Round nose, boat tailed bullets?

[andym79]

Hi guys, does anyone know of a mold maker who will custoim make molds that have a round nose, a boat tail or both?

I know mountain and accurate do custom work, niether do round nose and I think accurate only do a heel rather than a boat tail.

Lee do customs, but it would cost $200 and is limited to .900" and aluminium is the only choice.

I can't make out from RCBS website if there special order is actually a custom service.

I am asking because I have done some reading on subsonic and transonic bullet designs and a round nose bullet with a small boat tail maybe good for the transisiton.

In my mind I am imagining a bullet with 3 or 4 band, that has a medium length round nose and a short boat tail, a bit like a 22LR bullet only scaled up to 28-35 cal!

177608

a 60 grain 22LR bullet

I guess it would look a bit like this only scaled up and with driving band and lube grooves!

Any advise would be great.

[Djones]

NOE has a "quackenbush" design listed on their website:

http://noebulletmolds.com/NV/index.php?cPath=30

http://i604.photobucket.com/albums/tt124/duckwhackercmon/AB1A6905-1DC1-4CEB-B860-89167535E107.jpg (http://s604.photobucket.com/user/duckwhackercmon/media/AB1A6905-1DC1-4CEB-B860-89167535E107.jpg.html)

They also have a line of air pellets called "Bob's Boattails"

http://noebulletmolds.com/NV/index.php?cPath=374&osCsid=q3hsa5409vhji452okerh9ks62


I don't know your application but lately I have thought about trying the 30 cal air pellet powder coated in my 300 blackout.

[andym79]

I don't know how I hadn't seen the Quackenbush before I have several noe molds and didn't notice it! I think it is because I have been looking for heavier bullets! I never thought to look at pellets.

Al doesn't do 1 off customs does he, group buys only?

Really the Quackenbush is close but I am looking bigger and with grooves and bands. Also the link to Quackenbush doesn't work, does that mean noe have discontinued them?

As to the the pellets the large ones would be okay. Don't know what is going on as the website shows several calibers but only the link to the 30 cal works! Noe molds would force my choice to be 30 cal.

Regardless of if the weight is exactly what I am looking for is there any reason these could not be used in a centrefire rifle?

[Der Gebirgsjager]

Looks like it would have to be a strictly custom, one of a kind mold--at least in the beginning until if and when it caught on. I can't see any reason why such a bullet could not be used in a center fire rifle, but the original idea in jacketed bullets of a boat tail bullet was streamlining against wind resistance for long range, as was the spritzer point. The original pioneers in the bullet industry had some difficulty in making the boat tails accurately, and if they were not or are not the bullet wobbles, and I'm wondering if they could be cast with such precision on a repetitive basis. There are some other problems with the idea, the contradiction of velocity vs. leading of the barrel which is normally gotten around with gas checks. The gas checks do a fine job, but the velocity still has upper limits. In your proposed design the hot gasses could travel past the boat tail and up the sides of the bullet to the driving band, so your velocity would be limited it would seem and I think you could expect leading of the bore,
and if a big and hot enough powder charge deformation/melting of the base of the bullet causing inaccuracy. What is your thinking behind your proposed design?

[Ballistics in Scotland]

You may take this for a cruel jest... But if you have a lathe, drill press or case trimmer which can be rigged to rotate the bullet at moderate speed on its true central axis, why not boat-tail flat based bullets with a pencil sharpener, or a device made to imitate one?

[Wayne Smith]

Everything I have read shows that the boattail effect does not show effective difference until about 400-500yds. I do not remember reading about it's advantages in the transsonic transition - do you have references? If that were true I'd guess the BCPR guys would have investigated it already - they are shooting at such distances that it would be an advantage to them.

[runfiverun]

you can roll those grooves in easy enough with a canellure tool.
I have one that will roll 3 grooves into a boolit easily.

as far as the 22 lr having a rebated base it really doesn't it's a heel and hollow based. [heel like a 41 colt]
the skirt puffs up to seal the bore.
you could probably duplicate what you want with a swaging set-up.

[andym79]

Maybe just a round nose flat base would be the go! I ask questions like this on here so that wiser guys than me can save me money on stuff like this.

Thanks

So the opposite would be beneficial, with a Minnie style base.

I am really trying to find a bullet design which is great subsonic, but also could be used to shot a bit faster say 1450fps but stand up to transonic transition reasonably well. Would that be a round nose flat base?

[runfiverun]

yeah that's where I'd go.
the hollow base will start to fail you at the upper end.
a conventional lube grooved mold would be a lot easier to get too, and if your shooting smokeless I think you could even go as far as a slick sided powder coated mold.

down where your at I'd look for CBE 'cast bullet enterprises'.
they do very good work, and can cut custom stuff and get it to you.

[Wayne Smith]

I would do a lot of reading about the BPCR work on long distance shooting. Look up the "Money" bullet - it is the culmination of years of work. I think these ideas will point you in the direction you are looking to go.

[44man]

Might not work at all. FB is best. I have a BB mold and did not get accuracy so I removed it to a FB and accuracy improved a great deal.
Now I got no leading so I figure making the drive length longer helped with twist. Many go by overall length of a boolit but I figure drive length is more important. What is in contact with the rifling seems to work better.
Them making my own molds I went PB for my big bore revolvers. I refuse to wait for the ship to come from the asteroid belt with the expensive metal for gas checks. I use a WLN and WFN style and screwed up the .475 by making the bottom band only .080", said heck with it and cast a bunch. Darn thing was so accurate I poked one hole at 50 yards and clanged a steel ram at 500 meters every shot. I then made my .500 boolit the same and did this at 100 yards.177660
Now you will read a WFN goes unstable and it is not true, just match to twist and velocity. I used one to hit a 6" rifle swinger 4 out of 5 shots at 400 yards, first a sighter my spotter seen and my best group was 2-1/2" at 500 yards.
Now I shot BPCR and seen the transition through spotting scopes and I blame it on too long a boolit and too slow a twist. My BPCR has 1 in 18", 45-70 but my revolver, BFR, has 1 in 14" and will out shoot my rifle all day.
Why a mistake got me where Angels have not been, I don't know.
Over spin does not group well at close ranges so most slow the twist but at long ranges, you need faster spin. Heavy and long needs faster spin.

[Digital Dan]

Andy, at the low velocity realm you are looking at, the boat tail serves no benefit from the perspective of drag mitigation. Look at the Money Bullet profile, and that's about as good as it gets.

[andym79]

Hi guys, I am still considering a 33 cal cartridge. Would this bullet work well http://www.buffaloarms.com/Detail.aspx?PROD=163729

and does anyone have more detail on it, I can't find any on saeco/redding website!

It looks kind of similar to this! http://www.accuratemolds.com/bullet_detail.php?bullet=34-220B-D.png

[rosewood]

Wouldn't that increase the chances of leading in the barrel? Removes the ability to obturate? Unless you are planning on powder coating it??

Rosewood

[rosewood]

Over spin does not group well at close ranges so most slow the twist but at long ranges, you need faster spin. Heavy and long needs faster spin.

Never considered that. That makes sense, because at long range the boolit is slowing down and may become unstable as the spin slows also.

Rosewood

[andym79]

I am getting really confused now! so is the money bullet the best go?

like this one http://www.buffaloarms.com/Cast_Bullet_Molds_it-1096224.aspx?CAT=4155 ?

They don't do it in 338 though!

I thought loading the bullet so it was touching the rifling was a good thing?

Would this design work http://noebulletmolds.com/NV/product_info.php?cPath=33_240&products_id=1226 ?

My apologizes for a fair bit of ignorance, with most of my rifles I have just used a lyman, rcbs listed in the lyman book or a cbe or noe bullet that is similar. I am asking here to try and get so feedback from guys more knowledgeable that me on the subject, because I don't think its a good think for Lyman to be my sole guide in this.

[Wayne Smith]

I would suggest that you go to MountainMolds.com and play around on Dan's site. You can learn a lot looking at different configurations - and either Dan or Tom at Accurate can cut the mold when you figure out what you want. Confusion is good, it means you realize you don't know enough yet. This may not be rocket science, but it is not cut and paste either.

[Digital Dan]

Andy, no need to get lost here. Sit back and ponder a few things and maybe do a little doodling here. http://www.geoffrey-kolbe.com/drag.htm

and here: http://brooksmoulds.com/index.html

Ponder this: Bullet drag has 3 areas of focus from a design perspective. Nose, shank and base. Shank drag is typically in the 3% range, base is 7-15% and nose form accounts for the rest. The variability in base drag comes from both form (flat base/boat tail) and velocity (super and sub sonic). To develop the best form requires only that you define application. By that I mean velocity range. If you are considering low supersonic to subsonic velocities the simple solution is to look at forms used in the old days of BP arms, or perhaps more specifically, those used by long range BP shooters these days, such as the Money Bullet or variations of that theme. A flat base bullet exhibits better aerodynamic characteristics in the velocity realm you spoke of, pure and simple. The long radius nose with the round tip generates less drag and perhaps more significantly, reduced overturning moments re: spin stability because it is shorter than spitzer forms. It is a difficult task to argue with success. I note as well, that short range bench rest shooters tend to use flat base bullets too. I'm talking the 200 yard PPC crowd here.

Next on the agenda, once you settle on form, is weight. BC is a function of form and sectional density, the latter being a measure of weight to diameter. Same caliber, same form, the heavier bullet always wins the BC race. Question I'd pose on this topic, is how far do you plan to shoot?

Regarding the link to Brook's Moulds, if you are unable to find what you want anywhere else, you will not find anyone easier to deal with than Steve Brooks if having a custom mould made, nor will you find better quality. Equal perhaps, but not better. The bullets below are .30 caliber, 183.5 grains and intended for the very specific application of subsonic shooting with a suppressed rifle. The BC, calculated and observed is in the high .3 range with some measures suggesting about .390. I'm mildly skeptical of that, but cannot argue with the results on paper.

http://img.photobucket.com/albums/v298/muddler/Guns/Sneezer/Ducks_zpscqr0rx5a.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Sneezer/Ducks_zpscqr0rx5a.jpg.html)

I use ALOX and a dusting of mica/graphite and the shallow grooves were intended for that purpose. They function quite well up to 1050 fps, that being the target velocity when the project was developed. A 50 yard target shot with a red dot sight:

http://img.photobucket.com/albums/v298/muddler/Guns/Sneezer/5May4759%202_zps2higuf2o.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Sneezer/5May4759%202_zps2higuf2o.jpg.html)

[44man]

DD, that was good.

[Traffer]

I have been working on making 22lr bullets for about a year now. Have pursued several different methods. I am now working on powder coated bullets. They do not need grease grooves or rolled holes in them for lube. However there was a time when I experimented with these things. Here is a method that works remarkably well once you get the hang of it. Knurling with files. I use two identical single cut files (must be in good shape and very clean) and carefully roll the bullet between them to put a knurl into the bullet. I found that it is easier to do this after the bullet is seated. Then you don't have to worry about messing up the knurl while seating and crimping the bullet. 177727177728177729

[44man]

Now that is something we all could use with the price of .22's. if we could just prime the brass.

[Digital Dan]

Some years back Federal made a large run of .22LR primed brass. I'm blessed to have rubbed shoulders with some of the wingnuts loading that stuff, some with BP. They shoot some very tiny groups.

[Traffer]

Those are some beautiful bullets. I have a couple questions for you. Is there a formula for, or have you calculated the effect of a hollow base on a shorter bullet. There are some folks here experimenting with bullets that look similar to the old musket minie balls. Some being used in pistols with no grease grooves and powder coated, give quite accurate results. I am curious about the potential of using the combination of no grooves with hollow base in a wider range of bullet applications. It would seem because of the weight being forward with a much lighter base -being hollow, aerodynamically they would be more stable. Maybe not at all at high velocities. I am sure you have a better understanding of these variables. What do you think?

Andy, no need to get lost here. Sit back and ponder a few things and maybe do a little doodling here. http://www.geoffrey-kolbe.com/drag.htm

and here: http://brooksmoulds.com/index.html

Ponder this: Bullet drag has 3 areas of focus from a design perspective. Nose, shank and base. Shank drag is typically in the 3% range, base is 7-15% and nose form accounts for the rest. The variability in base drag comes from both form (flat base/boat tail) and velocity (super and sub sonic). To develop the best form requires only that you define application. By that I mean velocity range. If you are considering low supersonic to subsonic velocities the simple solution is to look at forms used in the old days of BP arms, or perhaps more specifically, those used by long range BP shooters these days, such as the Money Bullet or variations of that theme. A flat base bullet exhibits better aerodynamic characteristics in the velocity realm you spoke of, pure and simple. The long radius nose with the round tip generates less drag and perhaps more significantly, reduced overturning moments re: spin stability because it is shorter than spitzer forms. It is a difficult task to argue with success. I note as well, that short range bench rest shooters tend to use flat base bullets too. I'm talking the 200 yard PPC crowd here.

Next on the agenda, once you settle on form, is weight. BC is a function of form and sectional density, the latter being a measure of weight to diameter. Same caliber, same form, the heavier bullet always wins the BC race. Question I'd pose on this topic, is how far do you plan to shoot?

Regarding the link to Brook's Moulds, if you are unable to find what you want anywhere else, you will not find anyone easier to deal with than Steve Brooks if having a custom mould made, nor will you find better quality. Equal perhaps, but not better. The bullets below are .30 caliber, 183.5 grains and intended for the very specific application of subsonic shooting with a suppressed rifle. The BC, calculated and observed is in the high .3 range with some measures suggesting about .390. I'm mildly skeptical of that, but cannot argue with the results on paper.

http://img.photobucket.com/albums/v298/muddler/Guns/Sneezer/Ducks_zpscqr0rx5a.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Sneezer/Ducks_zpscqr0rx5a.jpg.html)

I use ALOX and a dusting of mica/graphite and the shallow grooves were intended for that purpose. They function quite well up to 1050 fps, that being the target velocity when the project was developed. A 50 yard target shot with a red dot sight:

http://img.photobucket.com/albums/v298/muddler/Guns/Sneezer/5May4759%202_zps2higuf2o.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Sneezer/5May4759%202_zps2higuf2o.jpg.html)

[Ballistics in Scotland]

Andy, no need to get lost here. Sit back and ponder a few things and maybe do a little doodling here. http://www.geoffrey-kolbe.com/drag.htm

I've got Dr. Kolbe's book on ballistics, and it is extremely good without being mathematically turgid. As Border Barrels he does really excellent work. They aren't worth importing to a country with as many good barrelmakers as the US, but they seem to be as good as any.

[Digital Dan]

Traffer,

I think your take on hollow base styles is correct. Same theory is at play with Forster shotgun slugs and the old Minie bullets. Their weakness is found in vulnerability to anything other than mild pressure which leads to skirt blowout.

I've used some some cup base bullets for paper patch work and they suffer the same fate.

OTOH, if a gun will stabilize a jacketed bullet of X weight it will do so for X+ lead. If it will stabilize X bullet at 1200 fps it will handle X+ at subsonic velocity. Gyroscopic stability is a bit complex if one gets lost in the fine details but it generally isn't necessary to riddle that stuff too much. Don't over think it.

[andym79]

Okay, so this would be the best profile for a subsonic, transonic bullet if it were not for the fact that gas cutting would destroy the lead as the bore would not seal, i.e this would be sweet if it held together like a jacketed bullet does?

177782

But lead being what lead is then this is the best compromise?
177783 or is this the best compromise 177784

The chart from the website seems to indicate that the second is!

That is loosely a NOE 311-230 FN
Is that about the sum of it?

Just to re confirm, so a boat tail would diminish accuracy in a cast bullet, unless you kept pressure very low, and even then a base that is not flat may lead to poorer accuracy because the bullet may not exit the muzzle square and true?

[eagle27]

You may take this for a cruel jest... But if you have a lathe, drill press or case trimmer which can be rigged to rotate the bullet at moderate speed on its true central axis, why not boat-tail flat based bullets with a pencil sharpener, or a device made to imitate one?

You do not speak in cruel jest, I do this very thing to turn a gas check shoulder on cast bullets for my 404J after they are thrown as plain base from my mould. Being a nose pour Hoch mould the bullets have a perfect base but I need a shoulder to take 44cal gas checks. Just replaced the handle on my RCBS bullet puller with a bolt and then set the puller die body in a three jaw chuck in a lathe. My die with a bullet inverted into the collet spins true and it is a simple matter to turn a shoulder or one could turn a boattail of any repeatable angle on bullets.
Weld a socket on a long tee handle to come in through the hollow lathe spindle and then it is a quick and simple matter to loosen the collet to take bullet after bullet without disturbing the die in the chuck. Works perfectly for me and I can put a gas check shoulder on a lot of bullets in an hour.

Viola!!

http://i606.photobucket.com/albums/tt146/Lindsayb_01/collet003.jpg (http://s606.photobucket.com/user/Lindsayb_01/media/collet003.jpg.html)

[andym79]

Sorry to bring this up again, but I am trying to confirm what profile is best to start off at say 1450-1600 fps and transition through the transonic!

Is a design like the money bullet178259 great for subsonic flight, but a sharper spire type nose for transonic and supersonic flight?

I assume when traveling up through transonic you want spire as passing through mach 1 and for supersonic travel and when traveling down through a round nose for subsonic travel, therefore a compromise is half way between if you are not sustaining super sonic flight, is that correct?

These old videos whilst not about bullets help to explain it

https://www.youtube.com/watch?v=LSmqsg0DbTY
https://www.youtube.com/watch?v=bELu-if5ckU

I am not sure however that I am fully understanding it!

Shame I can't have a swept back bullet!!

[220]

Have you looked at the Lee 230gr .309, would be the cheapest boat tail mould I can think of.

[Digital Dan]

Andy, the Money Bullet is typically launched at velocities somewhat above Mach 1 and slows over long distance to subsonic. They hit things reliably at 1000 yards and more. There's a sign?

You're over thinking this. Go with what is a proven winner for that velocity realm.

[OS OK]

SNIPER 101 part 66 - External balistics, pressure and gravity (https://www.youtube.com/watch?v=kThMXchUJ3A)...
SNIPER 101 part 67 - Bullet Stability[URL]...
[URL="https://www.youtube.com/watch?v=rj5wTsgO7ko"]SNIPER 101 Part 68 - Bullet Balance Issues EXPLAINED! (https://www.youtube.com/watch?v=Z3h0pMQAFUU) ... SNIPER 101 Part 69 - Bullet RPM & Overstabilization (https://www.youtube.com/watch?v=GH-Md1lTa4g) ... SNIPER 101 Part 70 - Aerodynamic Stability (https://www.youtube.com/watch?v=SKbbuZDPw80)

I would watch these five short videos before making up your mind...they are jam packed full of all the considerations...

These are just a few from his website...TiborasaurusRex (https://www.youtube.com/user/TiborasaurusRex)

Sorry fellas, I tried to add part 66 and screwed up the part 67 link but you'll see it listed there.