New CED M2

[pjb45]

I have been borrowing a friend's chrono for years. I finally go a few bucks ahead and got the new M2.

I like it! I can download the numbers to a spreadsheet.

So here is the deal, I have run 4.85 gr of VV320 for years and years. I typically chrono at Nationals with a 171-`173 PF.

I just chrono'd my SSNats load and it came in at 173, pretty much in line with history. The lowest was 945 fps.

I am thinking of lowering it to around 4.8 and dropping the PF to around 168.

What cha think? Taking too big of a risk?

My oal is 1.178-1.18, Federal primers and once fired brass.

My SS really turns to a sweetheart with a 166 power factor, feels like a 9 mm on steroids. Very little muzzle flip. I am thinking 166 is too risky but 168-169 might be ok?

Edited May 7, 2011 by pjb45

[SteveU]

"why" is the question I would ask myself. Any advantage to 168 over 171-3?

Most people like to stay around 171-3 anyway just because of the safety factor.

I started to chrono at 165.x-168 at the last few matches after changing my barrel. I'm going UP a tenth. The chrono is one stage I don't want to stress.

My .02 which is also, I think, CW.

Also, I probably wouldn't notice the difference between .05 grains of VVN320. I can't even measure hundys.

[Sarge]

172 is the common number that always crops up as the desired major PF. I would stay where you are.

[Pat Miles]

Don't screw with a good thing Paul. I don't want to have to listen to you if you don't make major.

CYa tomorrow.

Pat

[Skydiver]

What is more interesting is your standard deviation. If you can guarantee a standard deviation of less than 2 PF, then you can go as low as 169 PF average. 2 standard deviations of 2 PF will give you a better than 97% chance of any given shot being at or above 165 PF.

If you are a gambling man, 1 standard deviation of 3 PF and an average of 168 PF, gives you a probability that 84% of your shots will be at 165 PF or better. To go minor at the chrono station, you would need 5 or more shots to go below 165. With my feeble understanding of probabilities, the chances of just 3 shots going below is already less than half a percent: 16% x 16% x 16% = 0.41%, and the probability even gets lower to have 5 shots go below: 0.01%.

Remember that doesn't take into account if the chrono at the match you are going to is reading things "slow" which is why I think people recommend targetting 172 to give yourself enough buffer.

[pjb45]

Thanks for the input. I did drop the charge and chrono'd this morning before the match.

First string: 4 shots, X=938, H=951, L=929, pf =168.9

Second string: 5 shots, X=931, H=939, L=914, fp = 167.5

The gun was a whole lot flatter, significantly less muzzle rise.

Oh Boy what to do!

Risk it or play it safe!

[warpspeed]

As long as you never have one that goes lower than, 916 I think you are fine.

I seem to remember TGO saying something like never having one that goes under.

Load up 100. randomly select 25. Shoot all 25 and if there isn't one slower than 916, I'd run with it.

[gm iprod]

I tend to agree with staying with the lowest shot in a string of five making powder factor by three or preferably five points.

One thing you can count on. The chronograph will not be calibrated properly, by some one who actually knows how to do it. Anything (and I do mean anything) other than an Oehler at a match will not be correct. All chronographs are as good as they can be. BUT unless they are checked well before a match and properly they are guessing.

You can be as right as much as you like, but that will count for squat when a man makes a mistake in setting up the chrono.

[pjb45]

Ok, I caved! I bumped it a tad, not to the original setting but kind of a compromise. I think I am good to go.

I am taking 350 rounds to Quincy. Two wake up calls and off to the airport!

So far, I really like the ability to download the data to a spreadsheet. It shows just about everything I needed to make a decision. I unfortunately had one round that went 908 fps, the average was still good but it kind of spooked me a little.

This is a pretty good piece of equipment. The technology is fairly recent.

I thought about the Oelher but at three times the price, I just could not justify it.

[Skydiver]

I tend to agree with staying with the lowest shot in a string of five making powder factor by three or preferably five points.

One thing you can count on. The chronograph will not be calibrated properly, by some one who actually knows how to do it. Anything (and I do mean anything) other than an Oehler at a match will not be correct. All chronographs are as good as they can be. BUT unless they are checked well before a match and properly they are guessing.

You can be as right as much as you like, but that will count for squat when a man makes a mistake in setting up the chrono.

Out of curiosity, how does one calibrate one of the CED M2?

Even if i had a match airgun to shoot across the M2, all I'll know is whether it is measuring my expected speed or not. If it's not measuring the expected speed, all I'll be able to do is double check that the sensors are placed the correct distance apart and that the light levels are acceptable. Is there a hidden menu somewhere so that I can tell the chronograph to bump up or down it's measurements.

[cletus9mm]

I tend to agree with staying with the lowest shot in a string of five making powder factor by three or preferably five points.

One thing you can count on. The chronograph will not be calibrated properly, by some one who actually knows how to do it. Anything (and I do mean anything) other than an Oehler at a match will not be correct. All chronographs are as good as they can be. BUT unless they are checked well before a match and properly they are guessing.

You can be as right as much as you like, but that will count for squat when a man makes a mistake in setting up the chrono.

+1.

[gm iprod]

To calibrate a chronograph you do the following.

Get you a 22lr bolt action rifle with a barrel between 18" and 22". Use GOOD quality std velocity ammunition, 40gr Round Nose Solid. Winchester T22, CCI Std, Fed 711B, Eley Std or better, Lapua / SK Std and a few others. Do not use anything not made in Western Europe of the US.

Set the chronograph up at 10ft from the muzzle to the centre of the chronograph. This will give you "instrumental velocity", not true muzzle velocity. Seeing as many match rules specify where the chrono should be set up (NRA Action Pistol does not) I will follow what the rules say is the accepted technique for chronographing ammunition.

You need to record the following, date, load info (OAL, powder charge , bullet weight and case info).

Plus you get the following from the weather forcast, temp, humidity.

This will give you a base line to compare with later. At 10feet the load should give you about 20fps less than indicated on the box. There is a formula available online. i.e. CCI Std says 1070fps, I generally get from my BSA 22" Target rifle 1080fps at 10feet, from my CZ 452 Model 2E (24") I get 1060fps. So I know that the chrono is within spec if I get 10fps either side of that data from the appropriate rifle. My guns are very consistant over the last 15years plus, I have been using this system.

I then test the load I am working with. If for example the load is 125gr 9mm from a CZ Shadow and I am aiming for 130pf (1040fps) and I get 1050fps from the BSA and I am running 1020fps from the CZ then I will generally be happy, the 9mm load is being tested with a chrono that is reading low and therefore may be indicating low with your ammo. 1020fps will probably make PF anyways, but seeing as my chrono is running low due to the current weather conditions and I am expecting normal weather for my area then I will most likely get 1050fps from the match chrono.

Under no circumctances use homelaods to calibrrate a chronograph, the 22lr is the most consistant made ammo known to man.

However test again well before a match and confirm or any other way asure yourself that your are OK on PF. I test ammo for big matches well out from the match and more than once.

If you make unproven ammo the night before a match you will most likely, much sooner than later, foul it up. If anything proven left overs from a previous match are more likely to be OK that new stuff that was suggested by Range Lawyer Larry made in a hurry.

All else fails test at 10feet, and make sure the lowest in a string of 5 or more is making power factor with a little margin.

[Skydiver]

To calibrate a chronograph you do the following.

Get you a 22lr bolt action rifle with a barrel between 18" and 22". Use GOOD quality std velocity ammunition, 40gr Round Nose Solid. Winchester T22, CCI Std, Fed 711B, Eley Std or better, Lapua / SK Std and a few others. Do not use anything not made in Western Europe of the US.

Set the chronograph up at 10ft from the muzzle to the centre of the chronograph. This will give you "instrumental velocity", not true muzzle velocity. Seeing as many match rules specify where the chrono should be set up (NRA Action Pistol does not) I will follow what the rules say is the accepted technique for chronographing ammunition.

You need to record the following, date, load info (OAL, powder charge , bullet weight and case info).

Plus you get the following from the weather forcast, temp, humidity.

This will give you a base line to compare with later. At 10feet the load should give you about 20fps less than indicated on the box. There is a formula available online. i.e. CCI Std says 1070fps, I generally get from my BSA 22" Target rifle 1080fps at 10feet, from my CZ 452 Model 2E (24") I get 1060fps. So I know that the chrono is within spec if I get 10fps either side of that data from the appropriate rifle. My guns are very consistant over the last 15years plus, I have been using this system.

Okay, I understand until this part, and completely agree with this procedure of collecting data.

What I'm missing is what to do when the chrono is out of spec. How do I calibrate my chrono to get it into spec? Is there a menu on the CED M2 that lets me tell it to add or subtract more fps? Do I start trying to move the sensors closer together or farther apart?

Edited May 16, 2011 by Skydiver

[pjb45]

If the chrono is out of spec call CED. They are always very helpful.

For me, I have various batches of ammo from Nationals and Area 2. I keep all my chrono records.

So if there is a difference between what the chrono reads and the Chrono sheet, I take that into consideration when developing a load.

Having watched the two chrono process at both types of matches, I know that there will always be a variation. I never ever try to conclude that my chrono results will match exactly the chronos at Nationals. I just wanted the results to be close.

Just this past weekend at SSN, my average PF matched previous PF within 2.

[Skydiver]

If the chrono is out of spec call CED. They are always very helpful.

For me, I have various batches of ammo from Nationals and Area 2. I keep all my chrono records.

So if there is a difference between what the chrono reads and the Chrono sheet, I take that into consideration when developing a load.

Having watched the two chrono process at both types of matches, I know that there will always be a variation. I never ever try to conclude that my chrono results will match exactly the chronos at Nationals. I just wanted the results to be close.

Just this past weekend at SSN, my average PF matched previous PF within 2.

Remember that with a 200gn bullet, 2 PF is only 10 fps difference, but if a shooter were shooting a 115gn bullet, 2 PF comes out to be a little over 17 fps difference. 17 fps falls within the +/- 10 fps suggested margin above for checking to see if the chrono is within spec.

In the end, it sounds like the common advice given by people which is to shoot for 132 PF (for minor) or 172 PF (for major) average makes sense because it gives a much better margin of error for those rounds.

[pjb45]

Update, I dropped the charge a tad. It was cold, windy and rainy. Made PF with room to spare.

If the wind stops blowing here, I will drop it some more and use my SSNats ammo as calibration to bench mark the new loads.

I do like the new CED M2.

[RePete]

Minimum Game PF = 125 then you want a buffer and go to 132 PF.

Minimum Game PF = 165 then you want a buffer and go to 172 PF.

Minimum ame PF = 170 then you want a buffer and go to 177 PF.

These are the numbers that I recommend as a result of DQ'ing people who fail chrono.

YMMV.

[Skydiver]

You can DQ people for not making PF? What game/sport is that?

[RePete]

You can DQ people for not making PF? What game/sport is that?

Yes.

IPSC/USPSA/IDPA.

They shoot for fun if they don't make PF.

Now in IPSC/USPSA if you declare major and you PF is lower, then you will be bumped down to minor PF.

[Skydiver]

In USPSA, DQ means you don't get to shoot any more during the match. As you said, not making major gets you scored as minor. Not making minor, just means you shoot for no score (e.g. for fun), but you can continue on. It is by no means a DQ, although the effect on the final results is almost the same... What's funny is that EZWinScore will show DQ'd people's hits and times but have zero score in the stage scores, but not show up in the final results. People who go sub-minor get deleted out of the results and don't even show up. :-/

I don't play the IDPA game, but after reading the rulebook section about Chronograph (p. 28), I see now that not making the Power Floor in IDPA means a DQ. In IDPA, does a DQ'd shooter get to keep shooting the rest of the match?

[RePete]

In USPSA, DQ means you don't get to shoot any more during the match. As you said, not making major gets you scored as minor. Not making minor, just means you shoot for no score (e.g. for fun), but you can continue on. It is by no means a DQ, although the effect on the final results is almost the same... What's funny is that EZWinScore will show DQ'd people's hits and times but have zero score in the stage scores, but not show up in the final results. People who go sub-minor get deleted out of the results and don't even show up. :-/

I don't play the IDPA game, but after reading the rulebook section about Chronograph (p. 28), I see now that not making the Power Floor in IDPA means a DQ. In IDPA, does a DQ'd shooter get to keep shooting the rest of the match?

In IDPA they shoot for fun.