Go Figure! (45ACP Plated Bullets)

[Bucksnort1]

So, yesterday, I researched this forum for information on plated 45ACP round nose bullets. I found more information than I needed but what I did learn is to load either as a lead bullet or on the low end of the jacketed bullets recipes, according to Barry's Bullets.

I looked in my Lee Edition Two and found the following recipes for a 230 grain bullet.

Lead bullet - 4.3 grains of HP-38 resulting in 699 feet per second

Jacketed bullet - 4.2 grains of HP-38 resulting in 751 feet per second.

As Ricky Ricardo said to Lucy, esplain this please.

[74A95]

Just an FYI, but this article does a direct comparison of different bullet types loaded with the same amount of powder:

https://books.google.com/books?id=da...cketed&f=false

[Bucksnort1]

74A95,

I'm sure there is a good explanation. I will read the article from top to bottom. Thanks.

[disseminator]

Short answer: pressure.

[geosheaks]

Actually doesn't give an explanation but rather presents velocity in chart form for different bullet types or coatings with same powder charge. Includes my favorite, moly coated by Bear Creek. Obviously the different friction coating properties account for the velocity variations with cast lead leading the others in velocity.

[condor bravo]

For unknown reason I am signed in above from an earlier registration. Normally I am condor bravo.

[44 AMP]

As Ricky Ricardo said to Lucy, esplain this please.

Simple, 4.2/4.3gr HP-38 is an inefficient load for a 230gr bullet.
Assuming, your data is from a 5" barrel, And the intent of the load is full power GI spec.

The GI spec for a 230gr bullet was 820fps +/-30fps from a 5" barrel. The listed load doesn't quite make that, its below the low end, in that test barrel.

Is that wah you need esplained??

or are you asking why the velocity is different for the same load with different bullets??

The simple answer IS pressure. The slightly more complicated answer involves pressure/time and factors like friction and bore expansion ratio.

In simplest terms, the greater the friction of the bullet in the barrel, the higher the pressure needs to be in order to get it moving, and once it gets moving the higher pressure gets it moving a little faster a little sooner so you get a slightly higher velocity reading when it leaves the muzzle.

Now, with the data you supplied, we're only talking approx. 50fps, which is not a huge amount. Firing the same load from a different 5" barrel could very well show that amount of difference for either bullet from the figures they got with the test barrel they used. Another barrel might turn in 750fps for the lead and 800fps for the jacketed. Another barrel might show velocities in between or at either end of the range.

Its all about how the bullet fits the barrel what it takes to get it started (engaging the rifling) and how "easily" it slides once it does.

[Metal god]

This is a quote from Unclenick here at TFL from this thread

https://thefiringline.com/forums/sho...d.php?t=584273

Originally Posted by Unclenick

In general, a softer bullet swages into the bore more easily, reducing start pressure and causing the powder to take longer to peak. So I think what Ranier means is their starting load is half way between minimum and maximum jacketed bullet data, and their maximum load will be expected to exceed the maximum load for jacketed data.

By way of confirming that, I had a long talk with a Speer tech last year about their Gold Dot bullets which are, he said, definitely plated jackets, as he, personally, had run the plating machine. He also said he's found load data for Gold Dots with starting loads above the maximum jacketed loads, and many more that overlap. For this reason, when you look at Alliant data created with Gold Dots, you should not assume it is right for jacketed bullets.

Everything here hinges on how the plating is done. There is more and more of it. Hornady has a process for plating rifle bullets in actual gilding metal rather than soft copper, which they do with some newer match bullets because it allows them to make a virtually perfectly uniform jacket thickness all around. That said, I've bought thin-plated cast bullets that you couldn't even crimp lightly without cracking the plating on them. For all practical purposes, these were copper-colored cast lead bullets. They even had lube grooves that were filled. They needed to be fired with lead bullet loads.

Low loads: Generally speaking, bore friction is a much smaller consumer of powder energy than bullet acceleration is. Bullets getting stuck in barrels usually occurs either because the powder was way too slow for the bullet mass, which can cause it to extinguish (see Norma manual for an explanation of the effects of recondensing gases evolved off the powder but not consumed in combustion; this can drop pressure dramatically and cause extinguishing). Under-loading 296/H110 in magnum pistol cartridges has been known to produce this effect, but so can any slow powder under the right conditions). The other cause is pressure so low it can't keep the brass expanded against the chamber wall and the resulting gas leakage around the case and out of the breech drops pressure to the point the bullet never picks up enough velocity to coast the rest of the way past barrel friction and out of the barrel. These are typically super low loads.

In the case of the thicker plated bullets, like the Ranier and the Gold Dot, I think the starting load recommendation is high both to cover themselves with slow powders that aren't safe to load down much, and also just so you don't burn a lot of powder getting to maximum. Bore friction should not be the issue. While the softer copper will have higher friction with steel in a standard sliding test, in a gun bore friction is partly due to the bullet material springing outward against the bore, and the jacketed bullets spring hardest. The other part is due to pressure upsetting the bullet outward against the bore. This one is the main one and is the reason copper fouling in a high power rifle is always an inch or two in front of the throat: that's where the bullet is when pressure peaks and upset outward against the bore is at maximum. So the softer copper will likely have a lower peak pressure limit (probably apparent nearer to rifle pressure, though), but need a higher start pressure for slow powders.

That upset and pressure distortion are the reasons there are "velocity" limits on lead bullets and plated bullets. There really isn't a velocity limit: that assumes a standard barrel length. It's really pressure limits that are the problem. Too much pressure causes distortion that messes with accuracy as well as increasing metal fouling. You can use a longer barrel to get more velocity at the same pressure and the bullet won't care about that. Peak pressure is the main culprit, and Richard Lee's Modern Reloading has a good bit about this. Lead bullets get distorted and lose a lot of lead against the bore when pressure is too high, and soft copper plating will do the same thing, but at a higher pressure. A lot of work has been done with alloys and lubes and gas checks to get them up to high power rifle velocities, and this has been done (see Veral Smith's book, for example). But it takes some effort.

The way to tell how low you can load the plated bullets is to use a chronograph to watch for velocity variation to because erratic; a jump in SD as a percent of the MV. If it does, you are getting too low to count on never sticking a bullet in the bore. But with a fast powder like Bullseye, for example, this will be at a pretty low velocity

Rainier plated bullet load data which "should" work just fine for berry's bullets

http://cakesniffer.org/stuff/boom/RanierData.pdf

[Rule3]

The short answer

The "data" in the LEE manual is very dated. It is nothing more the data obtained from OTHER sources. They never tested anything. It does not list the "specific" bullet, barrel length or other relevant "stuff"


The long answer is posted above.

As always YMMV!

[robhic]

Simple, 4.2/4.3gr HP-38 is an inefficient load for a 230gr bullet.

The GI spec for a 230gr bullet was 820fps +/-30fps from a 5" barrel. The listed load doesn't quite make that, its below the low end, in that test barrel.

Not to hi-jack but the bullet type - coated, plated, jacketed - info given is understandable and makes sense.

One thing that puzzles me is why (example) a 120gr plated bullet may show 4.3gr of a certain type powder. Then, same bullet, different weight 125gr shows 4.0gr for same powder.

Bullet construction makes sense but same bullet higher weight using less powder leaves me fuzzy... Thoughts?

[briandg]

Another thing to consider is that all load data testing from one lab to another will little different results.

Barrels vary, lot numbers, sources, components, equipment, even to the point that decades may pass between one round of testing and another. Where some labs may keep every variable identical, others may change lots and sources of brass to widen the actual test data that they get.

Last but not least of all, even the guy who runs the machine, and the dies that he uses can have a small effect. At the very smallest level, how many digits does the lab use? .04 and .0455 (.05) are significantly different.

From time to time, there will be some curious anomalies.

I'd like to point out that variations in data are not an indication of stupidity or sloppy work on the part of any one lab or testing session. Each lab has huge variations in how the data is gathered, the materials tested, and different protocols. Then, it is absolutely the option of each lab to decide how to interpret and report it.

Expect variations.

[sevt_chevelle]

Not to hi-jack but the bullet type - coated, plated, jacketed - info given is understandable and makes sense.

One thing that puzzles me is why (example) a 120gr plated bullet may show 4.3gr of a certain type powder. Then, same bullet, different weight 125gr shows 4.0gr for same powder.

Bullet construction makes sense but same bullet higher weight using less powder leaves me fuzzy... Thoughts?

Simple bullet length.

A heavier bullet can't grow fatter so it must get longer. A longer bullet takes up more space in the case. With more space occupied by the bullet the available room for powder is less.

[Metal god]

A heavier bullet can't grow fatter so it must get longer. A longer bullet takes up more space in the case. With more space occupied by the bullet the available room for powder is less.

Bold section is correct and although your second part is correct as far as the bullet taking up more room in the case . That does not have to be by adjusting seating depth .

The issue is when bullet get heavier they generally move slower down the bore under same pressures . Also as they get longer they create more friction in the bore do to more baring surface . Those two things mean you can't put as much of the same powder behind because the bullet can't get out of the way fast enough for the expanding gases .

You generally need to go to a slower burning powder as you go up in bullet weight .

All that is generally speaking when talking heavy for caliber bullets . There are always exceptions . Yes a bullet being seated deeper can raise pressure . I however believe the extra mass and friction created by that extra mass has more to do with the different powder charges .

[robhic]

The issue is when bullet get heavier they generally move slower down the bore under same pressures . Also as they get longer they create more friction in the bore do to more baring surface . Those two things mean you can't put as much of the same powder behind because the bullet can't get out of the way fast enough for the expanding gases .

You generally need to go to a slower burning powder as you go up in bullet weight .

Thank you for that explanation. It kept making me wonder as I'd go down a list of data in a/some manuals that the heavier bullet used LESS powder with all else staying same. And I never considered slower powder. Good info and something else for me to make note of!

Thanks again!

[briandg]

Slower powders ignite less easily, burn less easily, and also require more pressure and heat to properly sustain efficient combustion. Slower powders need larger charges to do the same thin as quicker ones. They function better with longer barrels that allow the charge a longer period of time to fully burnt. They function best with heavier bullets that allow pressure to build,pressure and heat that are essential for the powder to ignite and efficiently burn.

Fast and slow are simple ways of cataloguing them, but if he truth is told, this is really a complex set of properties and variables that are really hard to predict. This is one of the reasons why data can sometimes seem completely arbitrary, and why you MUST approach maximum loads with a little caution. Throwing changes into a carefully balanced process changes it. Changing bullet weight, seating depth,brass weighting number of things will upset that balance and can cause failures, including destruction of the gun and personal injury.