.22 Ballistics questions

[komishe]

I'm looking for help finding the b.c. of Lapua Center-X,Wolf and SK standard, as well as the MV's from a stock CZ pt 20.5" barrel.

I found an extensive table of Lapua b.c's in the rimfire learnings, but no Center-X, and numbers from .109 to .150(ish) Wolf b.c's were missing, due to the mfg. not sharing the info.

I also found this, which I thought was kinda interesting-exterior ballistics

I'm just goofing around with the Strelok app on my fart phone. It's very close to the data I've gathered from 100y and in,and actual POI, with the numbers I guesstimated. I haven't had the chance to mess around with it beyond 100 yet.

If anybody could help me out with any input, that would be fantastic.

Thanks,
Komishe

 

[komishe]

Thanks,
Good enough advice for who it's for.

I've mostly been working on just shooting fundamentals. Just recently I've taken up silhouette shooting, and changing from afternoon leisure shoots in the sun at 2400' to 8:30am shoots at sea level in the fog has really opened my eyes up to how much there is to learn.

I rarely have a chance to use a chrono, so that kinda jams my app up a bit. haha
Added to the "buy" list.

 

[komishe]

More good advice.
Thanks again, I don't think the Strelok free version has truing. I am computarded though.......
I'll just keep dingin' with it 'till the numbers match best for now.
I'll take a peek around at some different programs too.

 

[clayne_b]

You don't need one.

Shooter,ATRAG, and a slew of others offer the ability to "true" your profile as long as your feeding it solid data.

Plus chrono's are a yard stick...get six lined up side by side and depending on quality, light conditions, distance away will give different numbers.

I load solid data and use an educated guess for speed. Then true it to downrange results.

Keep in mind to...rimfire can have some serious swings in muzzle velocity grabbing one round from the next.

The part about shooting threw a few chronographs at the same time. I agree!! I have done it. I dont really use my chronograph any more. I true the app, works much better.

IMO Chronographs are pretty much a waist of money lol Even when I do chronograph I end up tweaking the muzzle velocity to match drop shot in the field. So why even use it, Just guess. then true.

 

[komishe]

Thanks Clayne, I'm glad you guys nipped this one in the bud for me. I'm sure this will save me plenty of time,$, and frustration.

Your CZ did not dissapoint thread inspired me to investigate some "local" matches. I quote that because it's an hour and a half away.
I got fourth in my first silhouette match, and I'm junkied out on it now. Got my own set of targets and been having a blast ever since.
Next match is on the 14th, hopefully I can remember to bring what I've been learning haha.

Thank you

 

[clayne_b]

Good job. Getting 4th your first time out of the gate is pretty darn good! Glad your having fun with it

 

[ivanthesane]

For 22lr, you can build your own chrono, although it is best to do speed measurements further out with this method since you have to do some fine measuring.


First, build a box frame target stand plenty tall but doesn't need to be wide. Get some butcher paper or craft/kids paper on a roll, so you can easily cover the whole thing top to bottom.

Then, you'll need some sort of padded vise to put the gun it - you don't want it moving.

You'll also need a 22 cal cleaning rod, a way of measuring a precise 10 meters, and very precise one meter, a laser (keychain thing works fine, you need to shine it directly down your bore), a level, a calculator, and some note paper.

Put rifle in vise on bench, etc. and make sure the *bore* is perfectly level. If needed, wrap some tape around your cleaning rod to make it a friction fit and put a level on the rod. Measure 10m precisely out from the muzzle, and set up your target. Shine the laser down the bore, and mark where it is on your target. Remove laser from bore,

So, your rifle is in a vise, the bore is level, and the point straight out 10m from your bore is the mark on the target paper.

Fire a shot. Make rifle safe, remove from vise, put away, etc. Go to your target, and measure from the spot you marked using the laser as a guide and the bullet hole.

You know it dropped at a rate of 9.8 meters per second squared - simple fizziks right? So now just do the math. The drop divided by the 9.8 m/s tells you how long that bullet took to cover your 10 meters. Then work the velocity from there.

Thanks,
Good enough advice for who it's for.

I've mostly been working on just shooting fundamentals. Just recently I've taken up silhouette shooting, and changing from afternoon leisure shoots in the sun at 2400' to 8:30am shoots at sea level in the fog has really opened my eyes up to how much there is to learn.

I rarely have a chance to use a chrono, so that kinda jams my app up a bit. haha
Added to the "buy" list.

 

[clayne_b]

Hummmmmmmmmm got me thinking now!

 

[komishe]

you're insane

While it makes sense, the odds of me getting things precise enough are about as good as six chrono's all reading the same.

That is some badass rocket sciency stuff though, Thanks for sharing.

 

[blcouch]

For 22lr, you can build your own chrono, although it is best to do speed measurements further out with this method since you have to do some fine measuring.


First, build a box frame target stand plenty tall but doesn't need to be wide. Get some butcher paper or craft/kids paper on a roll, so you can easily cover the whole thing top to bottom.

Then, you'll need some sort of padded vise to put the gun it - you don't want it moving.

You'll also need a 22 cal cleaning rod, a way of measuring a precise 10 meters, and very precise one meter, a laser (keychain thing works fine, you need to shine it directly down your bore), a level, a calculator, and some note paper.

Put rifle in vise on bench, etc. and make sure the *bore* is perfectly level. If needed, wrap some tape around your cleaning rod to make it a friction fit and put a level on the rod. Measure 10m precisely out from the muzzle, and set up your target. Shine the laser down the bore, and mark where it is on your target. Remove laser from bore,

So, your rifle is in a vise, the bore is level, and the point straight out 10m from your bore is the mark on the target paper.

Fire a shot. Make rifle safe, remove from vise, put away, etc. Go to your target, and measure from the spot you marked using the laser as a guide and the bullet hole.

You know it dropped at a rate of 9.8 meters per second squared - simple fizziks right? So now just do the math. The drop divided by the 9.8 m/s tells you how long that bullet took to cover your 10 meters. Then work the velocity from there.

Wow! I'm impressed.

 

[ivanthesane]

Wow! I'm impressed.

I had to do it to pass HS fizziks class... skipped too many days, mostly while we covered gravity, but knew my stuff. All simple math and redneck engineering...