Shooting and Rocket Fuels

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Shooting Bare Copper Bullets

So far you may notice a lack of discussion on components: primers, sabots, bullets, etc. On this page they will have to be  considered but only so far as to make the needed explanations. Shooting a modern style muzzle loader has been reduced to how well a bullet can function when wrapped in a plastic container. Sabots are a great deal of what constitute advantages or problems of a modern design over truly primitive weapons.

There is no doubt bullets shot with sabots can be accurate . But a sabot is the weakest link in the chain when smokeless powder is employed.

Sabots are made from plastic that reacts to change in temperature. If you say, “all shooting is affected by heat” your point is well made but plastic suffers more than metal. Summer shooting sessions can be challenging.

To fight the problem some have taken to allowing cooling periods of up to 15 minutes between shots. Others have resorted to barrel coolers for faster sequence. All solutions have their own difficulties.

Beyond the nuisance factor accuracy groups with a strange flier were often encountered. The cause of this occasional flier couldn’t be blamed on sabots because all shots were fired with sabots. How would a flier be compared to a good shot?

Even with doubt about what would work best, shooters dove quickly into a search for a better way to shoot than wrapping the bullet in plastic.   

If the load doesn’t stay within a limited pressure or if too many shots are attempted in a short time frame this is what happens to sabots. It doesn’t help much for accuracy.

It soon became obvious that smokeless offered advantages other than less and easier cleaning. Besides bullet speed there was plenty energy for other things. You’d be surprised what you can do with a little extra energy.

One of the things extra energy can be used for is rifle engraving. Normally engraving is thought of as the forming action of the barrel as a bullet is forced into the rifling. Until the bullet leaves the case and enters the barrel it is round. However it is soon pressed into the barrel under pressure and is forced to take the shape of the barrel. That’s why recovered bullets are not round but are cylinders with grooves cut down the length.

The above process is necessary to create the twisting action that allows the bullet to fly point forward rather than tumbling point over base. Bullets that don’t spin in the rifling won’t shoot: least not with accuracy.. A bullet shot within a sabot relies on the sabot expanding into rifling and thus spinning itself and bullet. The sabot engraves because it has a flared base and because it is very soft compared to the bullet.

But as alluded to above you don’t have to have a flared base or soft material to engrave a bullet. What you need is energy applied to the right place at the right time.

 

 

The notion of shooting a regular jacketed bullet from a muzzle loader without a sabot is foreign to most shooters. Yet that is what this page is purposing.

The two possibilities on the left are copper, one jacketed, one solid.

 However under the correct conditions a sabot is not only unnecessary it might be considered a restraint.

 

 

The drawing to the right is another attempt to explain what happens when a bullet is fired.

The blue bullet is shown as the powder has turned to gas. The powder is trapped except for a very tiny amount on the sides. Not much gas can escape so the pressure has started to rise and the bullet is beginning to move.

With a normal load  the bullet will go from zero to perhaps 2000 miles per hour in a space of less than two feet.

At some early time period of our example the forces of resistance are equal to the force needed to bend or mold the copper jacket of the bullet. The bullet can’t deform in the front or rear because the forces are trying to equalize evenly across the bullet.

However the metal has some room to move sideways into the rifling and it is engraved to form fit the barrel.

That is not all there is to it. As with any system if it was obvious people would have done it long ago. And indeed this is not entirely new. Nor is any credit taken for creating the idea. For this to work as a system a few things must be attended to.

The first and most important concern is barrel fit. The bullet must fit the bore somewhat like a sabot for reliable ignition. Smokeless powder requires much more energy to ignite than black powder. It was mentioned earlier (see the page titled Pressure) that back pressure from a well crimped bullet was a requirement of some cased rounds for ignition. Some frictional resistance is needed to reliably ignite any smokeless powder. This frictional resistance can only be created by a good bullet fit. If the bullet slides down the barrel at about the same resistance as a firm fitting sabot then enough frictional resistance exist to have a working system.

If the bullet fit is too tight it won’t go down the barrel. There is no way to force fit copper, it would break the ram rod before it would pre-engrave into steel. If the bullet fit is too loose there is not enough frictional resistance and misfires could (and do) occur. So bullet fit is the most important part of shooting a bare jacketed bullet in a muzzleloader. There will be more on how to achieve the best bullet fit at the end of this page.

 

The graphic to the left is like the one above except one item has been added. The item shown in yellow is a 1/8” thick woolen wad. Bare bullets have been fired without the wad with some success. Still many loads show greater accuracy with a wad added.

The wad seems to act as an initial gas seal. This isn’t said to be an absolute truth but you don’t go against what works so the wad is recommended because they produce results.

How they work and what they do is less important than the functional results. Some people have had great results with so called “fiber” wads. Unlike the woolen wads they cannot compress so the debate of adding an air cushion is moot.

The use of a wad is the second area of attention. Almost everyone has had better results with rather than without. With those type of results they come highly recommended.

The final condition for consideration for shooting bare jacketed bullets is the load. It should not be concluded that this type of shooting has not been tried (and failed) in the past. Innovations to shoot bare bullets went back beyond the civil war. A lead bullet with hollow base turned out to be quite an innovation in it’s day over patched projectiles. Still copper jacketed bullets were the product of smokeless powder.

Smokeless began the age of speed. With speed the limits of a solid lead projectile were introduced. Even today without speed a copper jacketed or solid copper bullet won’t achieve their potential. It was noted that for the bullet to engrave a force equal to the energy needed to mold copper had to be created. Black powder falls short of the energy level needed for that forming effect.

Even some smokeless loads might not reach the rifling engraving level. So the load must be chosen with some energy. This makes the third point of attention for shooting bare bullets in a muzzle loader. Use a load with enough energy to engrave the bullet.

  

Since bullet fit is everything is this type of shooting. It’s then necessary we spend some time on how to get the proper fit. The most common way has to do with bullet sizing.

Sizing is not normally associated with jacketed or all copper bullets but it can be done easily enough. The first thing to do is evaluate how well the bullet(s) you want to shoot fit without any sizing. As noted since some bullets are slightly undersized (like the Parker BE) and some barrels are slightly oversized (perhaps a Pac-Nor) there is a small chance your 45 caliber barrel will work “as is”. Still, that chance is very small.

For most barrels and bullets the bullet will not fit the barrel unless you run it through a .450” or .4495” sizing die. When you size the bullet it then will probably be a close but loose fit. Since it has to be a good press fit you may think, “that will never work”, but it will work. It will work because a bullet can not only be down sized it can also be up sized by a process called knurling.

Perhaps the best method is to find a close fit by sizing the bullet trying for a near but loose fit, then knurling it up to be a tight fit.

Knurling is a process that’s been around for decades (or centuries) and normally it is used to make otherwise loose fitting objects match. If a valve guide has a little wear on it in your car engine an old machinist trick was to machine some knurl marks on the valve and soon the fit was matched to the guide as good as ever.

If you wish to debate if that’s the best method of engine repair it’s your privilege but  making a  temporary fit by scoring marks on a metal surface is a simple effective process.

What is achieved if done correctly is known as a “press fit” that is when the bullet is put into the bore it will take some effort to move it down the barrel. There is enough frictional resistance to allow for efficient ignition, even with smokeless powder.

So far this has concerned sizing and using .451” or .452” bullets in a 45 (.458”) barrel. That is not the only caliber choice. In states where it is legal rifles have been built to shoot .400 caliber bullets from the .408 caliber barrel. The lands for this barrel are .400” to .401”.

 

Strain

Gage

Sizing dies come in many shapes. Some work in a reloading press. Others like the ones above (Provided by Axly Tool in Michigan) are  used with a bearing press or vise.

Using a die is simple. Just lube the bullet (it won’t work if you skip this step) and press it through the die with a punch like this one I made from a ramp hinge. Of course some action must be taken to ensure the bullet is not damaged when it exits the die on the other side.

A .40 caliber bullet is a natural fit for this size barrel and that can be put to good use. Still, 45 or 40 caliber the principles of sizing the bullet are the same. A good fit is still a must. So starting with a near fitting bullet is the one constant for knurling to size.

Rater than trying to describe the knurling process a video of a bullet being knurled to fit would explain it much faster (and clearer) than a lot of print. Give it a look if you like.

Click here to view the

Video on knurling

Sabot-less shooting was started as an option for 45 caliber rifles. When first developed the 45 was a great deer rifle because the 200 and 195 grain bullets commonly used are great for that application. For bigger game they were not an ideal choice. So sabot-less was at first a way to shoot a bullet that could be called a big game round. That was a success for a tough 300 grain .450 caliber bullet is a match for any game in North America.

With time sabot-less began to be a choice for shooters with no aspiration for giant game because it offered advantages not them known. Let’s consider a few.

Targets like the one on the right began to appear. Some good 300 yard targets have been shown for sabots in the 45 caliber section so this isn’t impossible with a sabot but the point to be made is yet to come.

With time more and more shooters were able to find accuracy was surprising when some experience was obtained in how to get the load consistent between shots. Our shooter in this case timed all shots and the speed of this 275 grain Parker BE bullet is very consistent.

Though impressed with this target the one that follows below set a new standard for a muzzle loader. If you would like to see that standard proceed to the next page.  For more on shooting bare copper bullets click here.