Undersized T/C Maxi Ball

[Neslie]

Forgive me for being wordy......hey, its early in the morning.

I was given a Thompson Center Maxi Ball mould in .50 caliber many years ago by a friend who bought it on a traders' row. It looked new, still in the box, possible never used and was constructed of ALUMINUM. I used it for the first time recently, casting with lead obtained from and old (old) schoolhouse's bathroom plumbing. I am certain it was pure lead or at least as close to it as you can get.

I previously had a quantity of maxiballs given me that I had shot with favorable results, and they all had a slight resistance at the bore when loading, but were pushed onto the powder charge with a lot less difficulty than a patched ball. I don't remember where this batch of maxi balls came from and I had them for a long time, actually years, before shooting them. I used T/C Bore Butter, just to add even more words to this endless post.

Most of my casting and shooting experience since 1975 has been with patched balls, so I am accustomed to using a short starter and to the resistance to loading and seating. With the cast maxi balls I was given, there was some initial resistance at the bore but it was easier to seat them than a patched RB.

HOWEVER, the first batch of maxi balls I cast myself went into the bore with no resistance. I actually had to reseat the load several times on a hunting trip, and eventually UNLOADED THE PROJECTILE BY GENTLY TAPPING THE MUZZLE VERTICALY DOWN ONTO A PADDED DROP CLOTH. The maxiball actually fell out. I couldn't believe it.

At home I used my calipers and measured the newly cast maxi balls at .500, the same size as my bore. I didn't have any of the other maxi balls left to measure them, but they were certainly of a slightly larger diameter.

Can anyone explain why these maxies I cast myself came out like they did? I used pure lead, a T/C mould, I cast outside using a Lee Production bottom pour pot, the weather was just at freezing, and I was wearing blue jeans. Were the blue jeans at fault?? If it is of any consequence my rifle is an early 70's T/C Hawken (before they put "Hawken" on the barrel, without the "Quick Load" stuff in the bore, etc.).

Any (reasonable) comments appreciated.

Neslie

[runfiverun]

the maxi balls were made "undersized" to go in a fouled bbl easier, then upon firing.
they expand at the base and grip the rifling.
if you want thema bit bigger you will have to add some "stuff" to the mix.
but then your boolit will be harder also.

[Neslie]

Thanks for the info, Joe. My only casting in the past 34 years has been for round balls and I was always so careful to get pure lead. My father passed away and left hundreds of pounds of mixed lead he used for sinkers so I have plenty of lead with "stuff" in it. Problem is, I have no idea what the stuff is or at what proportions. Is there any formula for mixing pure lead (say, ingots from a Lee ingot mould) with ingots from another source) to get a good cast, or can I throw out the idea of needing pure lead and use anything in the maxi ball mould?

Neslie

[Larry Gibson]

Neslie

I don't think the blue jeans are the problem! However I think this is the problem; "I cast outside using a Lee Production bottom pour pot, the weather was just at freezing". The mold is still relatively "cold" by the time you cast and the alloy is not getting into the mold fast enough. I use the same mould and to get good Maxi's of the appropriate size with pure lead I have to cast hot and use a ladle (I use the standard Lyman one). This gets the hot molten lead into the hot mold before the alloy starts coagulating, thickening and generally allows for proper fill out to maximum size.

Another problem is the these TC moulds were made for the .50 cal Hawkins which had deeper grooves via a smaller bore than newer fast twist barrels. Thus while groove diameter is pretty much the same the groove depth is less meaning there is less resistance engraving and seating the MaxiBalls in newer barrels. I use a 20 or 16 to one lead to tin alloy because i drive the maxi at 1525 fps out of my TC Blk Mtn Magnum. Casting as above the bottom driving band runs .502, the middle bad runs .500 and the front driving band runs .505" I seat these over 777 fffg with a thin lubed felt over powder wad. I cut the wads myself out of felt material. I lube the wad and fill the bottom lube groove only with my own lube of 50/40(V) beeswax/olive oil. The lubed wads stick to the bottom of the bullet with just the lube for ease of loading. My rifle has an aperture rear sight and I can put 6 shots (one in the clean barrel and 5 reloads in speed loaders) into 2-3 moa fairly regular at 100 yards. As I said earlier velocity is 1525 fps.

Try casting hot and use a ladle to get the alloy into the hot mould quickly.

TC Bore Butter works fine also but I still only fill the bottom lube groove of the MaxiBall when using less fouling BP substitutes. Accuracy is slightly better out of my rifle that way as I think there is way to much lube on the bullet after it leaves the barrel and it has the bullet unbalanced before it spins the lube off.

Larry Gibson

[runfiverun]

another reason larry advocates the use of less lube in this application, is that if you get lube fouling in the bbl it can cause flyers,from lube purging.
the mix larry is using is pretty hard also20-1 and 16-1.
with a boolit that large you really don't need alot of expansion.
i am guessing that what you have is wheel weights,and pure lead.
i would try mixing them at a 1-1 ratio and see what you end up with for size.
all you need is ones that won't fall out the bbl or let the powder leak out if you tip the bbl down.
but you need them small /soft enough that you can seat them in your rifle.
you are gonna have to mess with what you have some, and shoot a bit till you are happy.

[Maven]

"Try casting hot and use a ladle to get the alloy into the hot mould quickly."

Larry is correct about the above and using less lube. Also, the T/C Maxi-Ball (and Lyman) cast of pure Pb should have a front band (at the nose) that is large enough to be engraved by the rifling. In essence, it is a bore riding bullet in reverse. If the higher temps. (800 deg. F) and ladle pour (nose of ladle in contact with mold) doesn't increase the diameter of the front band, try "beagling" the mold. (Search the site for tips on beagling a mold.). Hope this helps!

[Neslie]

Lots of information so quickly.

Thanks for the information from all of you. The first and easiest suggestion I will try is to cast in a more moderate air temperature, using a ladle to fill the mould. If that doesn't do it, I'll mix some of my Dad's old wheelweight/who-knows-what stuff with my lead 1:1 and try that, and lastly pick up some adhesive backed aluminum tape and enlarge the mould. Thanks also for the tip on lubing the bottom groove only. Too bad, though, because I picked up one of Dave Gafvert's Super Lubers, a testimony to American ingenuity, which does an amazing job of filling the lube grooves perfectly. I think it might lube only one band if I only insert part of the bullet.

Anyway, I'll post the results in the near future.

Neslie

[mooman76]

Try moulding as hot as you can and still get good bullets. They will come out some bigger when the mould is hotter. I tried doing just the opposite with minies to get the smaller. Unfortunately I couldn't get them small enough. Another thing try shooting some. The fowling will tighten up your barrel. Did anyone report how big they normally drop in the newer moulds or Lyman moulds?

[JeffinNZ]

..........and if the bullet is still undersize consider paper patching it.

I have recently become the new caretaker of a Lyman 39538 hollow base. Basically a .40cal Minie. It throws in 40-1 at only .396 which is a shade too small for me .40cal barrel so I am patching them with 9lb onion skin paper to .403 and they are shooting just dandy.

[Maven]

mooman76, I own a .50cal. T/C Maxi-, purchased used, but virtually new and a .50cal. Lyman Maxi-, new that I just rec'd. from Bullet Lady. I also had the opportunity to use Vly's .50cal. Lyman Maxi-, but found all three* to have slightly different dimensions. E.g., Vly's mold cast the heaviest (378gr.), largest diameter Maxi-, whereas my new Lyman mold casts the smallest, both in weight (~364grs.) and diameter. The T/C, on the other hand, casts in between the other two @ 368grs. However, all 3 have a large enough nose and base** to be engraved by the rifling. Accuracy with Vly's mold and the T/C were identical (5 shots in 1" @ 50 yds. with open sights). When we get a milder day (It was 29 deg. F at the range today.), I'll test my newest acquisition.


*All were cast @ 800 deg. F via ladle in contact with the mold.

**Base bands were lightly marked by the rifling. The nice thing about an in-line is that you can easily slug your bore.