Ricochet concerns when shooting against rocky areas

Varminting and vertebrate pest control. Small game, hunting feral goats, foxes, dogs, cats, rabbits etc.

Re: Ricochet.

Post by xDom » 28 Jun 2019, 7:31 pm

OK, I get that.

As a side question, what's the twist rate of that rifle? You can stabilise a 35gn through to a 80gr?

My .223 is a 1:12, I thought that limited me to a max of about 55gr?
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Re: Ricochet.

Post by bladeracer » 28 Jun 2019, 7:42 pm

xDom wrote:OK, I get that.

As a side question, what's the twist rate of that rifle? You can stabilise a 35gn through to a 80gr?

My .223 is a 1:12, I thought that limited me to a max of about 55gr?


8"-twist Ruger American Predator. I have some 90gn Matchkings I want to try as well, they're only slightly longer than the ELDM's so I'm hopeful :-)
12"-twist should be okay for 60gn, maybe a little heavier with flat-based soft-point bullets. Bullet length is what matters, not the weight.
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Re: Ricochet.

Post by Stix » 28 Jun 2019, 7:43 pm

xDom wrote:I've got another ballistics question, might as well keep it in an existing thread.
When people talk about a "flat" shooting round does that equate to a fast round? Is there a direct correlation between a flat round and a fast round?
ie the faster the flatter?


The answer is yes, there is a direct correlation...!! :thumbsup:

Ill have a crack at explaining it...dunno how sucessful ill be... :unknown: :lol:

So a 22-250 is known as "a flat shooter", where as a 223 is not so known for it.
The 22-250 has bigger case to hold more powder & push bullet out faster than the 223...
So...
Imagine a 50gn bullet shot out of a 223,
Then the same bullet shot out of a 22-250...

The bullet out of the 223 is travelling slower than the one out of the 250, so over any given 100m stretch of flight, the faster travelling bullet has less time for gravity to pull it down toward earth, therefor its 'arc'/trajectory over that given 100m is flatter than the slower moving bullet--(which has more time for gravity to pull it down over that same 100m).

As gravity is a constant value (it will pull a given bullet shot horizontally & travelling at any speed, toward earth the same amount per second (per second)), so the amount of drop over a given distance for that given bullet is determined by its speed.

The same goes for wind...a faster moving bullet wont deviate as much due to wind as the same bullet moving at a slower soeed over a given distance...because the wind has less time to push the bullet 'off track'.

Hope ive explained that well enough to understand easier... :unknown:
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Re: Ricochet.

Post by Stix » 28 Jun 2019, 7:46 pm

Ok...so you're already past that...yep...im a slow typer with one thumb on a mobile...

As you were... :lol:
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Re: Ricochet.

Post by xDom » 28 Jun 2019, 7:58 pm

Stix wrote:Ok...so you're already past that...yep...im a slow typer with one thumb on a mobile...

As you were... :lol:


Thanks Stix. :drinks: Cheers Blade
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Re: Ricochet.

Post by TassieTiger » 28 Jun 2019, 10:00 pm

^ that’s a pretty cool visual explanation !
Tikka .260 (Z5 5x25/52)
Steyr Pro Varmint .223 - VX 3
CZ455 .22 & Norinco .22 (vtex 4-12, bush 3-9)
ATA 686 U/O 12g & Baikal S/S 12g.
Adler a110 reddot
Sauer 30-06 - VX 3
Howa 300 win mag. SHV 5-20/56
Marlin SBL 45/70
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Re: Ricochet.

Post by xDom » 30 Jun 2019, 3:20 pm

What’s the flattest shooting, commercially available round on the market?
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Re: Ricochet.

Post by bladeracer » 30 Jun 2019, 3:37 pm

xDom wrote:What’s the flattest shooting, commercially available round on the market?


At close ranges, probably 40gn VMax .204, or something in .220Swift or .22-250 maybe.
At longer ranges something with heavy ELD bullets.
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Re: Ricochet.

Post by xDom » 30 Jun 2019, 3:46 pm

Would you say my 1:12 .223 Tikka, shooting a 55gr would be far behind these? In the spectrum of rifles, would it be towards the flat shooting end?
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Re: Ricochet.

Post by bladeracer » 30 Jun 2019, 4:42 pm

xDom wrote:Would you say my 1:12 .223 Tikka, shooting a 55gr would be far behind these? In the spectrum of rifles, would it be towards the flat shooting end?


Hmmm...not really, but the range of cartridges is massive, so it's a lot flatter shooting than most others by far. Within the spectrum of medium-range varminting cartridges I wouldn't consider it to be particularly flat-shooting.

I've just done some _really_ basic calculations.
I went to Hornady and grabbed some bullet specs for long-range, high-BC bullets in 6.5mm (147gn ELDM), 7mm (180gn ELDM), .308" (230gn ATip)and .338" (285gn ELDM). I'm sure other manufacturers have bullets that would improve on these figures. I hit ADI and determined the most capable standard cartridges for each - .264 WinMag, 7mm RUM, .30-378 Weatherby, and .338-378 Weatherby Mag.

6.5mm 147gn ELDM .697. 264WinMag 3000fps
140mm high at 160m, 300m zero, 300mm low at 400m, 750mm low at 500m, 1400mm low at 600m, 6.75m low at 1000m, 22.35m low at 1500m, 55.5m low at 2000m (wind 8.6m)

7mm 180gn ELDM .796 7mmRUM 3000fps
140mm high at 160m, 300m zero, 280mm low at 400m, 740mm low at 500m, 1380mm low at 600m, 6.3m low at 1000m, 20m low at 1500m, 47.8m low at 2000m (wind 7.2m)

.308" 230gn ATip .823 .30-378 Weatherby 3080fps
125mm high at 160m, 300m zero, 265mm low at 400m, 680mm low at 500m, 1300mm low at 600m, 5.9m low at 1000m, 18.4m low at 1500m, 43.5m low at 2000m (wind 6.6m)

.338" 285gn ELDM .829 .338-378 Weatherby Magnum 2850fps
150mm high at 160m, 300m zero, 315mm low at 400m, 815mm low at 500m, 1525mm low at 600m, 6.9m low at 1000m, 21.85m low at 1500m, 51.7m low at 2000m (wind 7.2m)


For comparison:
.224" 55gn VMax .255 .223Rem 3200fps
170mm high at 160m, 300m zero, 410mm low at 400m, 1190mm low at 500m, 2.5m low at 600m, 16.8m low at 1000m, 60.9m low at 1500m, 190m low at 2000m (wind 24.5m)

Based on that I'd say that .30-378 Weatherby Magnum has to be right near the top of the flattest shooting commercial cartridges.

For some further comparison:
.204" 40gn VMax .275 .204Ruger 3750fps
120mm high at 160m, 300m zero, 270mm low at 400m, 760mm low at 500m, 1550mm low at 600m, 5.9m low at 1000m, 18.4m low at 1500m, 43.5m low at 2000m (wind 6.6m)

.172" 20gn VMax .185 .17Rem 4400fps
100mm high at 160m, 300m zero, 270mm low at 400m, 820mm low at 500m, 1800mm low at 600m, 10.5m low at 1000m, 48.6m low at 1500m, 139m low at 2000m (wind 21.2m)
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Re: Ricochet.

Post by bladeracer » 30 Jun 2019, 4:49 pm

I'm messing with ballistics right now (while watching the Asia Road Race Championship from Suzuka https://www.youtube.com/watch?v=821U7NU1UkU)

I need to calculate trajectories for my milsurp loads so I can shoot the Bloke on the Range "competition" I posted in another thread. Calculate, then confirm the curve, then shoot the comp. I want to start with the 6.5x52mm Carcano which has no sight adjustment at all. I think I've got it sorted for a 100m zero, with 500mm and 1000mm holdovers at 200m and 300m (which should be easy as the target is a 1000mm-square board). Was hoping to confirm it today but it's wet and very windy here today.
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Re: Ricochet concerns when shooting against rocky areas

Post by xDom » 02 Jul 2019, 4:32 pm

E93197D6-A516-4730-9A50-A9321C751F4A.jpeg
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I’ve got another question unrelated to the previous ones. Hopefully it’s ok to keep it in this thread.
If a bullet passes extremely close to an object on the way to its target, could this interfere with the bullets path after said object?
I’ve got a rough drawing to show you what I mean.
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Re: Ricochet concerns when shooting against rocky areas

Post by bladeracer » 02 Jul 2019, 4:58 pm

xDom wrote:
E93197D6-A516-4730-9A50-A9321C751F4A.jpeg


I’ve got another question unrelated to the previous ones. Hopefully it’s ok to keep it in this thread.
If a bullet passes extremely close to an object on the way to its target, could this interfere with the bullets path after said object?
I’ve got a rough drawing to show you what I mean.


Not in my experience, no. If I were shooting over 1000m I probably wouldn't want my bullets passing a few millimeters from an object en-route, but I haven't seen that it affects it in any meaningful way. One of my 240m gongs is set up on the other side of a dam. The trajectory of .22LR is such that I'm sighting through two fences en-route, but the bullets are passing over both of them, and the dam, before coming down into the target. On the closer fence, the bullets pass very closely over a horizontal log fence strainer, close enough that I get an occasional strike. I could probably set up some sort of barricade situation and see if very close supersonic bullets are pushed off course to any measurable degree, but I really don't think it's a problem. A heavy steel plate set up a few meters ahead of the muzzle, and so close as to be virtually touching the bullets, and see if the groups move across the target three or four hundred meters downrange. Damn, looks like another project to add to the list :-)
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Re: Ricochet concerns when shooting against rocky areas

Post by xDom » 11 Jul 2019, 2:45 pm

“..Not quite, the story is if you zero an AR15 at 25yd it will also be zeroed at 300yd”

When zeroing a .223 for hunting , what distance would you set it for?
Is it a matter of preference or what distance you intend to shoot?
Last trip I had it set for 100m
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Re: Ricochet concerns when shooting against rocky areas

Post by SCJ429 » 11 Jul 2019, 3:08 pm

Try and keep it simple, sight in at 100 and if you shot is at 200 them aim for the top of the head and allow a little for wind. It should drop in for you. If you are set up in a position and have time to use a range finder, then dial the elevation with your turret. Of course this means you need to know the speed of your bullet and have a ballistics chart.
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Re: Ricochet concerns when shooting against rocky areas

Post by bladeracer » 11 Jul 2019, 5:44 pm

xDom wrote:“..Not quite, the story is if you zero an AR15 at 25yd it will also be zeroed at 300yd”

When zeroing a .223 for hunting , what distance would you set it for?
Is it a matter of preference or what distance you intend to shoot?
Last trip I had it set for 100m


Yep, totally down to how and what you're shooting with and at. I avoid shooting at live targets beyond about 300m maximum, closer is always better.
I put the .204, .223 and .243 30mm high (1MoA) at 100m, so they zero around the 200-250m area, basically so I can shoot to 300m with minimal holdover.
In .204 with the 24gn NTX at 4400fps it gets up to 40mm at 150m, zeros at 225m, and drops 120mm at 300m (the bullet first zeros at 40m).
In .223 with the 55gn RooMax at 3350fps it zeros at 180m, drops 20mm at 200m, 120mm at 250m, and 260mm at 300m (the bullet first zeros at 32m).
In .243 with the 58gn VMax at 3850fps it zeros at 210m, drops 50mm at 250m and 145mm at 300m (the bullet first zeros at 40m).

If I were going to sit over rabbit warrens though I might prefer to zero at 100m, then dial up as required for the range I'm shooting at.
If you're shooting at larger targets, like foxes or bigger you could zero at 100m and use a ballistic reticle to holdover.
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Re: Ricochet concerns when shooting against rocky areas

Post by bladeracer » 11 Jul 2019, 6:04 pm

SCJ429 wrote:Try and keep it simple, sight in at 100 and if you shot is at 200 them aim for the top of the head and allow a little for wind. It should drop in for you. If you are set up in a position and have time to use a range finder, then dial the elevation with your turret. Of course this means you need to know the speed of your bullet and have a ballistics chart.


Charts and chronographs are not required, you can ascertain your trajectory simply by shooting at several distances, say 50m, 100m, 150m, 200m and recording the height of your groups above or below your aiming point. With several known points in the trajectory you can work backwards tweaking velocity and BC figures until you have a matching curve. With CCI Std Velocity for example I did this and ended up with a BC of 0.165 although CCI claim it to be .115 from memory. Knowig that my muzzle vlocity is right around 1080fps meant all I had to tweak was the BC figure to match the curve. I'm finding this figure is spot on out to around 300m (.22LR groups are getting big enough to make definitive conclusions difficult by this distance), but I'm finding a little more drop creeping in at longer ranges so the BC may be dropping off by about 250m...perhaps...more testing required.
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Re: Ricochet concerns when shooting against rocky areas

Post by xDom » 11 Jul 2019, 6:49 pm

"..you can ascertain your trajectory simply by shooting at several distances, say 50m, 100m, 150m, 200m"


I'm gonna be a lot better prepared for my trip on coming Monday. I've prepared 4 different target holders which I plan to space out at intervals similar to what you have suggested.
During the day, in my non hunting periods, I'm looking forward to experimenting with different things.
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Re: Ricochet concerns when shooting against rocky areas

Post by bladeracer » 11 Jul 2019, 7:12 pm

xDom wrote:"..you can ascertain your trajectory simply by shooting at several distances, say 50m, 100m, 150m, 200m"


I'm gonna be a lot better prepared for my trip on coming Monday. I've prepared 4 different target holders which I plan to space out at intervals similar to what you have suggested.
During the day, in my non hunting periods, I'm looking forward to experimenting with different things.


I just made some 300m targets for my milsurps, painted onto a 1200x900mm sheet of MDF. Hopefully we'll get an hour without this damned wind and I can put some bullets out there.
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