Cast bullet diameter

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  • Last Post 31 October 2016
M3 Mitch posted this 18 October 2016

Reading on here, from .22 rimfire on up, it seems to me that most of the time when a bare lead bullet leaves lead in the bore, or does not shoot accurately, the root cause is inadequate bullet diameter.  Of course with a revolver, if the cylinder throats are smaller than the barrel, or the barrel is “choked” where it screws into the frame, a bigger mold or sizing die won't help.  And the alloy strength needs to be in tune with peak pressure, or at least that helps, particularly with a revolver that has non-ideal tolerances.

But, what do you think, if a bullet leads or is inaccurate, is the logical first place to look for the problem bullet diameter?

To take this another step, can we say if one does not start with some sort of bore/throat measurement, then order a mold made for that diameter, we are just guessing around when we buy a mold for the “standard"diameter for the cartridge in question?  Particularly with older guns, and calibers that are not well-standardized?

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David Reiss posted this 18 October 2016

When I began casting bullets some odd 40 years ago, I knew very little about bore to bullet matching, or cared. My main reason casting was to have more bullets to shoot more. My story is not unique other than at the time I was shooting 500 rounds of cast bullets each week, either practicing, plinking or competing in PPC matches. My rifle/cast bullet loads were very minimal at that time. At the time I blamed leading in various handguns to soft bullets or poor lube, more so in revolvers than semi-autos. However years later when I had more sense and time, as I began to read more, I began experimenting in different bullet sizes and lead hardness. As the bullet sizes began to be appropriate to the gun, leading virtually disappeared. Lead hardness only affected leading very minimally. Of course my revolvers shoot more accurately and show little to no leading when bullets are matched to throat size. For example I have one .401 mag revolver which has cylinder throats of .405 and a bore which measures .403. In the beginning I only had molds which threw .403 bullets and accuracy was good, but I experienced some, but not bad leading. Once I got a mold which threw a bullet I could size to .405, accuracy became great and leading disappeared. These bullets were as cast with wheelweights at about 1450 fps. So in conclusion I can say through my experience I would always look to the bullet size first, lube second, then lead composition & gun characterics.  

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
- Also deal in: Land, Banjos, Nails, Firearms, Manure, Fly Swatters, Used Cars, Whisky, Racing Forms, Rare Antiquities, Lead, Used Keyboard Keys, Good Dogs, Pith Helmets & Zulu Headdresses. .

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Ken Campbell Iowa posted this 19 October 2016

m3:: yes....almost always .... but cast are funny, so it is good to retain room for exceptions .

one example was that one load that worked well was seating the bullet about 1/4 inch from touching the lands ... never figured out how that helped ...

ken

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onondaga posted this 19 October 2016

http://www.castbulletassoc.org/view_user.php?id=9290>M3 Mitch

You don't even need any measuring to find bullet fit for any type cartridge firearm and cast bullets. It is easy to verify with ink on the bullet and feel. When the round slides in with the largest diameter bullet you can easily chamber, that equals the best fit. Less than that is in the direction away from the highest accuracy potential.

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45 2.1 posted this 19 October 2016

You're going to hear all sorts of things on this question, but Yes, most of the time people are shooting undersize bullets for the gun and get reports like most people post here. Bullet diameter AND alloy play a big role on what results you get. Mold manufactures get back molds that cast too big and won't fit in the gun, not molds that are less than optimal in size and give results like you see here. A hard undersize bullet will give 1.5 to 2 MOA groups pretty easily, but not better than that except on occasion. A rifles throat is tapered which causes problems getting a two dimensional bore riding bullet to keep straight going into the rifling when fired, especially when it's hard and undersize.

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M3 Mitch posted this 19 October 2016

onondaga wrote: http://www.castbulletassoc.org/view_user.php?id=9290>M3 Mitch

You don't even need any measuring to find bullet fit for any type cartridge firearm and cast bullets. It is easy to verify with ink on the bullet and feel. When the round slides in with the largest diameter bullet you can easily chamber, that equals the best fit. Less than that is in the direction away from the highest accuracy potential. OK, for .30 cal rifles and say 9mm/38/.357 handguns, I have a variety of bullet diameter molds on hand and can try say a .311 or even .314 bullet in the .30. 

But for example my .348.  I have exactly one mold, an old brass NEI.  Is there a practical way to “shim up” the bullet to see if what I have is near ideal, or should I go bigger?  Maybe cast some bullets in pure Linotype (I have read this gives the maximum diameter)?

Or is it better to just get some Cerrosafe, and break down and do a chamber cast?  Have never done one, have always got by without it, but it does seem like the proper engineering approach.

You are a very knowledgeable guy, I look forward to reading what you think.

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David Reiss posted this 20 October 2016

Without going into the detail, which can be found elsewhere on this forum, you can in most cases, “bump up” your bullet to a slightly larger diameter. There are some specific made dies that assist in this or it can be done with a loading press, lube-sizer or arbor press....  In essence you are swaging or squeezing the bullet to a larger diameter. 

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
- Also deal in: Land, Banjos, Nails, Firearms, Manure, Fly Swatters, Used Cars, Whisky, Racing Forms, Rare Antiquities, Lead, Used Keyboard Keys, Good Dogs, Pith Helmets & Zulu Headdresses. .

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John Alexander posted this 20 October 2016

Beagling the mold is another way to increase the diameter of the bullet. One way to beagle is to put layers of aluminum foil between the mold blocks  If you need more diameter to make the nose guide better this works well and can achieve excellent accuracy when everything else is right. Of course it will give purists the vapors because it is making the bullet more out of round than it was. But contrary to much opinion, CBs don't have to be perfectly round to win matches against shooters with round bullets.

if you need more diameter to seal and avoid leading it may or may not be helpful.

John

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David Reiss posted this 20 October 2016

There you go, from the mouth of our president. His wisdom has taught me something new. Always knew that my toothpicks wedged in weren't that great and made really weird looking bullets:shock: John, that is a great tip, you should write a book on 101 cast bullet tips. :dude:

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
- Also deal in: Land, Banjos, Nails, Firearms, Manure, Fly Swatters, Used Cars, Whisky, Racing Forms, Rare Antiquities, Lead, Used Keyboard Keys, Good Dogs, Pith Helmets & Zulu Headdresses. .

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onondaga posted this 20 October 2016

Beagling and bumping up can get bullets big enough to pass an ink test in your chamber. Chamber casting works and so does pound casting with lead in your chamber to suggest bullet size for verification by ink and feel.

Consider what you are looking for, and do your best to get bullet size established.  Many never do any of this at all and keep looking for a simpler and easier way. I hope someone does find it.

Sure, some depend on bullets bumping themselves up upon firing. There is a variety of solutions. The worst solution is doing nothing and checking nothing and being lazy enough to do neither while expecting others make it easier for you.

These are not jacketed bullets made to standards, cast bullets need individual fit. If you are unwilling to do that, you are wasting your time complaining and failing. Shoot jacketed bullets instead.

Gary

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R. Dupraz posted this 20 October 2016

Before you build a house, one needs to know the dimensions of it and all the parts “before” you start.   “But, what do you think, if a bullet leads or is inaccurate, is the logical first place to look for the problem bullet diameter?"   Yes.    

"To take this another step, can we say if one does not start with some sort of bore/throat measurement, then order a mold made for that diameter, we are just guessing around when we buy a mold for the “standard"diameter for the cartridge in question?  Particularly with older guns, and calibers that are not well-standardized?"   Yes.   Your questions  could take a full page in the Fouling Shot but this is as brief as I can make it.   In the case of a new caster who has no suitable molds and bullets to try for a fit and depending on the type of firearm, a pound cast of the throat, leade and bore at the breach end will first find out if there is a throat and also give it's dimensions as well as dimensions of the leade and bore. Then order a suitable mold that drops bullets of at least this diameter and at a length consistent with the twist. NOE gives that info for all their molds. Or order a custom one. I do this as a matter of routine with any new/old rifle or pistol and then keep the slugs for future reference.   For some one who already has molds of the same caliber that might work, one can see how it or they fit into the mouth of a case that has been fired with a full house jacketed load. If they are less than just a sliding fit with a small amount of interference, the mold can be “Beagled” The best way that I have found to do this is to use furnace installers aluminum duct tape. One thickness will increase the diameter of the bullet by about .001” + and sticks to the blocks but still can be removed if desired. It will stay put if the temp of the melt stays below 750 or so. Then the shooter can check for seating depth and fit in the leade/throat by blackening with a permanent magic marker.            

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gpidaho posted this 20 October 2016

First, I agree with Mr. Dupraz that you should do a pound cast to see just what you have. It is also a good idea to measure the inside diameter of a fired full house load for the maximum sized bullet your chamber will allow along with slugging the bore. You don't want to build a round that fits the bore and find it won't chamber being over sized in the neck of the chamber. I've found this in worn Euro military rifles. Second, I've had good success with powder coating to add dimension to bullets. Tests have shown PC to be near 40 BHN when properly cured. I can “Bump up” a bullet by around .003 with just one coat of PC. This has been especially helpful to me with the inexpensive Lee moulds where the noses on the bore riders seem to always be too small. NOE makes a very handy sizing tool with changeable bushings to get both nose and body measurements just right. Gp

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Dirtybore posted this 30 October 2016

M3 Mitch: you didn't say if your 348 is an original Winchester or a Browning. I have the Browning and Japan didn't give it a SAAMI spec lead. It's a long story and Browning wouldn't do anything about it.

I have the Rapine 235 gr bullet mould designed by rapine and Mike Nesbit. It was designed specifically for the 348. I had plenty of trouble with it and finally ended up quenching the wheel weight bullets, using Taurak T250 for lube and dusting the bullets with mica to get them to shoot well.

The Browning's are designed to perform perfectly with jacketed bullets, which they do. The problem is, the Japanese Browning's aren't designed for cast bullet shooting.

I finally got mine to shoot well but it took over a year and lots of helpful hints from CBA members. I became pen pals with several over the years. I prefer that mode of information because i get to know a few members better and I don't often visit the Forum.

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45 2.1 posted this 30 October 2016

Dirtybore wrote: The Browning's are designed to perform perfectly with jacketed bullets, which they do. The problem is, the Japanese Browning's aren't designed for cast bullet shooting. Send Veral Smith at LBT an impact throat slug. He can send you a mold to perfectly fit your rifle as he did mine. My mold gave bolt action accuracy out of a lever gun.

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M3 Mitch posted this 31 October 2016

Dirtybore wrote: M3 Mitch: you didn't say if your 348 is an original Winchester or a Browning. I have the Browning and Japan didn't give it a SAAMI spec lead. It's a long story and Browning wouldn't do anything about it.

I have the Rapine 235 gr bullet mould designed by rapine and Mike Nesbit. It was designed specifically for the 348. I had plenty of trouble with it and finally ended up quenching the wheel weight bullets, using Taurak T250 for lube and dusting the bullets with mica to get them to shoot well.

The Browning's are designed to perform perfectly with jacketed bullets, which they do. The problem is, the Japanese Browning's aren't designed for cast bullet shooting.

I finally got mine to shoot well but it took over a year and lots of helpful hints from CBA members. I became pen pals with several over the years. I prefer that mode of information because i get to know a few members better and I don't often visit the Forum.Mine is an original Winchester, not a Miroku.  It shoots decently with the one bullet I can currently cast, I think about 200 grains, from an old bronze NEI mold that I bought shortly after the gun.  Good info to get out there that we cast shooters should hold out for a “real” Winchester.  I am thinking about ordering an LBT or similar, oddly enough the NEI bullet is rather too pointed for my taste, both in a tube magazine and for possible hunting.

I have never liked to buy Japanese made guns.  I am very OK with European, Russian, whatever, but Japan has such damn awful gun laws, and very few hunters, I want my guns built by guys who shoot.  I am perfectly OK with Japanese cars, motorcycles, electronics, cameras, etc.  But I just don't like buying guns from them.  My loss I guess, I know Miroku has some good values on objectively good gats, but there you go.

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