Gas checks on or off for heat treating?

[35 shooter]

Do most of you ht with the checks on or off? I've done it both ways but not sure which is best method.
With my setup , which is a small toaster oven, i've been standing boolits on their bases to heat.
Sometimes a few will turn over while trying to get them out of the oven and i've had a few dinged bases that way. I use a flat tray to stand them on that slides into grooves in the side of the oven.

Also i have dry sized and installed checks first but only when i was only sizing a half thousandth.



I have also sized with jpw, installed checks and wiped the lube off then ht but that's a lot of trouble.

Have seen pictures where someone was using basket and stacking boolits in on top of each other
but when i tried that on my tray the boolits, at least some of them would kind of melt into each other and leave flat spots on the sides.

Would hand pressing the checks on before ht be a good idea and then size and seat checks afterward
or would the heat make the check too brittle to crimp? If it won't hurt the check it seems to be the best way for my setup. By the way i generally ht at about 460 to 465 degrees if that makes a difference.

Input PLEASE.

[451whitworth]

tried it both ways and I can't tell any difference. anymore I size and seat checks before going in the oven

[Dusty Bannister]

No gas checks is my preference because the copper transfers the heat more effectively. If you get too warm, the shank will start to slump and you wasted the check, and the labor in casting the bullet. If someone tried it both ways and it made no difference, he might have not been trying for maximum hardness. That would be a whole different situation.

Any reason you can not do both in the same basket and see what your oven setting shows to be of benefit?

[RickinTN]

I've done both and as long as temps are kept around 430 or less no difference. If I get up around 450 as mentioned earlier the check holds/transfers heat better and will cause the bullet shank to melt or slump. My oven has settings in 25 degree increments and the 425 setting actually delivers around 430. The 450 setting as actually pretty close to 450.
Good Luck,
Rick

[popper]

Agree with Dusty, unless I'm coating in which case the coating holds the check good. I just dump on a tray & don't go near the slump temp. If I want max hardness I ice drop. I only go to 350-400F for my alloy.

[451whitworth]

I should have mentioned i'm not going for max hardness as RickinTN and Dusty mentioned. I heat treat @ 425-430 degrees.

[onesonek]

I size and GC right after HT'ing.

[Sensai]

I install gas checks and size using case lube before heat treating, then lube with the same sizing die after heat treating. I haven't run into a problem with the boolits melting, but I heat treat at 10 degrees below melting (sloughing) temp for the alloy that I'm using. I use an old toaster oven, too, but mine's PID controlled within about a degree of process temp.

[35 shooter]

Agree with Dusty, unless I'm coating in which case the coating holds the check good. I just dump on a tray & don't go near the slump temp. If I want max hardness I ice drop. I only go to 350-400F for my alloy.

Popper when you said the word dump that gave me the confidence to try laying them flat on my tray again.
The first time i tried to ht that's what i did at only 450*. The result was a flat spot on the bands of almost every boolit.
I use an oven themometer now and it pretty well says the same thing the oven settings say.

Since that time i've been setting them straight up on their bases and easing up on the temp. Everything was working
unless one fell over while it was hot and i'd get a ding or flat spot on the boolit.

Anyway, it sounded like from everyones comments i could lay them down on the tray with no problems. So
tonight i did another run like that and even layed some on top doubled. I cut the heat to 450* down from the 465*
i was using pulled em out one hour later dunked em and took a look. No flat spots or any other defects.

The only thing i can think of is when that oven was used the first time it must have run at a higher temp than
it showed? I'll ease the temp back up a little at a tme to 465* some other time just because i know it shoots good at 2500 fps there. For that matter i'll try the 450* at 2500 first.

Without all of you guys comments i probably never would have laid another boolit on it's side which is definately the way to go. Was also interested to know if checks on or off made a difference. Does't seem that it does, so i guess i'll just go by preference there. (unless you go too hot---got it.) That tip alone was worth this thread
THANKS GUYS!!!

[oldandslow]

35 shooter, 7/25/13

I've done water-heat treating both with ice-water and 70 degree tap water with the gas checks on and off and can't tell any difference. It does make a difference on the heat-treat temperature and the temp of the water.

For example- 1. Alloy is 97.1% lead, 2.2% antimony, 0.435% tin (per Rotometal analysis). BHN hardness at 24 hours after air cooling in 8.2. Heat treated at 400 degrees (measured by oven thermometer) for one hour and 70 degree water dropped BHN is 10.4 (at 48 hours). When boolits from the same batch are heated at 465 degrees for one hour and then 70 degree water cooled the BHN is 15.4 to 16.6 at 48 hours. When heated at 465 degrees for one hour and then ice-water dropped the BHN increased to 20.9.

So for me with this alloy I'm getting a 50% increase in BHN hardness by heating at 465 degrees compared to 400 degrees. I'm also getting significantly harder boolits (about 25%) using ice-water compared to tap water.

The difference between ice-water dropping and 70-degree dropping persists when 2% tin is added (BHN 16.6 with ice-water and 14.3 with tap-water). When I start adding copper to the alloy the tap-water and ice-water BHN difference disappears (? why).

I initially stood all my boolits upright on a cookie sheet but invariably some would fall over when transporting them to the oven and others would fall like dominoes. Lately I just lay them on their sides and have had no flattening on their sides. I might add that these are all rifle boolits- for .308 and .223. I just finished heat-treating a batch of 48 .308 boolits about an hour ago which were sized and GC'd before heat treating. No problems. They are sitting in the pan lube at present.

One important thing to remember is that BHN hardness does not equal toughness. They can be too hard and the boolit nose will seperate from the base if too brittle. Good luck.

best wishes- oldandslow

[35 shooter]

Old and slow thanks for the bhn info, that helps. I don't have a hardness tester and need to get one.
I've been using my thumb nail as in that scratched easy or not so easy or shoot, that broke my nail, must be hard enough. Not too scientific.lol.

Do you get any expansion on the boolit at 20 bhn? If so what velocity? Just curious as i haven't run any tests on mine so far. Still working on a few loads and haven't stopped to test that. All i know at this point is the harder the boolit the better my whelen seems to shoot.

I'll take a guess on the copper thing that maybe like rickinTN and dusty said in that it holds and conducts heat so well maybe it kind of sheilds the lead a little bit with more heat retention than usual and the ice water doesn't have much more effect than tap water? As in it doesn't really cool it that much faster as it would if it were just a lead alloy mix or lead and tin? Just a guess cause i sure don't know and it sounds like your way more up on things like that than i am.

Thanks again, thats all usable info. Seems like i learn something every day on this site.

[oldandslow]

35s, 7/26/13

Regarding the BHN hardness tester- in my view for rifle boolits it is a necessity. You don't have to spend a lot of money on a hardness tester to get reasonable results. If you take a look at the Los Angeles Silohouette Club website (www.lasc.us) they have an article where they tested the most common hardness testers (click on the lower right area for index of all articles, then on the article about Cast boolit hardness testing experiment). Their data showed that the inexpensive Lee BHN tester was both accurate and reliable compared to the others. While I'm not a Lee fan mine seems to work well.

For the expansion of the .308 21 BHN boolit it started at 0.3105 and expanded to 0.3595 giving 16% expansion into water soaked paperback books which is not particularly impressive. This was from my 30-30 at 1748 ft/second. With the same boolit in my 30-06 I get nose separation from the boolit base somewhere between 1871 ft/second and 2200 ft/second. This illustrates how hardness and toughness differ. A boolit can be hard but brittle and suffer nose failure. One also needs toughness to resist the acceleration and spin forces- this is where adding tin and even copper or arsenic may help (see an associated thread regarding Copper/antimony/tin/lead alloys in this section). The real pros doing work with copper and arsenic to toughen boolits are badgeredd, popper, and 357 maximum. I've followed their reasoning and am trying to stabilize my long nosed boolits. Good luck.

best wishes- oldandslow

[35 shooter]

Oldandslow i ht,ed another batch at 465* without checks then lubed and sized with no problems. Had em stacked on top of each other like everyone says. Originally i treated some in that same oven without a thermometer and evidently it must have been burning hotter when it was brand new cause i was definately having problems with boolits being damaged....problem solved i hope.

Youv'e got me worried about something else now tho. I loaded 51 grains of h4895 behind a 200 gr. boolit . don't have a chrono right now,but thats got to be over 2500 fps or darn close?
Anyway i'll have to test for expansion but straight ww @ 465* is probably over 20 bhn?And brittle?
Question is if it is too brittle is it best to add maybe pb or tin? That load shot two groups in the .8 inch range. Since it's shooting where it's at i hate to change anything, but will if i need to.

[Jailer]

I size and install check before heat treating. I've ran into problems distorting the base of the gas check trying to size and check after heat treating due to the extra force needed to size the hardened boolits.

[Dusty Bannister]

What is your method, lube sizer or lee push through? Do not wait til tomorrow to seat and size.
Do it right after drying off the castings and you will have no trouble. They harden overnight.

[RobS]

I size and GC right after HT'ing.

+1 especially if I'm sizing more than .001"

[35 shooter]

Dusty i iuse a rcbs lube sizer. Mostly i size pretty quickly after ht, but sometimes i have waited till the next day because of my schedule but rarely more than 12 hours.
Robs #1 on the 001. I'm sizing no more than that, sometimes only half that.

Last night i ran a tray full of boolits on the top and bottom racks and set the thermometer on the bottom tray.
Long story short bottom tray was perfect and top tray all stuck together. That was the first time i had tried putting any on the top rack, and won't do it again unless i put the termometer up top also. Wasn,t thinking about the temp being hotter on top as there is a burner top and bottom. Ruined about 150 boolits and lesson learned. At least they were'nt checked, so i only lost the boolits.

Thanks for all the tips everybody. I'm finding out what to do and not to do according to experience here. Also teaching myself some hard learned do's and don'ts like last nights little ordeal.

Jailer i'll keep that tip in mind about distortion when i start adding tin to the mix for a bit better fill out in the mould and i have to size a bit more off. Right now everything seems to be working right and the rifle sure is shooting good. Thanks for all our comments everyone, i asked for input and i have certainly gotten it!!

[oldandslow]

35s, 7/30/13
If you're getting good accuracy with your present load then there is not much reason to change anything. If you're going to use these for hunting you might want to recover some boolits from soft media and make sure they are not too brittle and breaking up. Good luck.

best wishes- oldandslow

[hickfu]

I size before HT'ing, I place all my boolits standing up in my tray but I make sure that I fill it so no boolit can move or fall over. I have holes drilled into the entire bottom of the pan so heat can circulate and it makes it real easy to dunk the tray into a larger pan of water. I wait a day or so and then install the GC and since I sized already I have no problem getting it through the sizing die.

I havent noticed any issues with the GC shank but I heat treat around 430 to 450 degrees.

I bought some alloy off Feebay (it was supposed to be COWW but he added SOWW which I was not happy with.... air cooled its 9.6 to 10.1 but when I WQ it goes to 27!! I havent tried HT'ing it yet


Doc