Base defect tolerance?

[bbqncigars]

I just got to thinking (always a dangerous proposition), and got to wondering if I might be getting a little too persnickety on my boolit QC. My boolits are a cupped base 515 grain .457" 'Money' boolit. I've been rejecting any that don't have crisp edges on both the inside and outside of the base. My scale can't tell the difference between rejects and 'perfect'. Since the paper covers the base anyway, is the minor imperfection going to significantly affect accuracy under 500yds? FWIW, I used to be in charge of 'tuning up' large precision rotary dies, so I can be too OCD sometimes. I ask this because 'perfect' boolits are running about 30% of my casting.

[Old Coot]

If it were I, I would run the casting temp up and maybe dip my base plug into the lead just before casting. It sounds like you are casting just a little cold. More heat should help them fill out.

The problem with an uneven base is that the powder gasses push at varrying angles upon exit from the bore. An uneven base would still be one even if covered with paper. That said I would take two groups ; those with perfect bases and those nearly perfect treat them the same and see how each group of bullets shoots. Empirical evidence is always the best.
Brodie

[MBTcustom]

I agree with coot, but it also depends on what you plan to use them for. If you plan on shooting groups on paper any further than 100 yards, you are wise to be as persnickety as you can be (especially with PP boolits witch are very particular about the details being just so, even on a good day.) But, if you ever like to just go out to the dump and blast away at stuff to improve your snap shooting/hunting skills at 100 yards and closer, there is really no reason to be so fussy. Even a lousy batch of PP boolits with everything in the world wrong with them will knock pop-cans spinning every time at 50 yards. I like to plink a lot and it really bleeds the fun right out of it if you hesitate to go shooting a bunch just because of the enormous amount of time that it took to stack the loads.
I feel that the ultimate load is cheap as dirt, quick to make, forgiving with details, consistent as gravity, and accurate as hell. If your loads are still too expensive, time wise, then keep poking the dog till it barks.

[bearcove]

Use 30% for serious stuff and kill cans with the others. If you don't use all of the 70% put them in the pot.

I'd try some of the less than perfect on paper and then decide where to draw the line

[onesonek]

Being new to cast, I can't back anything up with any experience. But with shooting in general,,,I have always figured once a good load is developed, accuracy begins with the bullet/boolit base, and ends with the muzzle crown. Although I can see where cast differ to a point, within alloy and pressure variables. But I would still think sharp clean bases would be desired.

[docone31]

A lot of folks have questioned why I size, then wrap, then resize.
The first sizeing makes the casting symetrical. It flattens the base, makes nice and straight. It gets rid of fins, misalignments etc.
I then wrap. No biggee here.
I then size again.
That compresses the tail into the base. Even though the base started flat, the patch/tail eliminates any chance of gas leaks by making a wad.
Once fired, it is gone.
I use some daggoned hard alloy, and it takes an effort to size.
I am pretty satisfied with my loads though.

[badbob454]

load 10 perfect , and 10 with slight base imperfections and shoot at a 200 yard target ... if they shoot the same size group ,, i wouldn't worry about the minor difference.. only cull the poorly filled out ones or wrinkled :coffee:

[bbqncigars]

OK, I'll just try some of the nearly perfect ones and see how they group. I will try to ignore that I'm sending ''spoiled' boolits down range. ;-)

[bearcove]

You forgot to tell us how picky you are.

Process and,

Results.

[pdawg_shooter]

I recovered some bare lubed bullets I shot into water one time. No gas check. They all showed dings and dents in the base from powder granules slamming into them. A patched bullet with the tail twisted in place is protected from this. Does it make a difference in accuracy? I dont know. Patched always shoot better, and faster than bare lubed for me.

[303Guy]

Here is a boolit fired into a wet blanket. The base is as it would have exited the barrel. It started out flat with a small rebate but large enough to be seated firmly into a fired case neck (the only way to get that particular rust damaged bore to group). The 'alloy' is probably almost pure lead - very soft anyway. The reason for the absence of powder kernal peening of the base is the thick wad of wheat bran that separated the powder and the boolit.

http://i388.photobucket.com/albums/oo327/303Guy/PIGGUNintowetblanket.jpg 98% weight retention.

The white stuff is remnants of that skirt that got sucked through the wet blanket catch medium with the boolit.

This is it showing the patch 'tail' or skirt as I call it.
http://i388.photobucket.com/albums/oo327/303Guy/PIGGUN011.jpg

Here you can see the small rebate in the bases.
http://i388.photobucket.com/albums/oo327/303Guy/PIGGUN206gr.jpg

[bbqncigars]

The bases of my boolits are the only area that isn't frosted. I'm going to try a bottom pour 4-20 with a PID to see if that helps the base fill out. I don't know what to try if that doesn't work. Run the melt hotter than 725? Put some heat on the base pin area? Dang.

[bearcove]

Still don't know what your goals are. 2" at 500 meters or paper plate at 200 yards.

Shooting a 23 lb sharps or a 6.5 lb Encore. 45-70 or 45-120?

[Longwood]

Way back when, I read an article in one of the gun magazines about comparative testing of bullets with damage to the nose and damage to the base. The writer found that nose damage did not do near as much harm to accuracy as damage to the base does. It was pretty amazing how much damage could be done to the nose and not have much effect on the flight of the bullets.
I dump all of my bullets back into the melt that are even slightly irregular on the base.
I recommend working with casting techniques until you get a higher percentage of perfect bullets.

[303Guy]

bbqncigars, My molds are nose pour and I chose that route because of the reports that base damage and/or defects or rather critical while nose defects have little effect at all. My mods require that I run my alloy pot hot. Red hot - 560°C (1040°F). Does that sound right? Red hot is above 500°C right? I measured it with a thermocouple.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-487F.jpg
http://i388.photobucket.com/albums/oo327/303Guy/MVC-779F.jpg

[bbqncigars]

1040°F!! Yikes! What does that do to your alloy?

Longwood: FYI my PP loads are shot in a 45-70 Sharps Creedmoor w/iron sights. The goal is the smallest group at 200yds (max at my home range)

[303Guy]

1040°F!! Yikes! What does that do to your alloy?Nothing actually. I keep a layer of Kitty Litter on top of it. Eventually the Kitty Litter turns yellow and goes fine. Then I discard it. It does get heavy so that yellow stuff is oxide of lead plus whatever but fluxing with a wooden stick is a breeze with little or no smoke.

[Longwood]

1040°F!! Yikes! What does that do to your alloy?

Longwood: FYI my PP loads are shot in a 45-70 Sharps Creedmoor w/iron sights. The goal is the smallest group at 200yds (max at my home range)
I just bought a Hiwall 45-70 and am working with a Lee 405 grease groove bullet and a 535 gr Postell.
I have not shot it enough yet to work up the best load with either of those bullets.
I made a .450 mold for bullets for paper patching some from pure lead. I also am playing with a long nosed bullet that will look similar to a paper patched Postell when loaded but it is a smooth sided bullet made for paper patching.
I live on the left side of the United States portion of the big blue marble and have plenty of space for long range shooting.
I have been a fan of little tiny groups from when I started shooting back in 54.

"May we all own Big Guns that shoot little groups".

[pdawg_shooter]

I have had much better results with grooved bullets instead of smooth sided when paper patching. The grooves grip the paper better and they hold a bit more lube. I have had and sold half a dozen smooth sided molds over the years.