MIHec 135 (140) gr solid 8 cavity problems

[retrobass]

Got my new MiHec out early this morning, and I cast alongside my trusty Lee 120TC 6 cavity. I cast for several hours, and I found the new 8 cavity very difficult to work wih compared to the Lee. I'm thinking it could be related to the closer spacing and smaller sprue holes. Even once I got the mold dropping very pretty boolits, I'd say at least two bullets from every single pour were culls due to base imperfections. This was vexing, because the cavities with bad bases changed every pour. I'm sure it's just something to do with my technique, though I was able to rain tons of perfect Lee boolits with several different variations of pour speed, cadence, etc. I was casting with Isotype from an RCBS bottom pour, with my PID set on 400* C. Has anybody else experienced similar issues?

Here's what I cast today, it's a mix of both mold designs.

http://i.imgur.com/pxpyA46.jpg

[Drew P]

I had similar issues with one of my brass MP molds. I almost feel like the precision is so good on the mp mold that the sprue plate is sealing the air in maybe. I used a file and very slightly knocked the sharp corner off the mold top edges where they meet creating a vent line and it seemed to help a little. They do seem a bit more finicky for whatever reason.

[Lloyd Smale]

my guess is looking at your shinny bullets that you need to bump the heat up and maybe bump up the pace too to keep your mold hotter.

[retrobass]

my guess is looking at your shinny bullets that you need to bump the heat up and maybe bump up the pace too to keep your mold hotter.

I will crank it up hotter next time and give it one more try. I could also add a little tin, but can't bring myself to drain the Linotype supply when a cheapo Lee does fine with my regular alloy. I have serious doubts that it was my pace. If more heat doesn't work then I'm torn between 1) relieving top edge for a vent or 2) selling it. Fortunately I have enough keepers for some thorough accuracy testing. If I can get superior accuracy to my Lee bullets, then I will try to salvage her.

[John J]

Greetings

I have the same mold and it does take a little getting use to casting with the close sprue holes.
I run my temp up to just under 800 and all works well tho i do find some bases being rounded if i kinda shot pour the sprue puddle in fears of it running over into the next hole.

John J

[wrench]

Mine does the same thing. Got mine last week, washed it with Dawn and hot water, heated it up three times. Spare lube with the supplied lube, and away I went.
I cast ~1000 bullets, and found if I didn't really pour a huge sprue, I got poor fillout on the base. Not always, but enough to bug me.
I am going to break the edge before I use the mold again, that has helped on other molds. We will see.
Other than that, it's my current favorite mold. Drops a gorgeous bullet at 140g with my alloy. Coated with Hitek, they slip through my .357" sizer die easily.
Limited shooting so far, but the first 100 shot nicely through a Glock 34.

[retrobass]

Mine does the same thing. Got mine last week, washed it with Dawn and hot water, heated it up three times. Spare lube with the supplied lube, and away I went.
I cast ~1000 bullets, and found if I didn't really pour a huge sprue, I got poor fillout on the base. Not always, but enough to bug me.
I am going to break the edge before I use the mold again, that has helped on other molds. We will see.
Other than that, it's my current favorite mold. Drops a gorgeous bullet at 140g with my alloy. Coated with Hitek, they slip through my .357" sizer die easily.
Limited shooting so far, but the first 100 shot nicely through a Glock 34.

What kinda OAL did you end up using for the Glock? I know I'm probably a little too OCD about accuracy, but If I can't make it throw 8 perfect boolits/bases consistently, it's a deal breaker for me.

[Wasalmonslayer]

I just received one of his eight Cavity trunicated molds that match the Lee trunicated design and I had the relieve the top edge of the blocks as it was getting poor fill out also.
After relieving that edge bullets were perfect!!!

You don't have to remove a lot just enough to let the air out.

I used 800 grit paper on a piece of glass and wet sanded with oil the edge all at once very lightly until I had about a five thou 45 deg chamfer on both blocks.

I always wet sand any fine edge so to not creat burrs with a file or slip and nick a cavity.

Cleaned it real well with soap and water, hazed the cavitys with smoke from a lighter and wala perfect fill out and they rained from the mold like beer flows at a frat party!

I was using a range lead/ww mix running at 700 degrees on my pid.

Good luck :drinks:

[wrench]

What kinda OAL did you end up using for the Glock?

I am at 1.110"

[quasi]

sounds like it needs a troughed sprue plate ala H&G

[Drew P]

After a few sessions and an edge breake mine is GTG now. One or two sticky cavities but that's probably my fault.

[retrobass]

sounds like it needs a troughed sprue plate ala H&G

Got a link? If I end up keeping the mold I might be interested in one.

[runfiverun]

when he said hotter he meant the mold not the alloy.

a troughed plate is a DIY project or one you get from a group buy type thing.