Hollow bullets for high BC, low weight

[shazz]

For target shooting a lot like heavy (long) bullets for their high BC, among other reasons.

With the heavy bullet weight comes recoil though and if you can't shoot heavy recoil then you become a problem.

So... Could a long bullet which was hollow provide a solution of High BC with low weight - and low recoil?

[Chronos]

Interesting thought, I'll be keen to hear what others think.

I guess the jacket would have to be strong enough to stand up to firing.

Chronos

[SendIt]

I think the idea is sound.

As Chronos alluded to, maintaining the integrity of the bullet would dictate how much you could remove from the centre.

Too weak and the bullet would deform making it useless. Worse if it crumpled inside the barrel it's foreseeable the bullet would jam and you'd risk a catastrophic failure.

A solid copper bullet would seem like the best candidate for it, jacketed lead may work but it seems likely you'd be more limited in how much material you could remove.

Solid copper would allow for the most removal and the strongest bullet combination I think.

Wouldn't want to make a guess as how much you could reduce a bullet by but I think the idea is sound.

[Seik]

Too weak and the bullet would deform making it useless. Worse if it crumpled inside the barrel it's foreseeable the bullet would jam and you'd risk a catastrophic failure.

How strong is strong enough would depending on the cartridge velocities and pressure too.

A .30 cal bullet like this could be strong enough to load for .308 but not for 300 Wby Mag or other higher powered cartridge I'd think.

Something else they'd have to make sure they had right.

[Jack V]

No, weight is part of the BC calculation and performance of a bullet, the very light bullet will loose velocity faster and be more effected by wind. Compared to a heavier bullet with exactly the same external shape started at the same velocity .

Not to mention bad terminal ballistics for a certain target.

[Chronos]

No , weight is part of the BC calculation and performance of a bullet , the very light bullet will loose velocity faster and be more effected by wind . Compared to a heavier bullet with exactly the same external shape started at the same velocity .
Not to mention bad terminal ballistics for a certain target .

Yes but weight is also a factor in a bullets acceleration from zero to MV, are you suggesting the two will cancel each other out and you'd see no measurable reduction in drop or wind drift?

would be interesting to compare a lead core bullet and a solid bullet which are now more common though not identical in external dimensions.

Perhaps tests could be done using a monolithic bullet in its natural state then with various amounts drilled out from the base at say. 5gr increments.

If course this would change the bullets natural point of balance and change its in flight performance. I've read Interesting stuff about how bullets fly and how barrel tuning can change a bullets tip up/ tip down flight

Chronos.

[Warrigul]

Weight is important around the periphery, think about the different forces in play at the hub between big bicycle wheel versus small bicycle wheel of same weight rotating at the same rate.

I think this is the next big area for exploration in the accuracy world. Long(relatively) hollow projectiles.

The possibilities are endless and worthy of pursuit. I am not able to do the research the justice it deserves.

[Jack V]

I am saying what I said.

Just because a lighter bullet may accelerate faster to it's MV that does not mean it will be better down range. What happens that close to the Muzzle is not the whole down range performance of a projectile. For any comparison to mean anything you have to assume both projectiles are started at the same velocity and both have the exact same external physical shape.

A monolithic bullet is not hollow and still has a reasonable weight for their length and calibre making their performance acceptable for certain uses.

It's like saying how long is a piece of string? How light is the hollow bullet for it's length and calibre?

If it's a 30 calibre bullet.9 long and it only weighs 50 grains it's going to be useless for a 30 cal.

Not to mention structural integrity. It could collapse at the base under chamber pressures. It could suffer jacket failure at the ogive due to shock wave pressure if it's too thin. It would lack proper penetration on any game that you would normally shoot with a normal 30 cal.

Using 30 cal as the example it would basically bring it down to about the effectiveness of a 222 roughly speaking.

[Chronos]

How light is the hollow bullet for it's length and calibre?

If it's a 30 calibre bullet.9 long and it only weighs 50 grains it's going to be useless for a 30 cal.

Not to mention structural integrity. It could collapse at the base under chamber pressures. It could suffer jacket failure at the ogive due to shock wave pressure if it's too thin. It would lack proper penetration on any game that you would normally shoot with a normal 30 cal.

Using 30 cal as the example it would basically bring it down to about the effectiveness of a 222 roughly speaking.

If you read the Op you'll see he asks about target shooting

Chronos

[Jack V]

Does not matter a 50 grain 222 will not buck the wind like a 180 grain 30 cal will. The 50 grain hollow lighter bullet having the same external physical shape will be worse effected by wind due to it's ratio of weight to cross sectional area that the wind sees could be more effected than the 50 grain 222

I guess you can shoot a lot of things out of a barrel at a paper target but will it be very effective over range and consistently accurate. I don't think so otherwise we would all be shooting hollow light bullets for the calibre right now.

Also it's near impossible to make a good bullet out of a weak hollow core and jacket from the swage up process that they use to make jacketed bullets. The process has to have some reasonable amount of solid swageable core material at least in the base and shank part.

It would have to be a process more like a monolithic is made.

[Chronos]

For target shooting a lot like heavy (long) bullets for their high BC, among other reasons.

With the heavy bullet weight comes recoil though and if you can't shoot heavy recoil then you become a problem.

So... Could a long bullet which was hollow provide a solution of High BC with low weight - and low recoil?

Ok so here's my answer to your questions Shazz

I believe your idea has some merrit but without testing its just theoretical.

Yes I believe a bullet with the same external dimensions and therefor BC but lighter because of a well designed hollow core would produce less recoil obviously and more velocity but still maintain the benefits of a long high BC bullet.

For example a 7mm 180gr Berger Hybrid loaded to a velocity of 2740 (my load) would have a trajectory like this

1.gif (42.52 KiB) Viewed 4807 times

The same bullet 20grains lighter would have a trajectory like this assuming it's launched at the same speeds as my 162gr Amax load

2.gif (42.52 KiB) Viewed 4807 times

You can see the lighter bullet shows less drop, less muzzle energy (a rough representation of recoil) and only a minor increase in wind drift, under 2" at 1000m

Obviously this would apply proportionally to a modified monolithic bullet of which there are a few on the market now.

Hope that goes some way to answering your question.

Chronos

[Hatter]

Interesting idea.

Cost would be killer though. Target shooting typically means using a lot of ammo so cost is a factor.

Would someone pay twice the price for a 150gr bullet in the dimensions of a 180gr bullet for a little less recoil? Probably not, at least not for long.

[Warrigul]

Interesting idea.

Cost would be killer though. Target shooting typically means using a lot of ammo so cost is a factor.

Would someone pay twice the price for a 150gr bullet in the dimensions of a 180gr bullet for a little less recoil? Probably not, at least not for long.

There are some that would, I think the main benefit would be better stabilisation, from the mass being around the circumference, and needing less twist allowing (and it sounds obtuse but isn't) greater velocity from a given cartridge.

Checked out by greater brains than mine it is theoretically possible, but needs trialing.

[Hercl]

For any comparison to mean anything you have to assume both projectiles are started at the same velocity and both have the exact same external physical shape.

Why would you test the lighter bullet at the same speed as the heavier bullets? That's not how it will be used so that would make the comparison meaningless.

In practice a lighter bullet will be fired a higher velocity, a heavier bullet at lower velocity.

It's about measuring the performance of the bullets, for the comparison to be meaningful you'd test at the velocity they're going to be fired at, strike targets at. Used at.

[Harts]

I was going to ask the same thing.

I can't see what measuring them at the same muzzle velocity would do other than tank the results in favour of the heavier bullet.

[jackles]

No, weight is part of the BC calculation and performance of a bullet, the very light bullet will loose velocity faster and be more effected by wind. Compared to a heavier bullet with exactly the same external shape started at the same velocity .

Part of BC you say, so not all?

There could still be an advantage to the idea then.

[Jack V]

Because he wants to use a lighter bullet but also retain the high BC of an existing heavier one that causes extra recoil compared to a lighter one ..
Sure you can use any weight you want IF you can physically make it work but you will never retain the same BC as the heavier one of the same physical shape and calibre .
To understand any of this you do need to understand ballistics and how bullets are actually made . We can all image wonderful ideas but making them a reality is something else . Believe me if this could work I would be making my 30 cal bullet for a 1/3 of the price and so would the bullet companies.
How is it a fair comparison if one is launched faster than the other , then it just a faster lighter bullet against a slower heavier one . That's not a comparison of how the lighter hollow design would hold the same BC as the heavier one of the same physical shape. You have skewed the figures towards the faster velocity .
If you were testing two cars braking ability would it be fair if one drove at 100ks and the other at 50ks for the test ?
You have to keep some parameters the same or you will not see the thing you are testing for in the results .
If the two bullets are only a small amount of weight difference then it's not a valid argument as velocity difference will make it up .
BUT you will not get a great change in recoil with only a slight change in weight difference .

[1290]

Bullet mass allows the retention of momentum... and a higher BC.
Lighter bullet will accelerate quickly, have a higher MV, flatter shorter range trajectory, but the lack of momentum will cause them to decelerate quicker.... and fall out of the sky sooner - hence have a lower BC.

The trajectory is dependent on only 2 variables; Muzzle velocity and BC. Period.
As I think it has been mentioned, mass (not weight) factors have been 'built in' to the BC.....

So no, a high BC is not compatible with a low mass bullet, at least for the calibre and mass range (& therefore SD) we would normally encounter....