Check Base--Round & Sharp Edges...

[BCB]

Just cast about 300 NOE 279-124-FP boolits using this mold for the first time…

Mixed results for sure. The main issue was the check base was rounded on many of them—they did not fill-out to have nice a sharp edge. Although, I do think a check will stick on them as one puts it on before sizing, so they are not too bad…

Has anyone tried shooting the slightly rounded check bases and compared it to the ones that have “perfect” bases for the check?...

I will cull them later today after they cool and I think I will segregate 20 of the slightly rounded bases and shoot them to see if there is significant difference in accuracy compared to the “perfect” bases…

Anyone ever done such a comparison?...

Thanks…BCB

[runfiverun]

yeah you'll be fine.
the ones that are slightly rounded are probably from one cavity and it needs a little more venting.
or you need to speed up your fill rate.

on the other hand you might find the rounded bases take the checks easier and prefer them that way.
then you'll have to slow down the fill rate and dribble the alloy in the hole not allowing the air to escape.
or buy a G/C skiving tool from NOE and cut the square bases slightly.

[outdoorfan]

In my limited experience with NOE aluminum molds, I found that I needed to file the top inner edge to allow better venting. Then, I found that I needed to actually slow the pour rate to help get better fill-out. It seemed that there was a very fine temperature line where the mold just flat out worked great. At every other point other than that fine line I had some issues, even if they were small. I don't have or use a thermometer, so I don't know what that mold temp is, but I'm pretty sure it's well documented here.

[outdoorfan]

Btw, I've fired lots of gc boolits with slightly rounded shank edges. I couldn't tell a difference in accuracy.

[44man]

As long as it is even, you will not see a difference even if PB. They make BB boolits and you are not even close.
See if your mold has the "IGNORE" button.

[dragon813gt]

The only time I won't put a check on it is if the base is really deformed. And at this point there are usually a lot of other issues w/ the bullet.

[BCB]

I sort of figured it might be that way, but I just wanted to confirm…

44man—good point on the bevel base boolits—never gave that a thought…

The instructions say the mold is designed to cast at 600°. I simply could not get good “fill-out” at that temperature. I used an RCBS thermometer and adjusted the Lee furnace as needed. With a dozen pounds of wheel weights in the furnace, I could maintain a pretty consistent temperature. I did go to 650°-700° and better fills occurred as the check bases were much sharper at the end of my casting session than at the beginning…

I usually cast a bit hotter but I followed directions that came with the mold. At that temperature, I did not get smearing under the sprue plate or the top of the mold—that could be expected I suppose…

One thing that did bug me a bit was when I took the mold off of the handles and took the sprue plate off to rub it and the top of the mold blocks on crocus paper to help smooth them a bit as I was getting ever so slight marks on the top of the mold from the sprue plate swing. The steel screws were quite tight to turn from the aluminum. Almost so tight I was a bit nervous. I did get them apart and cleaned the threads with a 10-24 tap and die and they smoothed up perfectly…

Got a few of the boolits sized—I know, I should have let them “dry” for a few days, but I have really never had problems sizing the same day. I did use a push-thru to seat the check and then I used a LAM2 to lube. So there was not much pressure on the top of the boolit when it went into the LAM2…

These boolits have been shooting very well in my 6.8mm T/C Carbine and also a Model 700 in 270 Winchester cartridge. A member of this site as well as the 6.8 site sent me a few to try before I purchased the mold. Always a good thing as this mold was a bit pricey, but I think it is and will be worth the cost…

Thanks…BCB

[44man]

I cast everything with my pot dial at 750°, never used the thermometer to check as it just works for me.
They might have meant mold temperature, I heat mine in a little mold furnace to 500° to start.
Smears on top can mark a mold so just wait longer to cut.
Best to size soon after casting too, before they harden too much.
If you get a small smear, light a wood match and blow it out right quick, rub the smear with the match head. Works like a charm.
Never, ever lap a plate or mold top with sandpaper but crocus cloth is safe. It is only jewelers rouge and just polishes. If there is a burr, 400 wet or dry works but just a pass or so.
Before I cherry a mold I make a pass with an end mill over the mold top to get 90° to the cherry and I mill the plate. I leave the end mill marks on both, leaves perfect tiny grooves to hold a thin amount of lube. Anyway only way to get a plate flat.