Velocity Spreads?

If you get your ES low, SD will take care of itself (for all I care)
That is, unless you've figured out a way to further complicate the obvious...
 
...Like to have 10fps or less but the max is 25fps with 2, 5 shot strings.

Boss, I'm not trying to be a pain in the backside, nor do I say that a "good" chrony is not a valuble tool to the LR shooter. But for the sake of a little rhetorical discussion... How do you know if your ES is in fact 11 fps just because your gismo says it is? I know you you use good equipment, but do you actually know to what degree of accuracy and consistancy your chrony measures velocities? Does angle of sun or clouds or battery charge, etc. affect it?

Just curious.

Most guys who shoot sporters do not even have the right equipment or technique to properly evaluate the "complete" accuracy potential of a particular firearm at 1K. Primarily due to the importance of being able to judge condition..

Very true....
 
If you get your ES low, SD will take care of itself (for all I care)
That is, unless you've figured out a way to further complicate the obvious...

A couple of points...

How do you know you have low ES?

And... if you load up 100 rounds of a particular load, shoot three of them over a chrony and it says your ES is 15, is that the ES of the entire 100 rounds?
 
If you compete at 1K you would be murdered over the long term with vertical dispersion. Most guys who shoot sporters do not even have the right equipment or technique to properly evaluate the "complete" accuracy potential of a particular firearm at 1K. Primarily due to the importance of being able to judge condition.. Anyone can get lucky for 3 shots but to do it in a 20 or 30 shot string is another matter altogether. Just my .02

Always ask people when they tell me that a rifle shot a certain size 3 shot group at whatever range stating that they could "compete" with this rifle------OK when you do that 10 times in a row then you will have something.


I think that the key to my viewpoint is that I don't shoot competition.

To be real honest I read your post see it as validating

Not saying it's not useful. But ES is an indicator of the variability of the load more than anything (not saying it's the only indicator but it's the primary indicator imho). How consistent is the powder burning in your rifle / barrel combination? How consistent is the batch of primers that you used? How well did you measure the powder? How consistently did you seat the bullet? How consistent is the neck tension? How consistent does the barrel remain as you foul it with more and more rounds? I imagine that I'm leaving a lot out.

I never said it wasn't important...

OK when you do that 10 times in a row then you will have something.

Or 100... do it 100 times in a row and you have an order of magnitude better performance.
 
I think that the key to my viewpoint is that I don't shoot competition.

To be real honest I read your post see it as validating



I never said it wasn't important...



Or 100... do it 100 times in a row and you have an order of magnitude better performance.

Agreed as by your comment it is obvious and shows that what you think is not important in shooting at 1K is.
 
Boss, I'm not trying to be a pain in the backside, nor do I say that a "good" chrony is not a valuble tool to the LR shooter. But for the sake of a little rhetorical discussion... How do you know if your ES is in fact 11 fps just because your gismo says it is? I know you you use good equipment, but do you actually know to what degree of accuracy and consistancy your chrony measures velocities? Does angle of sun or clouds or battery charge, etc. affect it?

Just curious.



Very true....

Just my .02 but a Chrony I do not consider to be a precision instrument. I use the Oehler it works and works very well.
 
Agreed as by your comment it is obvious and shows that what you think is not important in shooting at 1K is.

When my custom long range rifle arrives in about 6-8 months I suspect my viewpoint will change are at least fine tune another notch. Probably still won't compete but I will strive for consistency and accuracy. :)
 
Re: Reliable Chronograph Readings

Yes, chronograph readings can be inaccurate, and there's no way to absolutely know if you're getting good readings or not with a single chronograph. Unless, perhaps you have the Oehler model with the proof option which actually provides two separate readings for every shot fired.

This became very clear to me when I finally purchased a 2nd chronograph and constructed a skyscreen rail which allowed me to mount two sets of skyscreens, one set for each separate chronograph.

I run an Oehler 33 with a 4' skyscreen spacing and a PACT Pro with a 4' 6" skyscreen spacing. The results from this two-chrono setup have proven very enlightening, educational, and most importantly - useful. With my dual chronograph setup, I can tell with high confidence when I'm getting credible data, simply by comparing the difference in the readings from shot to shot. When I'm getting high quality data, the difference in the readings between the two over a string of shots will be very uniform. It's not so important to me that I get the same exact number. What's important is that the difference in velocities reported between the two chronies remains consistent and within a fairly narrow window.

I've learned chronographs can provide very accurate data when they're funtioning well. I've also learned that they can and will throw a bad number every now and then, and that without having two running chronos, a person would have no way to identify the bad data from the good.

If I get 2910, 2900, 2917, 2923, and 2908 on the Oehler, and I get 2917, 2907, 2924, 2930, and 2915 on the PACT, then I conclude I'm getting very good, valid data because the velocity difference was 7 fps for each of the five shots. That would be the ultimate in chrono consistency.

If the PACT Pro reads 2915, 2909, 2927, 2931 and 2914, then I'm again getting really good velocity data. The difference between the two chrono's is a minimum of 5 fps for the first shot (2915 -2910) and a maximum of 10 fps on the third shot (2927-2917). I say this is really good data because the difference in readings due to all errors in the equipment and setup is only 5 fps (10-5) for this five shot string.

How do I know when I've got a glitch in the data? When the differences in velocity produced by the chronies for any shot is much different than is typically present. For example, if I shoot 7 shots and the difference between the velocities recorded for these seven shots is 12, 16, 11, 14, 17, 39, and 65 fps, I know I received at least one bogus reading from at least one chronograph with each of the last two shots fired. I can't know if one chrono or both spit out bad data. But I can know that if I remove the last two shots from the data pool, that the velocities from the first 5 shots fired are pretty darn accurate.

This is how I get around the uncertainty associated with chronograph data. Based on my experiences and observations, I would never invest a lot of time and effort, and place a lot of confidence, in the velocity data produced by a single chronograph setup. After you run two chronos in series, you'll find it's not uncommon for bogus velocity readings to crop up every now and then. Now that I can identify bad readings from good readings, I do rely pretty heavily on my chrono's for load development. I can do that only because, with the dual setup, I am able to identify and toss out the bad data and then reach valid conclusions based on the knowledge that the remaining velocity data is relatively accurate and precise.

Lastly, my Oehler 33 is a better performing chronograph than my PACT - for those that might want to know. The PACT pukes out in dimmer lighting conditions quite a bit sooner than the Oehler, and tends to act up a little more than the Oehler. But they both work well enough most of the time to produce high quality velocity data.
 
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Re: Reliable Chronograph Readings

Yes, chronograph readings can be inaccurate, and there's no way to absolutely know if you're getting good readings or not with a single chronograph. Unless, perhaps you have the Oehler model with the proof option which actually provides two separate readings for every shot fired.

This became very clear to me when I finally purchased a 2nd chronograph and constructed a skyscreen rail which allowed me to mount two sets of skyscreens, one set for each separate chronograph.

I run an Oehler 33 with a 4' skyscreen spacing and a PACT Pro with a 4' 6" skyscreen spacing. The results from this two-chrono setup have proven very enlightening, educational, and most importantly - useful. With my dual chronograph setup, I can tell with high confidence when I'm getting credible data, simply by comparing the difference in the readings from shot to shot. When I'm getting high quality data, the difference in the readings between the two over a string of shots will be very uniform. It's not so important to me that I get the same exact number. What's important is that the difference in velocities reported between the two chronies remains consistent and within a fairly narrow window.

I've learned chronographs can provide very accurate data when they're funtioning well. I've also learned that they can and will throw a bad number every now and then, and that without having two running chronos, a person would have no way to identify the bad data from the good.

If I get 2910, 2900, 2917, 2923, and 2908 on the Oehler, and I get 2917, 2907, 2924, 2930, and 2915 on the PACT, then I conclude I'm getting very good, valid data because the velocity difference was 7 fps for each of the five shots. That would be the ultimate in chrono consistency.

If the PACT Pro reads 2915, 2909, 2927, 2931 and 2914, then I'm again getting really good velocity data. The difference between the two chrono's is a minimum of 5 fps for the first shot (2915 -2910) and a maximum of 10 fps on the third shot (2927-2917). I say this is really good data because the difference in readings due to all errors in the equipment and setup is only 5 fps (10-5) for this five shot string.

How do I know when I've got a glitch in the data? When the differences in velocity produced by the chronies for any shot is much different than is typically present. For example, if I shoot 7 shots and the difference between the velocities recorded for these seven shots is 12, 16, 11, 14, 17, 39, and 65 fps, I know I received at least one bogus reading from at least one chronograph with each of the last two shots fired. I can't know if one chrono or both spit out bad data. But I can know that if I remove the last two shots from the data pool, that the velocities from the first 5 shots fired are pretty darn accurate.

This is how I get around the uncertainty associated with chronograph data. Based on my experiences and observations, I would never invest a lot of time and effort, and place a lot of confidence, in the velocity data produced by a single chronograph setup. After you run two chronos in series, you'll find it's not uncommon for bogus velocity readings to crop up every now and then. Now that I can identify bad readings from good readings, I do rely pretty heavily on my chrono's for load development. I can do that only because, with the dual setup, I am able to identify and toss out the bad data and then reach valid conclusions based on the knowledge that the remaining velocity data is relatively accurate and precise.

Lastly, my Oehler 33 is a better performing chronograph than my PACT - for those that might want to know. The PACT pukes out in dimmer lighting conditions quite a bit sooner than the Oehler, and tends to act up a little more than the Oehler. But they both work well enough most of the time to produce high quality velocity data.

Well said !!!!

The reason I recomend the use of a chronograph is to minimize the number of loads I have to
work up.

I have loaded hundreds of loads trying to find a good Powder,primer, bullet combination
without the use of a chronograph and then decided to run some through my chronograph
and withen 4 or 5 different combinations found a load that showed promise. and then focused
on them and found "the load".

I now test all loads through the chronograph and eliminate the worst and use the best
for the final testing.

I have a Oehler 35 P and have compared the velocity/trajectory against the balistic tables
to verify the accuracy of the chronograph and the proof channel and they are spot on.

I have found loads that have low SDs that still would not shoot well but buy changing the
seating depth they tightened up and at long distance and did not string vertically as mentioned.

Again, at short distance SDs are not very important but at long distance they are.

As to the actual velocity that is not as important as the SDs ,So if your chroney is not dead
on so what, it will still tell you if you have a good load to work on.

Just my 2 cents

J E CUSTOM
 
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Yes, it's true that Oehler discontinued marketing their basic hobby level chronographs a few years ago. They were still providing service up until recently, but maybe that service is no longer available at this time. All I know is I purchased a set of new skyscreens from them about six months ago after talking to Ken Oehler at the Orlando Shot Show last January. Even if all Oehler service has ended I still wish I owned an Oehler 35P - one like J E Custom owns. Occasionally a used one will come up for sale, but even the used ones bring pretty good money.

Oehler has always been synonymous with quality chronographs. But there are other chronographs marketed today that are also good.

I didn't state I preferred the Oehler better than my PACT because I thought others might be buying new Oehlers. I just stated my preference because someone will undoubtedly be interested. Used Oehler 33s show up every now and then too. That's how I aquired mine about 3-4 yrs ago. Prior to that I borrowed a relative's Oehler 33.
 
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I wish I had done more research a few years ago... I would have bought an Oehler. I think they still have sky screens and parts. I think their note was about the chrony itself... but I'm not 100% sure on that.
 
Yes, it's true that Oehler discontinued marketing their basic hobby level chronographs a few years ago. They were still providing service up until recently, but maybe that service is no longer available at this time. All I know is I purchased a set of new skyscreens from them about six months ago after talking to Ken Oehler at the Orlando Shot Show last January. Even if all Oehler service has ended I still wish I owned an Oehler 35P - one like J E Custom owns. Occasionally a used one will come up for sale, but even the used ones bring pretty good money.

Oehler has always been synonymous with quality chronographs. But there are other chronographs marketed today that are also good.

I didn't state I preferred the Oehler better than my PACT because I thought others might be buying new Oehlers. I just stated my preference because someone will undoubtedly be interested. Used Oehler 33s show up every now and then too. That's how I aquired mine about 3-4 yrs ago. Prior to that I borrowed a relative's Oehler 33.

It was a great loss to the shooting community when this happened and hopefully Oehler will
decide to start making there fine product again or some one will purchase that part of the
business and start building them .

Oehler has been the bench mark for all chronographs to be graded buy and rarely does a company build such a quality product at a very reasonable price and then offer great service
and warranty for the average person.

In my dealings with them I was always treated extremely well and was always surprised
that they could not seem to do enough to please there customers.

My understanding is that they are concentrating there energy and technology to building
chronographs for the military and although they need the best equipment possible
I can only hope they can see how much the shooting public needs the quality product and
service they offered.

They will be sorely missed !!!!!!!

Sorry I got of the topic.

J E CUSTOM
 
For OVERSTAFFORD(thread starter)
Today I happened across an example which connects my caution for your accuracy and testing.
It's my last 200yd accuracy testing with a T2K in 6xc. Haven't had this one outta the safe in over a year!


It was a 10min shot rate on 2shot groups. That is 2shots, wait 10min, 2shots, etc.
With regard to accuracy, I find this to show the worst in guns.
Anyway, each 1st shot is circled on the right/high. Each immediate followup is circled on the left/high.

What I see from this one sitting, good and bad:
Good - under 1/4moa grouping potential right after any sighter(not bad for a tubegun off a bipod)
Bad - this barrel will NEVER be accurate in the field

So I decided today not to pull out the gun and continue with that barrel. Is it possible to improve on it's accuracy if I start over with different components? Maybe... But those 4 shots in the right circle cannot be denied. They show that as that barrel warms up, it walks. This is a Schneider polygonal, my next will be a Krieger progressive, and my quest for that will begin tomorrow.

I believe this is an example of one performance definition -vs- another (accuracy -vs- consistancy)
 
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