A question for those with PIDs and temp sensors in your molds

[JohnH]

I recently weigh sorted a batch of bullets (Lee 225-55) that I'd run. It's been some thirty years since I weigh sorted anything throwing out the 30 or so at the extreme edges of the run, the bullets dropped with a max spread of .8 grains with right at half of the run falling within .2 grains.

My question is this, what effect if any does all the heat control you're putting into your casting having on your end product? Has it reduced the weight spread of your runs?

[gunarea]

Hello John
YES! There are many variables that will enter into and control weight consistency. Temp is one that is fairly easy to do. Your reported inconsistency will translate directly to accuracy. Although .2 grains seems small, it is a small projectile. Translate that into percentage and apply that into a large projectile, it becomes more apparent. The extreme spread becomes even more alarming with this same linear translation. Your differences will probably never show up in Joe average type shooting. Minute of can accuracy is not that demanding. When cloverleaf groups are achieved, a much crazier level of attention is required to a larger spectrum of practice and procedure. I have been there with 30 cal. What you are chasing can be the difference between bronze and gold. The bottom of this particular rabbit hole is quite deep. I can give guidance that will make one crazy.

Roy

[georgerkahn]

I recently weigh sorted a batch of bullets (Lee 225-55) that I'd run. It's been some thirty years since I weigh sorted anything throwing out the 30 or so at the extreme edges of the run, the bullets dropped with a max spread of .8 grains with right at half of the run falling within .2 grains.

My question is this, what effect if any does all the heat control you're putting into your casting having on your end product? Has it reduced the weight spread of your runs?

GREAT question! I had been "plagued" with too-many weight-related rejects and sought to reduce my numbers. Bion -- this when I was casting bullets using an H&G mould for .38 S&W Special for use in a S&W Model 52 -- temperature change of alloy -- AFTER about fifteen mould drops -- did not appear to be as significant to me as adding flux! Albeit ever so many people dislike the stuff, I found that adding a bit of Brownell's Marvelux plus a teaspoon full of pine sawdust plus a bit of the wax from Gouda or Edam cheese had a greater stabilizing effect than temperature variation. NOTE here, JohnH -- nothing was done scientifically .
However, for a good many years of Bullseye shooting I'd -- without weighing any -- reject the first fifteen drops. Then, from the one which followed, I'd drop in groups also of fifteen. I had two towel-stretch covered trays I'd drop my bullets onto, and after the fifteen I'd add an ingot to pot and the above-mentioned flux. I'd stir quite vigorously; change to 2nd drop tray; and, resume casting.
Move ahead 35 or so years, I acquired an XP100 in Fireball and had run-out (concentricity) problems! Bion, one of my first "suspects" was bullet weight variation, so I dumped all I had cast back into pot and did a similar sequence as I had done in my Bullseye shooting days with the .38. Again, there was not a significant change from temperature variation, but that could be attributed to the bullets being much lighter weight. Anyhoos -- I "fluxed the be-Jesus" out of my alloy and a MUCH greater uniformality of weight resulted.
Again, nothing "scientific" here -- just my experiences. Hope it helps!
geo

[HATCH]

A guy I know had some College students do a automation setup on his master caster.
He used temperature sensors in his molds and would calculate timing on the fly. Meaning the PLC would make adjustments to the timing on each cast based on mold temperatures.
The purpose was to increase consistency.
After several weeks of testing he found out that the consistency between my normal automated setup vs his mold temp setup was the same.
However the production level of my setup was higher then his.

I wouldn’t go to far down the rabbit hole has you might just be wasting a pile of time with no real return on investment.

[gwpercle]

John ...my name is gary , and I don't cast with a PID ... or a mould heat sensor or even a thermometer for the pot . No APP , no computer program ... No electronic anything !
Since 1967 ... When the alloy is melted in the pot and fluxed well , I fill my dipper and fill each mould cavity . The Boolits come out just fine ... If you don't want to go down those rabbit holes ... You don't have to ...you can keep casting simple and enjoyable and not get all tangled up in electronics , you don't have to impress any college professors around here .
I use a Lee Magnum Melter pot and a Lyman Ladle ... that's as complicated as I want my casting hobby and 50 years of turning out handgun boolits says it can work .
Gary

[gunarea]

Hey john
" My question is this, what effect if any does all the heat control you're putting into your casting having on your end product? Has it reduced the weight spread of your runs?" It has controllable, repeatable effects. YES! It has reduced the weight spread of mine and others. Excuse my attempt to answer the question, it was not meant as fodder for conflict.
Don't intend to argue with non competition players. Competitive players at higher levels know these things and tend to be more secretive about their efforts to achieve such precision. I have been at the top, don't care about winning anymore. My efforts have shown me how to get there. The nay sayers are not who I competed against. I am happy knowing what was learned on my way up. For those who are content with close enough, I applaud their attitude and wish them happy shooting.
Roy

[high standard 40]

John,
Not everyone who casts bullets has the same expectation of results. We each have our own standards of quality based on our shooting needs. I more closely align with "gunarea". I shoot in competition also so I set the bar high on acceptable results with my casting. Using a PID helps greatly towards getting consistent results and the smaller the projectile the more you'll need to pay attention to details in your equipment and techniques. Just as Roy stated, pay attention to percentage of weight variation. I cast 55 Gr 22 cal also. It does require greater attention to small details of technique to get consistent results. Also, multiple cavity molds can, and do vary from cavity to cavity. I have an RCBS two cavity 7MM mold that varies a half grain between cavities. For my match ammo I use only one cavity. With that mold, if I had absolutely consistent techniques, I'd still be facing 1/2 grain variation if I used both cavities. So it all boils down to your how much precision your shooting needs require.