Home-made Mould

[heathydee]

Bruce
The sponge on the box is for sitting on . Casting as I do using a gas ring and an old saucepan I prefer to have everything as low as possible . The floor is as low as I can go and I need a seat at a suitable height.
The front of this latest boolit is tapered slightly and that is reflected in the engraving of the patch. I wanted to seat the boolit out further than the Mk1 and Mk2 to maximize powder space in the smaller cartridges I use such as the 7.62x39 .

Longbow
The problem I have been encountering when I cast faster with this particular alloy , is the boolit base tearing , as the sprue is cut. The sprue plate is 1/4" thick , and may be retaining too much heat compared to the mould block . With a normal GC boolit I never worry too much about the base , because once the gas check is seated , an even base results , that can do no harm as the boolit exits the muzzle and high pressure gas is expanding past it. I have the opinion that a perfect base is very important in regard to accuracy so I have been waiting for the boolit base to solidify completely before cutting the sprue .
The mould block is aluminium 1.25 inches square and 2 inches long .

I tried the boolit in my single shot 7.62x39 and achieved an average five shot group size at 50 meters of 27mm , or just over an inch . Nice round groups with no fliers and a velocity of 2150 fps caused by a load of 23 grains of AR2207 with 0.5cc of shotshell buffer between powder and boolit.
I thought I was on a real winner when the first three shots were touching , but reality set in with the fourth and fifth shots, and the subsequent groups did not improve upon the first. This particular rifle does not do much better with gas checked cast boolits . On a good day it will average 1.5 MOA with the Lee 150 gn FP at 2080 fps.

[longbow]

I'm not the one to be giving extreme accuracy lessons as I am more of an accomplished "plinker" than target shooter and am still working on cast and PP loads for the .303.

As an observation though, I found I was getting good accuracy from my .308 using a cast boolit of 0.302" then paper patched to groove size. I tried using the same boolit for my .303 but with thicker paper to get to groove size but could not get decent accuracy from the .303.

Not sure what made me think of it but I decided to try knurling the boolits. That worked! Knurled they expanded to 0.304"/0.305" and gave good accuracy. Not sure if the knurling helped hold the paper patch or whether the increase in diameter did it or a bit of both but it worked.

The moral being that you might try a little larger or smaller boolit to see if it makes a difference.

The rule of thumb is to have the boolit at bore diameter then patch to groove diameter for smokeless powder loads. Mine was a few thou under bore diameter until knurled so... maybe that is what it needed.

Longbow

[heathydee]

Again Longbow , thankyou for the tips . Your interest is appreciated. The groove dimension in both of the barrels tried so far is .307". The 30-30 has a 1 in 14 twist and the 7.62x39 has a 1 in 13 . Both are ex target barrels . I am fortunate in having friends who compete in 1000 yard matches and 500 meter fly shoots . To keep at the top of their game they have to change out their barrels regularly . Once their groups get out past half minute of angle the barrel is replaced. Their cast-offs however are perfect for my homebuilds and I can rest assured that these barrels have never been abused and have been cleaned regularly and religiously .
Given that the barrels are second hand I am happy with the progress achieved with comparatively little effort. One of my goals was to achieve the same accuracy with PP as with regular gas checked boolits and I have done that . Another goal was to cut the time spent on fitting and crimping on gas checks , and lubing etc . Rolling on a wet patch , clipping the tail and rubbing on some LLA is quicker . Finally I hope to get better boolit expansion in game with the PP boolit . I willtest expansion in wet newsprint and compare it to a regular cast boolit sometime soon .
How do you knurl a boolit. All I can think of is to roll it over a hard surface using a coarse file and have the teeth of the file engrave and displace some of the boolit metal ?

[docone31]

That is one of the things I have been saying.
I have two molds. One is for .308, and it drops the nose at .302. The second is for .303. It drops the nose at .304. These two I size to .308, then wrap. The .308 I size .309, the .303 I size to .314.
Works for me.

[303Guy]

How do you knurl a boolit?

Between two files. I learned that from the folks right here on this forum!

There is an advantage to sizing the castings prior to patching and that is that mold can have more taper for easy boolit release. It's also difficult to get the right final dimensions when one has to polish the mold after machining. Push through sizing is quick.

Heathydee, do you have any AR2209 handy? If you do, load that case up with a slightly compressed charge of it and see what happens. (You'll only get about 1900fps with it - so I'm told, but accuracy is supposed to be very good. Only one way to find out).

[longbow]

I made a "knurler" that puts annular rings on the boolt. The idea was to use it to make grooves similar to Lee's tumble lube style.

Mine is a little bulky and crude looking (like my moulds) but it works very well and I even "knurled" jacket bullets to try in my oversize .303. I was getting very poor accuracy with it using factory ammo so decided to see if knurling to bring diameter up a bit would help and it did.

Corbin makes a nice rig that is very much more professional looking than mine and also a lot more expensive ~ but readily available and it works:

http://www.corbins.com/hct-2.htm

I was originally going to make one like this with knurled rollers but Corbin says you can't knurl hard lead so I decided I would put annular rings on using a threading tool bit then if I couldn't get deep enough grooves I would remove rings until I could press it into the lead far enough. It wasn't even a problem! I can knurl a entire length of an ACWW .30 cal. bullet with it making annular "thread" (close grooves).

Anyway, when I was having trouble with paper patch accuracy for the .303 I thought I would try bringing the boolit diameter up closer to bore size so from 0.302" to 0.305" or so. I can get about 0.003" expansion in diameter by knurling.

Still not sure if the diameter increase did the trick or the knurling to grip the paper or both. I suspect diameter as many people use smooth boolits for paper patching and my mould works fine as is for the .308.

If you are using standard .30 cal barrels you will likely need a cast boolit of .301" to 0.303". In my experience .303 bores run from .303" to .305".

Longbow

[heathydee]

Quote from 303Guy
There is an advantage to sizing the castings prior to patching and that is that mold can have more taper for easy boolit release. It's also difficult to get the right final dimensions when one has to polish the mold after machining. Push through sizing is quick.

Heathydee, do you have any AR2209 handy? If you do, load that case up with a slightly compressed charge of it and see what happens. (You'll only get about 1900fps with it - so I'm told, but accuracy is supposed to be very good. Only one way to find out).[/QUOTE]


I could not disagree 303Guy about sizing aiding uniformity but it is a step I am not prepared to take just yet . I am not doubting your experience and admire your results and value your input but for once I want to do it quick and easy .

I have a kilo or two of AR 2209 and have used it in both of my 30-30s and your suggestion certainly has merit . Since the 30-30 test exhibited no signs of pressure ; either by visual indications or measured case head expansion , and since the charge weight of AR2208/Varget was at the low end of the scale , I have loaded up 20 rounds with 32 grains of powder and left everything else the same . I would like to reach 2350 fps with this 152 grain boolit and have no deterioration in the accuracy achieved so far. This will match the ballistic performance if not the accuracy of the Remington 150 grain factory load that this rifle favours. By the way I am talking about the Chicopee CF shown in my avatar. This sort of testing is a slow process . I have to discipline myself to changing only one facet of the load at a time in order to learn something useful from a range trip.
The 94 Winchester is another story . Paper patched boolits in the tubular magazine of the lever action mandate a load which features 100 percent loading density to prevent bullet set-back . I believe that crimping the boolit ,as is normally done to prevent this happening ,will damage the patch. AR 2209 , needing more powder to reach the same velocities , would certainly assist in reaching 100 percent loading density in cartidges destined for the 94 and will be well worth trying.

[barrabruce]

I loaded up some 180's PP with 33 grains of Ar2208 last week -end. No accuracy for me but didn't have any hard pressure signs either.Too hot a load but tried it anyway.

Have you tried TurtleWax car polish???
It seems to harden up the patch when dry. I haven't tried any yet but when I slop a bit of Alox on my PP's they tend to go gooey sort of softish.Compared to dry plain paper.
The barrell don't heat up as quick though.
For me anyway.

You aint getting bits of pacth caught on you lead start are you???
I am ..but I didn't notice when I just ran a patch though the barrell.
When I used a brush running back from the crown it picked it up and I could see it then.Stuck to the chamber throat hanging on nice and hard by the alox I reckon.



Just a thought if they are grouping close then suddenly spits 'em out somewhere else.
Worst thing was they weren't keyholing in any way.at 100 yrds .Dohhh!!!
Barra

[303Guy]

... grouping close then suddenly spits 'em out somewhere else.
Worst thing was they weren't keyholing in any way.at 100 yrds .

They don't key-hole. I have had terrible accuracy with some of my loads but the boolits entered the paper target perfectly straight on!

Paper patching can be tricky and I suspect that many of us that are inclined to try it are also inclined to want to try different ways. I know I tried stuff just to see what was meant by; "It won't work" . The thing is, I don't wonder about it - I now know it. Hopefully I learnt something useful along the way.

[Four Fingers of Death]

Originally Posted by heathydee

Bruce
The problem I have been encountering when I cast faster with this particular alloy , is the boolit base tearing , as the sprue is cut. The sprue plate is 1/4" thick , and may be retaining too much heat compared to the mould block .

You might want to try the trick in the Lee reloading manual, he uses a shallow metal tray with a piece of towelling which is soaked in water. If the mould gets too hot, the mould is placed momentarily, sprus side down against the towelling as soon as the sprue sets which cools it some. The lead is solidificed at that stage so there is no danger, just a bit of steam and as soon as you remove the mould after a moment or two, the heat dries it off immediately. It may save you counting the bricks in the garage wall while you wait.

MIck.

[sav300]

To cool a very hot mould,I use a spray/mist to cool everything.
Before cutting the sprue and no water gets into the mould.

[303Guy]

... about sizing aiding uniformity but it is a step I am not prepared to take just yet.

I've been thinking about that. Mmmm .... that has lead me to think of a sizing/seating set up that sizes and seats in one step. I'll figure out a way of doing it in my loading press with a loose die that supports itself on the case shoulder and body or something and a fixed top punch.

[barrabruce]

If you dont over fill the mould and provide positive pressure to the lead in the mould will the base still fill out proper???

I am finding that once I get things hot!!!
I turn down the heat till I just plod along and everything just works!!!
But thats with a "normal" type mold

With the pure'er melt wouldn't the temp be lower than normal to keep it liquid???

The wet the sprue plate tricks be worth the looking at
Bad luck I'm pretty much new to this game.

Barra

[Zeek]

Originally Posted by barrabruce

If you dont over fill the mould and provide positive pressure to the lead in the mould will the base still fill out proper???

The trick is to keep on pouring on the melt until the CBoo has solidified in the mould cavity, THEN move on to the next cavity (= pour for ~4 seconds after the cavity is filled). This eliminates the air-suck-in thangy that puts destabilizing bubbles into the ass end of your CBoos. However, doing that means you will have LOTS of alloy running off, a condition you will tend to avoid (because of the mess) with a bottom-pour pot. That is why I find that using a one-liquid-ounce Rowell bottom-pour ladel (from Bill Ferguson "The Antimony Man" ~~~> bulletman1@cox.net), and holding the mould OVER the pot, to be the best approach ~~~> the excess moulten alloy runs directly back into the pot, so makes no mess. You'll find that you can use this ladel and still keep 1/2" of clay kitty litter floating on top (to protect your alloy from oxidizing) because the ladel draws from the bottom of its melt pool, and you don't get KL chunks coming out.

I am finding that once I get things hot!!!, I turn down the heat till I just plod along and everything just works!!! But thats with a "normal" type mold.

Yes, that will work. However, I find that my CBoo quality remains higher if I keep the melt a bit hotter than absolutely necessary, from that perspective. I watch for the slightest frosting (together with the poor fill-out) that indicates the mould is too hot. I then rest the bottom of the mould on that same wet sponge until the hiss intensity just starts to deminish, and I'm back in business again. So, the sponge serves well for cooling the solidified sprue pool (to avoid "cutting mush") and also for cooling the mould itself.

The wet the sprue plate tricks be worth the looking at Bad luck I'm pretty much new to this game. Barra

Mmmmm! Yes! Whut HE said!

[heathydee]

Thanks for all the comments guys . The wet sponge trick is what I will try next . As far as the mould thread is concerned I am all but finished . I am throwing good boolits out of the home made mould with good accuracy ( for hunting anyway) and all that needs to be done is test the expansion of the PP compared to a regular cast boolit . To achieve that end I set up two feet or so of wet paperback novels and fired a Lee 150 gn FP at 2200 fps into the medium at a range of 35 yards followed by the PP 152 gn boolit. The comparative picture is attached although I will also put this one and a couple of others in an album on my personal page.
Both boolits had a retained weight of just under 70 percent of their starting weights . The Lee boolit penetrated just on 13 inches of the wet paper and the PP boolit a little over 8 inches.

[Four Fingers of Death]

Wait till the missus finds out you've used up all of her Mills and Bloom novels for you dang experiment!