accuracy trouble

[Pilgrim]

My first RCBS lube sizer was out of alignment and gave me screwed up sized and lubed boolits. Sent it back to RCBS and very shortly got a replacement that is in line. Boolit problem eliminated

[cbrick]

Pilgrim, it's not so much an out of alignment machine, that's kinda rare. It's how and how well the nose punch grabs the nose of the bullet. However it grabs is how it's going to push the boolit into the die and often that's slanted somewhat. The more concentric method of sizing is a flat boolit base pushed straight thru the die with a flat punch.

Rick

[Pilgrim]

My only problem with push thru is then lubing becomes a seperate step. As I noted earlier, I'm a bit lazy. The sizer-luber, + nose punch is supposed to give you good boolits. If it doesn't, then you are not paying enough attention to what you are doing, or the equipment is out of whack. I completely agree with you re: flat base boolits and flat nose punches. You have a better chance at concentricity with that approach. However, the use of a lubrisizer does not necessarily result in out of round or otherwise screwed up boolits. Ya gotta pay attention...

[geargnasher]

But run out is a huge problem with cast. Maybe the very worst because lead will not straighten in the bore. Start crooked, shoot crooked.

Runout isn't the only thing that causes a crooked start, there are several, and all fixable at the reloading bench.

I see Rick caught it, but I'm surprised nobody else did. "Start crooked, Shoot crooked" is probably the single best thing to keep in mind when doping out loading techniques for cast boolits. They will not straighten out without accuracy-destroying damage once they're moving past a certain speed, and unless you're really stretching the pressure curve or cushioning the boolit while it's finding its way (hopefully) straight into the bore, you will have problems with a crooked start. Ever notice that rock hard revolver boolits in a gun with a slight cylinder wiggle and slow powder shoot well? I thought you might have! Ever notice that rifles, with tough, flexible boolits of the correct nose shape and a tiny bit of wiggle room when loaded shoot better?

Gear

[cbrick]

the use of a lubrisizer does not necessarily result in out of round or otherwise screwed up boolits. Ya gotta pay attention...

Nobody said anything about out of round, I said concentric and that's two very different things. I compared bullets sized in an RCBS and a SAECO and a Star on a machine shop comparator. The difference in CONCETRICITY was amazing.

Hhmmm . . . Pay attention, I'll give that a try now that I know what my problem has been.

Rick

[Pilgrim]

Pi***ng contest not needed. However, with a solid cylinder, just what is the difference between out of round and concentricity? I don't understand your point. Sorry...

[geargnasher]

Out of round means any cross-section of the boolit which isn't, well, ROUND, i.e. elliptical or even ovoid. Concentric means that the different-diameter cross sections of the boolit, i.e. bottom of the lube grooves, driving bands, nose portions, etc., aren't, well CONCENTRIC with each other.

An example of a non-concentric boolit is one that gets forced to one side as it goes into the sizer, resulting in more band swaging on one side than the other relative to the nose and lube groove minor diameters. If the boolit were collapsed, the exact center of the circles described by the middle of the nose, the driving bands, and the bottom of the lube grooves wouldn't be on the same center with each other.

An example of an out of round boolit is one cast from a "Beagled" mould, or many of the lyman moulds of late, which is like splitting the entire boolit lengthwise, removing a layer, and putting it back together again so a cross-section at ANY point is shaped more like a football than a circle.

Gear

[Pilgrim]

Thanks ! If I understand you correctly, the outside surface of the boolit becomes out of round which causes the bottoms of the lube grooves to become non- concentric with the outside surface of the boolit. That's well outside my experience base. With the bad RCBS lube-sizer, the outside surface of the boolit was distorted. For sure the bottom of the lube grooves would then be non-concentric with the outside of the boolit. At least it would seem so. I 've never attempted to measure that relationship. I've not observed sizing to ever effect the bottom of the lube grooves. Quite honestly I never concerned myself with that relationship. If the boolit came out of the mould concentric, and the outside of the boolit wasn't distorted during the sizing & lubing, then I assumed the relationship between the outer surface of the boolit and the bottom of the lube grooves remained as accurate as that mould was machined. With the replacement machine, the damage to the outside of the boolit went away. Re: paying attention I was referring to observing the top punch-bullet nose relationship. In my experience that has been fairly easy to observe. If the fit and alignment were close, I did not see any boolit damage in using the machine. Re: runout, when that has concerned me I used an in-line bullet seater. They help, but not as much as I expected that they would have. I still had some runout, but it was reduced to the .001 to .003 range and that is about as close to perfect as I could get using Wilson dies with my bench gun. When I was referring to seating the boolit into the lands and letting the barrel help to remove the runout, I had not considered that the round might be quickly rammed into the chamber, and that the boolit was not free (relatively speaking) to move in the case neck.

[geargnasher]

Roll a sized boolit across a smooth table and watch for nose and lube groove oscillations.

If you start a perfect boolit crooked into the throat, it will not be concentric by the time it is engraved, same as if you'd screwed it up with an out-of-alignment sizer ram and close-fitting top punch.

So the boolit needs to be concentric, have as little runout in the case as possible, and be straight with the bore when the cartridge is fully chambered. What methods you use to achieve that is up to you.

Gear

[44man]

Yes, rolling a round on a flat table is an instant way to see what you have. Some look like they are paddling a boat.
I found my old RCBS sizer top ram was worn and pushing sideways (front to rear actually.) even though I always kept it clean and lubed. Nothing came out concentric. I drilled and tapped around the boss and put brass screws in that I could adjust made it better but I still don't like it.

[cbrick]

An out of round bullet when measured with a micrometer is not the same all the way around. As an example, .454" on one side and .450" on the other.

Not concentric is the bullet can measure perfectly round when measuring the outside diameter with the micrometer but from the exact center line of the bullet (nose to base) it is a shorter distance from one side to the other, ie more of the bullet on one side of the center line than the other. The result is a very out of balance bullet even though round.

I first noticed this many years ago when holding some rifle bullets sized in a SAECO machine, with good light on the nose the front driving band was much thinner on one side but that sized bullet measured round on the outside. I sized up a bunch of bullets on the RCBS, the SAECO and a Star and took them to a friends machine shop and examined them at about 50X magnification on a comparator. The results were simply shocking, at 50X differences really show up. The center of the bullets sized with the RCBS and SAECO were offset (some worse than others) from the true center line of the bullets even though these bullets all measured round on the outside diameter. The Star (nose first straight thru) had some minor variations but insignificant compared with the in & out sizers. Thus I am firmly convinced that nose first straight thru sizing (Star or LEE) with a flat punch on a flat bullet base is a more concentric method of sizing.

That is the difference between out of round and not concentric. How much difference does this make? Probably little in short range and/or plinking ammo but I was working on 200 meter handgun loads where I had to be able hit a target the size of a pack of cigarettes with iron sights (shoot-off targets). I took that experiment seriously.

Rick

[Doc Highwall]

The Professor here makes a adapter for Lyman/RCBS top punch’s to allow them to float and find their own centers.

The top punch is held by a O-ring if I recall correctly.

[XWrench3]

sorry, forgot to mention bullet/bore size. i have been at the cast thing a while, and learned on pistols about that one, bore size is an actual .308" i have a Lee .309 and .3111 sizer. i bought the .311 after having trouble with lots of leading despite being +.001". i am now using the lyman 450 with .311 sizer. as far as throat size, i do not have a way to check it. no Cerosafe. yet. and definitely no machinists tools to reach in that far. leading is not an issue. period. i can shoot 200 or more without cleaning, and still have no detectible (shiny slivers) lead on the patches. i have used a bunch of different powders. pistol and rifle. Bullseye, Auto-Comp, HP-38, AA#2, IMR 4198, Varget, IMR 4831, Reloder 7 and 15, Win 748, IMR 4895 and Benchmark. the mold i am using primarily is a Lee 150g FNGC which i have used with and without gas checks. it by itself drops w.w. bullets @ .310". i have beagled it to drop bullets at .312 and .0316. i have shot it with unsized .312" slugs, hand applying lube, and wiping it off the cases afterwards. they chamber quite stiff. so i did not try to load an unsized .316" slug. not even sure i could get one into a case! i have also tried using the 300 mag bullet in the 30-30, which is a 200g rngc which drops out @ .311 and measures 186g in w.w. w a check. i also tried using some 170g fngc from a lyman die that a friend gave me. they were sized @ .311 and did not work any better. i am using the Lee FCD on every round. which i have tried setting to just de-flaring the neck to a very firm crimp. i do fine @ 50 and even 70, but after that the groups fall apart. as for the case necks, i am using a expander that lee sent me talking with them several times that opens the case up so that the o.d. measures a .001" difference after the bullet is seated. (no small hole gauges). i am flaring with the lee universal expander. if i could find a lyman "m" die, i would be using one of those. i love the idea of the chamber seating die. i just have no access to machines to make one, and really can not afford to buy one or more of them. boolit lubes, i have used, Lee lla, lla+ moly mixed in, Kendall "blu" hi temp grease, an automotive moly grease, my own home made concoction which basically has everything under the moon in it that has anything to do with lubricating. also straight alox from my friends press. ok, whats left, oh that's right, bore condition. i am a FANATIC about a clean barrel. i will probably put more wear on the barrel from brushes and patches that i will from bullets and boolits. i use so many patches that i really should start my own company! as far as copper goes, every time i shoot copper clad bullets the sweets comes out. period. fwiw, several years ago, i had a cast boolit load that shot less than 1/2" groups at 100 yards from the 300 mag. they were subsonic, and i had to aim 2 targets high on the board to get them to hit. but it was a good repeatable load. unfortunately, i kept all of my records in my computer, which died, and i could not retrieve any of 3 years worth of load data from it. now i have 3 different records of the newly acquired data. in "c" drive, in a flash drive, and in an external hard drive. plus i keep the original targets and shooting logs. so i should be able to retrieve data unless we have a fire or a tornado, or both. if that happens, everything will most likely be lost, and the data would dom me no good anyway.