A little knowledge is dangerous, especially in a gun shop

[308tikka]

Its

Maybe that is because it doesn't start seeing the bullet until it is some distance, slightly indeterminate, beyond the muzzle. Then it only starts when it hears the muzzle blast, or maybe you can trip it with an add-on device that detects the recoil from your rifle. It certainly cannot measure muzzle velocity.

They certainly are not "little".

Try shooting it over, say two decent optical chronys at two different distances from the muzzle, (or just one, used twice) and then see how it compares.

Not sure what an EU spec. neutered LabRadar brings to the party.

Some other jurisdictions, sensibly, specify deer legal energies at distances where they might realistically touch a deer, not at the muzzle.

But that is another can of worms.

Its been shot over lab radar and with magneto for precisely this reason when making ammunition for an international rifle match overseas.....

My point is-measure what you want, nobody is going to demand to test handloaded ammunition for deer. People worry far too much about unimportant issues, instead of: is the load accurate and repeatable? Is it doing its job?

 

[Sharpie]

Its

Its been shot over lab radar and with magneto for precisely this reason when making ammunition for an international rifle match overseas.....

My point is-measure what you want, nobody is going to demand to test handloaded ammunition for deer. People worry far too much about unimportant issues, instead of: is the load accurate and repeatable? Is it doing its job?

So maybe you agree. A Magnetospeed measures only muzzle velocity. A LabRadar cannot, but can do so much more. You started off by saying that your LabRadar close range results were consistently 10fps down on the Magnetospeed. Hardly surprising. But entirely expected, and doesn't put either in question. Just different devices for different uses.

 

[308tikka]

Yes - I do agree.

So maybe you agree. A Magnetospeed measures only muzzle velocity. A LabRadar cannot, but can do so much more. You started off by saying that your LabRadar close range results were consistently 10fps down on the Magnetospeed. Hardly surprising. But entirely expected, and doesn't put either in question. Just different devices for different uses.

I think people rely on a device to ‘make it legal’ and havent checked their device is either accurate or set up correctly. Mine is an optical chrono that requires placement 5m in front of shot (according to maker)-always going to be slower. But I use it for SD not necessarily MV or any other use.

 

[caorach]

As I understand it (and "understand" is a bit optimistic from this point in) as the length of a bullet increases it becomes harder to stablise. As a result, a rifle that can stabilise a short bullet made of lead won't be able to stabilise a longer one made of copper. To do this you will need to change (presumably increase?) the twist rate within the barrel and (possibly) lengthen the barrel itself.

You don't need to increase then barrel length at all. The length doesn't impact upon the rate at which the bullet will spin, though this may seem slightly odd. When you think about it say a barrel is designed to give the bullet one full turn in 11 inches then in a 22 inch barrel the bullet will complete 2 full turns before it exits. In a 5.5 inch barrel the bullet will complete half a turn but it will still be making a full turn in 11 inches, and 2 full turns in 22 inches even if it has exited the barrel by that point.

Increasing the twist rate of the barrel, or increasing the speed of the bullet, will both increase the rate at which the bullet spins. If you consider a barrel that gives 1 turn in 12 inches (just for simplicity) then at 3000fps it will be giving 3000 turns per second and at 2500fps it will be giving 2500 turns per second.

 

[Sharpie]

Actually, it is quite important to understand how a bullet may perform when stalking, at longer ranges. Particularly with lead free projectiles, where impact velocity may become a deciding factor.

A lot of anecdotal stuff on here as to what that means, but precious little actual testing using chronos at those distances. Maybe because it is difficult. Handwaving arguments making assumptions about BC, calculations, assumptions, maybe measuring bullet drop at a distance and back-calculating. Claims of "my combination will give 25XXX fps at YYY yards so is fit for the hill etc. Not that I have zeroed it beyond 100, or maybe 200 yards. But, nevertheless very few facts and data for me to get my teeth into.

Nevertheless what seems to work, probably does. Far too many variables to try to address this comprehensively.

Target shooting, frankly, is rather easier to explore. SD (or more importantly ED) is easily measured at , or near to the muzzle. But is not the be-all and end-all of that game.

 

[Sharpie]

You don't need to increase then barrel length at all. The length doesn't impact upon the rate at which the bullet will spin, though this may seem slightly odd. When you think about it say a barrel is designed to give the bullet one full turn in 11 inches then in a 22 inch barrel the bullet will complete 2 full turns before it exits. In a 5.5 inch barrel the bullet will complete half a turn but it will still be making a full turn in 11 inches, and 2 full turns in 22 inches even if it has exited the barrel by that point.

Increasing the twist rate of the barrel, or increasing the speed of the bullet, will both increase the rate at which the bullet spins. If you consider a barrel that gives 1 turn in 12 inches (just for simplicity) then at 3000fps it will be giving 3000 turns per second and at 2500fps it will be giving 2500 turns per second.

Not quite. A longer barrel is likely to shoot at higher FPS, properly loaded. Resulting in a faster bullet spin. If your bullet is marginally stabilised at faster spin rates, it might start to wander off if you try to use a shorter barrel, of the same twist.

The .243 is an interesting case, perfectly designed to suit 55, 70 or 80 gr lead projectiles at it's standard twist. Even managing to shoot 100 gr. Some better than others. You can even cut them down quite short and still work (but not get large deer legal muzzle energy, even if you don't care about that, or just ignore it). Once you start trying to use less dense non lead projectiles, well it is not easy. Perhaps some brass bullets and loads make the numbers, maybe by compromising the downrange performance (such bullets must be compromised in ballistic coefficient, so even if they can be spat out of the muzzle above the threshold, and be accurate, they are unlikely to have the downrange energy and velocity and flat trajectory that could be expected of the leaden ones.

So, shorten the twist rate I hear. Well that too introduces more complication. A significant extra drag on the bullet whilst inside the barrel, for one, and potentially degrading the accuracy with lighter "varmint" loads.

If the Scots do eventually get around to allowing 80gr bullets for large deer, well, OK, that might keep them viable, but don't count on it.

I have no idea what other EU ? countries mandate for the minimum to shoot their big game, but I suspect that they may set their targets a little higher than what a standard .243, with a decent length of barrel, might manage.

Maybe the 6.5CM will become the new .243 ? Seems to be going that way, and why not ?

Meanwhile, in England/Wales, crack on.

 

[J@son]

...then in a 22 inch barrel the bullet will complete 2 full turns before it exits. In a 5.5 inch barrel the bullet will complete half a turn...

but is it not the case that the longer the barrel the greater the opporunity to stabilise the bullet?

I appreciate the bullet is given its "twist rate" by the rifling within the barrel regardless of the length of the barrel itself. But surely it follows that the longer the barrel, the greater the twist imparted to the bullet and thus the greater the stability of the bullet once it leaves the barrel? Otherwise pistols would be as accurate as rifles or at least everyone would be using short barrelled carbines.

Please don't take this the wrong way! I am absolutely not saying you are wrong in what you have written.

I have no idea what I am going on about and it sounds as though you know more than me. Once again I am just thinking aloud in the hope of gaining a better understanding of ballistics so I can work out a long term plan.

My existing rifle shooting 100 grain RWS rounds allows me to consistently put three rounds inside a postage stamp at 100m. This is the sort of accuracy I am keen to find in lead-free substitutes as (increasingly) I am looking to take neck shots. So, for me, the most important things are (1) reliable/consistent accuracy and (2) delivering enough bullet to cause devistating damage to the deer's neck in order to drop it on the spot.

100gr RWS is perfect. Small entry wound. Slightly larger exit wound. Neck bones in between completely destroyed - devastating damage to the extent that my knife easily moves through the point of impact to remove the head.

Ultimately (and I appreciate I don't need a solution immediately - I've got enough RWS round to keep me going for a bit) I want to find a lead free alternative that will deliver this level of accuracy and this much punch at the receiving end. I would like to find it in .243 but if I have to move up to 270 or 308 in order to achieve the accuracy I want, then I would be willing to do so.

Really appreciate everyone's constructive input - so thanks for all the comments so far.

(sorry @Sharpie my last post crossed with yours)

 

[caorach]

but is it not the case that the longer the barrel the greater the opporunity to stabilise the bullet?

I appreciate the bullet is given its "twist rate" by the rifling within the barrel regardless of the length of the barrel itself. But surely it follows that the longer the barrel, the greater the twist imparted to the bullet and thus the greater the stability of the bullet once it leaves the barrel? Otherwise pistols would be as accurate as rifles or at least everyone would be using short barrelled carbines.


(sorry @Sharpie my last post crossed with yours)

Sharpie's point is a good one in the sense that more speed will cause the bullet to spin "faster" and so can increase stability and, of course, you can sometimes get more speed with a longer barrel. However I suspect that, basically, your question is along the lines of "if the rifling has longer to hold on to the bullet does it not give it more spin?"

Assuming the rifling fully engraves the bullet and there are no other "what if" type factors then the actual length of that rifling doesn't matter. If you have a 1 in 12 barrel - so it gives the bullet 1 turn in 12 inches - and you make it 12 inches long then the bullet will exit having made one full rotation in the rifling and it will be rotating 1 full turn for every 12 inches it travels. So if this bullet had a speed of 3000fps then it would be travelling that 12 inches 3000 times every second, and it would be rotating once for each of those 12 inches. If you make the barrel only 6 inches long but keep the rifling the same (assuming you can keep the speed the same) then your bullet will only complete half a turn in the 6 inch barrel but on exit it will still be rotating at a rate of one rotation in every 12 inches. If it is doing 3000fps on exit then it will be making one rotation in every foot and so will be rotating at the same rate as the bullet from the 12 inch barrel.

So, basically, under normal circumstances a 1 in 12 rifled barrel will gave the same spin to the bullet no matter the length of the rifling. I imagine, but don't know, that there would be a very short period as the bullet gets forced into the rifling when there may be some tendency of the bullet to "slip" relative to the rifling but as more and more of the bullet enters the rifling so it will have a greater "hold" on the bullet. Once the whole bullet is supported by the rifling then my guess is that it is either constructed to take the spin, or it isn't, and so after that the rifling length doesn't much matter. As Sharpie has suggested a 3 inch barrel on a rifle wouldn't give you much velocity but, assuming you could get the required velocity out of it, it would give you enough spin.

 

[Sharpie]

Sure, unless something is horribly wrong, a bullet will engrave in the rifling and be locked into that twist rate until it pops out of the muzzle. Whatever the length of the barrel.

Nevertheless the rotational rate of the bullet is a significant factor in it's stability. Which is a function of both the barrel twist, and the muzzle velocity.

Some simple reading: The State of the Art in Rifle Bullet Stability

Where Berger explain that their headline figures for their bullets assume a blanket muzzle velocity of 2800 fps.

Then invite you to delve deeper, using their online "twist rate stability calculator", where you can put in the details of what you are actually doing, of which both barrel twist AND muzzle velocity are factors. As well as air temperature and altitude, of course.

Twist Rate Stability Calculator

Their algorithm is not published, but a little research will lead you to plenty of work which shows that the rotational spin rate of the bullet is very much a factor in stability calculations. Simply fixating on the barrel twist rate alone is simplistic.

Another such calculator, with more detailed explanation, Bullet Gyroscopic Stability Calculator Again, muzzle velocity, as well as barrel twist, are both factors.

 

[Mr. Gain]

For FE and other landowners who insist on NLA, its their perogative but probably based on 1/ poor practice with gutshot gralloch by north american hunters and 2/ the California condor story which has nothing to do with lead but west nile virus. Ecoloons tell enough lies and it becomes established fact.

This. I'm delighted that copper bullets are proving effective at normal stalking ranges, but continue to be annoyed at the credence given to an anti-lead campaign that is based on unsubstantiated suppositions and outright lies masquerading as science and fact. There are undoubtedly some circumstances in which spent projectiles can cause unintended harm, but the partial and specific data relating to these circumstances does not begin to support the blanket propaganda that is being used to reshape legislation, disrupt an industry, and slander shooting. I can think of no other instance where such slender claims would be accepted as requiring such radical interventions.

 

[StephenToast]

Aren't you all overlooking the main benefit of a longer barrel?

Stuff spin and velocity. The longer the barrel the closer you are to the deer.

Me with my .30-06 at the range yesterday.

 

[25 Sharps]

Theres no (legal) requirement to shoot deer with copper. It is (some of) the game dealers who require it. Market forces (ie game dealers want a bigger share of a swamped market) driving it. If vermin is classed is inedible then there will be no requirement by GDs for animals taken with non lead ammunition.

I wouldnt be shooting rabbit with a 243, and even with rimfire, theres no requirement for non-lead from anyone I can see.

For FE and other landowners who insist on NLA, its their perogative but probably based on 1/ poor practice with gutshot gralloch by north american hunters and 2/ the california condor story which has nothing to do with lead but west nile virus. Ecoloons tell enough lies and it becomes established fact. Goebbels would be proud.

243 much maligned by the brainless and the dealers wanting to sell the latest fashion.

243 (or any 6mm) 80-90gn copper is fine apart from Scotland, where of course, so much common sense deer policy is enforced.

Solution for scottish 243 shooters-rebarrel to a 1:8.

Not quite, the HSE is running a consultation on ALL lead projectiles in ALL environments, so quarry shooting, clays and targets.

This is not just a food safety concern it is an environmental pollution one as well (specifically mentioned in the .gov press release). There is every chance that lead mullets will be banned for vermin and potentially for clay grounds and shooting ranges too.

 

[J@son]

every chance that lead mullets will be banned for vermin

Totally in favour of outright ban of all mullets (on vermin or anything else) along with double denim and the entire back catalogue of Billy Ray Cyrus.

As well standing squarely behind his views on 80s hairstyles, I think @25 Sharps makes a good point about the direction of travel - I suspect we are heading for total a lead ban in respect of all shotgun ammunition (both clays and game) and that the writing will soon be on the wall for rimfire rounds too. I don't think this is just about the risk of lead going into the foodchain. I think it is much broader than this.

 

[25 Sharps]

Totally in favour of outright ban of all mullets (on vermin or anything else) along with double denim and the entire back catalogue of Billy Ray Cyrus.

As well standing squarely behind his views on 80s hairstyles, I think @25 Sharps makes a good point about the direction of travel - I suspect we are heading for total a lead ban in respect of all shotgun ammunition (both clays and game) and that the writing will soon be on the wall for rimfire rounds too. I don't think this is just about the risk of lead going into the foodchain. I think it is much broader than this.

Fish, I’m talking about the fish

 

[Foxyboy43]

Fish, I’m talking about the fish

Thank gawd! Just imagine if this ever returned……..

 

[Sharpie]

FYI, just been playing around with the Berger Twist rate Stability calculator.

Selected their 105 gr VLD (lead) hunting bullet at 10" twist (normal for .243.

At 2650 fps:



At 2,800 fps, which is the minimum to get a 100 gr bullet large deer legal in both England (1700 fpe) and Scotland (1750 fpe), you still get SG=0.985. Still unstable.

However, when I look at the latest Viht. reloading data, for .243, for a 100 grain bullet, the best load that they can offer results in an MV. of around 2900 fps., at max load. Their figures, by the way, are measured using a 23" 10" twist barrel. Not a shorty.

For a 105 grain bullet, the absolute best (max) load results in 2933 fps.

So lets try try 2950 fps.

Yet again, no good. SG=1.0




OK, what to make of this ?

Well, trying to shoot a 100/105gr lead bullet from a 10" twist .243 with a good length of barrel, e.g. 23", at UK large deer legal muzzle energy, is marginal, and always has been, using top loads. Both in muzzle energy, and stability.

Trying to make it stabilise in a typical 10" twist barrel is marginal at best.

This is for lead projectiles. Copper, brass, tin etc, no chance at 100 grains. Though I think one person, ED, reckons he can supply lead free ammo that works. In Scotland. For large deer. Hmm.

Muzzle velocity does have an influence on stability, everything else being equal

So, suppose you can buy new, or re-barrel, a .243 in an 8" twist, maybe even 7", Well try running the numbers yourself.

Or, better, look into 6.5mm, 7mm or 7.62 mm bullets, from basically the same cartridge case and powder charge. All becomes so much easier.

Meanwhile in England/Wales etc. we may use the lighter bullets for which the 10" twist .243 was designed, so have more leeway. Nevertheless you need to be careful to actually meet the legalities for large deer, if you are bothered about actually complying with the law.

Move on to lead free projectiles, and that introduces further complications.

Would I buy a new .243 in the UK ? Sadly no, except for foxing and small deer. Time has moved on.

 

[Kjf]

It seems a lot of knowledge has descended on this thread lol lol, and it's online


Not even in a gun shop.ffs

Buy gun

Stick ammo in gun

Shoot quarry when safe to do so lol lol

 

[snake_2586]

It is nice to see a bit of the theory backing up the facts, and at least it allow people to decide whether or not the wish to follow law, and use legal ammunition.

 

[Sharpie]

OK, enough said by me. But innumerable discussions of factory ammo fussiness in factory rifles suggest, at least to me, that a little bit of knowledge is no bad thing. Particularly if you reload. Out.

 

[25 Sharps]

but is it not the case that the longer the barrel the greater the opporunity to stabilise the bullet?

I appreciate the bullet is given its "twist rate" by the rifling within the barrel regardless of the length of the barrel itself. But surely it follows that the longer the barrel, the greater the twist imparted to the bullet and thus the greater the stability of the bullet once it leaves the barrel? Otherwise pistols would be as accurate as rifles or at least everyone would be using short barrelled carbines.

Please don't take this the wrong way! I am absolutely not saying you are wrong in what you have written.

I have no idea what I am going on about and it sounds as though you know more than me. Once again I am just thinking aloud in the hope of gaining a better understanding of ballistics so I can work out a long term plan.

My existing rifle shooting 100 grain RWS rounds allows me to consistently put three rounds inside a postage stamp at 100m. This is the sort of accuracy I am keen to find in lead-free substitutes as (increasingly) I am looking to take neck shots. So, for me, the most important things are (1) reliable/consistent accuracy and (2) delivering enough bullet to cause devistating damage to the deer's neck in order to drop it on the spot.

100gr RWS is perfect. Small entry wound. Slightly larger exit wound. Neck bones in between completely destroyed - devastating damage to the extent that my knife easily moves through the point of impact to remove the head.

Ultimately (and I appreciate I don't need a solution immediately - I've got enough RWS round to keep me going for a bit) I want to find a lead free alternative that will deliver this level of accuracy and this much punch at the receiving end. I would like to find it in .243 but if I have to move up to 270 or 308 in order to achieve the accuracy I want, then I would be willing to do so.

Really appreciate everyone's constructive input - so thanks for all the comments so far.

(sorry @Sharpie my last post crossed with yours)

Sounds like an expensive target!