Modifying Lee mold -- a sacrificial lamb

[truckjohn]

Hey all

Got a 577/450 Martini rifle.
Shoots 0.470" dia slugs -- which are not too common.....
hence molds are scarce
(1) Not easily available
(2) Expensive
(3) Limited designs without going full custom.

Question.....

What are the chances that I would get reasonable results
taking a 0.459" dia 500g Lee 2-banger and lapping
'er out to 0.469-0.470?

I do understand that it would require a whole bunch of go rounds of
Cast a pile, pick best boolits, Charge with lapping compound, Lap -- probably couldn't go more than 0.001" on dia per casting/lapping go-round.

so... my "Sacrificial Lamb" is a Lee 459-500-3R 2-cavity mold.
Finished the 1st round of knocking the burrs down.
Currently in the process of gluing the handles down good
Probably gonna cast a few tomorrow evening -- begin the process.

Anyone here already tried this who could give me some advise?

Thanks

John

[grumpy one]

There's probably somebody here who's actually done it, but I think I can tell you what the major problem will be at least.

The lapping process blurs the features of the bullet. The most I've lapped a mould is from 0.309 to 0.314 - a Lee 309-170-F. I avoided the blurring problem by cheating: I didn't lap the regions around the crimp groove, the lube grooves, or the gas check shank at all. The result was that those regions are undamaged - but the region around the crimp groove is undersized, and leaks lube when lubesizing.

My point here is that I lapped the mould enough to increase the as cast diameter by .006, and it worked except for making bullet lubing a bit messy. If I had used the same method and increased to .010, I think it would be squirting lube out the top of the lubesizer like a fire hose. So, you can do what you propose provided you are prepared to lose the crimp groove - there won't be much left of it if you allow that part of the mould to actually get lapped.

Of course I assume your mould is plain base and you intend to keep it that way.

[AkMike]

TruckJohn,
You just missed the group buy which ended today for that mold.
There is a slim slight outside possibility that you could catch the last one if you hurry!
http://p223.ezboard.com/fbritishmilitariaforumsfrm16.showMessage?topicID=1 75.topic

There are several flavors to chose from also. It is advertized here also.

[dromia]

I'd try and get in on the British Militaria forum buy as suggested by AK Mike, its still open.

If not you could try the 476-400-RF by Lee casting a .475" bullet and size it down a tad.

The above forum will be doing a Lee type sizing die order soon for any diameter, if you need a .470 sizer that could be an option.

[Ricochet]

You might be able to paper patch a regular .45 rifle boolit thickly enough to work well with that rifle. That's the way they were originally done, and cast soft enough that they would "slug up" on firing to fill the grooves tightly.

[JeffinNZ]

Jim at CBE makes proper 577/450 moulds in the correct diameter.

I would just buy a proper mould and enjoy the results.

[truckjohn]

I got in on the MH mold group buy about a month ago.
The order was supposed to go to Lee today.....

I also have one on order with Mountain Molds....
It is a 510g WFN type -- almost all bearing surface
with a little curve at the Meplat end. It has a cavernous 1/2" of
throat to fill up before the slug hits anything resembling rifling.

I figure both will take a good 2-3 months for the molds to arrive....
and I have already had the rifle since Jan 1.....
and I am getting a smidge ansy to pull the trigger on something
besides air..... and loaded ammo is $100.00 a box.

I have been sorely tempted to lap out my Lee 452-255-RF mold....
into a Martini Plinker bullet.... I really doubt it has enough grease
groove to make it the entire 33" barrel without leading up like crazy.
It might work as a paper patch plinker bullet.

Thanks

John

[Buckshot]

.............truckjohn, you can just paper patch a .459" slug to .470/.472" by using 20lb bond (typing paper). I guess you have a MkIV Martini since you need a boolit that size?

Re: a pistol boolit not making the 33" trip. It will.

http://www.fototime.com/84C2840C23E9FD2/standard.jpg
http://www.fototime.com/B36421DF639D5DF/standard.jpg

I've had no problems at all with pistol boolits using a chamber conversion. No leading or other issues. It's absolutely amazing how accurate a .452" pistol slug is in the Martini! :-) The first I tried were some 190gr SWC's I had all lubed and sized to .452 for a 45 ACP Destroyer carbine. I forget the charge of Red Dot I had in there.

The chamber insert will handle a .454" slug so I loaded up the 45 Colt cases with a 255gr slug sized to .454 over 8.0grs of Unique. Five shot groups at 50 yards were in the 2.5 to 3" size. People called it the 'Big Burp' as the report was dull and not very loud at all.

................Buckshot

[truckjohn]

............

I've had no problems at all with pistol boolits using a chamber conversion. No leading or other issues. It's absolutely amazing how accurate a .452" pistol slug is in the Martini! :-) The first I tried were some 190gr SWC's I had all lubed and sized to .452 for a 45 ACP Destroyer carbine. I forget the charge of Red Dot I had in there.

The chamber insert will handle a .454" slug so I loaded up the 45 Colt cases with a 255gr slug sized to .454 over 8.0grs of Unique. Five shot groups at 50 yards were in the 2.5 to 3" size. People called it the 'Big Burp' as the report was dull and not very loud at all.
................Buckshot

Ok, so you are getting closer to convincing me to just go try it.
I have about 300 slugs cast from my Lee 452-255-RF mold and nothing to shoot
them in....

And... I have a Lee 459-500-3R mold that is going to get opened up to 0.470ish dia. The mold definately needs a good round of Lee-menting 1st....

So.....
A. Paperpatch the 0.453" slugs up to 470-ish... which I have never tried doing before....
B. Slather on some lube and shoot 'em as-is
C. Tumble lube them with Liquid Alox and shoot 'em as-is

Thanks

John

[The Double D]

You can also order the RCBS 055015 468-480-MH mould for grease groove bullets or the 055015 465-475-MB paper patch mould specifically designed for Martini of all persuasions.