Lead vs jacket

[RED BEAR]

I have seen this asked before. But can't remember what the conscience was. Ever since i started loading i have loaded by bullet weight charge weight and col. I never paid much attention to wether a bullet was jacketed or lead. I never never start near the top charge. Always work up. I have been cautioned not to switch data between jacketed and cast. I always thought that weight being equal that a jacketed bullet gave more resistance and thus higher pressure.
Am i wrong?
Does anyone else do this?

[Land Owner]

I use manuals for jacketed bullets and different manuals for cast boolits. I have not done the side-by-side research to determine whether the two are interchangeable, but am of the opinion that they ARE NOT. Ordinarily, cast boolits are "driven" at slower speeds than jacketed. This make empirical sense as the copper jackets are not "shaved" off as they are sped down the steel barrel, while lead tends to strip off if driven too fast.

I too seek a mid-or lower-level charge weight of powder and do not opt for the velocity extreme that I can wrest from my barrels. In my hunting world, dead is dead and the game will not know or care that the boolit (or bullet) was traveling at sub-maximum velocity. But I do not use jacketed bullet information as a starting place for cast boolits.

[RED BEAR]

I do not shoot any jacketed bullets in anythink. I cast everything i shoot. As long as i get no leading not sure why this would be a problem. I do not hot load anything. All i do is plink at the range.

[Mal Paso]

I did side by side and found lead about 100 fps faster in the 1300 fps range using 240g bullets in a 44 Mag 6" revolver. I assume lead pressures were lower but had no way to measure.

Isn't Mr. Gibson working on this project?

The powder was MP-300 and Ben at Alliant suggested my inability to achieve their published speed was due to lead bullets. Copper jacketed bullets were 100 fps slower measured 15' from the barrel.

[bluejay75]

Decided not to post my thoughts on this one. But lead seems to be faster with less pressure same weight projectiles (jacketed:cast) and same charge.

[Time Killer]

hmm going to make comment on this but many here are more knowledgeable than I am. Within there capabilities pressure is what matters. If a cartridges max pressure does not exceed the limitations of lead projectile It can be considered in the same manner as a jacketed projectile. Bullet weight in only one factor in cartridge pressure. Case capacity, seating depth (both case seating depth and distance to the lands, throat size, Crimp and crimp style (light heavy), bore size, type of powder used, and barrel resistance. This is with both cast and jacketed. Every gun has its own limitations. This is why we work loads up and depend on published load data and the few that have pressure gauges to help guide us.

[JBinMN]

Reading this "might" help, but you should read "all 6 pages". ;) :
http://castboolits.gunloads.com/showthread.php?238516-Lead-bullet-pressures-are-greater-than-jacket-bullet-pressures-of-the-same-weight

[RED BEAR]

Reading this "might" help, but you should read "all 6 pages". ;) :
http://castboolits.gunloads.com/showthread.php?238516-Lead-bullet-pressures-are-greater-than-jacket-bullet-pressures-of-the-same-weight

Tried the link. Guess you wanted me to read the western powders article but link no longer works. After reading the post i am still not sure as many say one thing as the other.
After reading through the post when ever one says one thing and list data to support it someone else turns the page and the data it the opposite. More up in air than ever.

[JBinMN]

The Western link was not the reason I posted the Cast boolits link, it was the discussion. That is why I said it is best to read the whole topic all the way to page 6 & the current end of that discussion.

In particular, read some of the comments by Larry Gibson, who owns & uses pressure testing equipment.

---------------------------------
Edit:

I removed some of this post as I think I went maybe a bit more "advanced" in what I was trying to share & did not think it was very well done.

I will say that using the COL for a same or similar weight lead boolit using the jacketed data can lead to issues, as the depth of the lead boolit in the case may not have the same location as the depth of the jacketed round. If the COL indicates that the base of the jacketed bullet is at one spot in the case & creating a certain amount of volume left in the case, and the lead boolit is deeper in the case reducing the volume of the case by using the jacketed COL, a person is likely going to be increasing pressures.

That is why many times when one compares a cast boolit data to a jacketed data, the same/similar weight boolit has a reduced powder charge range from that of the same/similar weight jacketed. As well, as many times, a change in the OAL.

I do not recommend using jacketed data for equivalent usage to a lead cast boolit. There should be some changes made to account for the difference between the two types of projectiles.


Note that extrapolating data( converting from one to another) is possible if one takes into account many variables that may cause changes in results. Taking into consideration the length of the projectiles themselves, meaning the bullet to boolit possible difference in length, the amount of case volume remaining when the projectiles are seated, the difference between the malleability of lubed cast lead boolits & the jacketed bullets ability to conform to the bbl. when the round is fired, and the amount of powder necessary to balance those differences.

As an example of some of the difference between lead & jacketed load data I will show one of the comparisons that Hodgdon provides.


Case: Winchester Twist: 1:18.75" Primer: Winchester SP, Small Pistol Barrel Length: 7.7" Trim Length: 1.145"

Bullet Weight 158 GR. MEI CAST LSWC

Manufacturer - Hodgdon
Powder - 700-X
Bullet Diam. - .358"
C.O.L. - 1.475"
Starting Load - 3.0 Grs.
Vel. (ft/s) - 795
Pressure - 13,700 PSI
Maximum Load - 3.4 Grs.
Vel. (ft/s) - 867
Pressure - 15,800 PSI



Bullet Weight158 GR. HDY XTP

Manufacturer - Hodgdon
Powder - 700X
Bullet Diam. - .358"
C.O.L. - 1.455"
Starting Load - 3.2 Grs.
Vel. (ft/s) - 688
Pressure - 13,000 PSI
Maximum load - 3.7 Grs.
Vel. (ft/s) - 798
Pressure - 15,900 PSI

{ Source:http://www.hodgdonreloading.com/data/pistol }


While the projectiles are the same weight of 158 grains, Note the difference in OAL between them with the Lead one being longer, the powder charge is also reduced for the Lead boolit, then look at the differences in velocity, and then compare the pressures.

I think that will help to share what I am thinking with out me going into detail on how to convert the two back & forth to find load data that is Safe & usable.

At least I hope it helps.
;)

[RED BEAR]

Thanks jb i guess i better get a manual for cast bullets. Most of the ones i have have very little in the way of cast data. And some of what i do have seems very low ( hornady). I guess i am lucky i always start out low with this data.

[Petander]

Pressure-wise, cast bullet hardness and size matter quite a bit,too.

It's hard to generalize loads,that's why we start low and build up.

[RED BEAR]

I always start low and seldom get near top loads. I just don't need to. The only thing i work up to top loads are for my carry guns. I like to simulate the ammo i carry so my practice ammo is pretty much the same. Everything else is just plinking ammo. Wife doesn't like recoil at all has several operations on her wrist. I have a little arthritis in my hands. So almost everything is mild.
As for hardness i generally use very soft lead for anything under 1000 fps. Over that i have found about 12 bnh works good for me. I usually size .001 to .003 over bore. Depending on what the gun likes.
Haven't done a lot of rifle shooting lately price of powder limits my shooting. But picked up a bit of surplus powder at a very good price $5 pound for one and $8 pound for other so i am bout to hit the range and go nuts just as soon as i get the loads worked out.
Going out today and try a couple boxes before i load a bunch.

[fredj338]

IT takes more force to move the jacketed bullet down the bore & it generally will not seal the bore as well, there is also more friction. So the bullet tends to be slower than a sim bullet, same weight in lead. So while you can swap bullets in lower pressure loads & not see any serious pressure issues, if you work a jacketed load up to max, you will likely be over lugging in a lead bullet.

[JonB_in_Glencoe]

RED BEAR,
Regarding the question in your OP, I think you will be fine safety-wise...but it should be stated that typically castboolit loads are lower than J-word loads in published books, because the typical "accuracy range" with a castboolit is lower in pressure, than the J-word accuracy range. Please note I said "typical", there are several factors that effect that. Anyway, you said you always start Low...so I think your are golden.

If you had a bunch of reloading manuals (that include pressure in their Data section) in front of you and started looking for similar loads of J-words and Castboolits, you will likely find that many times a J-word load will have a higher pressure than a Castboolit load (same weight, same charge). But there are a few instances where the Castboolit generated a higher pressure. If you read through the entire thread JBinMN gave you, I believe someone posts such Data.


Reading this "might" help, but you should read "all 6 pages". ;) :
http://castboolits.gunloads.com/showthread.php?238516-Lead-bullet-pressures-are-greater-than-jacket-bullet-pressures-of-the-same-weight


Tried the link. Guess you wanted me to read the western powders article but link no longer works. After reading the post i am still not sure as many say one thing as the other.
After reading through the post when ever one says one thing and list data to support it someone else turns the page and the data it the opposite. More up in air than ever.

As to the topic in the Quoted thread:
I have a Theory (quoted below), that I posted in that previously linked to thread. I surely won't say this is anything more than a theory...and if you read Larry Gibson's reply to me, you will see he is skeptical of my theory, and he surely has lots more knowledge and experience in all facets of castboolits, than I do...It wasn't that long ago, when I was a newbie to the silver stream known as Galena. So anyway, I anxiously await Larry's planned test on this, and will accept his results.


Post #178
12-31-2018, 02:20 PM

What if this is a paradox ???

> We know that as the pressure increases in a ladder test of castboolit loads, the amount of obturation to the castboolit increases.
> As that obturation increases, I suspect that friction increases.

What if that obturated lubed cast boolit friction surpasses the friction of a unlubed J-word?

My theory on a pressure test comparison of castboolits and j-words:
Light loads will yield results showing J-words creating higher pressures.
Increase the loads to the point that obturation is creating enough friction to surpass that of J-words, then results will start showing castboolits are creating higher pressures.

One great problem of this pressure test, centers on what I have previously stated in this thread [years ago], All things can not be equal, OR BETTER PUT, all "other" things can not be equal.

[303Guy]

JB, there is another consideration regarding obturation and that is boolit riveting. Riveting in the neck and in the throat. I discovered this for myself (having heard about it) with paper patched boolits. With the patch, the riveting doesn't necessarily get ironed out so it can be seen on the recovered boolit.

One possible mechanism for increasing boolit friction is the process of elongating the boolit forward during the swaging process from throat to bore. Again, I discovered this with paper patching. Not saying it will make a significant difference to pressure but it's a consideration. Another consideration is bullet/boolit nose shape. My patched boolits are jammed up into the throat while one would expect a jacketed bullet to have a jump.

[Petander]

Jacketed bullets are usually very soft inside. I use lower charges for my hard cast boolits unless I want to flatten primers.

[JBinMN]

JB, there is another consideration regarding obturation and that is boolit riveting. Riveting in the neck and in the throat. I discovered this for myself (having heard about it) with paper patched boolits. With the patch, the riveting doesn't necessarily get ironed out so it can be seen on the recovered boolit.

One possible mechanism for increasing boolit friction is the process of elongating the boolit forward during the swaging process from throat to bore. Again, I discovered this with paper patching. Not saying it will make a significant difference to pressure but it's a consideration. Another consideration is bullet/boolit nose shape. My patched boolits are jammed up into the throat while one would expect a jacketed bullet to have a jump.

While that "riveting" of the boolit might be a consideration, it is one that I have not run across myself, "yet".

I do not have the experience to comment more on that possibility, but I would think it uncommon, or at least not recognized by many, so it is possibly less of a consideration than the other ones mentioned, but still in the list.

Thanks for mentioning it here. I think it was a worthwhile thing to consider for some who are using jacketed data for cast lead boolits.


----------

I might add that having some cast boolit manuals, at their relatively inexpensive cost, would be a lot less expensive than making a mistake sometime, using jacketed data for cast & what results from that mistake to both the firearm & anyone around at the time.

I am simply advocating that folks lean towards the "Safe' side. If someone is not sure of what they are doing by trying to adapt jacketed info into lead alloy cast loads,( or even vice versa), IMO, they should not do it until they "are" sure of themselves & what they are doing.

Of course, All folks can do as they like with their handloading/reloading, as it is, of course, "at ones own risk".

Just Be Safe & G'Luck!
:)

[RED BEAR]

I really thought this was going to be a simple question. I am just an old country boy after reading the other post and the answers on this one i actually don't feel very smart.