Bullets casting smaller than mould Dia.

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  • Last Post 16 April 2008
mosinutty posted this 09 April 2008

I am new to bullet casting and casted for the 1st time last weekend. My problem is this, I have a Lyman #314299 .314 Dia. mould. I casted with ingots made of range scrap with no alloy. The Dia. of the cast bullets turned out to be .001 shy at .313. I attached the gas checks and ran the bullets through my .314 sizer to seat the Hornady .30 cal. gas checks. The gas check Dia. is larger than the bullet and when seated into the case is over expanding the case neck and causing the bullets to be very loose in the case. Why is my mould producing under dia. bullets? Will an alloy of harder lead increase the Dia? Will quenching the bullets in water directly from the mould affect the diameter? The bullets looked great and shot quite well but were loose in the case.

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RicinYakima posted this 09 April 2008

Mosinutty,

Lyman moulds are rated at their #2 alloy, 90 parts lead, 5 parts tin and 5 parts antimony. Using range scrap which is mostly lead, will lead to smaller bullets.

So, you can increase the tin and antimony, or bump up the bullets if you really need .314". Quelching will not increase the diameter of the bullet. If it shoots good and you aren't rapid firing from the magazine, the loose bullets help groups, as that is a common benchrest shooter's trick to help center the bullet in the bore. If it really bothers you, you can lower the seating die and add .001 crimp, which will tighten the bullet in the case, but will not make it shoot more accurately.

Ric

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mosinutty posted this 10 April 2008

A family member that works at a print shop has given me some linotype. What would be the correct combination of linotype to range scrap to give me the alloy I am looking for? I am using a 10 lb. capacity production pot. Should I pre-melt and cast the linotype into ingot form, or add as is to alloy? Thanks for all the information!

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RicinYakima posted this 10 April 2008

Mosinutty,

If you have a scale, you can do it by weight, i.e. 5 pounds of scrap and 5 pounds of Linotype. That should get you close to .001” larger. Most folks do cast their Linotype into ingots as it is easier to store that way.

Ric

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CB posted this 10 April 2008

Somewhere there is a chart on how much what alloy shrinks when cast... I think Joe Brennan put that chart in his book, I will see if I can round it up and put it in the reference section.

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R. Dupraz posted this 10 April 2008

mosinutty:

 Another solution for molds that drop under size bullets is to affix very thin strips of high temp. adhesive tape on the inside of one of the block halves. I have used Aluminum tape that furnace installers use for heat ducts. On one two cavity mould that I have, I used four strips. one down the middle between the cavities. one on the bottom and one on each of the two sides. This .308 mould now drops bullets at .3095". Just right for my Mauser .308.

A short time ago, someone else on the forum suggested another kind of high temp tape, that which is used on stove pipes I think. Haven't found any yet but think I will give that a try as well.

RD  

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mosinutty posted this 10 April 2008

Thanks fellows, I'll try some lino mix this weekend and see if I can achieve a .001 increase.

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giorgio de galleani posted this 11 April 2008

I do not see mentioned what gun and in what caliber you have this problem.

I usually lube rifle bullets in a larger sizer (313 bullets in a314 or 315 die)with no problems in .30cal.,308 win,7.62mosin nagant and 303br.My trick is to heat treat,anneal the gas checks in the wood stove and them quench them in cold water.

I feel that softer cas checks are better,as they require  less effort to run the bullet through the die.and do not bulge the cases

Another cause of your problem might be in excessive sizing of the case necks,and or insuffucient expanding,as I use Lee collet dies and Neil Jones's neck dies with custom bushings ,or a 308W die in a .30-06 or .303BR.

I think that preparing uniform alloys in meanigful quantities and doing that constantly and exactly every time is a bit complicated.  

Hope to have helped your shooting.

 

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mosinutty posted this 12 April 2008

Giorgio,

 I am loading for a Mosin nagant M91/30 7.62x54R. Bore slugged at .312. I now know for sure it is the larger than bullet diameter gas check that is causing the problem. I took my Dremel tool and lightly sanded down an attached gas check to .310 and then seated the bullet. The bullet was then very tight in the case, with no crimp. The only solution is to increase the bullet diameter my mould is producing. I've briefly read about low velocity rounds using Bullseye that do not require a gas check, I would also like to try this. Is this pistol powder? Where can I find some load data for this? Thanks for all the help!

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hyoder posted this 14 April 2008

You don't mention at what temperature your pot is. The higher the temperature the greater the shrink. Keep your temperature just high enough to give you a well filled out bullet. 

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mosinutty posted this 15 April 2008

hyoder: I have yet to purchase a lead thermometer which I know is a must. I did cast some 100% linotype bullets this weekend that did measure .314, so I know my mould is ok. I will try a lino-lead mix next time I cast and see what mixture it will take to keep the bullets at .314. 

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hyoder posted this 15 April 2008

The lino bullets are going to cast larger than the normally much softer range metal. .001” is within reason.

If you are looking for bullets softer that lino, tru cutting the lino with, say 25% range metal and see what happens.

Do you have a hardness tester? I use both the Saeco and LBT.

The thermometer is a must, at this stage the Hardness tester would rate “very nice to have". You'll want one eventually - make that soon.

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mosinutty posted this 15 April 2008

No, no hardness tester either. What brand thermometer do you recommend?

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hyoder posted this 15 April 2008

Lyman or RCBS will work.

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454PB posted this 16 April 2008

Since your bore is .312", it would be easier to get a smaller sizing die. That way you don't have to mess around Beagling the mould, annealing gas checks, mixing alloys to suit, etc. Looks to me like a .313” sizer die would solve all your problems.

 

I cast bullets for 36 years before I owned a hardness tester or a thermometer. Yes, they are fun to play with and interesting, but not required.

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mosinutty posted this 16 April 2008

I casted several bullets this weekend using 100% linotype and they all came out at .314. Now I will experiment with a lino-lead mixture that will give me .314 aswell. I noticed to that I was seating the bullet to low in the case to the minimum OAL. I seated the .314's longer and this helped with the loose seating because the gas check remained in the neck. Going to the range tomorrow to give them a try.

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