Why boolit designs differ?

[EOD3]

Hi guys! I've been contemplating the "why" of various boolit designs. Some boolits have several like-sized narrow lube grooves, others have only one or two wide grooves or one wide and one narrow.

The reason behind the washboard design of the Lee Alox lubricated boolits is obvious but, other designs are a little more mysterious. Can anyone help me out with the "why" behind the various designs?

[fredj338]

Everyone thinks they can build a better mouse trap; bullets, cars, whatever. On shorter bearing surface bullets, I like one large lube groove. On longer bullets, two works fine.

[EOD3]

So, after all is said and done, it's all about bearing surface and lube distribution?

[Bret4207]

No, it's about someone having an idea of the perfect boolit design. Read Keiths "Sixguns" and of how many designs he went through. Read about Dr. Hudson and Mann and the experimenting they did. In the early Lyman years they'd cut anything a customer wanted and then catalog it. That's why we have so many ancient oddball designs. Same for jacketed. It was a progression of trying and experimenting till they found something that worked. We do the same things her with our GB's. Someone gets an idea and tries it and maybe it's great or maybe it's a a flop. We've had both.

[Bass Ackward]

Everything has a center of balance that works in partnership with ballistic coefficient (which with cast usually is quite low) that determines actual performance. The higher the ballistic coefficient, the less important CofB is, if your bullet can hold bore center to achieve it.

The location of that center of balance (not always in the center) tells you the velocity range and twist rate you will need to stabilize it and at what velocity range it will destabilize.

As an example, if you have a rearward weighted design, (semiwadcutter) it will require less velocity and twist rate to stabilize than a more forward weighted design such as an olgival. It will also DE-stabilize at a higher velocity (over rotate) than a more forward weighted design.

That's why most cast bullets are semiwadcutter designs or bore rides for rifles which is just a semi-wadcutter with a large enough nose diameter that it hits the rifling. Bullets designed for low velocity flight.

Why people don't understand more of the basics to this is the tendency to describe the effect with math instead of diction. Even old timers said to shoot the heaviest bullets per caliber. That means the longest and highest ballistic coefficient designs. These designs also had the longest bearing area to hold bore center so that they launched well. And at normal cast distances, bullet design for purposes of flight, aren't needed if you do some better than a wadcutter.

It's all in the launch. So the elaborate differences you see in designs are the brain child of certain individuals thoughts and maybe purposes for that slug.

Take a wide base band. That is to move CofB back and make a design easier to stabilize. An advantage for a short barreled gun, a slow twisted gun, or just better low(er) velocity use.

Take a single WIDE grease groove. For the same weight bullet, a wider groove extends bearing length and puts wider bands at each end of it. A wider band is a stronger band at a set hardness. Where would this be advantageous? How about a launching system where the bullet exits supporting steel and is forced to align and reach across a gap until it can be centered and supported again? Like a revolver maybe? :grin: It also has the advantage of carrying more lube where it also might be needed in a revolver. Is that needed by a rifleman? Maybe if he has a long throat, but semi wadcutters offer feeding issues in some cases. Balance of use.

So everything you see has a purpose, just does the intended purpose add enough in advantages to overcome the weaknesses / short comings that it is going to create in another area? Anybody can design a heavy bullet that will fly fairly well. (again to shoot the heaviest bullets per caliber) It is the shorter / lighter bullet that takes more knowledge. Also why hollow pointing makes such a HUGE accuracy difference across a wider velocity range along with air flow properties that simply work. People who don't understand design, tend to become twist rate theorists or simply go by a certain bullet weight for a velocity range.

And now that you understand how to break a design down, you can think of possible purposes for other things when you see a different design. Was a certain bullet designed for wide rifling? (S&W revolvers) Or narrow? (Ruger style) Rifle or handgun? (lower velocity or high) For a gun with poor or good alignment? If it has narrow bands and was designed for a Smith, then that bullet will need to be harder to work well for a Ruger style gun at the same velocity level. The more surface contact you have in excess of what you need, the more lube or better quality lube it will take to make something work. And it goes on and on.

Then maybe you can learn to understand WHAT the designer was trying to accomplish to solve "his" problem in order to launch it well or have it fly well at longer ranges or lower velocities. Why some designs become more generic but no one design works for everybody? (for people that don't have that problem) Etc, etc.

[John Boy]

BA ... A very nice overview. Can't add more that is relevant other than the specifics for the design of a bullet for it's intended purpose. But that would be going deep into the details that most folks don't understand anyway.

Ideal up until the time they were bought out by Lyman in the '70's produced moulds that worked based on your overview. Here are those moulds:
http://www.castpics.net/IdealandLymanMolds.pdf
And it is truly sad that Lyman cleaned out the warehouse when they bought Ideal: moulds with PROVEN accuracy and the corresponding schematics.
Here's one for the 38-55 that for a group buy, we had to draw the schematic FROM SCRATCH and provide the details to Lyman because they were void of any details for the bullet
http://i222.photobucket.com/albums/dd220/Meadowmucker/38-55/Final2_13_2009.jpg

Bret mentions Dr Edward Hudson ... here is one of his bullet designs that has superior accuracy, the 375300. There are only 2 existing known moulds for the bullet. One collector lent me his 375300 mould and I now have 25#'s of bullets :-D
Note the bearing surface design! It's balance point is also dead nuts on! Plus it's bullet stability calculation for a BPCR 1:18 barrel is again, dead nuts on. And with 42gr of FFg powder, takes Rams down at 500 meters. Thanks Doc Hudson!
http://i222.photobucket.com/albums/dd220/Meadowmucker/Bullets/Ideal375300.jpg

Since that time, there have been a few knowledgeable 'gun cranks' that have taken the basic principles of bullet design and have come up with improved bullets. Here's one designed by Dan Theodore ... the Mini Groove, for example. It is a proven 1000yd bullet and stable all the way from 100yds out to the 1000
http://i222.photobucket.com/albums/dd220/Meadowmucker/Bullets/Docs45-cal18-TMiniG5-groovetappered.jpg

[44man]

Bass, I finally did it, I have a boolit I made that will not group better then 2" at 50 from a revolver. I have not worked too much with loads yet though, it might come in.
I made this for the Marlin and it shoots better from the rifle then any I have tried so far. It does an inch at 50 and 3" at 100. That is the best this rifle ever did with a hunting load.
Why it will not shoot from a revolver, (Yet.) I don't know.
The boolit weighs 295 gr.

[Bass Ackward]

Just looking at it, I would say try slowing it down a little in the revolver or change to a slipperier lube.

[kirb]

john boy,

That 375300 is a great looking boolit what size is it dropping from the mold. Is it possible to get a mold cut for this boolit.

Kirb

[EOD3]

I should know by now that asking you guys a question is going to result in a headache :groner:

I appreciate the effort you guys put into this.

I think I know just enough to be dangerous now :???:

[John Boy]

Kirb, some 375300 numbers for you:
* as-cast weight of 312 grs with 1:20 alloy.
* 1.182 - Length
0.150 - Metplat
0.324 - Nose
Three front bands 0.367 and the two base bands 0.379
0.105 - Band 1 dia
0.102 - Band 2 dia
0.111 - Band 3 dia ... more bearing surface from the middle to the base
0.162 - Band 4 dia
0.162 - Base dia

Shaft Diameters measured at GG's
0.340 - GG1
0.342 - GG2
0.332 - GG3
0.332 - GG4

Is it possible to get a mold cut for this boolit.
It's possible with 2 conditions:
Step 1. Would Lou Sellman, the Lyman Distributor in Pittsburgh, want to front $1800 again like he had to when we did the group buy for the remake of the Ideal 375166?
Step 2. Would 85+ shooters subscribe to the Group Buy? Lou needed this number to cover the cost for 2 cherries/carry the extra moulds in inventory and Lyman needed this minimum number to cut the molds

If you want an Ideal 38-55 that just as accurately,
http://www.shilohrifle.com/forums/viewtopic.php?t=13911&highlight=375166
the remake of the Ideal 375166 might be had if Lou has any extras. Best to call him and find out. His contact info is

Order By Mail, Check or Money Order …
Price of the Mold - $75
Shipping - $10.00 plus $1.70 Insurance ($11.70)
Price of Top Punch - $8.50 (Optional)
Price of the Sizing Die - $19.95 (Optional
Send a letter with your shipping information and a check or money for your total purchase to:
Lou Sellman
2003 Ewings Mill Rd
Corapolis, PA 15108-3311

Order By Credit Card
Call Lou at (412) 299-0412

Lou Sellman email address … reloadersequipmentonline.com or customcastbullets@yahoo.com

[John Boy]

I think I know just enough to be dangerous now
EOD, you also have to add to the development of a good lead bullet, the 'cranks' going back to the middle 1800's that spent weeks tweaking a bullet design and in the aggregate, a library of books they all wrote on the subject BPCR shooting and bullets.

I'm a BPCR shooter. So original gunpowder and lead bullets go hand in hand along with good loading data. Personally, I have many of the 1800's books and have read all of them. Another modern day 'crank' is Paul Matthews and I have and read all of his books too. His tried and tested 'spitzer' bullet is the Lyman 457166. My reloads have shoot it to 1000yds with accuracy

[44man]

Just looking at it, I would say try slowing it down a little in the revolver or change to a slipperier lube.
OK. I just have not had the time to work revolver loads and just used what I use with all other boolits near the weight.
I was getting a lot of fliers from the Marlin until I got to 23 gr of 296, then groups rounded out. Have to smoke them out of the Marlin to get any spin. [smilie=1:
Bioman has a .44 Marlin with Micro Groove and his rifle groups much tighter then mine with the same boolit and less powder. So far it is out shooting the 265 RD by half.
For the first time I have extended the Marlin to 100 yards for deer.

[1Shirt]

Have always liked 44Mans replies. It is however my thought that as all firearms (rifles in particular) are female, and all like to be fed differently. No two women the same:roll:, no two rifles the same:roll:, and for sure no two bbls the same:twisted:. And then there is the single cav issue vs. the multi cav, and the itty bitty multi groovers vs. the big old lots of lube in one deep groove issue, and the beat goes on. Sure does keep us thinking however!
1Shirt!:coffeecom

[BAGTIC]

Hi guys! I've been contemplating the "why" of various boolit designs. Some boolits have several like-sized narrow lube grooves, others have only one or two wide grooves or one wide and one narrow.

The reason behind the washboard design of the Lee Alox lubricated boolits is obvious but, other designs are a little more mysterious. Can anyone help me out with the "why" behind the various designs?

Why are there so many different churchs?

[runfiverun]

my take on it
i plain look at the designs and see the same thing we are trying to accomplish.
iv'e got a short angle cut throat in one rifle.
my next one will not shoot the boolit the first likes.
hmmm.. it should, you'd think, they are fairly close in measurements.
but this one has the boolit sitting really far out of the case, and the angle of the leade seems different a little.
maybe something with an angled driving band here and this long nose just dont seem right it's really far away from the lands in this and this spot so i'll add some size here.
next thing you know the boolit you started with has four different different dimensions from the origional.