How sharp does the bullet base need to be?

[5Shot]

I know in theory it should be perfect, and I love it when the bullets drop from the mold with razor sharp bases, but how sharp do they really need to be?

I cast mostly for revolvers, WW + 2%, and I have been culling any that show the slightest bit of rounding on the bases, but part of me is thinking that I am remelting a lot of bullets that would otherwise shoot quite well in a wheel gun at normal ranges.

Thanks

[JSnover]

For casual shooting a small radius is ok, as long as it's consistent all the way around. There are a handful of YouTube videos showing some pretty terrible bullets flying straighter than you'd think. You could always use the rejects for plinking/load development.
How many per 100 are you culling? Maybe all you need is a smidge more tin.

[murf205]

I wondered the same thing and finally got around to shooting some cb's that were not razor sharp. They were not what you would call bevel base boolits, but they were a bit "smooth" on the bases. My load was 16.5 grs of 2400 with a std primer and a 429421 Lyman for around 1000fps out of a 4" 629 and 1170's from a 9 1/2" Super R'hawk. The accuracy was as good as ever from both guns and the Super R'hawk had a 2x Leupold scope on it. Who knows what it would effect if you drive them really hard, but I have been there and done that and these moderate speed boolits will shoot through a Buick, so why punish the gun and hands.

[tazman]

I shoot boolits with the bases slightly rounded or sharp. I can't tell the difference in accuracy to the limits of my eyes. I have tested them several times over the years and it just doesn't seem to matter.

[country gent]

A small radious probably wont hurt accuracy to much, if it is consistant all the way around (ie bevel based bullets shoot well ) a bullet with radious on one side and sharp on other will be an issue. I have seen some pretty rough looking cast bullets shoot pretty dang good for guys.

[montana_charlie]

I know in theory it should be perfect, and I love it when the bullets drop from the mold with razor sharp bases, but how sharp do they really need to be?

I cast mostly for revolvers, WW + 2%, and I have been culling any that show the slightest bit of rounding on the bases, but part of me is thinking that I am remelting a lot of bullets that would otherwise shoot quite well in a wheel gun at normal ranges.

You probably are not shooting groups with less than a 2 MOA spread ... right?

If your accuracy requirement is met with a 10 MOA group (1-inch at ten yards), having truly sharp bases is probably not necessary.


When do you do your culling?
If you cull at the moment when you open the sprue plate, you know when you are creating sharp bases and when you aren't.
If you know when they are coming out sharp, you also know how to keep that going.

If you do the culling at the dinner table ... after the casting tools are put away ... you can only wonder what you were doing when the good ones were born.

[Shiloh]

I shoot boolits with the bases slightly rounded or sharp. I can't tell the difference in accuracy to the limits of my eyes. I have tested them several times over the years and it just doesn't seem to matter.

Gotta go with Tazman.

FOr pistol boolits up to 50 yards open sights, no difference. Same with the service rifles. Those are gaschecked though. I have separated into groups of a grain or two. One day I'll put a decent trigger on the modern '06 and experiment with a scoped rifle.

Shiloh

[bedbugbilly]

I agree with taxman. While I don't get many that aren't sharp out of any of mu .358 molds . . it does happen once in a great while. I was casting from 358-242 120 grain mold the other day and I think I had maybe two out of close to 500 . . I still kept them and they'll shoot just fine.

What the difference if it has a small radius around the base (if it's equal all the way around) than a bevel base design? Not being snide when I say that . . . I'm asking the question as I'm curious.

I've never noticed any difference for the shooting I do either.

[mdi]

No more than a .010" radius on the corner of the base. Striving for perfection = striving for accuracy!

JK! As you can see from the replies so far, it isn't that big of a deal. Remember, there are round bases, boat tail, hollow and beveled bases on bullets so as long as they are relatively even/consistent they'll be fine...

[Motard]

This is a question I was going to pose myself too. Shooting mainly extremely dangerous sheets of paper I was mpore concerned from eventual leading coming from a (small) rounded base than accuracy
Curled 6-8 every 50 casts untill now

[tazman]

This is a question I was going to pose myself too. Shooting mainly extremely dangerous sheets of paper I was mpore concerned from eventual leading coming from a (small) rounded base than accuracy
Curled 6-8 every 50 casts untill now

For a properly sized/lubed boolit, having a slightly rounded or beveled base will not make it lead your barrel. If the boolit shoots without leading with a good base, it won't lead your barrel if rounded a bit. It will still seal the barrel with the bottom driving band.
If you are getting a lot of rounded bases, I would suggest pouring a larger puddle on top of the sprue plate. This will help the base to fill better.

[MBTcustom]

Theoretically, the base of the bullet is just like the crown of the rifle (it is in fact, the opposite side of the same coin) so a radius makes no difference as long as it is ABSOLUTELY square concentric and perpendicular to the line of travel.
In reality though, the only way to make sure that all of your bullets are effected identically at that critical point where they cross the crown of the pistol/rifle, is to make sure they match the mold that created them exactly (i.e., sharp and consistent bases across the whole lot).
If you are striving for perfection, the place to do it is at the casting pot. Not by culling for any reason. My philosophy is to strive to be confident that anything that drops from my mold and is allowed to fully cool, gets shot with full expectation of excellent results.
Culling bullets is the same as putting a piece of black tape over your check engine light. Rounded bases, wrinkled bullets, varying degrees of frost, and varying weights are all things that are trying to push you towards perfect casting technique, and if you allow yourself to see these things as you are casting, and if you allow yourself to make corrections as you are casting, you will very quickly find you have to look very hard to find anything to throw back in the pot once everything is cooled off.

Montanna Charlie is right on the money.

[shooter93]

A lot depends on what you're shooting them out of or at. Plinking tin cans for an afternoons fun....it doesn't matter so much. Shooting a full blown bench gun or rail gun looking for the new world record or shooting at extreme ranges perfection starts to matter a lot more.

[David2011]

I rarely get rounded corners on the bases. When I do it's usually due to a mold that's not hot yet or has cooled off a little when I had to pause for whatever reason. Since the vast majority are sharp I cull the rounded ones because they weigh less than those with square bases. I never tested their accuracy. The cure is too easy.

OTOH, for 10-25 yard plinking why sweat the details? For hunting and competition boolits, leave nothing to chance.

David

[Schrag4]

I'm a fairly new caster and I recently decided that I was being too picky in sorting my cast 9mm (all I cast so far). I haven't noticed any difference in accuracy, but then again all my shooting is done inside of 15 yards, for the most part. In my first casting session, I probably rejected 15%, but on this last one, it was more like 1.5%.

If I ever get into casting for precision rifle, I'll take a much different view on quality control.

[5Shot]

Thanks. I will shoot some of the culls to see what affect it has. This is my only aluminum mold, and being used to brass, I may need to change my tempo to keep the temp up.

[BAGTIC]

Don't need to be sharp at all as long as they are consistently uniform.

[5Shot]

You probably are not shooting groups with less than a 2 MOA spread ... right?

If your accuracy requirement is met with a 10 MOA group (1-inch at ten yards), having truly sharp bases is probably not necessary.


When do you do your culling?
If you cull at the moment when you open the sprue plate, you know when you are creating sharp bases and when you aren't.
If you know when they are coming out sharp, you also know how to keep that going.

If you do the culling at the dinner table ... after the casting tools are put away ... you can only wonder what you were doing when the good ones were born.

Re-read this one a couple times. Really is good info there.

[5Shot]

Lowered my melt temp and increased my tempo...much better. Apparently I usually cast pretty slow.

The issue I am having now is that it takes forever for the sprue to cool. I'll have to add another mold to the rotation.

[rodsvet]

I'm with bagtic.

[lightman]

I've wondered about this too. I cull mine really hard and remelt some that my other shooting buddies would keep. My weights will challenge Sierra's SMK's for consistency. I have a few rejects that I saved to test, just have not done it yet. Most of these are the driving bands being rounded and not the bases.

[Motard]

+1 on this. need learming more:-))

Sent from my C6903 using Forum Fiend v1.3.3.

[bangerjim]

If they are consistent on the base.......I shoot 'em!

banger

[Love Life]

Honestly, you'd be hard pressed with pistols to see the difference between a sharp base and a slightly rounded base. I like my bases sharp. When I cut the sprue, I check the bases. If they are not sharp, then they go back into reject bin. Using a stopwatch, hotplate, and mould oven, I have to reject very few.

[huntrick64]

Amen to what Charlie and Love Life are saying. I used to get a bunch of culls until I started inspecting each boolit as I cast (which includes weighing it), and put a PID on my pot. Once you figure out what you are doing for that particular mold, write it down for the next time. Keep track of the outside temp as well. After a while, you will simply look up your notes for that mold and outside temperature, and take off casting. You will be amazed at your results. Don't worry if your total cycle time is longer that what you are used to. If your are keeping 98-99 percent of what you are casting, you are way ahead in the "time game". Don't forget to keep the sprue puddle size large and consistent. That helps create crisp bases when everything else is right.