Came across a RPM limit given for cast bullets of 130,000. Anyone know if there is a technical basis for this? If there is, is it based on a standard alloy like Lyman #2 or maybe wheelweights?

Nels

We had a contest once put on by Mountain Dan, he bet any takers a free mold they couldn't exceed 120,000 rpm out of a Swedish Mauser (that's 2,020 fps) while shooting any known cast bullet three one after another minute of angle groups.

More'n few tried, but nobody took his mold. A mathematical relationship between spin rate, diameter and bullet length was proposed and seemed to somewhat predict 6.5 bullet perfomance based on those criteria.

Yes, there is something behind that thought. You might get up to those spin rates in a very short for the caliber bullet, but you will not get stellar accuracy.

Oldfeller

Where did you find that information? In "The Art of Bullet Casting", there are articles about extremely good accuracy (less than moa) with heat treated cast bullets. I am talking about velocities in excess of 3k... And the paper patching guys do the same thing.

quote:

Originally posted by Nelsdou:
Came across a RPM limit given for cast bullets of 130,000. Anyone know if there is a technical basis for this? If there is, is it based on a standard alloy like Lyman #2 or maybe wheelweights?

Nels

Can't be quite that simple. Diameter has to play a role. Angular momentum is the issue rather than simple rpms. At some point the angular momentum exceeds the yield strength of the material.

As Oldfeller pointed out, length plays a role, too. I'm unclear on why it does, but I'm sure he's right about that.

I was the one that come the closest to winning that 200,000 rpm contest spoken of here. In fact Oldfeller thougth I was going to do it. The round was a 7mm-08 out of my Sako, the bullet a Lee 135 gr of very high linotype content and heat treated. The powder was IMR 4350 and the velocity I got was 2640 fps and the accuracy was under an inch at 100 yards. Problem was for the contest you had to fire 5 shot groups, and you had to shoot five of those groups without cleaning the gun. Now the problem for me was the rifle and the scope. See, the rifle was Sako Mannlicher carbine with 18.5 inch barrel and wore a mini 3x9 Burris scope. Oldfeller said "Joe put your 6x24 scope on the rifle." I wouldn't do it. So for a wood to the end of the barrel rifle, with a small scope, I think I done well. I know I would have done better and possibly beat it with a full size rifle, or just the better scope.

The rpm of my bullet was just a hair over 200,000.

On another case I was shooting 70 gr 22 caliber cast bullets out of my AR15 with 1-7 twist. Althought accuracy wasn't great, the bullets sure didn't fly off into the Oldfeller Zone, and I was shooting them at 3000 fps. That's well into the 300,000 rpm bracket.

Joe

Good stuff. OK, sounds like the 130,000 rpm is a generalization of sorts that applies to some calibers, and not necessarily to the harder alloys like linotype. I can understand that.

Now a point on math; appears Joe's Sako has a barrel one in 9 twist that corresponds to 200,000+ rpm/~2600 fps. But Swedish mausers have a one in 7.87 twist. 120,000 rpms would correspond to ~1312 fps, and 2020 fps corresponds to 184,800 rpms, so Oldfeller, maybe you have a typo in there? Or were you using a barrel of a different twist?

Nels

Well here's what I get and how I did it. My Sako by the way has a 9.5 twist. We use a constant figure of 720. So 720x2640 (my muzzle velocity) divided by 9.5 (the twist)= 200084 rpm. So lets see what we get for Oldfellers spin, using your twist. Yup got about what you got 184803 rpm. Look at my AR15 with the 7 twist. I get 308571 rpm. So looks like oldfellers numbers are off some.

Joe

Naw, Nelsdou I got something more basic -- an aging memory that ain't worth doodley for fine details a year or three out from the event.

Joe didn't tell you that he was the only "straight" contestant left by the end of the contest -- since Mountain Dan kept changing the rules (and he did) and he forgot to say we couldn't cheat I machined up some VERY short 6.5 bullets, trued up the gas check bases on the same lathe set up and shot almost 3 winning groups in a row and posted them. But everyone knew the only part of those sub-length slugs that wasn't machined was the bottom of the lube grooves, so I never tried to claim a prize or anything like that.

What this did was allow me to do was verify the theory that bullet length and caliber and rpm do play against each other. I also made some full length slugs (cruise missiles) with a large steel dowel pin inserted straight down the middle of them, this to prove out the theory that mechanical strength of lead wasn't up to the stress put on it. These bionic slugs did shoot marginally better (shooting was done by Buckshot so it was impartial).

The Swede and its bullets push bullet length and
RPM to the max at a very skinny diameter (especially in cast slugs with lube grooves to weaken the structure)

That 130,000 may be a best accuracy number, run it against a 10 twist and see if it doesn't get somewhere close to 1,300 -1,600 fps (which is emperically known as the 30 caliber "sweet spot").

Oldfeller

Isn't the issue predicated on alloy yield strength and bullet fit in the throat? I keep hearing 1442 x Bhn = pressure to obdurate, and not much higher number starts to strip in most calibers under .358", or twists faster than about 11:1".

Rich

Well as oldfeller admitted few post ahead of this that he believes the faster the twist the more the length of the bullet becomes critical. Few others on the "that other forum" believe that too. I sorta believe it to a degree and not the one we've seen so far in the Swede or my AR15 with the 7 twist. Let me tell you that a 70 gr 22 cast bullet is every bit as skinny and long as is a 6.5 long skinny bullet. The guys on "that other forum" have tales of the 6.5 Swede bullet bending and flying off into never never land. Well just didn't happen with those long skinny 22 caliber bullets out of my 7 twist AR15 at 3000 fps. Won't sit here and type lies to you, it sure wasn't minute of varmint angle at 100 yards, BUT every and I mean every bullet hit the target. None bent and flew off to that never land. These were not linotype either. I still think that there is "just something" about the 6.5 bore. I have a 260 Rem with a 9 twist. Note, that's much slower then what the 96 Swedes use, and although it shoots pretty good at low velocities, it doesn't want to shoot at the higher ones. Oh it will shoot a few, then go south on me. But...none of the bullets go to never land. So I don't know. I have a new 6.5 caliber and that is the 6.5 Grendel. The twist is 1 in 8. So we'll see what it does.

Joe

Idaho, issues with the cruise missile weren't fit related, the slugs fit the Swede's throat like a glove (designed that way). Powder pressure was checked, and yes slower powders were slightly better (worth maybe an extra 500-1000 fps before "dizzyness" took place). They were tried both hard and soft. Still, if you went over 1,900 fps your groups opened up drastically. If you went over 2,100 fps you didn't hit the backstop very often. You could drive the slugs up to 2,600 fps without leading the bore (I did it many times).

At those speeds the gun would lay over strongly from the rifling spin up effects. I didn't see any hits on backstop or hillside worth talking about, except to say they seemed to be off to the right ...

It's funny, at that point in time I considered the bullet to be a failure and started investigating a mathematical tool to keep from ever again making bullets that were too long for the caliber. However, the mold remains popular and sells well even now as at 1,650 fps boosted with slow powder people keep posting 1 inch groups they shot with it. At that speed it will penetrate and penetrate and penetrate and penetrate. It fires like a very mild acting thing at 1,650 fps. Folks have shot & easily killed deer with it.

Kelly

Guess it's time for me to jump in here as I'm the one on a couple other forums generally refers to the 130,000 to 135,000 RPM limit for best accuracy with cast bullets. I did not come up with it and honestly don't recall who did. I would gladly pass the credit to them. The general RPM limit refers to bullets cast from the readily available commercial moulds most of us have access to when fired in most rifles, commercial or milsurp. It refers to the RPM limit of these bullets to obtain the best accuracy that bullet and rifle combo are capable of. We all realized that some pretty accurate shooting has been done with custom moulds in custom barrels at pretty high velocity but those are the exceptions, not the rule. This comes up most often when someone says they want an accurate cast bullet load at 2200 fps out of their '06. First question in my mind is; what is accurate?. To me "accurate is the most consistant grouping load over the practical rangge of its use. To me there's a world of difference between a load only shot off hand at 50 yards and one used for target shooting out to 300 yards. If the '06 has the usual 1-10" twist then the most accurate load isn't going to be at 2200 fps (158,400 RPM). It will be down around 1800 fps (129,600 RPM) 1900 fps (136,800 RPM). For the 6.5 Swede it is around 1400 (129,360 RPM to 1500 (138,600 RPM). As mentioned the length of the bullet, the smoothness of the barrel, the burning rate of the powder, and numerous other factors can influence the RPM limit somewhat but not a great deal.

Joe (Starmetel) and I have discussed this at length. He still thinks he got "acceptable accuracy" with his AR cast bullet loads. I think the accuracy sucked. Boils down to what your style of shooting is and what is "accuracy" to you. Doesn't change the fact that the best accuracy will come at or under the 130-135,000 RPM limit.

Larry Gibson

Larry,

No no no no....I do not think I got acceptable accuracy out of my AR with that long cast bullet. I merely used that information to say that the bullet was long for caliber, very long, and the twist was fast, very fast, and all I meant to rely here was that my BULLETS DID NOT DISAPPEAR. That's all. The ONLY reason I shot those and that fast was to prove that the fast twist and a long bullet wasn't bending them from the high spin...at least not with a long 22 caliber bullet. For just a basic alloy that wasn't linotype, I'm surprised that at 3000 fps those bullets weren't stripped down that 7 twist barrel. The holes in the target, by the way, were round too, not one of those bullets key holed. There's one person on your forum that can get the accuracy from high velocity cast loads in the 6.5 Swede and that is 45 2.1.

To me acceptable accuracy is 2 inches, good accuracy is 1 inch, and very good accuracy is 1/2 inch...for my cast bullet shooting.

Gawd...my head is still reeling that you think I thought that was good acceptable accuracy for...when it was just a test to see if they stripped or bent.

Joe

Sorry Joe, my bad....well at least I woke you up! Now that I've pinned you down on what accuracy is to you I'll hold you to it as that's pretty much how I see it...great minds thinking alike again. I've discussed 45 2.1's loads with him. He is using specially designed bullets and get more anal about his loading techniques than the average guy. Remember I said the RPM limitation applied to regular designs out of regular rifles that 99% of the cast bullet rifle shooters use. I too have gotten some pretty good velocity out of my M70 .308 target rifle with special bullets at high velocity/RPM but I don't get that accuracy with a regular cast bullet such as 311291. With that bullet in the M70s 1-12" twist I can push 2200 fps (132,000 RPM) and maintain 1 to 1 1/2 MOA at 100 yards IF I get anal about culling defective bullets. WITHOUT being anal culling the bullets the goup MOA jumps up to 3+ MOA. I get the same 1 to 1 1/2 moa accuracy down around 1900 fps (114,000 RPM) and can get consistant sub MOA around 1700 - 1800 (102,000 - 108,000 RPM) without any anal culling. Getting the extra fps isn't that important to cull out a large percentage of the bullets I've cast. Just me, 45 2.1 does some good shooting and I've no argument with his way.

Larry Gibson

Larry,

I would say I'm going to have to break down and buy a 6.5 Swede, but with this AR15 I build in 6.5, I'll skip till I see what this does with cast. I am working with a very very short throat though. Only commercial bullet that may fit is the Saeco 140 gr, which is about 2/3 bore rider. We will see. The twist in for this round is 8, so should be interesting.

I'm still amazed the Lee 135 gr 7mm shot just beautifully in my 7mm-08 at 2640 fps. The rifle has a 9.5 twist. Even more amazing was my double gas checking kept the bore every bit as clean as shooting jacketed. Didn't even get that greasy black from the lube, or dry black. Only thing I can figure is MAYBE that with high velocity loads in that caliber the powder gases may be burning the bore clean of the normal lube crap...sort of like a self cleaning oven. The double checks gave a super seal too. That has to be an awesome varmint load and I'll try it out when I get the chance.

Joe

quote:

Originally posted by Larry Gibson: I've discussed 45 2.1's loads with him. He is using specially designed bullets and get more anal about his loading techniques than the average guy. Just me, 45 2.1 does some good shooting and I've no argument with his way.
Larry Gibson

We have discussed several things, but I haven't said exactly what I do. You have posted that I use BR methods and am anal about my loading. How you can say that without knowing what i'm doing is very subjective. I have achieved a lot higher velocities with the Swede than anything that has been posted with STANDARD Lyman boolits with excellent accuracy. I don't weigh or do much boolit sorting either. Ask Joe how my boolits shot as he has some of them. I don't sort or prepare cases via BR methods, I do use reformed military cases to get a thicker neck though. As far as us doing the same thing, I doubt that or else you would be posting about high velocities with accuracy with the Swede also. I use easy to do, somewhat unusual methodology to get the results I do. I have taught a couple of other guys on the other board how to do the same and they found out it works fine. Over a couple of years, I have posted everything you need to know on how to get velocity out of the Swede with not much comment from anybody. I guess that everyone elses self imposed limit of 1650 fps for the Swede suits them fine.

Yeah, 45 2.1 is telling the truth. I do have some bullets from him and they are ordinary bullets from over the counter moulds. Now not sure if the mould number is still available, but they aren't custom ones. He uses a certain alloy blend which isn't exotic either. Using military brass and getting the thickness neck that will still feed and still have room to expand and release the bullet certainly helps a lot. Bob's right about not weighing the bullets and all that stuff too. I wouldn't say he's anal about the reloading, he's just found what works for those Swedes. He's right too that everyone reads what the others say about that self imposed velocity limit and don't even try to beat it. One reason I'm not on that forum, I went again the grain...or outside the envelope, thus why all the arguments with me.

Joe

Don't get your dander up guys we're about 99% on the same page here. I didn't say 45 2.1 WAS anal. I said you use more anal techniques than I like to use. We have discussed your loading techniques and you have given lots of advise on that other forum. I read your posts because you are always giving very good advice. If my subjective perception was that you give the advice out of experience and knowledge based on your loading techniques was wrong then I apologise for the mistake. I believe I also said you did some "fine shooting" with your loads but I really don't believe that I was wrong in either case.

The point here is some of us (myself included) have used more anal technique (my description of paying closer attention to minute details or BR techniques if you will) and produce good accuracy at higher velocity/RPM that is normally achieved. The normal caster with normal cast bullets in normal rifles with normal reloading techniques is in fact not going to achieve the best accuracy above 130-135,000 RPM. In other words they are not going to get good accuracy (2 MOA or less at 100 yards) from a 140 gr cast bullet out of a 6.5 Swede with a 1-7.8" twist barrel at 2400 fps using normal loading techniques.

Ask ourselves this; how many times is the normal cast bullet shooter going to use TWO gas checks? Starmetal is the first I've read about it in years and quite frankly I've never done it! Most of them are sniveling about the cost of one GC let alone use two! Such techniques are not normal.

Tell you what; I currently have 4 Swedes with military barrels all in good condition, two with scopes and excellent shooters. I would really appreciate the finer details of 45 2.1's 6.5x55 loads (bullet mould, lube, size, GC, alloy, powder, cases, case prep, rifle and scope used, and any the loading techniques if any, etc.) so that I may test them to prove it one way or the other for myself. Given that opportunity to test 45 2.1's 6.5 swede loads I promiss I will shut my mouth and not utter another word about RPM until I do test them. That fair enough?

Larry Gibson

Larry,

You've heard a lot of fellows on your other forum say they shoot cast because of the economics of it, thus the reason a lot of them use small doses of pistol powders. Not me. I shoot cast because I like to shoot bullets I make. I also shoot them with rifle powders and not small doses. NRA classified the power of cast loads into three categories. Light, medium, and heavy. Most of mine are in the medium and some in the heavy, hardly any in the light. So that brings up the gas checks. I buy what I have to buy to shoot my cast loads. So I pay what it takes to buy it.

Now for those thinking about shooting double checks there are some criteria to follow. One the bullet you use must not go past the neck shoulder junction, nor even be even with it. What I do is push a gas check inverted into the case mouth, the I seat my bullet (with a check crimped on it) into the case over top the loose check I just put in there. No air space as the loose check is upside so the checks are base again base. In theory this loose check is like an over the powder wad on the old shotshells. For me it worked and made for a very clean bore. You don't want the loose check dropping into the power, so that is why you can't got past the neck shoulder junction with it. Larry I don't think that is anymore abnormal then using a filler. In a sense my second check is almost a filler because my powder was very very close to that check to give you an idea of that 7mm-08 load.

Joe

Larry, I think what you really need are some of those SPECIAL bullets Starmetal(aka Joe, MaxPayne,et al ,ad naus.)had..you know the ones that spun faster after leaving the barrel then when inside...Eh ?

quote:

Originally posted by starmetal:
Larry,

Now for those thinking about shooting double checks there are some criteria to follow. One the bullet you use must not go past the neck shoulder junction, nor even be even with it. What I do is push a gas check inverted into the case mouth, the I seat my bullet (with a check crimped on it) into the case over top the loose check I just put in there. No air space as the loose check is upside so the checks are base again base. In theory this loose check is like an over the powder wad on the old shotshells. For me it worked and made for a very clean bore. You don't want the loose check dropping into the power, so that is why you can't got past the neck shoulder junction with it. Larry I don't think that is anymore abnormal then using a filler. In a sense my second check is almost a filler because my powder was very very close to that check to give you an idea of that 7mm-08 load.

Joe

Most of my bottlenck rifle cast bullet loads fall into the medium/heavy catagory also with medium to heavy bullets for the caliber. I also use medium to slow burning powders (4895 to RL19/22 and 4831). My light loads are usually light bullets with really light charges of powder (most often Bullseye or Unique) down in the 800 to 1200 fps range. Only occasionally do I load with the slow pistol/fast rifle powders (4759, 5744, 2400, 4227, 4198, etc).

I'm going to have to try the double GC method. My 308 CBC has a long '06 neck and I should be able to use the GC without problems. It's built with a new 2 groove '03A3 barrel set back and rechambered. Shoots quite well in the 1800 - 1900 fps range. Might be interesting to see if I can get into the 2200 - 2400 fps range with the same accuracy. Guess I'm getting "anal" too!

Larry Gibson

Very interesting 45.2.1!

Now to my original question about the RPM limit. If I'm reading what 45.2.1 sez right, this RPM limit is perhaps more of a perception than fact. Just need to know the "facts".

Excuse me for my lack of cast experience, but I'm on the edge of my chair 45.2.1! Let's hear more on what it takes to avoid the "RPM Limit".

Nels

The 6.5 Swede is a graduate level cartridge and doesn't allow mistakes being made. Barrel length is your enemy as is boolit length. A load that shoots fine in a 38 will flunk in a 96. You want velocity, shoot shorter boolits.

45 2.1

So I'm up for some graduate level work. I've two rifles with M38 barrels on them; a M38 with a 2X Leupold scout scope on it an a Mexican SR M98 action sporter with a 3x9X scope and a new M38 barrel on it. Both shoot sub MOA.

To quote Starmetal; "Yeah, 45 2.1 is telling the truth. I do have some bullets from him and they are ordinary bullets from over the counter moulds." The "over the counter mould" I have is a single cavity Lyman 266455 which runs 119 gr in Linotype and 125 in WWs. I size them .266" which is a tight fit in the tw barrels throats. Is that a short enough bullet? If not what "over the counter bullet" is?

Larry Gibson

I looked into this rpm thing a few years ago when I just found out how to figure it and using the CBA BR guys as the data base came to the same conclusion that 130,000 rpm and under seemed to be the sweet spot for gas checked 30 cal bullets The plain base guys did their best at around 70,000 rpm. I shot the last few years with a 6.5 PPC and it did pretty good at 157,500 rpm using HTWW and 4350 powder. A lot of these are custom guns but the same holds true for the production class. There's so many variables in cast bullet shooting that I don't know if coming up with a spin rate has any value in load development but it's interesting to see. It would seem to me that the smaller the caliber the faster you could spin it for the simple reason that any defects would be closer to the center line of the bullet making it more balanced but that's just conjecture on my part.

Never tried double gas checks but do use a polywad in my 6.5 which probably does about the same thing. Might be a little safer and cost less too.

Starmetal, you have higher accuracy standards than I do because if I was getting consistant 100 yard half inch 3 or 5 shot groups out of a production gun I wouldn't call it very good accuracy I'd call it UNBELIEVABLY FANTASTIC accuracy, especially at the velocities you say.

Pat

Pat I,

My little Sako carbine is an amazing rifle for wood to the muzzle. It shoot's jacketed bullets very well. The Sako is the one that I really pushed cast bullets. Now my CZ 550 30-06 shoots cast better then it shoots jacketed, although I haven't tried a lot of jacketed bullet to see it would find one it really liked. But boy does it love the Lyman 311284 and the 314299. Now with that 314299 it will shoot 1/2 inch consistant, BUT not at real high velocity. It will shoot that from 1850 to 2000. Remember all my rifles don't shoot those kind of groups. Take a look at that CZ 550 30-06. First it's a heavy rifle. Second it has a set trigger which makes a world of difference. Third it wears a scope. Sako is the same escept it's just the standard Sako trigger. A lot of my other rifles are mil-surp. For example my 30-40 krag. It will shoot those two bullets mentioned to about an inch, IF I can consistantly hold it right and be able to see the target. That's getting harder with age and failing eyesight. Believe it or not one my better accurate mil-surps is my Steyr M95 Mannlicher carbine in 8x56R. That rifle is just unbelievable. First it's short, short barrel of 19.5 inches and it's a very very thin barrel, and the trigger is, well, mil-surp. With Oldfellers bullets (he designed two bullets and had the moulds made) it will consistantly shoot 7/8 in nice round groups. It wells a peep sight. Oldfeller has one of these, but honestly it's pretty worn out and he has a scope on it and can't beat mine. I've been tempted to scope my, but why mess with it the way it's shooting. What I like about it too is I can leave it in the safe, it gets knocked around in there getting outher rifles in and out, take it out, it shoots to bullseye at 100 yards and that same group 7/8 in. I have an unissued Yugo 48B mauser in 8x57 with peep sight that shoots the Lee 175 gr bullet pretty darn good too. I spent a lot of time on getting some of these rifles to shoot. The Krag is very forgiving, seems anything you feed it, it shoots really good. I tried a friends krag and it was the same way. Heard a lot of shooter say that about Krags. Now my 260 Rem, modern with scope, I flat out admit I couldn't get it to shoot the way I wanted until I got some tips from 45 2.1. I was beginning to think all 6.5's were bastards and my 260 has a 9 twist, not near what the Swede has.

I wish I could take pictures of the Sako's bore after those high velocity loads with my double checks. It's the cleanest I've ever seen cast shoot.

Joe

Larry-
PM me your e-mail address on Boolits. There are several things you probably don't want to answer on a public forum to talk about.

Starmetal,

I don't know if you're a member or how you feel about the CBA but if you're getting consistant 1/2 inch groups out of your 30/06 CZ and consistant 7/8 out of your M95 Mannlicher you should consider shooting in some postal and shoulder to shoulder BR matches, you'll clean house in the production and military classes.

Dan Willems won the production class and the national title last year shootng 5 and 10 shot 100 and 200 yard aggregates in the 6, 7,and 8s. He was using a Savage varmint rifle in 308, Eagan 214 gr. MX-ARD, 36x Weaver scope, at over 2000 fps. I thought an over the counter rifle that could do that with cast bullets was pretty amazing to tell you the truth.

Pat

quote:

Originally posted by Pat I.:
Starmetal,

I don't know if you're a member or how you feel about the CBA but if you're getting consistant 1/2 inch groups out of your 30/06 CZ and consistant 7/8 out of your M95 Mannlicher you should consider shooting in some postal and shoulder to shoulder BR matches, you'll clean house in the production and military classes.

Dan Willems won the production class and the national title last year shootng 5 and 10 shot 100 and 200 yard aggregates in the 6, 7,and 8s. He was using a Savage varmint rifle in 308, Eagan 214 gr. MX-ARD, 36x Weaver scope, at over 2000 fps. I thought an over the counter rifle that could do that with cast bullets was pretty amazing to tell you the truth.

Pat

Pat,

Tell all that to 45 2.1. I don't want to do it. He's younger, shoots better then me, and makes more rifles shoot then I can. Although I don't think he has the time.


Joe

I found someone in Calumet City, Ill, who does a nice job of making lead bullets but not in the .338 225-250 gr. size I would like to use. I do have some Hornady rounds but getting lead for my application works fine - as would rolling my own. Problem is that while plain lead is nice primitive make-it-yourself stuff it also takes a lot of odd machinery and working.

An alternate is swedging and as I have some hydraulic equipment I'm sure I could do a super-whammy job on the motive force end. On the other hand we might fill copper tubing with lead, perhaps roll to straighten and then cut off in a lathe. This would give a cylindercal lead filled soft copper tube which could be fitted with a point. Might be worth while for special applications. And heavy soft copper tube could be turned or ground a bit for the final diameter if stock tubing insn't quite close enough to the caliber.

Thing with swaging is you can't swage harder alloys easily. Add to that the fact that swaged bullets don't have lube grooves.

I do believe there are some 338 molds out there. You can also design your own bullet on Mountain Molds, that should about solve any problem.

Copper raises the costs too much. Might as well just buy factory jacketed bullets then.

Joe

Well I am getting moa groups with the Lee .22 Bator at more than 2400 fps in my Savavage .223. That means they are doing more than 180,000 RPM from the 1 in 9 twist barrel.

These are just cast from ww alloy and lubed with Lyman supermoly.

Andrew,

Joe got a similar result and some very good groups with his AR -- so Mountain Dan immediately changed his contest rules to say it had to be a deer legal cartridge. But Joe then asked me how to explain how he could spin a .22 that fast and we couldn't spin a .264 bullet anywhere near that fast. It caused some real thinking to take place.

This led to the analysis of diameter to length to spin RPM which in the end was quantified as the CBI (cast bullet index) which explained both the .22 and the .264 using the same emperically derived formula.

Wanna copy? Excel 97 spreadsheet. It's disgusting to some of the oldtimers -- lots of folks hate it but they can't explain the facts of "dizzyness" any other way.

What it did for me was to give me a quasi-tool to keep from EVER again making a bullet that will get "dizzy" again. I also used it to make some predictions on when a new bullet design will begin to open up its groups -- it is about 60% successful in that use which makes it an "indicator", not an real answer.

E-mail me at kellyalexander@engineer.com if you want a copy to look at. I'll attach it to the response.

Kelly