to shoot accurately because you have 2 surfaces that MUST fit in order for it to work. If the nose of a bore rider doesn't have a large enough OD to at least touch the lands, guidance suffers.

I believe bore riders do their best work engraved. If not then the entire nose is kind of just hanging out there. It's possible for the nose to enter the leade crooked. While I also like to see Loverins engraved, it is a design where you may size to the throat which will provide initial guidance. A bore rider may have such a short body length that it is all in the case.

That brings up the only real negative I see in the Loverin. As it is all body except for a small portion forming the ogive/nose, it may require deeper seating in modern sporting rifles. Normally these do not have the long throat and leade of military pieces.

For my money the Loverin is easiest to get shooting well right off the bat. Assuming it casts large enough (which ALL cast boolits have to do) you can ignore the land diameter. They work very well in most old 30-40 Krags with loose barrel dimensions, and also foreign 'Fat 30's' where lands can run up to .304". Try to fire a 314299 with a .301" nose OD in a barrel like that and see what happens.

Probably 95% of my rifle shooting is with milsurps of vastly differing ages and barrel dimensions, even amongst like rifles. I have 5 Argentines and all 5 vary from each other in bore and groove dimensions although 2 (1891's) are tight and do well with the same bore rider slug (314299). The others require Loverins as their lands are .302 or .303 and my copy of that Lyman barely produces a .302" nose.

If all a person shot was modern production rifles then they may never even consider a Loverin boolit. For the average cast lead shooter with a modern rifle, say a 30-06, they could probably do very well with one mould like the Ly 311291, which is kind of a benchmark design. But that would be so boring :-)

Without all the details involved, assuming the shooter has a cast boolt that fits I don't believe a bore rider or Loverin has much over the other at normal ranges commonly shot.

..................Buckshot

[Old Jim]

I know very little aboout the subject but Dan from Mountain Molds has told me he likes to see 60 to 75% of a pistol bullet in contact with the barrel. He also told me that a 70-75% meplat seems to be the best of both worlds. Small enough to be aerodynamic and large enough to be effective.
Pitiful when you can say all you know about a subject in three sentences.

[44man]

Can you say VOODOO? I have made two moulds of the same boolit, same weight, same diameter, same nose but just a slight change in grease grooves or drive bands and one shoots like crazy and the other is a slug even though the total drive area and grease groove area is exactly the same but in different places.
Same with the semi wadcutters, one will shoot and another will not no matter what is done. The main reason I got away from the Keith style. The LBT style truncated cone seems much more forgiving.
A mystery that will never be solved! No one can say this boolit or that boolit will shoot the best out of your gun. You are stuck with trying a bunch to see what works for you. You are going to be dissappointed more often then not, but somewhere out there is one that will work. Welcome to the mould collectors site.

[LET-CA]

Pitiful when you can say all you know about a subject in three sentences. You've got me beat by two and one half!