69gr or 75gr bullet for .223

[Woodlander]

I'm looking for a fast twist .223 and have come across a nice looking gun with a 1:9 twist barrel. It is unlikely to stabilise the 75s or77s,which would be my first choice,my question is,would 69s be losing out much,in distance and accuracy,to the heavier bullets? Thanks.

[fieldwanderer]

http://www.jbmballistics.com/ballistics/lengths/lengths.shtml

 

then

 

http://www.bergerbullets.com/twist-rate-calculator/

 

 

I did a lot of research and comparing when I first got a c/f and started loading my own. I picked a handful of suitable bullets and compared their drift and drop, picked the best and found it's length then used the stability calculator to tell me what twist rate I'd need.

 

Personally, I ended up with the 65gr sierra gameking and loaded them pretty hot, even for a .22-250. I think you'll find a lighter, faster bullet better ballisticly but it's all personal preference really.

 

Accuracy, has little to do with bullet weight, velocity and twist rate as long as it's stabilised.

 

A long, heavy bullet like you have in mind will likely be blown about more than a lighter, shorter bullet that's going quite a bit faster - you'll also find the heavier bullet drops more over a given range even if it's b.c. is significantly higher - particularly as you won't get a very high velocity from a .223 (not knocking the .223, just sharing the gyst of what I've read).

Edited January 13, 2017 by fieldwanderer

[casts_by_fly]

Woodlander,

 

What range are you talking about? Out to 300-ish there isn't really an advantage for the heavies. If you are pushing 600+ then there is.

 

Rick

[Woodlander]

600+ is the idea. I have a .204 for up to 400ish and want something to take over from there. Just targets and long range rabbits.

[Savhmr]

I shoot 69 TMKs with mine. There is little real advantage using the 77's and you can push the 69's faster. I saw some 4 inch groups shot two days ago at 600 yards with a 223 shooting 69 TMKs.

 

 

http://www.jbmballistics.com/ballistics/lengths/lengths.shtml

 

then

 

http://www.bergerbullets.com/twist-rate-calculator/

 

 

I did a lot of research and comparing when I first got a c/f and started loading my own. I picked a handful of suitable bullets and compared their drift and drop, picked the best and found it's length then used the stability calculator to tell me what twist rate I'd need.

 

Personally, I ended up with the 65gr sierra gameking and loaded them pretty hot, even for a .22-250. I think you'll find a lighter, faster bullet better ballisticly but it's all personal preference really.

 

Accuracy, has little to do with bullet weight, velocity and twist rate as long as it's stabilised.

 

A long, heavy bullet like you have in mind will likely be blown about more than a lighter, shorter bullet that's going quite a bit faster - you'll also find the heavier bullet drops more over a given range even if it's b.c. is significantly higher - particularly as you won't get a very high velocity from a .223 (not knocking the .223, just sharing the gyst of what I've read).

 

 

No!

 

A longer bullet usually has a higher BC. The main criteria for wind drift is BC. The higher the BC, the less a projectile sheds velocity, the less wind drift it suffers at the ranges being discussed here. Lighter, smaller bullets with lower BC will be far more affected by wind drift at 600+yards....fact. I don't know where you got your information from, but it's plain wrong. I mean this in a positive way, not a sarcastic one: I suggest that you read some of the applied ballistics offered by Litz or similar if you want to learn a little more about external and terminal ballistics. A longer, heavier, higher BC bullets is more likely to hold onto its velocity at distance and will outperform and lighter bullet every day of the week, if one starts with the exact same MV.

 

OK, so MV of a lighter bullet will give it an advantage at shorter ranges. In 223, we're talking 45 to 55 grain for the lighter projectiles. However, they lose that advantage and start shedding velocity FAST once out past 300 yards. By 600 to 800 yards, a 69gr bullet which is fired 200 fps slower from the muzzle will have by far the velocity advantage.

Edited January 16, 2017 by Savhmr

[Woodlander]

Thanks Sav. It doesn't seem to be an exact science when it comes to 1:9 twist stabilising the heavier bullets,but apparently the one I'm considering stabilises 69gr PPU,so should do the same with home loads. I've heard of some 1:9s shooting 75Amax well,which would be my choice.

Thanks again for your knowledge. Cheers

[Bewsher500]

be wary of using weight as a stability factor

 

my sako .222 in 1:14" stabilises 60g soft points but NOT 52 gr AMax

 

its length

 

all the 67-80gr range are high calibre secant ogive and usually shallow angle boat tail making them VERY long

The PPU is a shorter bullet length compared to say a TSMK .....IIRC