Thoughts on boolit design

[44man]

I was casting today and of course the boring job makes the mind wander. Got to thinking about accuracy and my boolits. I tried to list what works and what doesn't.
The worst for accuracy is the semi wad cutter.
Next worst will be a boolit with one large grease groove. I have better accuracy with 2 or 3 grooves and even the Lee TL with Felix lube shoots great.
Then a strange thing is that my most accurate boolits for the .475 and .500 both have a very short base bands of about .075" to .080". Now some will say I get base expansion to obturate but not with my hard boolits. I also shoot .4765" from those size throats and if my boolits age, they expand to .478" and it makes no difference. I do not believe in any boolit expansion. I also do not believe in weight forward or weight rear. I feel match to twist is where it is at and a hollow point will not cure anything or be more accurate.
A flat nose is supposed to go unstable past 50 yards but I find they are stable to as far as they can be shot. I shoot them to 500 meters but am sure they will do 1000 yards or more.
Just how much junk science is passed around?

[BABore]

Well,,,,,,,,,,,,,,,,,,,,,,,, everybody's entitled to their own opinion. No matter how narrow minded or hard headed they may be.[smilie=l:

[kir_kenix]

I'm not so sure about SWC being the least accurate boolit design. Then again, I guess that depends on the distance. If your criteria is 500 meter plinking, then of course the SWC may not be considered accurate.
I think band length does play a big part in accuracy. I've never done any in depth analaysis on base band length vs accuracy, but I imagine there is a "sweet spot" in each caliber (probably a ratio of length to caliber).
I also whole heartedly agree that flat nose boolits are good well beyond 50 yards. Havn't done alot of 500-100 yard shooting (with handguns anyway, rifles are another story) to say one way or the other.

[Blammer]

I too have found that my least accurate bullet at 100yds is a SWC, my most accurate is a Trun cone and Round flat point coming in second.

this for 44 mag caliber.

[targetshootr]

As long as I live I'll never get enough range time to know exactly what works and what doesn't. If I can shoot 3" groups offhand at 25 yds I'm good. I recently shot a glock for the first time and couldn't keep it on typing paper at that distance and that taught me all I'll ever need to know about glocks.

[leftiye]

The one thing that comes to mind is that a tangent ogive shoulder (round nose shoulder) helps center the boolit in a revolter's barrel and reduce deformation thereby. So, in my opinion, if there is any band there it should be no deeper than the rifling.

I can't document any proof, but when I see narrow base or other bands shoot ewll, I consider it a fluke (lucky). This is based solely on the perception of how easily these narrow bands can be deformed. Hard lead is not proof at all against gas cutting, and only marginally resistant to deformation, though it does improve the probabilities. On the other side, a very wide band makes me nervous in terms of friction/leading/and lubrication.

I have no problem with the issue of balance being neither forward or to the rear, but very long unsupported noses are flirting with insanity. Balance should be in the middle of the bearing portion of the boolit.

Bruce, how about sum opinion? Ye're entitled to yours too, and they might even be valued by summa us'ns.

[Bass Ackward]

1. The worst for accuracy is the semi wad cutter.
2. I also do not believe in weight forward or weight rear.
3. I feel match to twist is where it is at.
4. A hollow point will not cure anything or be more accurate.
5. A flat nose is supposed to go unstable past 50 yards but I find they are stable to as far as they can be shot.



Facts are facts until they aren't. So let's look at these shall we.

1. Over 100 years of history has had cast bullets in a semi wadcutter configuration otherwise known as a bore riders for rifles. Are we smarter than those in the past? They had truncated cones and LBT style bullets in the 1800s and changed to the semiwadcutter. But they didn't have pop bottle cartridges, multiple slow powder selections, and 10" barrels on a handgun to make them work.

2 and 5. All craft designed for supersonic flight through air have the weight centrally balanced or to the rear such as rockets, missiles, or planes. None have a wide meplat nose that I can find. Bullets experience the same reactions to air that planes do, just that planes have occupants to observe and record what is really happening. We can only guess with bullets as we have to spin them to stay true.

3. 44 Special and 44 Mag share the same basic case design and twist rate. Which caliber has the reputation for target accuracy for 100 years? (shooting light semi wadcutters by the way) :grin:

4. Hollow points hold virtually every record for target accuracy at virtually every distance in the modern era. You forgot to slam bevel bases otherwise known a boat tails as the longer range records are obtained with them too.

5. If twist rate is everything and weight distribution means nothing, then a bullet should be equally accurate forward or backward at the same velocity level. All semi wadcutters therefore should be JUST as accurate as any olgival. Please don't tell me that you have you been shooting them the wrong way all this time? :grin:


I am going to try to keep an open mind. My cue is going to be when rifles and boat tail hollow points are scrapped in preference for revolvers and wide meplat, PB slugs for 1000 yard competitions. I'll be the first one to say I was wrong.

[Lloyd Smale]

i kind of go with bass. I dont nessiarily think any design is better then another. If i did have to pick one that is the easiest to work with id take a lfn though. I know youve had good luck with wfns but ive not and i know alot of others that agree with me. Ive even seen them filmed in flight and they just dont stay stable at long range. Now im talking LONG range. As to swcs heres my opinion. Yes they can be hard to deal with. in my opinion the reason isnt nessiarily the design. There are just so many differnt designs of swcs that you almost cant lump them in one big bunch. Ive got guns that shoot a certain swc like a rifle but will spray another design. Ive got swcs that shoot well in about every gun and some that are just duds. I dont see that same thing as drasticaly with wfns and lfns. Most wfns shoot real well at short range and that especially goes with loads on the hot side. Most lfns shoot well in every gun and at about any speed. To lump any bullet into a dud catagory just isnt fair. Theres to many variations in bullet size alloy speed and chamber pressure that can be tried to get a bullet to shoot. Even the molds i consider duds can be made to shoot if you work at it in a particular gun long enough. Thats the reason you get arguments when you badmouth a bullet. Someone else might have gotten lucky and found the combination that bullet like the first time in his particular gun and will claim its a great bullet. As to flight caracteristics the same almost applys. Most lfns just fly well. Ask me why and i have no reason. A swc is in the middle. Some seem to fly and some just dont. Wfns are the toughest. Im not doubting 44man that you can get them to shoot. But it takes finding some kind of sweet spot and not everyone has the knowlege to find it or the time and patients to find it. What makes on bullet say a swc be a better bullet then another. I dont know and wish i did. Ive seen bullets that looked ALMOST identical shoot side by side and one will shoot like a rifle and one will spray like a shotgun at long range. Ive even seen this happen with bullets that weve had group buys done on that were suppose to be copys of a good design. Change just one minor thing and the bullet falls on its face. I like swcs and especially keith bullets as im a bit old school and just think thats what a handgun bullet should look like but if i was on a buget and could only buy one mold for a gun it would be a lfn design hands down. As to hollow points again im with bass. Ive seen them shoot better and ive seen then shoot worse and i dont believe its a majic answer that will gurantee a bullet will be more accurate.

[1Shirt]

I am not much of a handgunner, but shoot a reasonable amount one handed. For what I do shoot, sure do like a nice clean semi wadcutter hole in the paper. Shoot 357 & 44 rifle, and the swc shoot well in them out to 100, and still cut nice clean holes. In the 44's, my Marlin shoots the RN 240 lee very well, but sure punches a ragged looking hole. Looks wise in handgun ctgs, think that the Kieth style, and the Ranch Dog are the best in 357 & 44.

That said, for rifle in other than 357 & 44, have found from my experiance that all styles can shoot well. Have also found, and tend to agree with Beagle that regardless of stylle of rifle blt, in a HP vs. a non HP of the same stiyle(mold), accuracy seems to improve some. This in my experiance seems to be true of the HP's that I shoot in my 30's, and in my 22's.

Just my thoughts and opinions.
1Shirt!:coffee:

[runfiverun]

hmm boolit preferences.
i favor rnfp's with a single lube groove and a fairly good sized rear drive band.
for most everything.
some of my guns don't agree, like my 44 levergun it dotes on the 429421 so much so that i modified the carrier to make it feed flawlessly..
it may do better with a 44 copy of something like the 452664 but i haven't run across one yet.
i gave up trying to figure out why one gun likes a particular design long ago, and just try the molds i have on hand.
the best one becomes clear in a matter of just a few shots, i might investigate the matter further by tweaking that design a bit but most often not i just load up the winner and shoot it.

[44man]

All of you are correct and I just relate what I have found with my guns. Bass is also right and I used hollow points in my varmint rifles but I don't think they are as important in a revolver.
Yes, most of my boolits are accidents too. I have nothing on paper and when I cut a cherry on the lathe, I just guess. To have goofy looking boolits that I can shoot 1" targets at 100 yards with is most likely 100% luck.
I don't profess to know what I am doing most times.
My original 429421 and 358156 both shot good but I have never duplicated them.
Luck is a larger factor then most of you think! 8-)
I will not argue with Babore either because he does make some of the best boolits I ever shot---except for the semi wad cutters, I still have not shot the groups I like with them.
Anyway, I will never cut a mold for myself for a Semi wad cutter. They are just too tricky.
I made two molds for the .475 that are almost the same and one is so accurate it is scary but the other was a waste of time. Whatever change I made to the GG's and drive bands did not work.
Then with my super scientific method, I cut a .500 JRH boolit that shot into one hole at 50 and Whitworth and I have both shot into the same holes at 100 yards.
I might be able to explain it after I beat myself with my rubber mallet for a while! :bigsmyl2::bigsmyl2:

[Bass Ackward]

I find bullet design easier to understand:

1. if your shooting platforms and calibers are diverse. (You learn more from poor guns than great guns.)

2. if you shoot all over the velocity spectrum. (Higher velocity work just helped me immensely.)

3. if you stick with a single design until it performs to show you that it is possible.

It's MORE important to understand why something failed. And most cast shooters won't take this time. Without this persistence or varied experiences, you tend to get narrow opinions on why stuff works or fails.

You spend more time and thought on failures than successes. In this case, rough seas do make you a better sailor.

[45 2.1]

Well,,,,,,,,,,,,,,,,,,,,,,,, everybody's entitled to their own opinion. No matter how narrow minded or hard headed they may be.[smilie=l:

+1 on this opinion. You would be suprised just how well a SWC can shoot if you do it right (i.e. a whole lot better than your doing now).

[turbo1889]

In my experience there are very few boolit designs that are in and of themselves bad designs and either cannot be made to shoot well or are very difficult to make shoot well. How a particular design is loaded and what it is loaded for and shot in are significantly larger factors. A design that shoots terrible loaded a particular way or used in a particular gun may shoot great if loaded differently or used in a different gun. The potential variances that influence that difference being quite numerous on both the load and the gun.

The one major exception I would note would be that of designs intended to be used in smooth bores such as shotgun slugs where projectile balance and aerodynamic pressure forces directly and massively affect the boolits stability in flight and thus its accuracy.

On the other hand it is true that design does make a difference, however, the exceptional accuracy of the Ranch Dog boolits which as I understand it are designs that are mathematically balanced using certain principles of ballistic and aerodynamic engineering being one example.

[MtGun44]

I sure have had a lot of good accy with SWCs most with single lube grooves.

Bill

[geargnasher]

My experiences have shown that SWCs don't shoot well in guns that lock up like Fort Knox, where an ogival boolit with no shoulder or even a TC will. In guns with about the right amount of cylinder play it doesn't really seem to matter, they shoot all designs about the same.

Hollow points can make a huge difference in accuracy at shorter ranges (50 yards or less) all else being close to equal. Long distance I can't really tell. I think reducing the central mass tends to make up for low velocity and slow twist rate in revolvers.

Two smaller lube grooves has always had an accuracy edge over one big one in my experience, but that may or may not have anything to do with the groove design, maybe it was other attributes of the dual-groove designs that gave them the edge.

Just my dos centavos.

Gear

[turbo1889]

The theory I have been operating on with designing my own cast boolits (the various quality lathe bore or multi-tool milled "one off" mold craftsman ~ they get a lot of money out of me) has been "squeeze fit tight nose" or in other words do a chamber cast and then make the mid-nose (from the mouth of the case to the base of the tip of the tip) of the boolit fit the throat and beginning of the rifling like a hand in glove fit with the dimensions taken from the chamber cast and the mold cutters tolerance being on the plus side thus making the finished boolit squeeze tight in the throat. Then I cap the top of that off with whatever tip of the tip profile I think will serve my needs best, usually that is some sort of TC shape. Then I strap a good foundation of sharp angle lube grooves and body bands to fit the length of the case neck to the bottom capped off with a nice thick PB bottom drive band on the very bottom of that if at all possible or for the few calibers where it is really need such as 9mm use a gas check shank instead of the usual PB bottom drive band.

So far that has worked very well for me. Basically what I’m saying is that in my mind the fit of the nose of the boolit in the guns throat is second in importance only to having a fat enough boolit in the first place. Which might explain why the original poster has such a negative view of SWC boolits; at least for revolvers most people seat SWC boolits way, way too deep inside the case. Most of the time for me such boolits are hanging as far out the mouth of the case as possible without the nose interfering with free rotation of the cylinder when loaded. In fact, one of my more recent boolit designs has a whole lot of bearing length outside the case and is absolutely perfect for my revolvers when properly sized for each gun requiring firm pressure from the thump to seat the finished cartridges in the revolver cylinder since the nose of the boolit is a press fit in the cylinder throats.

http://farm5.static.flickr.com/4148/5094831259_5c105b3ecd_m.jpg (http://www.flickr.com/photos/54455625@N04/5094831259/) http://farm5.static.flickr.com/4150/5066225503_fe8f2754bf_m.jpg (http://www.flickr.com/photos/54455625@N04/5066225503/) http://farm5.static.flickr.com/4146/5066836760_021caa562e_m.jpg (http://www.flickr.com/photos/54455625@N04/5066836760/)

The significantly greater bearing length my boolit has in the cylinders throat compared to any conventional boolit design and how the slightly oversize micro groove nose makes for a tight hand-in-glove press fit in the throat of the gun compared to either a RN jacketed load or a cast lead SWC boolit are clearly visible. So far the theory is working.

[joeb4065]

This is the most interesting and thought provoking thread I can ever remember reading. Thank you one and all. My first semi-custom mold was an LBT LFN for my 41. Made sense to me to have the bore riding dia nearer the front of the bullet, and the accuracy was better than any SWC I had shot. Common sense to me now.

[Bass Ackward]

Bullet design is basically a two part game. The launch and the flight after. 99% of us are here cause we can't get the launch right.

So the real key for me is breaking the gun in so that I know "THE GUN", it's strengths and weaknesses, what it will let me do and what it won't. This relationship between man and gun causes quests for perfect designs, lubes, perfect hardness, sizing preferences, case neck tension debates to hold them and everything else that is discussed. Things that affect the launch.

The guys who have most of the trouble are the "new gun" owners. Or those that just don't shoot. And what ends up working, (that builds their cast bullet theories) is that the man finally learned how to load for or broke in his gun. Course this may have taken enough rounds that in the mean time he went through 5 or 10 molds before it got there. Or 5 or 10 lubes. But the gun finally changed enough for him based upon what he insisted on doing. Or he gave up and sold it and now you HAVE it. :grin:

Big diameter bullets, heavy (long) bullets, hard bullets, heavy charges of slow powders rough up and smooth so that they expedite gun break in. Which is exactly why I advocate these things for "new gun" users or new casters these days.

Bullet fit or bullet design can almost be a matter of "gun fit" (wear) to your slug for people that aren't flexible. :grin:

Make your gun (or only buy good ones) and we become so much better at "bullet design" and everything else. Not because we are really, but because our gun launches well in spite of us.

Coarse you CAN develop patience and become flexible enough to bang your head off the wall until you get it right. The penalty for this path is active membership on this board for life. :grin:

Sorry, I gotta go now cause somebody might be posting JUST the information I need.

[44man]

Bass does have something there and some guns do change for the better. Mostly a rough bore.
I prefer a gun to shoot right out of the box and most really do.
Take my 45-70 BFR, tiny groups after just a trigger job and it will shoot anything I have made or been sent to test with the exception of every semi wad cutter of any weight and design. I have tried many with nothing more then decent shooting good enough for deer. I have a pile of molds for it now and it shoots every boolit.
This is my boolit lineup for the gun, not counting jacketed.
Then my SBH "Hornpipe" bought in early 1983 that has never changed and shoots the same as when new. I still measure end play at .0015", the same as when I bought it and with 61,000 heavy loads and uncounted light loads it has not changed. The forcing cone and rifling is not worn and still slugs at .430", same as new.
SRH's have done 1/2" at 50 right out of the box.
Then a SBH Bisley Hunter that I sold because I hated the grip, I could not get what I wanted but another that Scott bought with a hog leg grip does 1/2" at 50. HE shoots 1/2" groups from bags.
The .475 BFR shoots out of the box except for the one boolit I made or a semi wad cutter, they both shoot the same. About 2" at 50.
Then an expensive gun that we worked with for two years with every single boolit, bullet and powder made. Loads from mouse squeak to over max. Three to six inches at 50 is normal.
And now the S&W .45 ACP that will not shoot.
Yes some guns need sold off because 10 years down the road, they will not improve. If a gun does not shoot, dump it! [smilie=l:
Yes, it happens with every gun maker and even a revolver with perfect dimensions can be a pig. To think 100,000 rounds will correct it means it is worn bad in the wrong places while a good gun will show no wear at all.
To actually see an expensive gun wear out the throats, cone and rifling off center, with around 300 rounds of jacketed is a revelation to me. Bass is right but it is the bad gun that wears, never a good one. Force boolits sideways and slam them into the cone and rifling off center and you have a piece of junk to start with.

[44man]

Forget the guns. I was just talking about some boolit designs that shoot no matter what and others that fail.
If you have a good gun, try other boolits. You might find better accuracy or worse. Never get stuck with one boolit.
I understand that you can spend big bucks for a mold but the boolit might not be right.
I would depend on Babore or RD for good boolits and molds but I will not go so far as to say balance is the reason. They just have it right and I would bet if Babore had boolits without a HP, I could make them shoot. Everything else about his booits works.

[Bass Ackward]

And now the S&W .45 ACP that will not shoot.
Yes some guns need sold off because 10 years down the road, they will not improve. If a gun does not shoot, dump it! [smilie=l:


:violin:

Still kickin your A$$ huh? That's too bad. I was wondering how that was workin out.

The 45 ACP is about as easy as it gets. Sure it's the gun? Maybe some H-110 :bigsmyl2:

Are you baggin just like before? I am going to enter another variable that I have never talked about. Some guns (mostly smaller and lighter) won't shoot bagged as well as they do off hand. Yep. I got one that does WAY better when the gun never touches a bag. I can rest my wrists on it, but steel touches bag and it's a pie plate killer.

Maybe you ought to try that. That'll cause you some head scratchin.




Just because you are you I went off the porch at the 33 yard target using the banister / bag. (hurry up operation, just 16 degrees + 4" snow) One shot from the bagged found it's way onto the other target. (Ooops.)

Here is this years horns that I finally mounted. The right set my wife got.

[44man]

:violin:

Still kickin your A$$ huh? That's too bad. I was wondering how that was workin out.

The 45 ACP is about as easy as it gets. Sure it's the gun? Maybe some H-110 :bigsmyl2:

Are you baggin just like before? I am going to enter another variable that I have never talked about. Some guns (mostly smaller and lighter) won't shoot bagged as well as they do off hand. Yep. I got one that does WAY better when the gun never touches a bag. I can rest my wrists on it, but steel touches bag and it's a pie plate killer.

Maybe you ought to try that. That'll cause you some head scratchin.




Just because you are you I went off the porch at the 33 yard target using the banister / bag. (hurry up operation, just 16 degrees + 4" snow) One shot from the bagged found it's way onto the other target. (Ooops.)

Here is this years horns that I finally mounted. The right set my wife got.
Well the group on the right is about what I get with the gun shot either off my leg or benched. I consider that bad for a revolver at 200 yards. I MIGHT be happy with a 50 yard group like that from a friends gun, but never one of mine.
Now the left pattern looks so much like a Freedom group! [smilie=l: :kidding::kidding:
The .45 ACP has proven great with several 1911's but this revolver is a bust.
I wonder about the 45 Colt, .45 ACP convertibles. Does the APC cylinder ever match the Colt?

[runfiverun]

iv'e heard of a few that the acp does better than the colt cylinder..

you tried the ar brass in that 625?
mine will tighten groups up considerably with rimmed brass vs's the acp and clips.
i haven't tried the 454424 in it yet , but the rnfp's do well [from 160 through 250]
even better than general acp boolits. [230 rn 200 swc] kinda proving your theory.
this is set up for the house gun and as such the sights are best under 50 yds, but my chances of hitting the soda can at 50 are greatly increased with the rnfp's and ar brass.

[44man]

iv'e heard of a few that the acp does better than the colt cylinder..

you tried the ar brass in that 625?
mine will tighten groups up considerably with rimmed brass vs's the acp and clips.
i haven't tried the 454424 in it yet , but the rnfp's do well [from 160 through 250]
even better than general acp boolits. [230 rn 200 swc] kinda proving your theory.
this is set up for the house gun and as such the sights are best under 50 yds, but my chances of hitting the soda can at 50 are greatly increased with the rnfp's and ar brass.
No, we have not tried rimmed cases because my friend wants to shoot everything in the 1911 and the revolver.
I have even neck sized brass and had to force loads in the chambers with a dowel but accuracy was no better. I don't think you can name any process I have not tried. The gun is just one of those that should be sold off.

[Bass Ackward]

I figured you'd jump on the group. That was 5" loads of 260 gr LBT LFN in the 4". You need another .6 of a grain of Unique to bring that in with the 4".

I don't have any loaded for the 4" except what I keep in the gun for self defense which .... I didn't want to use. And it is the 4" that exhibits that trait. Figured you wouldn't believe me unless I showed ya.

But I am here to cheer you on. Don't let that little case / gun beat you. Shorter barrels and lighter guns are just a little tougher, huh?

[44man]

I figured you'd jump on the group. That was 5" loads of 260 gr LBT LFN in the 4". You need another .6 of a grain of Unique to bring that in with the 4".

I don't have any loaded for the 4" except what I keep in the gun for self defense which .... I didn't want to use. And it is the 4" that exhibits that trait. Figured you wouldn't believe me unless I showed ya.

But I am here to cheer you on. Don't let that little case / gun beat you. Shorter barrels and lighter guns are just a little tougher, huh?
I seen a strange thing working with a 200 gr boolit he brought to try. I had the normal 2-1/4" group with 5.9 gr of Unique. I went to 6.1 gr and sprayed the whole target, 8". 6.3 gr shot 4-1/2" and 6.5 gr came down to 3".
I have never seen 2/10 of a gr powder difference do that since it is within what most powder measures throw. I weighed every charge.
I don't have a problem with short barrels, they are just as accurate as long ones if you stick to twist demands.
Here is one that would drive you crazy! :bigsmyl2: It is a .500 Linebaugh, a real bear to control, yet we have done less then 2" at 50 yards. 50 shots with this thing will make you quit shooting for a month! :veryconfu Notice it is fluted to reduce weight for carry.
This is a strange puppy to load and brass thickens fast towards the base. Heavy boolits are out because they seat so deep, they expand the brass too much to chamber. A 458 gr boolit is max length. 29.5 gr of 296 will make you sit up and take notice. :shock:
I wish we lived closer, you could shoot it.

[44man]

Jack Huntington made this revolver and it shoots better then any man can shoot it. It is a crazy monster to say the least. [smilie=s: