Chronograph Experiments

[jac714]

OK folks, due to some extremely generous family members I am now the proud owner of a chrono, so what does that have to do with us you ask? I am looking for interesting things to do with it. I have already thought of the classics, different barrel lengths, the great .38/.357 snubby argument.

This is a neat toy but if all it gets used for is to test reloads it won't get as much use as I would like. I mean how many different loads do you need to chrono, once you know the data for a given load I would think you would only retest that data once a year at the most.

[chunkstyle]

This is reloading, but I've been doing lots of experiments over the years on reloads for 7.62x25 for the CZ-52. Chrony data would be a big enhancement.

[JFettig]

I too got one. I did my first experiment on it which I found very interesting. Crimp vs no crimp. my loads are 9mm max loads from the lyman manual(yeah, I worked them up). I shot a string of 9 with straight walls, no crimp they averaged about 1050fps. Then I took some I previously loaded with the same charge, these had a tighter crimp and they shot at 1150fps. My Lyman manual said that this load should be at 1150fps for a barrel 1/2" longer.
I also shot the same rounds out of an 18" barrel and gained up to 300fps.

I will soon load up a series of different crimp diameters with a certain load and test them.


Jon

[farmerj]

how fast can you push a bullet before you start to cause throat erosion.

I know I don't like shooting those ity bidy 58 gr pills out my .243. Would be nice to see if you could push one up over 4000 fps.

[jac714]

This is reloading, but I've been doing lots of experiments over the years on reloads for 7.62x25 for the CZ-52. Chrony data would be a big enhancement.

I am willing to spend some time and allow other reloaders to develop data.

Would need to be a nice day, and an outdoor range.

[Rip Van Winkle]

how fast can you push a bullet before you start to cause throat erosion.

I know I don't like shooting those ity bidy 58 gr pills out my .243. Would be nice to see if you could push one up over 4000 fps.

Every time you shot you cause some throat erosion, how much depends on how much and what type of powder used. A general rule of thumb, the faster powders are harder on barrels than slower ones.

Also, 243's are known barrel burners.

[farmerj]

how fast can you push a bullet before you start to cause throat erosion.

I know I don't like shooting those ity bidy 58 gr pills out my .243. Would be nice to see if you could push one up over 4000 fps.

Every time you shot you cause some throat erosion, how much depends on how much and what type of powder used. A general rule of thumb, the faster powders are harder on barrels than slower ones.

Also, 243's are known barrel burners.

Let me rephrase it then....

Wonder if you could push that 58 gr pill out the .243 at over 4000 fps.

And if you could, how fast could you do it? and what kind of accuracy will you have..?


and if said round could be found....

What would it to to prairie dogs...

[Rip Van Winkle]

Let me rephrase it then....

Wonder if you could push that 58 gr pill out the .243 at over 4000 fps.

And if you could, how fast could you do it? and what kind of accuracy will you have..?

According to the Hodgdon Reloading Data Center
55 GR. NOS BT, 51.0gr H380, 4010 fps
58 GR. HDY V-MAX, 49.5gr H380, 3874 fps

Accuracy and weather the bullet would survive being pushed that fast would depend on barrel twist and condition.

and if said round could be found....

What would it to to prairie dogs...

The phrase "Red Mist" comes to mind.

[farmerj]

55 GR. NOS BT H4895 44.5 gr 4058 FPS

My preferred powder is the H4895 also...

[farmerj]

Rip, do you by chance shoot at Gopher Rifle and pistol club?

[Rip Van Winkle]

Rip, do you by chance shoot at Gopher Rifle and pistol club?

Yes, I shoot at Gopher. No, I'm not a member. I'm a member of Northstar Rifle(north of Red Wing) and I am President of the CMP program at Post 435 Gun Club.

[gunnerbmg]

I loaded some of those 55 gr Nosler's and they measured out to 3870 with the starting load in the Nosler book out of my rifle. They shot so well that I did not try to get anything more from them. Red Mist in the dog town was the order of the day.