Non-lead bullet design theory

[NigelM]

There is a lot of discussion on the forum at the moment relating the impending move away from lead. The camps are pretty polarised for many different reasons. I'm not going to get into the rights and wrongs here, but it got me thinking about how you build a better mousetrap. Talking specifically about rifle bullets rather than shotgun pellets.

There are a number of issues with the current offerings in Copper.

1. Because the density of copper is 20% less than the density of lead a bullet of the same length is 20% lighter and carries less energy at the same speed.
2. Because the formula for ballistic coefficient is sectional density divided by form factor, the reduced mass of a copper bullet of the same length as a lead one will always have a lower BC presuming bullet design (FF) is the same. Result is that the copper bullet looses velocity and therefore energy faster reducing effective range.
3. Most of us are used to using lead bullets that loose up to 50% of their weight in fragmentation and those fragments are often fatal even if placement is not perfect. Copper tends to retain 100% of it's weight and poor placement can result in more runners.

There are a lot of people talking about how the only solution can be to find a material with the same specific density as lead, but I don't believe this is the answer - even if it is viable which I doubt - an element with the right properties just doesn't exist at a viable cost.

Now if we look for an engineering solution to the above problems we might be able to build a better copper bullet than a lead one.

1. If we build the copper bullets 20% longer than their lead counterparts and maintain the same weight the bullet will maintain the same energy at the same velocity. Bullet makers are doing this already - a Barnes TTSX at 130gr in .277 is 1.322" and a Nosler 130gr BT is 1.220". Same SD, similar FF, BC of the TTSX is 0.392, the Nosler 0.422 (but nosler are always a little optimistic).

2. If we run bullets in copper of the same weight as our lead ones we keep the same SD and the extra length should enable the designers to improve the FF - the longer a bullet is for calibre the easier it is to minimise drag. So it is very possible to design copper with a higher BC than a lead bullet providing the same weight is maintained.

The down side here is twist rate. We will all need to up the twist rates in our rifles by 1" - 2" to stabilise these longer, more slippery projectiles. But that's possible. Even though it will limit some of the rifles in circulation. Buy rifles with a higher twist rate and we could take advantage the new bullets.

3. This is the killer at the moment. Most manufacturers are making copper bullets that retain 100% of their weight. Some are starting to make fragmenting bullets. There is an argument against the ones that retain 100% from some because they want fragmentation which leads to faster killing. There is an argument against the fragmenting ones from others because they don't want fragments of any metal in their carcass. But this is the same argument that has been going on for donkey's years on SD regarding AMax vs Partition - Fragmenting or not. If both options can be offered in copper it keeps both sides of the divide happy.

The big issue is terminal expansion at slow velocity. I personally don't trust a TTSX below 2400 fps, I trust an Accubond down to 2000 fps, an AMax to 1600 fps. Most of the current copper offering limits range especially for those who prefer the "slow and heavy" over the "fast and light". This is a design and engineering issue and is starting to be solved by some manufacturers. I think makers like Peregrine/Neilson/GSC might be the answer and look forward to trying them in the not too distant future. All those who have tried them seem to be very positive.

So at the end of the day, a change to copper could, if we all up our twist rates, give us better BC bullets that if the designers get it together expand down to below 2000 fps giving us all the range we could want in both fragmenting and expanding bullets. The future might be better than the present, but it will take a few years for the transition to take place and the bullet makers and rifle makers to work together to give us a better option than we have today with lead.

In the mean time load them lighter, shoot them faster and limit your range to the effective TV of the bullet - which is fine for most normal stalking ranges.

 

[User00040]

What matters more is the quality of factory ammunition. Copper bullets call for faster/hotter than average loadings for good performance.

I think 24" barrels will matter more than twist rates for velocity.

 

[Steff]

Jesus ..... but your concerns and thoughts have been heard - a decade ago.
Have a look at Aero bullets by Styria Arms in Austria.

And if you want fragmenting copper bullets look to Jaguar bullets.

 

[nick.308]

also if bullets are getting longer then magazine housings need to accomodate this change

 

[Steff]

also if bullets are getting longer then magazine housings need to accomodate this change

They‘re not getting longer but lighter and faster. If you want to retain your initial bullet weight, go up in caliber.
Lead free will bring on the revival of larger diameter calibers.
Eventually 8x57IS will be the new . 308 Win.

 

[NigelM]

They‘re not getting longer but lighter and faster. If you want to retain your initial bullet weight, go up in caliber.
Lead free will bring on the revival of larger diameter calibers.
Eventually 8x57IS will be the new . 308 Win.

They are getting lighter and faster only because the majority of rifles in circulation don't have the twist rates to run an equivalent weight bullet at the additional length that the density of copper requires and because the current copper offerings from the major manufacturers require higher velocity than lead for reliable expansion.

There are boutique bullets about from people who have thought outside the box, I pointed out Peregrine, Neilson and GSC, you have added Styria and Jaguar. We are starting to get options.

However, the standard twist rates mean that we are having to go down in weight and BC's are naturally coming down because the formula involves sectional density which is going to be lower on a same length copper bullet.

I'm talking about thinking outside the box a little so we can revert to high BC bullets that expand in the way we want them to without pushing them at 3300 fps plus. I think it's getting there in bullet design but unless you go custom barrel and tighten the twist rate you can't take advantage of them. It needs rifle makers and bullet makers to work together so we can get back to enjoying the best of all worlds. They are not there yet but it can be done.

Im putting a 6XC together at the moment with a 7.5 twist barrel to shoot Peregrine 91gr bullets. They have the BC of a 95gr lead bullet, MV will be 3000 fps and they expand reliably to 2000 fps. High BC means energy and velocity are carried well to extended ranges, very close to what I'm used to with lead.

You can't do that today with a factory 6mm rifle and factory ammunition. In the future I hope you will be able to.

 

[Apthorpe]

I believe that Fox are not the only manufacturer to state their bullets expand adequately at 500m/s...about 1600 fps. What penetration is like at that speed, I have no idea.

 

[borbal]

also if bullets are getting longer then magazine housings need to accommodate this change

Indeed.

And those magazine housings will be in rifles with larger cartridges in consequence.

As has been noted many times by many people, the move to non-lead will also mean a drift to rifles with bigger engine rooms for the given calibre. Firstly, to overcome the ballistic coefficient deficiency of bullets made from a less dense material, and secondly because there is now a large body of experiential evidence that monolithics need higher terminal velocity (compared to lead-jacketed bullets) to expand properly. This, I believe, will be the main effect from the (inevitable) change to non-lead bullets.

It may also result in the total disappearance (in Europe anyway) of what is undoubtedly the most popular cartridge in the world today - the 22LR.

With its 16" standard twist, 22LR barrels are actually quite marginal in stabilising the standard 40 grain lead bullet in the 22LR cartridge, and moving to anything less dense would inevitably mean a faster twist barrel. There are a few attempts at creating a non-lead bulleted 22LR cartridge that will stabilise in a standard 16" twist barrel, but are generally well super-sonic and so erode the advantage of the 22LR as a discrete small game/vermin cartridge. The move seems to be to something like a 17 Hornet which offers good accuracy using non-lead bullets, with the added bonus of extended range over the little mouse guns.

 

[25 Sharps]

There is a lot of discussion on the forum at the moment relating the impending move away from lead. The camps are pretty polarised for many different reasons. I'm not going to get into the rights and wrongs here, but it got me thinking about how you build a better mousetrap. Talking specifically about rifle bullets rather than shotgun pellets.

There are a number of issues with the current offerings in Copper.

1. Because the density of copper is 20% less than the density of lead a bullet of the same length is 20% lighter and carries less energy at the same speed.
2. Because the formula for ballistic coefficient is sectional density divided by form factor, the reduced mass of a copper bullet of the same length as a lead one will always have a lower BC presuming bullet design (FF) is the same. Result is that the copper bullet looses velocity and therefore energy faster reducing effective range.
3. Most of us are used to using lead bullets that loose up to 50% of their weight in fragmentation and those fragments are often fatal even if placement is not perfect. Copper tends to retain 100% of it's weight and poor placement can result in more runners.

There are a lot of people talking about how the only solution can be to find a material with the same specific density as lead, but I don't believe this is the answer - even if it is viable which I doubt - an element with the right properties just doesn't exist at a viable cost.

Now if we look for an engineering solution to the above problems we might be able to build a better copper bullet than a lead one.

1. If we build the copper bullets 20% longer than their lead counterparts and maintain the same weight the bullet will maintain the same energy at the same velocity. Bullet makers are doing this already - a Barnes TTSX at 130gr in .277 is 1.322" and a Nosler 130gr BT is 1.220". Same SD, similar FF, BC of the TTSX is 0.392, the Nosler 0.422 (but nosler are always a little optimistic).

2. If we run bullets in copper of the same weight as our lead ones we keep the same SD and the extra length should enable the designers to improve the FF - the longer a bullet is for calibre the easier it is to minimise drag. So it is very possible to design copper with a higher BC than a lead bullet providing the same weight is maintained.

The down side here is twist rate. We will all need to up the twist rates in our rifles by 1" - 2" to stabilise these longer, more slippery projectiles. But that's possible. Even though it will limit some of the rifles in circulation. Buy rifles with a higher twist rate and we could take advantage the new bullets.

3. This is the killer at the moment. Most manufacturers are making copper bullets that retain 100% of their weight. Some are starting to make fragmenting bullets. There is an argument against the ones that retain 100% from some because they want fragmentation which leads to faster killing. There is an argument against the fragmenting ones from others because they don't want fragments of any metal in their carcass. But this is the same argument that has been going on for donkey's years on SD regarding AMax vs Partition - Fragmenting or not. If both options can be offered in copper it keeps both sides of the divide happy.

The big issue is terminal expansion at slow velocity. I personally don't trust a TTSX below 2400 fps, I trust an Accubond down to 2000 fps, an AMax to 1600 fps. Most of the current copper offering limits range especially for those who prefer the "slow and heavy" over the "fast and light". This is a design and engineering issue and is starting to be solved by some manufacturers. I think makers like Peregrine/Neilson/GSC might be the answer and look forward to trying them in the not too distant future. All those who have tried them seem to be very positive.

So at the end of the day, a change to copper could, if we all up our twist rates, give us better BC bullets that if the designers get it together expand down to below 2000 fps giving us all the range we could want in both fragmenting and expanding bullets. The future might be better than the present, but it will take a few years for the transition to take place and the bullet makers and rifle makers to work together to give us a better option than we have today with lead.

In the mean time load them lighter, shoot them faster and limit your range to the effective TV of the bullet - which is fine for most normal stalking ranges.

So all I have to do is change the barrels on all 5 deer rifles then? well 4 of the 5 and sell the 25-45 for a donor action as it won't drive lead free fast enough

Splendid

 

[25 Sharps]

Indeed.

And those magazine housings will be in rifles with larger cartridges in consequence.

As has been noted many times by many people, the move to non-lead will also mean a drift to rifles with bigger engine rooms for the given calibre. Firstly, to overcome the ballistic coefficient deficiency of bullets made from a less dense material, and secondly because there is now a large body of experiential evidence that monolithics need higher terminal velocity (compared to lead-jacketed bullets) to expand properly. This, I believe, will be the main effect from the (inevitable) change to non-lead bullets.

It may also result in the total disappearance (in Europe anyway) of what is undoubtedly the most popular cartridge in the world today - the 22LR.

With its 16" standard twist, 22LR barrels are actually quite marginal in stabilising the standard 40 grain lead bullet in the 22LR cartridge, and moving to anything less dense would inevitably mean a faster twist barrel. There are a few attempts at creating a non-lead bulleted 22LR cartridge that will stabilise in a standard 16" twist barrel, but are generally well super-sonic and so erode the advantage of the 22LR as a discrete small game/vermin cartridge. The move seems to be to something like a 17 Hornet which offers good accuracy using non-lead bullets, with the added bonus of extended range over the little mouse guns.

It won't, it will mean subsonics disappear - in a lot of other countries moderators are not allowed or hard to get hold of so everyone shoots SV or HV anyway, hornets are replacing magnum rimfires, .17 HMR in particular at the moment due to historic ammunition issues and potentially in part to rising ammunition costs

 

[25 Sharps]

I believe that Fox are not the only manufacturer to state their bullets expand adequately at 500m/s...about 1600 fps. What penetration is like at that speed, I have no idea.

Yes but the issue is their shape means they reach that speed quite quickly.

 

[NigelM]

So all I have to do is change the barrels on all 5 deer rifles then? well 4 of the 5 and sell the 25-45 for a donor action as it won't drive lead free fast enough

Splendid

Don't shoot the messenger. I'm not talking about the politics of whether lead is right or wrong, I'm thinking about how we get back to the performance of lead after it's been banned.

 

[25 Sharps]

Don't shoot the messenger. I'm not talking about the politics of whether lead is right or wrong, I'm thinking about how we get back to the performance of lead after it's been banned.

Stockpiling

 

[CarlW]

In my .308, I am currently planning to stick to copper at the same weight as my lead bullets. I will take lead (Nosler BT 150gn) when it is allowed, and copper (Nosler ET 150gn) when it isn't. Assuming the latter shoot well in my rifle (I have some on order), I will maintain (slightly improve?) my bullet's BC (although Nosler generally tend to be optimistic).

On the expansion front, I shall choose just to believe the manufacturer's claimed 1800 fps minimum. However, I do so in the knowledge that - although I'm a mediocre shooter - I'm a pretty good dog-trainer...

All the above, of course, subject to them actually shooting in my rifle when they arrive.

 

[Dunwaters]

Don't shoot the messenger. I'm not talking about the politics of whether lead is right or wrong, I'm thinking about how we get back to the performance of lead after it's been banned.

Its not going to be a problem, not even in the .243, you’re missing out the increased penetration as a factor in humane kills because of weight retention, theoretically you’re probably right but in the real world it wont matter.

 

[muddy42]

Copper being 20% denser doesn't necessarily mean bullets have to be 20% longer, if we ditch the Spitzer (pointy) bullet design for flat nosed bullets like the Peregrine Bushmaster (expanding) VGR3. Shorter length for same weight. I don't profess to be an expert but understand that shorter bullets are easier to stabilize. In the olden days I think more bullets used to look like these.

Has anyone any experience of these on UK deer?

 

[NigelM]

Its not going to be a problem, not even in the .243, you’re missing out the increased penetration as a factor in humane kills because of weight retention, theoretically you’re probably right but in the real world it wont matter.

You've missed the point.

A few years back I spent a couple of seasons using Barnes TTSX and LRX exclusively. 120 TTSX and 145 LRX in 280ai at 3400fps and 3150fps respectively and 100 TTSX in 6.5mm at 3250 fps. At normal stalking ranges they were good, little carcass damage everything exited, lots of internal damage and more bang flops than I was used to. The 120's at 3400 fps were particularly spectacular with almost 100% bang flops. Velocity kills very well.

But there is a downside to copper if you're shooting beyond normal stalking ranges. BC's are poor because SD is lower for the same length of bullet, they loose velocity and energy faster than lead and get hit harder by the wind. They also don't expand well at lower velocity. When taking longer shots these are significant disadvantages.

I then went to ABLR's driven slower. Much better BC's, more velocity and energy retained down range, more reliable expansion at lower velocity and still exited 100% of the time. A great bullet.

But now there will come a point when I am no longer allowed to use the ABLR so the thinking was around how I can achieve the same performance but with copper. I think the answer is out there but it's not mainstream yet. It's a bullet designed to expand better than a Barnes at lower velocity, keeping the same weights as we are used to with our lead bullets rather than down sizing and taking advantage of the higher BC potential and putting them through rifles with higher twist rates to make sure they stabilise.

 

[User00040]

also if bullets are getting longer then magazine housings need to accomodate this change

Not necessary, copper bullets tend to like jump.

 

[CarlW]

Copper being 20% denser doesn't necessarily mean bullets have to be 20% longer, if we ditch the Spitzer (pointy) bullet design for flat nosed bullets like the Peregrine Bushmaster (expanding) VGR3. Shorter length for same weight. I don't profess to be an expert but understand that shorter bullets are easier to stabilize. In the olden days I think more bullets used to look like these.

Has anyone any experience of these on UK deer?

The problem is that you then have the BC of a brick, which means they arrive at their minimum expansion velocity in a much shorter distance (plus other associated annoyances).

 

[User00040]

You've missed the point.

A few years back I spent a couple of seasons using Barnes TTSX and LRX exclusively. 120 TTSX and 145 LRX in 280ai at 3400fps and 3150fps respectively and 100 TTSX in 6.5mm at 3250 fps. At normal stalking ranges they were good, little carcass damage everything exited, lots of internal damage and more bang flops than I was used to. The 120's at 3400 fps were particularly spectacular with almost 100% bang flops. Velocity kills very well.

But there is a downside to copper if you're shooting beyond normal stalking ranges. BC's are poor because SD is lower for the same length of bullet, they loose velocity and energy faster than lead and get hit harder by the wind. They also don't expand well at lower velocity. When taking longer shots these are significant disadvantages.

I then went to ABLR's driven slower. Much better BC's, more velocity and energy retained down range, more reliable expansion at lower velocity and still exited 100% of the time. A great bullet.

But now there will come a point when I am no longer allowed to use the ABLR so the thinking was around how I can achieve the same performance but with copper. I think the answer is out there but it's not mainstream yet. It's a bullet designed to expand better than a Barnes at lower velocity, keeping the same weights as we are used to with our lead bullets rather than down sizing and taking advantage of the higher BC potential and putting them through rifles with higher twist rates to make sure they stabilise.

Everyone who pushes for lead bullets to be phased out has missed the point.

If the 'non-lead/non-toxic only' malarkey is pushed to it's logical end point, with government legislation preventing the use of otherwise conventional, lead-based, cup and core bullets, some which have well over 50 years worth of results and data behind them (think Nosler Partition or similar hunting bullet designs from Sierra) will follow.

Don't get too excited with all your gucci chamberings and home loaded ammo, they will be just as worthless as the older rifles with supposedly obsolete barrel twist rates .

All government forestry leases and contracts in Scotland currently operate under a factory made only,lead-free ammunition policy which is clearly stated in the terms. Anyone who has stalked under the BASC scheme in Arran should be familiar with this.

Guess where organisations like NatureScot (formerly SNH) are going to draw from when it comes to advising ministers (some of whom may have never seen a deer or rifle up close) when the time comes to make these new laws? NatureScot have this policy for their own ground too, so don't be surprised if you find such wording in your lease when it comes up for renewal.

Reloaders with their 280AI's, 300WSM's etc. will not be catered for, so bear this in mind when you preach about copper and why lead is 'so last season dahhling...'

You will be left out in the cold too when the time comes, enjoy paying £60+ for a box of 20 cartridges which are under-powered and over-priced.

And another thing, if you don't have a deer dog for follow up, be prepared to call someone who does and compensate them for their time and effort.