Post by encore50a on Feb 28, 2024 13:30:10 GMT -5
BH209 loading only. NOT FOR SML.
EXTREME LONG RANGE
Defining ELR with muzzleloaders……….. 800yds +
Consistency isn’t good enough anymore.
Things I’ve learned.
Measuring propellant by weight is a must. Measuring and verifying the weights twice or more is a requirement. Velocity from shot to shot must be as identical as possible. SD’s must be as low as possible.
Bullet weights must be identical.
Higher bullet loading force increases velocities therefore bullets must be sized exactly identical for loading forces. Simultaneously, the higher loading force also provides quicker and fuller bullet obturation. Pressures are higher.
Seating force for bullet to propellant must be identical. Changes in seating forces can also affect velocities, which will change POI.
The longer and higher BC bullets have an advantage in supersonic flight, but are more unstable at their transonic flight before going subsonic. Shorter bullets are more stable during the transonic flight period before going subsonic.
Wind and time can be your worst enemy. When shooting ELR, the amount of time between loading and shooting can have extreme wind changes and observation and corrections are a requirement. Learning it isn’t easy.
Drop tubes are not a gimmick. They put 100% of the propellant at the ignition source. Their funnels are necessary in windy conditions.
Optics must have a large amount of vertical adjustment, along with using an angled rail to increase vertical travel. Bullet drop becomes excessive as the bullet speed slows at ELR.
How much does a 30fps difference in velocity affect a bullets POI at 1,000yds?
One way to help determine it, is to just change the velocity by 30fps in your ballistics program.
Just as an example.............
Assume we're shooting a 350gr bullet with a known BC and the velocity is 2,196fps.
To reach 1,000yds, it would require 64.4moa.
Now, we'll slow the bullet down 30fps to 2,166fps.
To now reach 1,000yds, you'll need 66.3moa.
That's 20" difference in POI at 1,000yds.
This is why it's so critical when shooting ELR, that charges and velocities are as identical as possible.
EXTREME LONG RANGE
Defining ELR with muzzleloaders……….. 800yds +
Consistency isn’t good enough anymore.
Things I’ve learned.
Measuring propellant by weight is a must. Measuring and verifying the weights twice or more is a requirement. Velocity from shot to shot must be as identical as possible. SD’s must be as low as possible.
Bullet weights must be identical.
Higher bullet loading force increases velocities therefore bullets must be sized exactly identical for loading forces. Simultaneously, the higher loading force also provides quicker and fuller bullet obturation. Pressures are higher.
Seating force for bullet to propellant must be identical. Changes in seating forces can also affect velocities, which will change POI.
The longer and higher BC bullets have an advantage in supersonic flight, but are more unstable at their transonic flight before going subsonic. Shorter bullets are more stable during the transonic flight period before going subsonic.
Wind and time can be your worst enemy. When shooting ELR, the amount of time between loading and shooting can have extreme wind changes and observation and corrections are a requirement. Learning it isn’t easy.
Drop tubes are not a gimmick. They put 100% of the propellant at the ignition source. Their funnels are necessary in windy conditions.
Optics must have a large amount of vertical adjustment, along with using an angled rail to increase vertical travel. Bullet drop becomes excessive as the bullet speed slows at ELR.
How much does a 30fps difference in velocity affect a bullets POI at 1,000yds?
One way to help determine it, is to just change the velocity by 30fps in your ballistics program.
Just as an example.............
Assume we're shooting a 350gr bullet with a known BC and the velocity is 2,196fps.
To reach 1,000yds, it would require 64.4moa.
Now, we'll slow the bullet down 30fps to 2,166fps.
To now reach 1,000yds, you'll need 66.3moa.
That's 20" difference in POI at 1,000yds.
This is why it's so critical when shooting ELR, that charges and velocities are as identical as possible.