The perfect cartridge case for cast bullets is ...

[9.3X62AL]

Great discussion here. I'm fond of the 30-30 WCF for a number of reasons in the context of cast boolits, all of which were mentioned above. The 45-70 is another chambering I like a lot. These are both "natural" cast boolit calibers, and lots of casters have them in their gun safes. The 30-06 has treated me well, too.

The less commonly-used cast calibers call to me also. I have had wonderful luck with the 243 Win in my Rem 788 using the RCBS 95 SP (thanks again, Uncle Ray). Lyman Loverins did almost as well. The 250 Savage has been a fine cast boolit rifle for me, my 1930-made Savage 99 and its 1-14" twist get along well with castings up to 100 grains.

I've driveled on ad nauseum about the 9.3 x 62 since I got it in 2002, so I won't belabor that further--but I do enjoy its fine work with castings.

These are my "rifle favorites" with cast boolits.

[felix]

None, Charles. It is more perception than anything. In some situations, a long neck can hurt things, like when it won't let a boolit center itself into the barrel. Looser fitting boolits within the case show greater accuracy for the most part, but their cartridges are typically too difficult to handle outside of the target range. ... felix

[Bass Ackward]

John, I remember you posting boolits with huge lube capacity. Have you changed your mind on this? I for one don't like harder lubes and lube shouldn't cost enough to be much of a consideration with several suppliers now.

More importantly than case design to me is throat design. Your going to have to explain, you have said in past threads that the throat changes rapidly. If so, you would loose your prime dimensions immediately. Especially if you want the flexibility to shoot soft lead for hunting or if you simply want to avoid the abrasive nature of antimony. Hmmm

And of coarse you haven't discovered the cast bullet bore diameter yet either. Only important for the nose diameter.

Now Bob,

Bullets with huge lube capacity? That was a semi wadcutter for a rifle. It was designed that way for less lube in winter and more in the summer, since a semi wadcutter scrapes everything out ahead of it. That was a 2000 fps plus, 45 caliber bullet design. I change lubes from winter lubes to summer also. Always soft. When using olgival designs, you don't need and DON"T WANT as much lube. So no change in my thought process.

My throats lengthen rapidly under pressure with antimony bullets. The ball seat portion doesn't change. My 35 started out with a 210 grainer, went to a 220, then a 250, and now has stabilized so a 255 meets my requirements. All in less than 800 rounds. But a fairly tight ball seat supports my bullets and allows me to run the same velocities as guys with tapered throats that need WDWW to achieve.


Molly,

Antimony is a rock. It posses abrasive qualities. While antimony has been around since the begining of time, many ol timers with big names wouldn't shoot any lead if antimony was present. You can shoot a lead / tin mix forever and only the guy who get's your guns may see any change. But put antimony under pressure and it will wear a throat faster than copper.

And the 35 bore was the discovery you needed to make.

[Nueces]

Molly, I think yours is a cool idea. My own thoughts have run toward the 300 Savage case, just because I have a 722 so chambered. My plan has been to make cases from 308s and trim to max length allowed by the factory chamber, yielding a small gain.

More could be gained by your idea of lengthening the chamber neck portion, a nice option. The 300 sharp shoulder would provide increased neck length in a 308-length case. I don't have any reamers to measure, but I checked the cartridge drawings in Wolfe's 'The Illustated Reference of Cartridge Dimensions.' The 308 neck is shown as a straight 0.343 in diameter, while the 30-40 neck tapers from 0.339 at the shoulder to 0.338 at the mouth. I found no other 30 case with a neck as large as the 308 (beside the 308 x 1 1/2). The 300 neck tapers from 0.3405 to 0.339.

Looks like a custom reamer would be necessary to lengthen either neck. If I were to go this way, I'd open my 300 neck up to 308 size, since that's where the cases would come from, and this would cut down on neck turning. The shoulder of a 308 reamer is too large for use in a 300 chamber.

Might go halfies with you on the reamer.

Mark

ps - We need a smilie that connotes blue-sky wool-gathering like this

[leftiye]

Nueces and Molly, You might consider buying the correct sized decimal chucking reamer from MSC. A lot cheaper, and almost no waiting time.

If you want a pilot then grind off the flutes at the front and fit a bore dia. O.D. sleeve over the front of the shaft. Actually, this is probably unnecessary, as the reamer should self center quite well while cutting if you only take about ten thou. at a time. You can taper it if desired by hand if it's only a thou., and you'll have to reconstruct/reshape the front cutting edgesif you make the pilot.

If you were to use a throating reamer first, and remove the rifling as far as you wanted to extend the neck, then the aforementioned reamer should cut smoothly (not catch on the rifling), and remove the excess throat.

What's your idea as to how tight/loose a chambers neck portion should be on the case?

[drinks]

Molly;
You have overlooked the .303 Savage, a lot longer neck than the .308 or .30-30, slightly more case capacity than the .30-30 and with a rim, which the .308 is missing.
Easily made from.220 Swift brass and the fibbing varmits at Gaff & Son keep promising to have some new brass at affordable prices, not the $1.50 a case of the sorry Bretram brass.

[Obsolete]

Well on paper the 348 Win looks promising and does have some history of being necked up to 40 and 45 cal.I have zero expirence with the 348 Win.... Anyone else using it with cast boolits ?

[Marlin Junky]

Two cartridges that I would like to see on a nice short action would be the .30 and .32 Remington. Has anyone had a chance to play with the .338 Federal yet?

MJ

[Molly]

Bass,

> My throats lengthen rapidly under pressure with antimony bullets.
> Antimony is a rock. It posses abrasive qualities. While antimony has been around since the begining of time, many ol timers with big names wouldn't shoot any lead if antimony was present. ... antimony under pressure and it will wear a throat faster than copper.

Ummm... Well, this isn't an area in which I have a great deal of personal experience, but I'm under the impression that those who HAVE studied the question generally attribute throat erosion to tempeatre effects: I've had it explained that the exceedingly high temperature of high pressure loads actually liquifies (melts) a micro-thin layer of the steel surface ofthe bore. As soon as the bullet has progressed down the barrel, the gas expansion cools the gas to the point that the remainder of the bore isn't liquified. That's what limits errosion to the throat, instead of the entire bore. Once the gas temperature has dropped, the micro-thin liquified steel is instantly quenched by the rest of the metal in the barrel, which is much cooler. But this only sets up the real problem: The bore surface is now much harder than the rest of the barrel metal, as is typical of quenched steel. When the next shot is fired, the same pressure that pushes the bullet down the barrel also causes the barrel to expand very, very slightly, much like a balloon expands under pressure. The brittle layer cracks instead of expanding. These cracks continue to grow and embrittle with each continued shot, until they are large enough to be actually broken off by the bullet's passage. This seems to be consistent with the fact that it's the high velocity rounds (220 Swift, etc) generally have a lot more problem with erosion than lower pressure (which equates to lower temperature) rounds like the 30-30, even though they use the same metal in their jacketed bullets.

You are the first person I've encountered who attributes erosion to the bullet itself. Interesting. Could you explain why a copper (or antimony alloy) bullet doesn't wear the entire bore uniformly?

Oh, and antimony is NOT a rock. It's a metal. More precisely, in cast bullet alloys, it's generally present in the form of Sb-SN, an intermetallic alloy. And it's a great deal softer than the typcal copper jacket. Why would it be more abrasive?

You are right that a few of the old timers refused to use antimonial alloys, but the accounts I've read of those days didn't complain about abrasion, they complained about the lack of accuracy of antimonial alloys. Now we can understand that this was probably because the antimony hardened the lead, and their bullets wouldn't upset uniformly and consistently like lead-tim alloys.

> And the 35 bore was the discovery you needed to make.

Ahh, no. If you re-read my original post, I discounted the larger bores because they are too destructive on small game. I HAVE played with 35 bore rifles a good deal, and know this to my own satisfaction.

[Molly]

Mark

> More could be gained by your idea of lengthening the chamber neck portion, a nice option. The 300 sharp shoulder would provide increased neck length in a 308-length case. I don't have any reamers to measure, but I checked the cartridge drawings in Wolfe's 'The Illustated Reference of Cartridge Dimensions.' The 308 neck is shown as a straight 0.343 in diameter, while the 30-40 neck tapers from 0.339 at the shoulder to 0.338 at the mouth. I found no other 30 case with a neck as large as the 308 (beside the 308 x 1 1/2). The 300 neck tapers from 0.3405 to 0.339.

> Looks like a custom reamer would be necessary to lengthen either neck.

Umm. yes, in theory you're right. But take it from a former gunsmith, in the real world, there are manufacturing tolerances to deal with in the cases, as well as in the chambers themselves. (That's why there are "go"-"no go" guages.) The 30-40 Krag was a 30 caliber, right? That's SUPPOSED to be a .300 bore and a .308 groove diameter. But the smallest Krag bore I ever measured went 0.310". Most were 0.311 - 0.312, and I've seen them go 0.314! Trust me, a little fine sandpaper on a dowel will sometimes do wonders in chamber work.

[Molly]

> You might consider buying the correct sized decimal chucking reamer from MSC. A lot cheaper, and almost no waiting time.

Excellent thought! Sometimes I'm too close to the woods to see the trees!

> What's your idea as to how tight/loose a chambers neck portion should be on the case?

Despite a great deal of delight in theories, I'm not a purist, I'm a pragmatic. I've never worked with a "tight chamber" to any extent. From what I've read, most of those who have tried them found themselves rechambering in pretty short order.

That said, when (not if) I do this I expect to make a chamber cast, measure the neck diameter of the rifle in question, and try to duplicate that for the throat extension. If I can find a 30-40 reamer to do the job, all the better.

[Molly]

Hi Drinks,

> You have overlooked the .303 Savage, a lot longer neck than the .308 or .30-30, slightly more case capacity than the .30-30 and with a rim, which the .308 is missing.

Ah, not so. I've used the 303 Savage a fair bit, and got good results with it. But I don't regard the rim as an advantage, because bolt action rifles (which I strongly favor) generally don't feed well with them. BTW, you can make servicable ammo for it with 30-30 brass. Worked for me back when, though I'd probably build up the base a trifle with half an inch of telescoping tubing if I were to do it today.

[Frank46]

OK, here goes. Some schutzen shooters at one time played around with the lowly 32-20 case. They found that they could launch saeco's 175gr tapered benchrest bullet at respectible velocities while shooting at those ring targets. Thus you would need to not neck down your 8mm case to fit a 308 chamber. But your idea has much going for it. You get to keep all or most of the lubricated portion of the bullet inside the case. That in itself is a worthwhile goal. In shooting the 7x62x54 russian case with lyman's 314299 that is an impossibility. Especially if you seat out far enough to get yourbullets out to engage the rifling. Course since they are so long they don't readily feed from the magazine. I usually let them lay partially in the mag so the bolt can do the final seating. Can't do anything about that. Very good idea. Frank

[PPpastordon]

"And the 35 bore was the discovery you needed to make."

While it is true that a .35 might do more damage on small game, at low velocity it is still quite satisfactory for many. Some even use larger calibers. I have a friend who commonly uses his .45 Colt for small game. He uses slow, round nose bullets. He says, as Elmer Keith used to say, "You can eat right up to the bullet hole." He has also commented that these loads are easy to tell from his usual loads.
There are still .35 caliber fans out there and a long neck .358 Winchester can be as easily made as the long neck .308. While the long neck can cover more boolit, it therefore potentially covers more (or all) of the lube. Besides; some people simply like longer necks.
I like cases with long necks - and I am a .35 fan. Years ago I had a long necked .35 rifle on the .30-30 opened to .35 caliber. However, I personally like straight sided rounds that also fit in a revolver. The .357 Mag., DW, and Max are all quite good for me. The DW fits nice on Ruger SA's.

Molly, I know that doesn't help you a bit. But it might help the .35 fans out there.

[Molly]

Hi Frank,

> ... Some schutzen shooters at one time played around with the lowly 32-20 case. They found that they could launch saeco's 175gr tapered benchrest bullet at respectible velocities while shooting at those ring targets.

That approach has also been seen in the CBA. I had the remarkable experience of watching a fellow competitor drop ten consecutives into a 200 yard target, any one of which would have hit my thumbnail. And he was using something quite close to that. And I dearly love the 32-20: I have a couple of Martini Cadets so chambered - with modern barrel liners - and an almost new S&W M&P revolver for it. But as neat a little round as it is, I don't feel comfortable deer hunting with it. No doubt it will kill deer, but then so would a .22 LR - and I'm not going that route either. The deer deserve greater respect.

> ... But your idea has much going for it. You get to keep all or most of the lubricated portion of the bullet inside the case. That in itself is a worthwhile goal. In shooting the 7x62x54 russian case with lyman's 314299 that is an impossibility. Especially if you seat out far enough to get your bullets out to engage the rifling.

Exactly right. And that's why the 7.62x54R didn't make the short list either.

[Molly]

Hi PPpastordon;

> While it is true that a .35 might do more damage on small game, at low velocity it is still quite satisfactory for many. Some even use larger calibers.

Well, all I can say is that I remember an article on squib loads of years ago. (Maybe Gun digest) The author gave some really good tips, but the one that has stuck with me was his development of squib loads for a 45-70. I don't recall the details, but I do recall his description of the results. It went something to the effect of "I really thought I had something. And when I shot the first squirrel with it, I DID have something. I had a two-piece squirrel." (BG)

Seriously, the larger calibers have some major drawbacks for small game: Unless loaded VERY lightly, they are still quite destructive. And when loaded THAT lightly, they have trajectories that are not too dissimilar to that of a safe dropped off of the roof.

> There are still .35 caliber fans out there and a long neck .358 Winchester can be as easily made as the long neck .308. ... I like cases with long necks - and I am a .35 fan. Years ago I had a long necked .35 rifle on the .30-30 opened to .35 caliber.

I'm a fan of the 35 bore too. I've owned several of them, including the 358 Win, and I've seriously considered buying the 35.30-30. I've also looked longingly at the 35 Whelan. But they're a bit too specialized for me. I find that - excellent though they are - the 30 bore is a better all-around choice for my needs.

[Bass Ackward]

Molly,

I have many examples. What you describe with cracking is high pressure wear. You will NEVER see that even with high pressure cast as it is continually worn away. Tubbs made his throat maintainance system to remove that hard layer every so often.

What lead does is polish very well. Where powder roughs up the bore surface, lead will smooth it. The more antimony, the less time. I have an 06 in Remington stainless, a 35 Whelen in Shilean chrome molly, and a Krieger 458X2 that all have throat wear out to the point where the powder impact or heat or what ever has roughed up the bore.

The two bottle neck examples NEVER have been run over 40,000 psi and never heated up. The 458X2 has seen 70,000 psi. Benchrest cast rifles will have throat wear to the point of barrel replacement in 1000 rounds while still having tool marks in the bore. Why so much slower wear than my results? They are shooting hard lead. I shoot soft and thus the pressure limit. Soft lead deforms more under pressure and thus opens throats faster.

If I shoot fast powders for cast velocities, I shoot rock hard. When I need to go fast for hunting, I go soft. I use magnum rifle primers for fast loads to burn the powder in the case and I use pistol pistol primers for the high velocity, slow powder stuff. Sorta Bass Ackward from conventional thought. I have been told that Freedom Arms warns about shooting soft lead causing increased forcing cone wear because of increased deformation of the base, but I have not found that yet.

Dan at Mountain molds took his chrome molly 30-06 Remington from .311 to .318 in less than 1000 high pressure rounds. The data is included in all of his post relating to high pressure testing he was conducting. He makes custom molds at Mountain Molds.

My antimony comes in little rock shapes before blended. It will engrave steel when you test it just like a diamond.

[drinks]

Molly;
Yes, I have made .303 cases by cutting .3" off a .40 S&W case and pressing it over a .30-30 case and even simpler, using the SS trim tape from the autoparts and cutting .3" wide strips and wrapping the case with it until it is .440" just at the body/head junction.

[felix]

Molly, the BassAckward(BA) words are true. Antimony is your friend when you have a new gun because it will smooth out the barrel to make for mo'betta' cast rounds. Typically, the abrasiveness will be minimized when the amount of tin surrounds all of the antimony, which is assumed to be when they are equal in proportion by volume, by weight, or maybe its on a molecular basis. The so called 90-5-5, Lyman #2, is supposed to be this-a-way. Antimony crystals are sharp, tin crystals are smooth in comparision. So, luckily tin will surround antimony at the expense of pushing actual lead out of the way at the points of junction. ... felix

Yes, we are shooting rocks. It just so happens the rocks we shoot are mostly metallic in nature. The familiar term of rock is nothing than an alloy of a bunch of materials, where only some constitutents are metallic in nature. In fact, the aluminum folks have been raising the silicon content high enough to allow the minimization of expansion of aluminum in a engine, so the tolerances can be made tighter between piston and bore. Engines that can last 200K miles versus 50K with the same compression/gasoline ratios. ... felix

[Molly]

Felix, BassAckward,

> Antimony is your friend when you have a new gun because it will smooth out the barrel to make for mo'betta' cast rounds. ... Antimony crystals are sharp, tin crystals are smooth in comparision.

You know, I’ve long felt that the best friend I have is someone who teaches me something new. And while I have absolutely no reason to think you guys are reporting exactly what you’ve observed, your explanation of it was so new to me, and you were so sure of it that I decided to do a bit of research; Here’s what I found.

From: environmentalchemistry.com
Hardness Scale (Sb) (Fe)
Brinell: (MN m-2 ) 294 490
Mohs: 3 4

Other sources gave similar values, though they were not all in exact agreement. For example, Sb was quoted with hardness up to 3.3 Mohs, and Fe up to 4.5 Mohs.

If you are not familiar with Mohs hardness, it is a scratch test, while Brinell is a penetration test. They don’t measure quite the same things, but as you can see, they’re close to one another proportionally. The thing about the Mohs test is that it’s logarithmic. Each level is TEN TIMES as hard as the level below it. So iron alone is roughly ten times as hard as antimony. And that’s just soft, unalloyed elemental iron. I’d expect modern steel alloys to have an even greater margin of hardness over antimony.

So it looks like what you are telling me seems like saying that you’ve worn hard steel away with a soft abrasive. I suppose that’s possible, but I’d tend to suspect that your soft material has picked up some pretty hard grit somewhere. If you’ve scratched a steel surface with antimony, I believe I’d suspect some sort of contamination in your antimony.

The only other explanation that occurs to me is that what you are seeing as a scratch mark on the steel is actually a smear of antimony left behind, much like chalk will leave a smear of dust on a blackboard. In either case, you’d be looking at fresh white metal, and it would be easy to do. Is this possible?

Hope you find this interesting.