What gr for 223

BillyBoy13

We are going out with the 223's next week and going to see just how far out we can push them. Obviously a lighter bullet goes faster but in turn gets thrown all over the place with the wind, and then a heavy bullet handles the wind but moves like a turtle. So in regards to bullet weight whats a happy medium? Im sure some of you lads have experimented with this already. What worked for ye?

DMW22

What rate of twist is your rifle?
The rate of twist will determine how heavy you can go and still have the rifle stabilise the round.

BillyBoy13

DMW22 wrote: »

What rate of twist is your rifle?
The rate of twist will determine how heavy you can go and still have the rifle stabilise the round.

Well I was thinking we could have more of a theoretical discussion about it and maybe see what different lads experiences are.





(But for what its worth its a 1 in 8 twist- and usually use 75gr TAPS since its the heaviest we could find but I'm starting to wonder about using a lighter faster round)

amadablam

Theoretically the tighter the twist, the heavier the bullet you can stabilise but in reality, getting anything tighter than 1:6.5 is going to be hard.

1:8 is good for up to 80gr but unless you reload, getting hold of factory ammunition above 75gr is a challenge.

My 1:8 24 inch is happy with everything from 40vmax -75bthp but if you are looking for a compromise round you need to think of the distance and conditions you shoot in when the compromise is needed.

Otherwise it's how long is a piece of string thread.

For target and long range, you will shoot 75gr bthp in factory loads as speed is not so much of a factor, unless you are shooting a moving target.

Hunting is a different story and 40-60 gr seems to be the preference.

BillyBoy13

amadablam wrote: »

1:8 is good for up to 80gr but unless you reload, getting hold of factory ammunition above 75gr is a challenge.

Yes, as I said, we were shooting Hornady TAPS as it was the heaviest we could find.

amadablam wrote: »

if you are looking for a compromise round you need to think of the distance and conditions you shoot in when the compromise is needed.

This is exactly what Im getting at. I see lads on youtube in the US shooting targets at 1K with the 223. Im guessing Texas, great weather, miles and miles of desert like conditions and not so much as a breeze of wind. That's all well and good for them, but here in Ireland its basically wind and rain all the time. So Im trying to work out whats a good weight for an average Irish day.

amadablam wrote: »

For target and long range, you will shoot 75gr bthp in factory loads as speed is not so much of a factor, unless you are shooting a moving target.

Im not sure I understand you?

A bigger bullet travels slower and thus more drop.

Hence I'm considering going for lighter/faster bullets that wont have as much drop.

Which of course brings us back to our crappy weather situation because a lighter bullet gets thrown about in the wind. Then again, if its not in the air as long it has less time to be influenced by the wind.

So I'm kinda wondering, whats the sweet spot for Irish shooting.

amadablam

For the distance you are looking at, a small fast bullet won't cut it. A slower heavier bullet in 223 is much more suitable. Plenty people shooting 223 at 600 yards. When I want to shoot mine further, I use the 75gr bthp as it copes with the wind much better. Yes it drops faster but a drop chart will give you all the information you need. Go onto most manufacturers sites and check out the ballistic coefficient of 223 rounds and you will generally see the heavier rounds are better.

ormondprop

Heavier bullets sometimes don't drop as much as light bullets at long distance, lighter bullets start out faster and flatter but after a while run out of steam and drop and get blown by wind a lot, a heavier bullet starts slower and drops more starting out but due to it being heavier it carries more energy which means it wont drop in speed as much as a lighter bullet and heavier bullets tend to be longer which give them a higher bc, due to their more aerodynamic design, so fly better and are less effected by wind hence why most target rifles are designed to shoot heavy bullets in their given calibre

BillyBoy13

amadablam wrote: »

For the distance you are looking at, a small fast bullet won't cut it. A slower heavier bullet in 223 is much more suitable. Plenty people shooting 223 at 600 yards. When I want to shoot mine further, I use the 75gr bthp as it copes with the wind much better. Yes it drops faster but a drop chart will give you all the information you need. Go onto most manufacturers sites and check out the ballistic coefficient of 223 rounds and you will generally see the heavier rounds are better.

I know when it re-enters back into the sound barrier it tends to de-stablise, but aside from that, when the bullet is falling at a considerable rate, suppose you are expecting to compensate by maybe 4 or 5 meters in elevation, is the trajectory still predictable with that much drop?

BillyBoy13

Seeing as its somewhat related I suppose I may aswell ask here, to stabilise 70 grains from a .223 Id need a 1:8 (or similar) but yet I can send 150 grains down a 1:12 from the 308 just fine

Cass

A 1:9 would work on a 70gr bullet. A 1:8 would be suited to such target bullets as the 90gr VLD.


As for the 150 in the .308. It's all relative to the caliber.

In .308 terms the 150 gr are classed as light(er) bullets. Where the 168 - 185 are medium, and 190+ are heavies. So you'd have say 1:13/1:12 for 150s, 1:11 for the mediums and 1:10 for the heavies.

For your .223 you're looking at (approximations only):

• 40 - 53gr = Light = 1:12
• 55 - 65gr = Medium = 1:10
• 65gr - 75gr = Heavies = 1:9
• 75gr + = 1:8

Ormondprop is exactly right. Taking a .308 as an example.

At 1,000 yards a 155.5gr bullet, with a muzzle velocity of 3,150fps will drop less than a 185gr. However at 1,000 yards the 155.5 is running out of steam and at a push might manage just over 1,000 yards accurately.

The 185 on the other hand has a muzzle velocity of 2,750fps yet it can shoot out to 1,200 yards and still be supersonic.

The thing about drop is once you have it for a given bullet, you have it. The wind is the key factor as it's a constantly shifting set of values depending on the conditions.

ormondprop

Theres a few different formulas to work out the perfect twist for a bullet, and modt of them its all about the relation between bullet length and bore so you cant compare twists of a .223 with a 308

bravestar

BillyBoy13 wrote: »

Seeing as its somewhat related I suppose I may aswell ask here, to stabilise 70 grains from a .223 Id need a 1:8 (or similar) but yet I can send 150 grains down a 1:12 from the 308 just fine

That's a subject for another day! Lol

Basically, use 75gr hornady BTHP match for your .223. Unless you have a custom build and can reload the heavier .223 rounds then this is really your only option.

Try as I did, I could never find anyone stocking a round with a 69 SMK as it would have suited my 1/9 barrel better.

For cheaper long range plinking try the fiocchi 50gr vmax but be prepared to put your wind reading skills to the test!