True or False

[Oklahoma Rebel]

True or False: a lead boolit can be substituted for a jacketed load of the same bullet weight and the pressure will always be lower.
example: 9.3X62-286gr/58grs(imr4895)=2350@56,300cup (a guess) a 286 gr cast rnfp with 58grs imr4895 will always be +or- 56,300cup
be clear while close (from memory) this is NOT a correct load (disclaimer) thank you-Travis

[William Yanda]

ALL generalizations are false, including this one. I believe the theory is that a boolet will present less resistance to engaging the rifling than the copper alloy of the jacketed projectile, thus producing less pressure for similar charges.

Edit: This assumes similar diameters and ignores the possibility of different alloys responding differently in terms of slugging up or obdurating.

[Oklahoma Rebel]

so you say its false then explain why it could be true? are you saying, " eh, most of the time"?

[Scharfschuetze]

Pick up Lyman's Reloading Handbook #49.

You can compare jacketed and cast bullet pressures for similar weight bullets and velocites for many calibres for many hours.

[Hick]

At the risk of exposing myself to ridicule, I will say that for starting loads I treat them as TRUE, and have never encountered a problem. That is, when I am looking for a starting load I don't care if the load is for cast or jacketed-- but I am wary of going close to the maximum load unless I know it is for the exact bullet I am using.

[Oklahoma Rebel]

that is the point of this thread, I have heard, and it would seem logical, since lead offers less resistance, that it is true, but I wanted to hear a lot of opinions from well educated and experienced casters. so no ridicule here! I will compare the lyman books loads to the only other loading book I have, the lee 2nd edition. but I have already noticed inconsistencies in the same loads, so I don't know how accurate those comparisons would be.

[Landy88]

I read John Barsness stating that the new, better, and faster pressure testing equipment has actually shown lead bullets to actually have higher peak pressures with identical loads, because they seal the bore better faster. Before and after that higher peak he wrote that the conventional wisdom for lower lead pressure is correct; and noted that the earlier equipment didn't capture this peak of such short duration; thus recording the lower average pressures for lead with otherwise identical loads.

Makes sense.

We have seen data evolve as pressure testing gear has improved.

[shoot-n-lead]

I read John Barsness stating that the new, better, and faster pressure testing equipment has actually shown lead bullets to actually have higher peak pressures with identical loads, because they seal the bore better faster. Before and after that higher peak he wrote that the conventional wisdom for lower lead pressure is correct; and noted that the earlier equipment didn't capture this peak of such short duration; thus recording the lower average pressures for lead with otherwise identical loads.

Makes sense.

We have seen data evolve as pressure testing gear has improved.

I think Quickloads alludes to this cast bullet pressure spike, also.

[rintinglen]

True, sort of. I have heard the claims of quicker peak pressures, too brief to register on the old pressure-crush equipment, but I don't think it matters. The notion that extreme precision assures "best" results may be true, but the old adage "best-is-the-enemy-of-good" has a great deal of relevance. Billions of rounds were made for many decades before piezo electronic pressure measurement devices came into use. One can search the literature in vain for accounts of masses of people being maimed or slain by exploding guns ruined by mis-measured cartridge pressures. Provided that your load is well under the yield strength of the metals used to construct the chamber and bolt face or frame that contains the pressures, you'll be alright.
I would point to the experience of the many thousands who for years loaded 22.0 grains of 2400 under the grand old Kieth 429421. I dare say millions of said rounds were loaded and fired. That was hunky-dory, until about 1992 when the science wonks at SAAMI determined that the old measuring techniques were giving too high readings. Now we are told that 20.6 grains is a threshhold which we cannot cross. Fine, except for those of us who had been wandering across that thresh hold for years and years.

[reed1911]

Also keep in mind the design/shape of the bullet matters a lot as well. Seating depth will effect the volume in the case, thus effecting the pressure.

[reddog81]

I'd guess that it would depend on the alloy and size of the bullet. Harder alloys wouldn't necessarily behave in the same manner as soft ones. I remember hearing before that your typical .001 or .002 oversized bullets take a little more pressure to get started down the barrel vs jacketed bullets. All these variables make any broad generalizations hard to confirm.

Also, you have to beaware that a pure lead bullet and jacketed bullet that weigh the same will not be the same size.

[williamwaco]

False.

It is an ABSOLUTE question.

Replace "always" with "usually" and I will accept it as a general rule of thumb as long as you start low and work up.


I have seen data instances where the lead bullet produced higher pressure.

[Der Gebirgsjager]

I'll go with "often" or "sometimes". I believe that soft lead will often create higher pressures with identical charges than will jacketed or hard lead.

[LAGS]

Why would you want to shoot Cast Boolits at Jacketed pressures or Velocity.
A lead bullet deformes if shot at more pressure than the lead is capable of withstanding.
There is a good section in the Lee Second edition chapter 10.
So if shot at Jacketed pressures, what are you really gaining.
But do you ask yourself, Why do they not show loads for Jacketed bullets with powders like Unique or Red Dot that you would use for cast Boolits.
I forgot,
Many years ago, I had a friend Blow up a 45/70.
He was loading Cast Bullets, and used the same powder charge as what he had been shooting the same weight of Jacketed Bullets.
I am not sure that was the whole reason, and it was several boxes of ammo before the rifle let go.
But he could have been experiencing a build up of lead in the barrel from the previous Over Pressure Loads that raised the pressure just a little Too Much.

[Larry Gibson]

Why would you want to shoot Cast Boolits at Jacketed pressures or Velocity.

Because it can be done. Multiple other reasons but that one really defines the reason.

A lead bullet deformes if shot at more pressure than the lead is capable of withstanding.
There is a good section in the Lee Second edition chapter 10.

Unless shooting in a muzzle loader very seldom is "lead" used. Most cast bullets are either a ternary or binary alloy. Many now add copper to the ternary alloy to further strengthen the alloy. PC and heat treating also further strengthen the cast bullets. Thus Lee's use of the tensile strength of lead is not correct for the alloys most often used in cast bullets and is often misleading. Heat treated bullets of appropriate design cast of ternary alloys such as Lyman #2 do not deform when pushed to far greater pressures than the Lee formula allows. Paper patching also allows the use of softer alloys, even lead, to be used above the "maximum" given per the Lee formula.

To illustrate what actually can be done with cast bullets when shot at jacketed pressures considerably above what Lee's formula prescribes as "maximum" here is a 10 shot group of the NOE 30 XCB bullet shot at 2950 fps at 50K psi (measured during firing). The aiming diamond is .75 on a side.

198936

So if shot at Jacketed pressures, what are you really gaining.

Longer range capability both for target shooting and hunting.

Some of us do not look upon cast bullets as a cheap alternative to shooting jacketed bullets but look at shooting cast bullets as our primary choice in shooting with jacketed bullets as the alternative.

Larry Gibson

[Oklahoma Rebel]

I will use 4/4/.5%copper, and the reason for using jacketed loads, is that I cannot find any loads for cast except one page that has very reduced loads, you have probably seen me asking for load info for the 9.3X62, but have mostly come up empty handed. I am learning a lot from this thread so thank you! ps larry g I believe what you do, it is possible, with some alloy experimentation and LOAD DATA I will get there. besides it is a lower vel. round with 286gr bullets going around 2000-2200fps and 250gr bullets going 2300-2400fps.

[Landy88]

...here is a 10 shot group of the NOE 30 XCB bullet shot at 2950 fps at 50K psi (measured during firing). The aiming diamond is .75 on a side.

198936


This hints that the better obturation can be a feature that combined with lower friction allows greater efficiency, if we get everything else right; and is mostly only a pressure spike bug in direct load swapping from jacketed data.

[LAGS]

That does make sence.
And using Paper Patched will keep the leading down with the higher pressures.
But without a Jacket or a paper patch, my experience with Cast has been, if you go much over 2000 FPS the accuracy goes downhill fast

[Oklahoma Rebel]

I have heard many people talking of shooting over 2000fps, I wonder if it just comes down to sizing ( is .001 over groove better than .002 over for that high of vel.?) and also lubrication. I plan on using the new carnauba blue lube made by a company with " white" in the name I think. he posts often in the lube forum and I will go have a look-see.

[LAGS]

@ oklahoma rebel.
What about trying Powdercoating ?
I swear by it, and 98% of my cast are PCed.
Never had any kind of leading in my rifles.
That includes a 35 Whelen that is close to your 9.3

[Oklahoma Rebel]

ive thought about it, but it seems like quite a bit more extra work. what velocities are you running your boolits to, and what wheights? I don't intend on going over 2200,w/ an accurate 286gr rnfp, if I have him make me a 250gr mold maybe 2300-2400max, but I think I will stick with the 286 for a while. I figure shooting just one boolit I will get better with it faster, kinda like the saying, " beware the man with only one gun"

[LAGS]

For the Whelen, I have a 245 gr a 280 gr made by NOE.
I havent clocked the 245 gr yet, but I did test the 280 gr using 3031 at 2300 FPS.
But accuracy was best around 2000 FPS with the 280.
I think it is the 1 in 14 twist with the heavier bullet that it doesn't want to work that fast.
So far the 245 is more accurate, but I dont know at what speed.
But I have seen posts that they are using IMR4350 with the 280 gr boolit and going very fast, but I think they have the 1 in 12 twist barrel.
What is the twist rate on your barrel.
That will help you decide which boolit might do best.
The heavier the boolit, the faster the twist is required to stabilize it

I also did buy a Lee 200 gr mold, but I havent had a chance to try out any loads with it yet.

[Oklahoma Rebel]

you may be right, but 280 is pretty heavy for a 35 whelen, maximum I would say, but 286 for the 9.3 is heavy, but not max weight.but that also means the 35 W has a higher sec. density.also it is basically the same weight so the 9.3 has more area for the powder to push on, which I have read makes it more efficient,i'm not trying to say one is better than the other though, just comparing. so it may be alright with it's 1-14 twist. if I can only get 2000, so be it. but I think it is possible and not too unreasonable to try for 2200fps, and 2350-2450fps if I also get the 250 gr.

[Oklahoma Rebel]

I also worry that a faster (like 1:12) twist would be more likely to strip lead off the boolit. is that fear rational? it seems like it would put more stress on the boolit.

[LAGS]

I have been reading posts about someone using the 310 gr NOE Thumper in the Whelen
Might have to look into that if I find a load for the 280 gr that I already have that shoots decent, and shows the barrel and twist will handle the heviest boolits.
If you use a Harder lead like Lino, then the chance of stripping going down the barrel is lessened.
I shoot mostly Lino or Harder in all my rifles since I dont use cast at this time for hunting.
I want Heavy Boolits, Large Caliber and long range.
I dont care if it has the trajectory of a Rainbow.

[Oklahoma Rebel]

I hope you shoot into a backstop so that you can re-use those lino boolits! that's expensive. I am working on a 250lb batch of 3.75%-3.75%-92.5%+.4%copper. the copper really helps the hardness, but without being any more brittle, it makes it harder and tougher. I would recommend you try it, might save you some lino!

[LAGS]

I smelt my own lino mix , so the cost doesn't bother me.
I have Armored man pick up the Tin I need from SeaFab metals down by where he lives and order the Antimony from an outfit in California near where I use to live.
The lead I usually get for free from the roofer on my construction jobs or the plumber.
My lino or stuff even harder is costing me about $2.00 a pound for materials including the shipping on the Antimony.

[Oklahoma Rebel]

wow, you are doing well! were is sea fab located? and do they do the same kind of stuff as rotometals?

[LAGS]

Seafab metals is in Casa Grande Arizona.
They are a supplier of all types of lead products like anodes and stuff.
But they sell a good 92-6-2 bullet metal and lead wire for the Swedgers
They will also sell the pure tin.
I haven't compared their prices to Rotometals.
Mainly because Armoredman picks me up 62 pound ingots of the 92-6-2 and I meet up with him when we go shooting to pick it up.
That saves me a bunch on the shipping.
I make it worth his while.
Same when I get some tin for the Lino I smelt
up.
I also smelt up any other mix from 96- 1-3 , WW ,or what ever suites my fancy to shoot in my handguns

[Oklahoma Rebel]

i'll have to check into them! yeah I have heard that a lot of people have hade really good results with the thumper for the whelen. and you might put a cleaning rod with a brush or tight cleaning patch,run it down the barrel slowly, while counting how many times the rod turns, then figure out your twist rate that way, if you have a 24" bbl it would be 1:12 if it makes 2 turns. but 1:14 may stabilize that 310 also. you should go to cast boolits forum and ask if anyone would send you a few to try. I,ve done that before, and people were happy to oblige!

[Tom W.]

I tried that once when I had a .308 Savage target rifle with jacketed bullets hits out to 1000 Yards was easy, but using the same load with a same weight gas checked boolit I got patterns at 100 yards rather than groups.

[LAGS]

@ Oklahoma Rebel
I did a cost check tonight using Roto's Pricing on the Tin and Antimony since I get the free lead.
Without shipping costs, it would come out to about $1.70 a pound to make Linotype.
They sell there Lino for $3.60 a pound which IMO is still a very good price.
But if I use the tin and Antimony to make a 96 -1-3 mix that is only $0.40 per pound if I use the free lead.
I also only pay a scrap yard I know .40 per pound for lead or WW

[Oklahoma Rebel]

the only scrapyard that I know of that sells lead is 1$/lb but I gotta have lead! ( this is soft stuff, mainly plumbing) I am going to try some more u pull it yards and other salvage yards. just a thought ( just popped in my head) what if you tried to order a counterweight from an old tractor made by say john deere(or another one that hasn't gone under) they were lead right? I wonder if you could still get one?

[LAGS]

Counterweights were made of Steel or Cast iron from my experience as a former heavy equipment mechanic.
Talk to Roofing contractors.
Especially ones who do roof tear offs.
They usually just throw the old lead flashings away.

[guicksylver]

I also worry that a faster (like 1:12) twist would be more likely to strip lead off the boolit. is that fear rational? it seems like it would put more stress on the boolit.

Thank you some one finally mentioned twist.....

Maybe Larry will explain that that group was not shot out of an "over the counter" gun...just don't want folks out there thinking "hey if he can do it,it should work in my 6.5 Swede"... with a what 1 in 7 twist I don't think so..

Larry's gotten up there with good accuracy..doesn't necessarily mean it's going to happen out of my 270 Winny

[Larry Gibson]

Faster twists "stripping lead off the bullet" is a myth, even softer cast bullets. The inaccuracy from pushing cast bullets to fast in fast twists has to do with RPM and the associated centrifugal force creared. The cast bullets will still be stable, up to a point, but will just get really inaccurate the faster they're pushed.

At a certain point the bullet can be swaged down smaller than bore size and then it loses stability as it no longer is engaged and spun by the lands. Recovered bullets shot up through 2900+ fps have provided the proof. The lands do not strip the bullet.

Larry Gibson

[Oklahoma Rebel]

ok, well that settles that..