Rimfire Ballistics -- longer range BC?

[4xforfun]

Is there a special app for long range rimfire, or can I use my Shooter App and use G1? Sk says .172 BC for the 40g round nose. Do I need to know exact bullet length? how about caliber.....223. .224?

 

[dellet]

Did you look on the bullet library?
It’s not uncommon for the 22’s to be listed. I know JBM has them

 

[4xforfun]

Did you look on the bullet library?
It’s not uncommon for the 22’s to be listed. I know JBM has them

LOLOL,.....well, I will now. Thanks

 

[4xforfun]

LOLOL,.....well, I will now. Thanks

Nope.....not in my shooter app. My Sierra I-6 has some, but not SK , and from what I read on ALGORE'S INTERWEB, the Lapua is incorrect in the I-6 also.

 

[dellet]

I know library in the JBM trajectory calculator has Ely, Lapua, CCI bullets, not sure about SK.
I wonder how big a difference there is off the weight is correct.

 

[Blue-Mule]

Hate to say it, but with 22, It depends.

.132 is a good starting point for +175 yds.
It'll take some truing once you get further out.

 

[4xforfun]

I know that SK publishes on line a balistics app (out to 100), and on it it says that all flat nose ammo BC is 139 and all round nose is 172 BC. Lapua states that their ammo is .172 also. I don't know if it matters weather or not you need to know the bullet length to get good data.

 

[dgeesaman]

It’s my understanding that the G1 ballistic model is not a great fit to subsonic lead bullets. So you can try it but you’ll see errors.

Airgun slug models might be better. I haven’t tried it myself.

If anything newer and more advanced comes out in this area I would expect it from Brian Litz / Applied Ballistics. Last year he was dropping comments about the unintuitive behaviors of subsonic and transonic rimfire.