Help ID Unknown Mold blocks

[Pistolero]

The mold is a double cavity, .44 cal RN PB, about 240-250ish I would guess.

Sprue plate is pivoted between the cavities, rather than on one corner, and stop pin
is also between the cavities, directly across from the sprue plate pivot screw. These
screws have long, skinny unthreaded noses which are the handle attach pins, and they
are locked in place by a pair of screws at the bottom corner of the mold blocks, going
in horizontally to hit the bottom tip of this long sprue pivot/handle attach screw. Unique
screw setup seems like it would ID the maker.

The only markings are "A-429" above the handle slot, and "750" below the handle
slot. On the ends the halves are marked "5" on each, apparently a block production
number to keep the halves together during manufacture.
So, it would seem that the A-429 refers to bullet diameter, not sure what the A means.
The '750' seems likely to be the design number, but maybe a SN.

Any idea who made this mold? Seems fairly old, at least 50s or 60s vintage, perhaps
older.
My guess is that somebody will instantly recognize it from the description. If not,
will post a photo when I get a chance.

Thanks.

Bill

 

[RicinYakima]

Your mould is a Modern-Bond (either Corporation or Company depending upon when it was made). The "A" is their first 429" design, "B" is next, etc. It should cast 240 grains out of 1 part tin and 20 parts lead. The "750" is the in stock standard two cavity, but you could special order singles if you wished. The kicker is that they are hard to use if you don't have the special M-B handles, lee's will work but are so sloppy that they beat the alignment pin holes out unless you set the mould on a flat surface every time you close them. HTH

ps. They invented the removeable blocks from the handle in 1920 and went out of business about 1951. Reports are that they never modernized their business practices and plant. Did fine during WWII, but were left in the dust for Government contracts during Korean War.

 

[Pistolero]

OK, thanks for the info. I thought of that name, but had never actually seen one
of the molds before, so didn't know. I figured somebody would have the facts
on the site. What a great resource! I appreciate you taking the time to ID the mold.

I tried putting it in a set of Lyman handles and it wouldn't work, will try the Lee
handles. Sounds like kinda a PITA mold. Need to make a new screw for one side, the
stop and handle mount pin is missing. Cavities look perfect, so should cast well when
I get it all together in handles. I wonder if SAECO or RCBS handles might fit. I'll see what
I can do with the various handles that I have.

Bill

 

[RBHarter]

I have used "D" shaped flat washers to shim slop before I found a price point set of RCBS handles using Lee 2 C handles .

 

[RicinYakima]

Pistolero, You are welcome not a problem. I didn't even have to get up from the chair but lean over into the file cabinet of "Antique Reloading Tool" stuff and pick out the M-B catalogue. The only thing I had to look for a little bit was the date they went out of business. That 1951 isn't a hard number, but last year they advertised in AR or listed in Gun Digest.

 

[Pistolero]

They have been out of business my whole life, then.

Cast with the mold, will post another thread about that.

Bill