AusVarmint

As a non-reloader, occasional shooter I'm going to fess up to being a complete newb when it comes to the art of projectile choice etc.

While I know a zillion different factors apply to cartridges, projectiles, primers etc can someone help me understand the basics of bullet weights? I know different projectile weights will behave differently (assuming all other factors are basically equal) but can someone explain how accuracy over range is affected by projectile weight?

Considering standard calibres such as 308 and 223, what differences would one expect to see between 'light' and 'heavy' projectiles.

Yes, I know I could run that through a ballistics calculator but I've yet to find a simple one that shows any distinct difference between light and heavy.

Edumecate me...

I tend to look at bullet construction and pick the one that is designed by the experts to do the job at hand. Tough bullets for when you want them for larger critters and lighter fragile ones for smaller critters. Don't give two hoots about the ballistic characteristics of bullets generally, I usually don't shoot extended rangers, say more than around 300 yds. Bullets like Sierra Pro hunter are a good standard tough bullet, Hornady Interlocks are built pretty much the same, don't know much about solid copper bullets as I haven't used them, and the price generally scares me away. I'd say that there have, and will be, shit loads more critters shot and killed easily with cup and core bullets than there ever will be with solid copper. I use plastic tipped bullets in varmint calibres cause I want them to splatter and stay in the critter if possible. Light bullets are made to do this.

I dare say other will disagree, that's fine, just my ramblings.

Camel wrote:I tend to look at bullet construction and pick the one that is designed by the experts to do the job at hand. Tough bullets for when you want them for larger critters and lighter fragile ones for smaller critters.

I dare say other will disagree, that's fine, just my ramblings.

I'd pretty well agree with Camel on that one.

Don't over complicate things, weight is considered a little in my thinking but generally google and ponder then buy and shoot.

Cheers,
Waldo

Camel wrote: Don't give two hoots about the ballistic characteristics of bullets generally, I usually don't shoot extended rangers, say more than around 300 yds.

This is also my main consideration. My ranges are even shorter, 150-200 m, max. I am a light skinned animal shooter and a projectile that will go through a tree is NO good to me. Accurate, function, fast and light, in that order. Weight would only come into the equation when the barrel twist rate dictated that a heavier projectile would be more accurate. That does no apply to my rifles. I can not see the point of throwing 55 grains+ down range when 40 grains or less will do the job just fine and is more accurate.
I build a very thin skinned projectiles and they work very well on thin skinned critters.

Hopefully the target shooters will jump on board and go through their thoughts on wind deflection, drag, BC and the like.

Bill

Im one of those target shooters and will indeed argue that BC, velocity, barrel twist etc is very important in choice. For target shooting. If your shooting to 300 get a bullet that does what you want it to do. Expand rapidly on vermin- ballistic tip style bullet. Thin skinned game- soft or hollow point. Less holdover under the spotlight- lighter bullet and push faster. More knockdown- heavier bullet. In 308 if your just shooting foxes, dogs etc a 110 vmax or sierra hollow point will be evil. Step it up to pigs and smaller deer and you might want to bump up a little in construction and weight. Target shooting the 308 and 155's go hand in hand and serious 1000yd shooting the best bullet is probably the 185 berger juggernaut. 223 I like 50gr ballistic tip bullets for everything. But 40's will work fine as well. Lots use 55 but Im finding them to start getting a little loopy out for further shots under a light.

Lastly can I suggest its never worth forcing a gun to shoot something it wont. Accuracy trumps velocity, terminal performance, wind drift and all that other stuff. If it likes something and it works, dont fix what isnt broken.

Varmint pills are supposed to explode on or in the animal. A bigger boned thicker skinned animal needs to be killed with a bullet designed to hold together until it's in deep enough to reach the vitals. Though in saying that really big creatures fall down dead if a small varmint pill meets the base of their ear. So pick one designed to do the job needed on the target.

Now go google sectional density and ballistic co efficient and some other things I forgot and add those into the mix if you pull needs to do its job way out there.

If you are target shooting terminal performance is irrelevant. A target pill may zip thru an animal without expanding and you might have to go looking for a wounded one. No such problems aiming at paper long range. Then the scientific stuff is king and the only consideration


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Just to expand slightly on what trev said, ranges with timber frames do not like you using varmint/hunting projectiles at long distance as they smash the frames up more if you miss a change

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Tested some different weights of ammo on the weekend.

Can anyone explain a 6.5-9 inch drop between a baseline of 130gn and anything from 150-180gn? That seems excessive.

Yes, it was a mix of brands and projectile types. So it wasn't a fair test but....

Geez 6.5inch drop moving from 130gn to 150gn? Very surprising. 180gn fell off-paper (well over 9 inch drop).

FWIW 308W over 100yards.

DSD wrote:Just to expand slightly on what trev said, ranges with timber frames do not like you using varmint/hunting projectiles at long distance as they smash the frames up more if you miss a change

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I don't use timber frames, and the metal ones don't last any better

Found the solution, have a much bigger frame!

I'm no expect at ballistics mate but it really depends what you want to do with your rifle/bullet combination.

If you're planning on hunting with it then you need to look at the energy figures as well. Adjusting for drop is relatively easy compared to trying to allow for windage. To be honest, drop is the least of my concerns when picking a hunting projectile. I just don't hunt at far enough distances to make it that much of a worry. That might all change one day though but my hunting style at the moment is limited to 200-250m shots max.

The lighter projectiles starting off faster generally have a lower BC and tend to slow down quicker so the heavier pills (even with a slower starting velocity) can catch up to the lighter ones at distance. There's a free program called Point Blank which allows you compared drop data between loads which is really interesting.

Hope that makes some sense.. best I can do at 4am sorry!

The Raven wrote:Tested some different weights of ammo on the weekend.

Can anyone explain a 6.5-9 inch drop between a baseline of 130gn and anything from 150-180gn? That seems excessive.

Yes, it was a mix of brands and projectile types. So it wasn't a fair test but....

Geez 6.5inch drop moving from 130gn to 150gn? Very surprising. 180gn fell off-paper (well over 9 inch drop).

FWIW 308W over 100yards.

Increase in projectile weight generally means a decrease in velocity (relative to the lightest pill you started with). If you sighted in using the lighter pills then it stands to reason that as the weight increased they got slower and their trajectory became more of a rainbow than it started out as with the lighter pill.
Gravity is a bitch even with something as small as a projectile.

The Raven wrote:Tested some different weights of ammo on the weekend.

Can anyone explain a 6.5-9 inch drop between a baseline of 130gn and anything from 150-180gn? That seems excessive.

Yes, it was a mix of brands and projectile types. So it wasn't a fair test but....

Geez 6.5inch drop moving from 130gn to 150gn? Very surprising. 180gn fell off-paper (well over 9 inch drop).

FWIW 308W over 100yards.

What you are seeing on paper is not drop but a different point of aim. Different projectile weights can shoot to very different points of aim, all to do with barrel harmonics and position when the projectile exits.
A 222 I have will put just about any 50,52,53 or 55gr bullet into the same group, if I swap to 40gr projectiles they still shoot similar sized groups but hit the target about 6" higher.

The Raven wrote: Yes, I know I could run that through a ballistics calculator but I've yet to find a simple one that shows any distinct difference between light and heavy.

Edumecate me...

You wont unless it will some how allow you to calculate maximum point lank range.
As a example using 223 if you plug in 40gr 55gr and 69gr with a 200y zero you will get the following
40gr approx. 2" low @ 250
55gr aprox 3" low @ 250
69gr approx. 3.5" low @ 250

Not much difference but what your not factoring in is the mid range rise before the projectile arrives at 200y on point of aim.
The 40gr doesn't get much more than 1" high, the 55gr about 1.5" and the 69gr nearly 2" high.
For rabbit sized game this mean you may well shoot over the top of them with the 69gr load if you don't allow for it.
I like to work on about 1.5" mid range rise for rifles that will be used for varmints.
This means I would bring the 69gr zero range back to 175 it would then be no higher than 1.5"from the muzzle to 175y and about 3" low at 225
The 55gr load I would leave zeroed at 200 it would be no higher than 1.5" from the muzzle to 200y and about 3" low at 250
The 40gr load I would push the zero out to 225 it to wouldn't be any more than 1.5" high from muzzle to 225y and still only about 2.5" low at 275

As you can see from the above with a 200y zero there is only 1.5" between the 40gr load and 69gr load at 250y but when sighted to give the maximum point blank range the 40gr load shows a advantage of over 50y or about 25%.

Regardless of calibre the lighter projectiles will always give you a longer point blank range usually it isn't until somewhere between 4-500y that the higher BC of the heavier projectiles starts to catch up and show any advantage in drop.

The Raven wrote:Tested some different weights of ammo on the weekend.

Can anyone explain a 6.5-9 inch drop between a baseline of 130gn and anything from 150-180gn? That seems excessive.

Yes, it was a mix of brands and projectile types. So it wasn't a fair test but....

Geez 6.5inch drop moving from 130gn to 150gn? Very surprising. 180gn fell off-paper (well over 9 inch drop).

FWIW 308W over 100yards.

I think in my old swede the difference between 100 and 140 is similar, Heavier pill slower velocity etc etc Were they different makes of factory loads? Two factory loads with same weight pill can even be quite different. Handloaded 140's are very different to factory 140 in the old girl as well.

If you just shooting factory loads be a case of select a weight and see how it groups and go from there.

Ryan

Hi Guys,

Been tied up with a few work related things so I haven't had time to do much beyond the odd quick post. So, I do appreciate your comments on this and will hopefully have time to think it all through shortly.

Just wanted you to know I wasn't ignoring the comments here.