Airgun Ballistic Calculator Question

[radford56]

I recently decided - for a lot of reasons - to shift a lot of my shooting efforts away from powder burners into air rifles. I've dabbled in airguns for years, but they were always just a pleasant diversion. I've owned a Beeman FWB-124 for around 30 years and a Beeman P-1 pistol for even longer than that. I love the springers, but I felt like there was a lot more capability to be had with PCP air rifles.

So earlier this year I sold a couple of safe queens and made the jump into PCP airguns with a .22 caliber FX Impact MK3 with 700mm barrel. I absolutely love it. Currently it's set up for pellets, though it also shoots the FX Hybrid slugs very well. I'll probably keep it set up the way it is for the time being - I'm mostly limited to shooting at approximately 100 yards right now - but I know I'll eventually make changes to optimize shooting slugs and start extending the ranges I shoot the rifle at.

For those of you who shoot airguns at long range, can you recommend a ballistic calculator that works well with pellets and airgun slugs? I currently have AB Mobile, but I'm not sure if it's a good choice for airgun use.

 

[JEFFPPC]

One way to find out. Test targets against the data give. Very simple. I have been shooting my Diana 54 spring gun in .22 at 100 yds this summer usually 1.5 or a bit under for 5 shots. Goal is 5 shot 1 inch. I think you have a lot more potential than 100 yds. Stretch it out, you will probably be surprised. If you don't have wind flags, get some. Nice calm 1 0r 2 mph wind, miss a reversal at 100.....There went your good group. Hit an Airgun chicken silhouette, about like a nickel, at 100 yards and you will smile.

 

[Rank Amateur]

Chairgun. Includes calculations for diablo pellets.

 

[radford56]

Chairgun. Includes calculations for diablo pellets.

Thanks, I'll take a look at it

 

[radford56]

One way to find out. Test targets against the data give. Very simple. I have been shooting my Diana 54 spring gun in .22 at 100 yds this summer usually 1.5 or a bit under for 5 shots. Goal is 5 shot 1 inch. I think you have a lot more potential than 100 yds. Stretch it out, you will probably be surprised. If you don't have wind flags, get some. Nice calm 1 0r 2 mph wind, miss a reversal at 100.....There went your good group. Hit an Airgun chicken silhouette, about like a nickel, at 100 yards and you will smile.

I know the rifle has the potential to go well beyond 100 yards! The only problem is that right now my 300 yard range is planted in soybeans. Once they're picked I'll start shooting at longer ranges.

 

[Rank Amateur]

You're right about the rifle. I have the Impact in .25 cal, also with the 700mm barrel. You are also right about transitioning to slugs if shooting over 100 yds. Your current pellet barrel will probably do just fine for those in the short term, but the slug barrel will get you a bit more precision if/when you make that change.

Enjoy!

 

[radford56]

Yeah, the wonderful thing about the Impact is that it offers me so many tempting ways to spend money! I'm already looking at the .22 caliber 800mm tensioned barrel. Oh well, its just money.

 

[dgeesaman]

I’ve been modeling my extreme field target trajectories in ChairGun using the Ga ballistic coefficient model and it works well for .22 to .30 pellets from 15 to 110 yards.

Actual ballistic coefficient varies from the book value. It’s my opinion that because pellets can get into a spiral motion (not ideal) the ballistic coefficient can vary quite a bit. It’s important to use both a good BC model (Ga for pellets) and also collect real world BC data for the gun and projectile.

I’ve tested a couple dozen slugs in .30 and .22 and never found one that really sings. So I haven’t shot enough slugs to model trajectory in that case.

 

[Rank Amateur]

I’ve been modeling my extreme field target trajectories in ChairGun using the Ga ballistic coefficient model and it works well for .22 to .30 pellets from 15 to 110 yards.

Actual ballistic coefficient varies from the book value. It’s my opinion that because pellets can get into a spiral motion (not ideal) the ballistic coefficient can vary quite a bit. It’s important to use both a good BC model (Ga for pellets) and also collect real world BC data for the gun and projectile.

Agree. Another consideration is the pellet to pellet conformation variability is higher than slugs/bullets due to the thin walls of the skirt, very soft lead, etc. Yes, the skirt is blown out to conform to the barrel during firing, but my presumption is that this is neither perfect nor uniform, so the shape of the pellet fired doesn't perfectly conform to the Ga standard (of course, neither do the shapes of centerfire bullets conform to the G1 or G7 standards). If trajectory/targeting is critical for your application, as @dgeesaman wrote, collecting real world data is necessary.