I have .30 RAW tuned around 70fpe for 44.75 JSBs.
Out of general ignorance and the long habit in airgunning of buying ammo just to see how it shoots, I ended up here with these various slugs. In terms of pure precision, the JSB 44.75 is still winning. But I borrowed a Labradar to collect some velocity and BC data to better inform myself on just how good the ballistics might be with the "right" slug.
Test method: Labradar, 100y range, 56F, breezy, rainy. Airgun / microphone trigger for the Labradar, velocities reporting at 10, 20, 30, 60, and 80y. (Yes, those uneven distances bother me too but I didn't notice until later). 5-10 shots per projectile.
Nielson 47, 51, 55gr. These are from 2019 so I don't know if they match the .300 or .303 they're making now. They mic .300 though.
JSB Hades and Exact 44.75.
FX Hybrid 44.5.
AVS .3013 Cup base, 51, 55.
BC was calculated in Chairgun using initial velocity and adjusting BC until velocity at distance agreed with my measurements. Velocity is an average of 5-20 shots, with a few measurements omitted due to obvious bad results. These occurred primarily at the longer ranges and I'm not sure if it's from the projectile tumbling or from the Labradar losing the projectile among the raindrops. I will make sure it's not raining if I run these tests again.
Observations:
- JSB Exact shot better than published BC. JSB Hades doesn't have a published BC but it's significantly lower than the Exact.
- The JSB Exacts were washed and sorted (44.70 to 44.79gr). All other projectiles were straight from the tin.
- Slug BCs are well below published values. My RAW is not particularly a slug gun so may be everything. But it highlights the value of testing BC's for yourself.
- Time of flight for the pellets is very close to time of flight for slugs of similar weight. But BC is drastically different. (This begs the question of whether wind drift is more directly affected by BC or by time of flight.)
- From what I've read, 70fpe is below the optimal velocity range for slugs.
- Not clear if the NSA slugs have changed in 3 years, but I pulled the nearest BC data from their site today.
- It occurs to me I've never cleaned this barrel. It doesn't have many shots through it, but that may not matter.
- I was mostly unable to see the accuracy of these shots owing to the conditions and me using an 8.5x11 target at 100y on a well-shot backer board. The AVS though seemed to shoot well and so I got extra shots at the 50y target with them. Accuracy is not one ragged hole like the Exact, but close enough to hold promise.
Out of general ignorance and the long habit in airgunning of buying ammo just to see how it shoots, I ended up here with these various slugs. In terms of pure precision, the JSB 44.75 is still winning. But I borrowed a Labradar to collect some velocity and BC data to better inform myself on just how good the ballistics might be with the "right" slug.
Test method: Labradar, 100y range, 56F, breezy, rainy. Airgun / microphone trigger for the Labradar, velocities reporting at 10, 20, 30, 60, and 80y. (Yes, those uneven distances bother me too but I didn't notice until later). 5-10 shots per projectile.
Nielson 47, 51, 55gr. These are from 2019 so I don't know if they match the .300 or .303 they're making now. They mic .300 though.
JSB Hades and Exact 44.75.
FX Hybrid 44.5.
AVS .3013 Cup base, 51, 55.
BC was calculated in Chairgun using initial velocity and adjusting BC until velocity at distance agreed with my measurements. Velocity is an average of 5-20 shots, with a few measurements omitted due to obvious bad results. These occurred primarily at the longer ranges and I'm not sure if it's from the projectile tumbling or from the Labradar losing the projectile among the raindrops. I will make sure it's not raining if I run these tests again.
Observations:
- JSB Exact shot better than published BC. JSB Hades doesn't have a published BC but it's significantly lower than the Exact.
- The JSB Exacts were washed and sorted (44.70 to 44.79gr). All other projectiles were straight from the tin.
- Slug BCs are well below published values. My RAW is not particularly a slug gun so may be everything. But it highlights the value of testing BC's for yourself.
- Time of flight for the pellets is very close to time of flight for slugs of similar weight. But BC is drastically different. (This begs the question of whether wind drift is more directly affected by BC or by time of flight.)
- From what I've read, 70fpe is below the optimal velocity range for slugs.
- Not clear if the NSA slugs have changed in 3 years, but I pulled the nearest BC data from their site today.
- It occurs to me I've never cleaned this barrel. It doesn't have many shots through it, but that may not matter.
- I was mostly unable to see the accuracy of these shots owing to the conditions and me using an 8.5x11 target at 100y on a well-shot backer board. The AVS though seemed to shoot well and so I got extra shots at the 50y target with them. Accuracy is not one ragged hole like the Exact, but close enough to hold promise.
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From what I understand...— BC measurements and calculations are pretty sensitive to the atmospheric conditions, especially the local air pressure. 
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