.20 Cal bullet BC's

[247sniper]

Hi guys, can anyone help please?

I'm looking to see if there is a G7 Standard bullet BC for the 39 grain SBK bullet.

Seirra advitise this bullet to have a G1 BC of .287 at a velocity of 3600+.

Seirra also advitise multiple BC's for velocity boundries.......but which one do you use in your ballistic programs???

Is there a G7 StNdard figure at all for this bullet??

I calculated my own BC for this bullet with two chronographs and came up with a figure of o.251, but when shooting out to 4-500 yards a BC of somewhere between 0.230 and 0.240 seems to work with real time trajectory results!

Can anyone cast there opinions on this and advise me if there is a G7 standard figure?


Cheers in advance guys,


Steve

 

[CatShooter]

Hi guys, can anyone help please?

I'm looking to see if there is a G7 Standard bullet BC for the 39 grain SBK bullet.

Seirra advitise this bullet to have a G1 BC of .287 at a velocity of 3600+.

Seirra also advitise multiple BC's for velocity boundries.......but which one do you use in your ballistic programs???

Is there a G7 StNdard figure at all for this bullet??

I calculated my own BC for this bullet with two chronographs and came up with a figure of o.251, but when shooting out to 4-500 yards a BC of somewhere between 0.230 and 0.240 seems to work with real time trajectory results!

Can anyone cast there opinions on this and advise me if there is a G7 standard figure?


Cheers in advance guys,


Steve

It is not a G-7 bullet. For all practical purposes, it is a flat base - that itty bitty boat tail does nothing but make bullet seating in the press easier.

Use G-1 - pick the one from Sierra that fits your muzzle velocity, and live with it... or you could get the Sierra Infinity program. IF you do, get V.6... V.7 sucks!

Since the sole purpose of these numbers is to calculate drop, and you already have drop figures for YOUR gun, scope, and program... then use what you have since you know that it works.

 

[22BRGUY]

I contemplated quite awhile on a 20 PPC. Still think it would be a fun one.

 

[247sniper]

I contemplated quite awhile on a 20 PPC. Still think it would be a fun one.

A 20 BR with 3940 grain bullets would be good, or even the high BC 55 grain Berger Bullet.

I love my .204. There is not much that will beat this caliber as a vermin/fox gun out to 350 yArds in terms of wind drift and drop. Great caliber.


Steve