Slightly Rounded Cast Bullet Base Edge

[detox]

When casting pistol boolits I try to achieve a consistant slightly rounded corner a base of bullet edge. Seems to me that a bullet exiting crown of barrel will be more accurate if base is slightly rounded. This is not hard to do using a bottom pour furnace or by keeping you ladle away from sprue hole while pouring. You may have to use just one cavity of the mold to get best consistancy. I use high quality RCBS molds and this is not hard to achieve using both cavities if melt is hot 750-800 degrees. If melt is too cold bases you will have too much rounding at bases.

BTW i hate my Lee melting pot. Temperature varies too much and gets too hot while constipating (i mean concentrating while casting):)

[Cherokee]

You'll get some argument from folks that think sharp, square bases are best. ME, I'm not shooting any matches so I don't worry about it. As long as they are consistent, I doubt any negative effect and they are easier to start in the seating process. YMMV

[220swiftfn]

Well, I fall into the camp of "well filled, sharp bases shoot best", so I'm thinking the only thing I should say here is that if you are convinced otherwise, just buy bevel-base molds and be done with it......



Dan

[Fluxed]

Sharp and fully filled out.
Anything else and I doubt you can repeat each pour to the same level of incompleteness.
A bevel base mold let you have the soft edge and fully filled out bullets.

[.22-10-45]

Hello, detox. If you happen on any of the early Ideal moulds, most if not all have a very slight bevel machined into the bottom of the base band. This is not a beveled base as the modern moulds..more of a very slight chamfer..just to break that sharp edge. I think it is a bit easier to cast with. It does make starting in case mouth easier & reduces amount of belling necessary on the brass. But since care was necessary in cutter set-up..as opposed to having a straight shanked cutter..the bean counters probably decided to drop the idea.
On my custom rifle moulds, I ask if this small beveled edge can be incorporated.

[Larry Gibson]

Sharp and fully filled out. Have proven several times with several calibers they are the more accurate.

Larry Gibson

[cbrick]

My first boolit inspection is opening the sprue plate, if there is even slight rounding or incomplete bases that boolit goes straight into the sprue pile. There is no easier/better time to see a incomplete base than before opening the mold halves. Don't care what the rest of the boolit looks like it's no better than shooting sprues.

Intentional rounded bases? Well, if that winds your clock but I see no way to make sure they are all rounded uniformly. Like Larry my testing says 100% filled out square bases are more accurate.

Rick

[btroj]

Square and sharp. Always.

Want rounded? Get a bevel base mould.

[DeanWinchester]

For plain base bullets I'm " It's gotta be square" kinda guy.

The only place I may fudge is on a gas check type. That's only because I separate everything by weight and the gas check squares things up again. Even then, if it's got a very noticeable radius I'll chunk it back in the pot.

[detox]

I weigh all my cast bullets (with rounded edge bases) and these are more consistant in weight than ones that are completely filled out with square base. Why do lower and higher velocity gas check bullets shoot more accurately than a regular non gas checked well filled square base? Rounded trailing edge maybe? I may be wrong

[cbrick]

Gas check or plain base a rounded base is a defect. A defect is still a defect even when you cover it up with a gas check and can no longer see it. The base of the boolit steers it, not the nose and if accuracy means anything the base will be as perfect as possible.

If your concerned about an uneven base at the exit of the muzzle use a bevel base boolit but you still will need to check the fill-out when you open the sprue plate to know it is filled out all the way around or it is still a defect.

Rick

[10mmShooter]

square bases are my preference, my 44 and .357 and .32 molds are factory flat bases...on my 10mm molds i removed the bevel, I want only square bases.

[detox]

Gas check or plain base a rounded base is a defect.

Rick

A gas check base is a defect? I learn somthing new everyday

[cbrick]

A gas check base is a defect? I learn somthing new everyday

That is not what I said. I said a rounded base is a defect whether it has a gas check or not.

Rick

[swheeler]

Square sharp and completely filled out, if you are pouring rounded bases you are casting defective bullets.

[btroj]

I am entirely with Rick on this.

A rounded base is a defect. Period. Always.

I don't knowingly make, load, or shoot defect bullets. The base is the steering end of the bullet. A rounded base also means that bullet is under weight. The rounded base could also be a sign of internal defects as that bullet was obviously not poured quite the same as others.

[Echo]

My first boolit inspection is opening the sprue plate, if there is even slight rounding or incomplete bases that boolit goes straight into the sprue pile. There is no easier/better time to see a incomplete base than before opening the mold halves. Don't care what the rest of the boolit looks like it's no better than shooting sprues.

Intentional rounded bases? Well, if that winds your clock but I see no way to make sure they are all rounded uniformly. Like Larry my testing says 100% filled out square bases are more accurate.

Rick

A big Plus 1 for initial inspection on opening sprue plate.

[detox]

Guys, You can adjust roundness by loosening or tightening sprue plate. You will be surprised at how consistant in weight your bullets are if you use a consistant temp and pace. My bands are completely filled out by the way. Just the base is slightly rounded 1/64". I may even try 1/32". Do not knock it until you try it.

[detox]

You'll get some argument from folks that think sharp, square bases are best. ME, I'm not shooting any matches so I don't worry about it. As long as they are consistent, I doubt any negative effect and they are easier to start in the seating process. YMMV

Logical thinking. Thanks, Cherokee !

[243winxb]

Lyman 200 gr bevel base mold in 45acp is best accuracy wise for me.

[MtGun44]

IME, square bases shoot the most accurately. Especially in pistols, the demands of the user vary wildly.

Some require 2" accy at 50 yds, others want that at 100 yds. Many are pleased with 4" at 10 yds. As your
accuracy requirements get higher, the need for square bases will be greater.

For the 4" at 10 yd folks, it makes zero difference. When I was shooting IPSC, the accuracy requirements
were about 4" at 25 yds or so, and pretty much any well filled out boolit would meet that in a good
gun. So for that sort of ammo, base corner squareness was not on the inspection criteria. I also used whatever
brass was at hand, mixed mil and comm any headstamp.

When competing for trophies in target matches, only square bases pass the inspection, and the brass is
selected lots of matched cases.

Bill

[montana_charlie]

Guys, You can adjust roundness by loosening or tightening sprue plate. You will be surprised at how consistant in weight your bullets are if you use a consistant temp and pace. My bands are completely filled out by the way. Just the base is slightly rounded 1/64". I may even try 1/32". Do not knock it until you try it.
What you are doing is affecting the venting at the top of the mould.
The trapped air prevents a full fillout of the base corner.

I have 'tried it' ... in that I know when rounded bases are occurring, and I know what to do to get proper fill.
And, getting the base fully filled (on a consistent basis) is MUCH easier than getting the same degree of rounding on all bullets in a given batch.
Heck, the amount of rounding is not even the same around the entire base on some bullets.

I'm with cbrick on this issue. If the base isn't perfect when the sprue plate is rotated out of the way, the bullet isn't worth anymore time.

CM

[detox]

Here are pictures. I know my sprue holes are not perfect, but all bullets weigh less than 1/2 grain from one another. From start up of cold mold about 20 percent were culled back into pot. Very easy for my mold to produce these or I can get complete fill at base...very simple...just hold ladle against sprue hole with weighted lead.

This is the 38/357 RCBS 158 grain Cowboy mold. Same roundness all the way around base. Most RCBS molds are verygood at casting. My RCBS is verygood and produces bullets within .001" round. Size as cast .360-.361". I use both cavities when i pour.

Silhouette Pistol is a S&W 686 with 6" barrel and 2 power Leupold scope. I have not tried these bullets in pistol yet. I am just experimenting.

[detox]

the brass is selected lots of matched cases.
Bill

Bill, So you check case wall thickness for perfect uniformity (same thickness all around case) using your NECO concentricity gauge?

[snuffy]

Every one of those boolits in those fuzzy pics would go back into the pot. All defective boolits!

What does it take to get through to you? There's huge amounts of experience here at your disposal. In my case, that's over 50 years of reloading, 45 years of casting experience.

You ask our help, then argue with us when we tell you you're wrong. Better change your tactics, we do not tolerate that kind of attitude, wellI don't!

If you're ladle pouring, keep it full, then pour a big sprue puddle so that the bases fill-out properly. Trying to make defective boolits on purpose is silly. Then to defend that practice in the face of nearly everybody saying it's wrong,,,---[smilie=b:

[detox]

BS ! Quit beeing so narrow minded and think outside the box. Maybe I am wrong, but I just have to try it to believe it.

[btroj]

Some of those look to be beyond a rounded corner. Some have a base that isn't even flat. Those would never be shot by me.
If they meet your needs and standards then by all means shoot them. I would not.

We may just have to agree to disagree.

[montana_charlie]

When casting pistol boolits I try to achieve a consistant slightly rounded corner a base of bullet edge. Seems to me that a bullet exiting crown of barrel will be more accurate if base is slightly rounded.
Did you notice that rifle crowns are never rounded? Just sayin' ...

If rounded bases really did shoot better, I bet every mould maker would have models with them.
Since that isn't true, we substitute bevel base bullets into the consideration.

Why do bevel base bullets exist?
Do they shoot more accurately that flat base bullets (with sharp corners)?

I don't happen to know, and I expect somebody here will post the reason.
But, if the reason for bevel base is that it improves aerodynamics ... or loads easier into case mouths ... then even that style won't substitute to prove your theory.

That would leave you with 'rounded corners' as the only feature to be considered, and it would be up to you to prove they are more accurate when they leave the crown of a rifle.
That would require (at least) a hundred careful shots with round corners compared with an equal number with sharp corners, just to establish a baseline for speculation.

Good luck, and let us know if the search for truth was easier than just casting sharp bases to begin with.

CM

[longbow]

I'll add my $0.02 worth here too.

I am afraid I side with the "I'd throw those back in the pot" crowd and I freely admit I am not real picky. They do not look even to me.

If they suit you by all means go ahead and shoot them, it certainly won't hurt anything and you may well be happy with the results. If they perform to your satisfaction, that is all that matters.

Longbow

[ShooterAZ]

My first boolit inspection is opening the sprue plate, if there is even slight rounding or incomplete bases that boolit goes straight into the sprue pile.

Same here, and if a few get past that initial inpection, when loading I will pull them out and toss them into the "remelt" bucket.

[Raven_Darkcloud]

To be honest it does not seem to be a big deal to me as most people don't do match shooting and are not looking for a 1/2" group at 20 yards. Most jacketed and plated bullets I have loaded have a slightly rounded base and shoot just fine. I get some with perfect bases and some with a small rounding and have yet to see any major difference and still let me hit as well as factory rounds. I try for perfect but will except ok. Is a 5" @ 20yrds group from a pistol good enough for me? Yes! As far as chasing different base styles for absolute accuracy, It is not worth my time. Adjusting the sprue plate to get better crisp edges, That is worth knowing.
With no intention to step on any toes or smash any egos, a little more tact when you disagree with someone will go farther then bashing their ideas and work. Don't forget not all of us are loading match rounds nor are we all experts. Kindness fosters interest, but harsh words push away. Ok now I will descend from my soapbox.

[btroj]

Those jacketed and plated bullets are generally run thru a die to ensure that the base s consistant. It isn't the shape that matters as much as making every one the exact same.
Cast bullets with a rounded base are not consistant. That is the issue.

[mpmarty]

If those were mine they'd all go right back into the pot. DEFECTIVE.

[detox]

I have allways strived to get perfect square bases also. If i had to bet...i bet there would be verylittle difference in the way the bullets in picture shoot vs. bullets with perfect square bases.

BTW these bullets are veryeasy to seat in case:)

[detox]

I have allways used a ladle to cast for best fill and square base. Is it possible to get complete fill and square bases using a bottom pour pot? I figure you would have to hold sprue plate hole against pour spout to build up enough pressure...much like ladle casting.

I am really interested in purchasing the RCBS Pro Melt (2 year Waranty). I hear it holds the most consistant temps during casting. Lyman (1 year Waranty) has a new bottom pour furnace coming out in April that uses digital controls and sells for nearly half the price of the RCBS. Should i wait and buy the Lyman?

[btroj]

I get good, square bases with my bottom pour RCBS. I can get a few with poor fill out on the base if I don't get a decent spruce puddle or pour wrong. Some moulds want a specific pour angle or something like that. I do what the mould wants in order to get good base fill out.

[detox]

Is using the Pro Melt bottom pour your preferred method to cast?

[btroj]

It is my ONLY way to cast. has been since 91 when I got it. Before that I was a dripomatic guy.

[MtGun44]

Oh, good grief, not on pistol ammo. But it is all the same headstamp and bought together and loaded the
same number of times when I am competing in pistol matches, other than IPSC.

Bill

[fredj338]

It's been a constant debate sicne the bb bullet came out. I have accurate bullets/loads using either, but if it's a flat base design, that is how I cast it. If you want a bb design, buy that mold. Trying to guess it is giving you bullets w/ a lot of variation IMO.
FWIW, all I have ever casted w/ is a BP pot. IT's quite easy to get well filled, square bases using one.

[detox]

It is my ONLY way to cast. has been since 91 when I got it. Before that I was a dripomatic guy.
I think i will go ahead and purchase the Pro Melt. Thanks for your response.


Oh, good grief, not on pistol ammo. But it is all the same headstamp and bought together and loaded the
same number of times when I am competing in pistol matches, other than IPSC.

Bill

Bill, Have you ever noticed after a pistol bullet is seated in case, case always buldges out on thin side of brass case. Unless your brass is concentric (uniform thickness). Then you get equal bulging all around case. I use my Neco gauge to sort my most uniform cases for accuracy loads and out of round cases for plinking. I have found only about 20 percent of Winchester brass is near perfect with less than .001" runout. That number can vary with different lots of brass.

Case runout can vary as much as .005"

[Cherokee]

detox - I just bought a Pro Melt, it works great. Graduated from the use of Lee pots for um-teen years. If I'm concerned about match grade accuracy, then flat/square bases are my target. Plinking, well, imperfect boolits will still shoot 2" at 25 yd and that is the best I can see. What works for me and my shooting might not satisfy most of the folks here. YMMV BTW, rifle cast boolits are a different story, flat/square it is.

[Norbrat]

BTW i hate my Lee melting pot. Temperature varies too much and gets too hot while constipating (i mean concentrating while casting):)

Build a PID, works great.

http://castboolits.gunloads.com/showthread.php?187918-So-I-would-like-to-build-a-PID-control

http://castboolits.gunloads.com/showthread.php?115724-Project-PID-on-Lee-Pro-4-20-furnace

[Le Loup Solitaire]

A pro-melt is an excellent choice for a bottom pour pot. The quality is good and the pot's reputation goes a long ways back. But it in itself is not a guarantee that good cast bullets will result unless other factors are correct. Classically, sharp and well filled out cast bullets are considered the ideal objective and most casters will strive to achieve that. Round based or poorly filled out bullets particularly in the bullet base area result from air that is trapped in the cavity of the mold. This can occur because of the pour stream being to thick and flooding the sprue hole too quickly, and/or the sprue plate being too tight against the top of the blocks. if the air in the mold cavity cannot escape/get out of the way of the incoming lead fast enough then the result will be a part of the casting being not correctly/completely filled out. The pour stream should be less in diameter than the size of the sprue hole. The sprue plate should sit flat on the tops of the blocks...not sloppy up and down, and when the retaining bolt is snugged up the plate should swing free on its own weight when the mold is tilted. Lastly, pour a generous sprue puddle so that as the melt solidifies and shrinks...that there is enough puddle to feed the bullet in the cavity so that there are no voids forming in the bullet body...those are usually off center anyway and cause accuracy problems. Some casters particularly with bottom pour pots will run the mold back and forth twice while continuing to pour so that there is an abundance of melt always feeding the cavities. Sloppy...yes... and horrible looking sprues to be sure, but good fillout. Its worth trying...you ought to get good bullets. LLS

[guninhand]

FWIW, I have found when ladle pouring that the best bases result when you pour into the sprue plate cavity so that you get a standing wave that lasts about 3 seconds. This usually means the sprue plate gets too hot to hold a deep puddle for draw down, but it doesn't matter. I cool the sprue, flat though it may be, with a 5 sec. blast from an air compressor nozzle pointing directly at the sprue plate hole before swinging the plate out.

[detox]

Some people also touch the sprue to wet sponge for cleaner cut with no cavity on base of bullet. Seems air would also work and may be better than wet sponge.

[guninhand]

Yes, I tried the wet sponge thing and it works but the steam rusts up the sprue plate and handles. This way gives me the best , most consistant, sprue cut-off remains; no smear or tear out.