Rounded base ...like bevel base?? Am I too picky

[10mmShooter]

Okay guys am I just being too picky???....and does it matter??

Pictured below are 6 samples of my 10mm RCBS 180g Flat Nose, they are positioned upside down so the we can discuss their bases. From the LEFT we have 3 samples that show slightly rounded bases, the 3rd one from the left being the most rounded. The samples on the right are what I consider acceptable and do not exhibit any rounded bases very sharpe edges on the bases.

I've shoot both types no difference in accuracy at <25yrds and no leading in either case. Charge is 7.4g of AANo5 at roughly 1000fps

So should I care about the round bases?? And how are the rounded base any different than the actual beveled base bullets. Seems to me they are really the same, because the bevels are simply beveled to improve bullet seating to avoid shaving lead.

Normally while casting I pitch the rounded base ones in the reject pile to recast, some slip through and this what prompted the question. I normally reject them while lubing and final inspection before loading on the 650.

[randyrat]

I don't think you'll find much lack of accuracy in a pistol boolit with a slight rounded base... Now if your talking long range rifle boolit, if they ain't perfect you would see a difference in accuracy in long range shooting.

[Blammer]

I have found that sharp bases on my pistol boolits matter at distances past 25 yards.

I shoot at 50 and 100 yds with my 44 and 41 cal and rounded base boolits don't do nearly as well as the good square base ones.

From my perspective, no you are not being too picky!

[Cherokee]

You've already answered your question - you can not tell the difference in accuracy. Longer range as said, diff would show up. I shoot rounded bases all the time but 3" @ 25 yd is norm for me now days.

[canyon-ghost]

I'll second what has been said, you don't shoot the 10mm past 50 meters. The more distance, the more it would show, 100 meters and you'd see quite a difference in groups. Although, to a guy shooting an automatic, 100 meters seems extreme. I shoot 32-20 in a TC Contender to that distance, also other calibers. Some, I don't shoot that far and it does make it more difficult to tell any change at all. I immediately miss my scopes and distance.

It's all the type of shooting you do-
Ron

[softpoint]

The only one I might reject would be the #3 on left. Some mixes of alloy that are perfectly good for pistol bullets just will not cast perfectly razor sharp edges every time. But those boolits are fine.

[Echo]

If really anal, re-melt the ones on the left. If only partially anal, use them for plinkers or practice.

(You must be some anal, to have asked the question)

[geargnasher]

Just make a bigger puddle on the sprue plate and they'll all be sharp!

I reject rounded bases on everything, but that's cuz I have an OCD!

Gear

[Bret4207]

Yup, what Gear said and cast a little faster. Hot moulds make good boolits.

The difference between a rounded, incompletely filled base and a BB is consistency. It will show in the best loads, best guns, best shooters even at short range. At longer ranges it really shows. Not being a fan of BB designs i will point out you can get rounded, incomplete BB too, but it's harder to see.

[qajaq59]

One thing that really helps accuracy is consistency, so being picky is a PLUS!

[mdi]

"Being picky" is a matter of opinion. The bullets you show are not completely filled out. Tin, temperature control , and casting speed can all improve the boolits poured. I personally like the sharp edges on the boolits to be just as sharp as the edges in the mold, but, I enjoy casting, don't have a quota and I'm casting boolits for me so I can be as "picky" as I want!

[geargnasher]

I come from the school of "If something is worth doing, it's worth learning to do a well as you possibly can".

Again, just my opinion.

Gear

[qajaq59]

I always figured that if I wanted bullets that were almost right I could go to the store and buy them. But to each his own.........

[243winxb]

Sizing in a die or in the barrel makes them look better.

I've shoot both types no difference in accuracy at <25yrds and no leading in either case.

Proof is in the shooting. Now test at longer yardage and report back.

[45r]

Put the nozzle almost all the way in the sprue hole and pressure pour till you see lead start to spirt out lower mold and pour a big sprue with the mold leaned to the side so it doesn't go in the other hole.Get the second sprue big and overlap the first to keep sprue plate hot.Cut the sprue soon as it hardens.Keep the mold hot with fast pouring or high enough alloy temp,If the mold gets too hot cool it with fan cooling or pat top and bottom on wet towel.The inside seam area will start to shrink and get grey sometimes when mold is getting too hot.I like to use around 3 percent tin for better flow and fillout.Your bases should always be sharp.The right 3 would be OK for a gascheck boolit.I would recast the left 3.

[mooman76]

I don't mind slightly rounded boolits as long as they are rounded even all the way around. I also agree that at 25 y or < you won't see any noticable accuracy loss. Lifes to short to be that picky but if that's what you or anyone else wants then go for it.

[HeavyMetal]

I garontee if you load the boolits on the left, say 50 rounds, and then 50 of the ones on the right and go to a machine rest and fire 20 or 30 5 round groups you will see a difference in group size as well as group shape!

About now everyone is gonna say group "shape" ?

Yeah group shape! This intails a lack of vertical stringing, possible "short" flyers anything that makes the group seem not symitrical.

I realize this sounds wierd but a load that shoots a nice round group is going to score better long term!

This means boolits that might have been a 9 are now 10's because they are grouping symitrically.

I've seen a lot of groups in gun mags that were 2 inch at 50 yards, but the group itself was oblong in some way.

The base of any boolit is critical as to how straight it flys. The boolits you show on the left will perform just as if you had a damaged crown on the barrel, you'll get some flyers maybe some lite stringing maybe a shot out of the group by 1/2 inch or so.

Suffice it to say I want the best ammo I can make when I shoot for score and the stuff on the left would not pass Q.C. at my place and would never get to the lube sizer let alone near the Dillon.

I have had, and still have, this issue with casting. My cure has been to heat the mold, on it's side, on a hot plate, with the sprue plate in contact with the plate that I use to keep the mold warm.

My theory is that rounded base's don't come from having the mold to cold but from having the sprue plate to cold!

The proof of this is in the casting. Using two 6 banger Lee molds I have reduced the reject rate in my castings greatly since I started turning the molds on thier sides during rotation on the hot plate device!

Hope this makes sense to you guys.

[casterofboolits]

Looks like your sprue plate may be too tight. Loosen the sprue plate a bit and the bases should should square up. Also make sure you have plenty of lead on the sprue plate.

[44man]

Pressure pour is a myth. It does not matter if a ladle is half full or full or the whole pot is full of lead or half empty with bottom pour.
What counts is if the bullet when shrinking can pull molten lead in from the ladle or spout and NOT THE SPRUE. Ignore sprue size, it means zero and if you get a huge divot in the sprue, you have cast wrong.
My bases are so sharp I cut the rag when wiping lube from the base.
Pouring fast and trying to have a boolit pull lead from the sprue is silly because it sets up faster then the boolit in the mold.
Sprue plate tightness also has nothing to do with base fill out. It should be adjusted for each mold to lay flat on the mold top, nothing more or less. Some need tighter then others and if you see light between the blocks and plate, change the tightness. YOU SHOULD NOT SEE LIGHT IN BETWEEN THEM.
Speed casting makes more bad boolits then anything. Why would you cast 200 boolits and throw half back in the pot when I make 100 perfect boolits without a singe reject? Who is farther ahead?
Speed casting is like speed loading where you jam boolits in the brass so fast it shaves lead from the boolits.
Casting perfect boolits is so easy it can't be explained and it is NEVER to see how many you can dump in a short time. 100 perfect boolits is always better the 100,000 scrubs.
How I wish I could have all of you here. I would show you how to relax, slow down, make perfect boolits from ANY mold and shoot better then you ever could.
There is no magic or special process with any mold. It is plain and simple logic with a mechanical system.
Casting is so easy and no different with steel, aluminum or brass molds. Only the alloy governs the lead temps with softer needing hotter. A million posts telling you what you have to do and I will cut it to ONE post. If something is not right I can change it before the next boolit and all of you should too. There is no excuse to keep pouring bad boolits.
My confession is that I can not bottom pour without trouble so I plug the hole. It is not worth the trouble.

[montana_charlie]

Round corners on the base occur when air cannot vent between the sprue plate and the top of the mould blocks.
It happens when the sprue plate pivot screw is too tight, and it occurs when you hold too much pressure on the sprue plate with your ladle (or bottom spout) while the bullet solidifies.

If you simply must keep the plate down tight, break the top corners of the block faces to create a vent groove for the escaping air.

If a base corner 'looks' rounded, it is badly rounded.
It is not a 'square' corner unless it feels sharp when you drag your finger over it.
If it looks square but doesn't feel sharp, it's a rounded corner, too.

CM