Chrono Certification

[Skydiver]

Trip to major match/entry fee/travel/hotel/ammo/food ~ +/- $1000

Custom Open gun/mags/rig ~ +/- $5000

Custom Olympic grade air pistol/accessories for chrono calibration ~ +/- $2500

Chrono ~ $199.95

Back up chrono [optional] - $119.95

Look on shooters face after 7 shots and PF hits 164.9 – PRICELESS

Would it have been better to buy the $750 chrono with 1% accuracy and then had the $200 chrono as the backup? :-)

[kgunz11]

My method for validating my chrono comes from shooting a bullet with a know BC at long range. If the MV of the chrono is correct my come ups at 1000 yards will match. If it is even 20fps off I'll see it on the target at that distance. I had a CED M2 with alllllllll the screens and gadgets and it still gave me inconsistent readings from time to time in different light conditions. I called them about that and they said it was normal despite my using the IR screens. I sold the chrono to someone here on the board. Do I think the chrono was broken? Nah, I just think I have higher standards in a precision instrument used to measure the velocity of a projectile.

This has been an interesting and informational thread. I'd like to thank everyone that's participated so far.

[kgunz11]

So we did our test yesterday which included 3 chronographs set up in tandem. The chronographs used were a Shooting Chrony, a PVM-21, and an Oehler 35. We found all 3 units to be within 7 fps of each other when the sun was behind a cloud. As the sun came back out it would throw a stream of light on the front sensor (because of the angle of the sun at the time) of the Shooting Chrony. We had screens over it which blocked direct sunlight to the rear sensor. We also used this opportunity to test some temperature sensitivity of Clays and N320. We put a sample of each in the fridge over night, left another sample in the truck all day to heat up, and kept some at an ambient temperature of about 72*. I have some video I'll upload soon and link it here.

[LT45]

Here’s a brief history of the two chronographs that we used this year at the Area-6 pistol mach.

They were the same CED Millennium’s used for the last six Area-6 pistol matches. We got them new in 2005. The box that we put the sensors and screens in is closed on all sides. We use the powered infrared screens and close the ends of the box with targets, cutting only a small triangle in the front for the aiming point. This setup only lets in a very small amount of light, taking sun and shadow out of the equation. This same setup was also used at the last two Area-6 3-Gun / Multi-gun matches, a couple of GA State 3-Gun / Multi-gun matches, and the last two GA State Championships.

Now for some interesting stuff… I was the Chrono officer for three of the above mentioned matches. What I witnessed, on average, most of the shooters were not surprised with their chrono results. When my buddies came through it was business as usual. Everyone was right were they said they should be, unless they had fidgeted with their load just before the match. I also ran my personal .40 cal rounds that are a 171.3 PF through them and there was very little deviation with that load (using N320) and of course I ran the match calibration ammo through the RM’s pistol with little deviation.

The only variable that I saw come into play was temperature. When it got cold I saw power factors change. At the 2008 GA State match, my 171.3 PF ammo dropped to a 167.8 PF on the last day when it got considerably colder, which, from what I understand, is not uncommon for N320. The ammo that we used this year for the Area-6 official calibration ammo was checked each morning before the match. There were two pistols used each day. Between Friday and Saturday there was little change in the PF for both pistols, however on Sunday morning it was a bit colder and the readings were surprisingly a little bit higher from both pistols. I’m not sure what powder was used in the calibration ammo.

What I can conclude from all this is… setup consistently, these chronographs have shown consistent readings over the years when used in the Atlanta area. The effect that temperature has on loads can vary, depending on the components used.

I would also contribute a change in PF to the effect of the variables in atmospheric conditions from one geographic location to another and the deviation of readings given by the various makes and models of chronographs.

Bottom line… add some fudge factor into your load… just in case.

[Alan Adamson]

Coming late to the discussion, but 2 comments, (and no I didn't read the entire thread above, but most of it).

a) I suppose you ruled out someone else's ammo in your baggie? I always put the little sticker with my shooter number, etc on the *inside* of the bag, and not the outside, it's a PITA to do so, but stickers and plastic bags don't really work very well, when the corner lifts and your sticker gets transplanted to another bag in the standard handling of bags of ammo, etc.

Inside, it can't go anywhere, but inside the bag, outside it can go anywhere.

Second thing that I don't do, but this may prove to me that I should... is somehow mark your rounds... not so much to pick up yours but to verify at least for yourself that the rounds that are going in the gun at Chrono are indeed your rounds.

second and probably more likely.... I've read, but have not been able to prove, that MG bullets (brass jacketed bullets) can be harder for a sensor to pick up than copper jacketed bullets. I've not experienced this, but have read that it does happen and can give funny results at the Chrono.

As an aside, my rounds (124g MG JHP 9mm's) over the A6 chrono were exactly where my rounds chrono'd 2 days prior on my Chrono. Both times over CED chrono's... Mine and both of theirs.

Alan

Edited May 4, 2010 by Alan Adamson

[Mark K]

This has been a fantastic learning tread.

Again, because my situation at Area 6 came up, I wanted to report on our triple check of my ammo that I used at Area 6, when Bobby ran the 3 chronos.

The long and the short of it is 1) No significant difference in the velocity hot or cold with Clays. 2) We found that the box of ammo that I took to the range post-Area 6 did test at near 180pf, but that another box from Area 6 tested at the 160pf level.

We found that I probably had a problem with my powder bar returning consistently on the powder measure that I use on my 40SW reloads and I have corrected that with a rubber band assist from the powder bar, around the powder hopper.

As I stated earlier in the tread, my concern was not that there was a problem with the Area 6 chrono, but how I could keep it from happening to me again. I found that, I think.

Luckily, it spurred this interesting and informative thread.

Thanks all.

Mark

[Flexmoney]

Bottom line… add some fudge factor into your load… just in case.

That is SOUND advice !!!

Over the years here, we have seen...after many a Major match...lots of threads about the chrono.

[G-ManBart]

The long and the short of it is 1) No significant difference in the velocity hot or cold with Clays. 2) We found that the box of ammo that I took to the range post-Area 6 did test at near 180pf, but that another box from Area 6 tested at the 160pf level.

We found that I probably had a problem with my powder bar returning consistently on the powder measure that I use on my 40SW reloads and I have corrected that with a rubber band assist from the powder bar, around the powder hopper.

Glad you found the source of the problem...it's still a bummer, but at least it's not a mystery! R,

[Flexmoney]

We found that the box of ammo that I took to the range post-Area 6 did test at near 180pf, but that another box from Area 6 tested at the 160pf level.

We found that I probably had a problem with my powder bar returning consistently on the powder measure that I use on my 40SW reloads and I have corrected that with a rubber band assist from the powder bar, around the powder hopper.

I figured that might be the situation in your case. A drop from 180pf to 160pf is rare...without something weird in the mix.

Were the 160pf loads pretty consistent? Maybe you are dialed in wrong with the powder measure. I have heard a number of cases of FOD (foreign object damage) getting into the powder hopper. And, you can't tell by dumping the hopper out, as the powder bridge in the bottom traps the FOD when you turn the hopper up-side-down.

[boz1911]

This has been a fantastic learning tread.

Again, because my situation at Area 6 came up, I wanted to report on our triple check of my ammo that I used at Area 6, when Bobby ran the 3 chronos.

The long and the short of it is 1) No significant difference in the velocity hot or cold with Clays. 2) We found that the box of ammo that I took to the range post-Area 6 did test at near 180pf, but that another box from Area 6 tested at the 160pf level.

We found that I probably had a problem with my powder bar returning consistently on the powder measure that I use on my 40SW reloads and I have corrected that with a rubber band assist from the powder bar, around the powder hopper.

As I stated earlier in the tread, my concern was not that there was a problem with the Area 6 chrono, but how I could keep it from happening to me again. I found that, I think.

Luckily, it spurred this interesting and informative thread.

Thanks all.

Mark

Even though I'm always careful loading ammo, I'm really discriminating when loading Major match ammo. I always chrono my major match ammo and mark the ammo as such. That ammo is set aside and only used for Majors, even though in reality it is the same as all my other ammo. Chrono'ing from "major match" ammo is a must.

[BillD]

I shot Area 6 and the SS Nats. Same gun, same loads. I went from a 178.6PF at Area 6 to a 170.2PF at the Nats.

Also, I weighed 10 Bayou Bullets at work on a $15K, PM'd, calibrated scale. All of them weighed within 0.1 of 206 grs.

The bullets weighed 202 gr at the matches.

[Mark K]

Yes, at least I know what the problem was.

HOWEVER, I also learned that I cannot depend on the Dillon Powder Sensor to detect minimal changes in the powder charge. It is great for way over full loads (that I would notice anyway) and for really low loads (that I might miss). Not so good for .2 charge variation. That can be bad for PF, but also safety issue with a powder like Clays).

Mark K.

[Mark K]

We found that the box of ammo that I took to the range post-Area 6 did test at near 180pf, but that another box from Area 6 tested at the 160pf level.

We found that I probably had a problem with my powder bar returning consistently on the powder measure that I use on my 40SW reloads and I have corrected that with a rubber band assist from the powder bar, around the powder hopper.

I figured that might be the situation in your case. A drop from 180pf to 160pf is rare...without something weird in the mix.

Were the 160pf loads pretty consistent? Maybe you are dialed in wrong with the powder measure. I have heard a number of cases of FOD (foreign object damage) getting into the powder hopper. And, you can't tell by dumping the hopper out, as the powder bridge in the bottom traps the FOD when you turn the hopper up-side-down.

Yeah, the 160pf were VERY consistent, as were the 180pf. With Clays, it would have only taken about .3 to make this shift.

Mark

[Flexmoney]

If you trace down the source, let us all know...so that we can watch for it.

Heck, I might bump the knob I have on my adjustment bolt and make a 0.30 difference.

Good info here.

[kgunz11]

Right now we think it might have been an improperly resetting powder bar. I use a rubber band on mine and Mark has added one to his. This cheap little mod gives me pretty consistent throws.

[kgunz11]

I was asked for a photo of the rubber band fix I was talking about. The first photo is of the wire spring included in the Uniquetek micro powder bar. The 2nd photo shows the factory Dillon powder bar with a rubber band attached. Both of these machines happen to be 1050's but they share the same powder system.

[wide45]

Tighten the blue wingnut.

[aztecdriver]

I was asked for a photo of the rubber band fix I was talking about. The first photo is of the wire spring included in the Uniquetek micro powder bar. The 2nd photo shows the factory Dillon powder bar with a rubber band attached. Both of these machines happen to be 1050's but they share the same powder system.

You have a picture of the front side of the powder bar or the lock link, powder measure bellcrank and failsafe rod installation? I'm curious as my setup seems to almost impossible to need this. I see your installation has more customizations and wondering if that leads to the need for the assist in reset.

Edited May 5, 2010 by aztecdriver

[kgunz11]

The blue wing nut also controls the powder bar return, yes, this activates the powder bar return long before the wing nut would make contact.

[Skydiver]

More drift from USPSA rules, is there a way to break off this thread and move it into the reloading section?

Anyway, some people don't like the ka-chunka sound and feel that the bellcrank and failsafe rod system. They revert their systems to the older version of the press that used the spring to pull the powder measure bar back, instead of the failsafe rod. The claim is that this gives a smoother motion and therefore a more consistent load.

[XRe]

I would argue that the "kachunk" insures no bridging is occurring inside the powder measure, and helps insure a more consistent charge. My measure has not problems throwing consistent charges, even with the kachunk...

[aztecdriver]

Interesting. I'm too new to Dillon stuff to know about old styles. Thanks for the info!

[Singlestack]

I would argue that the "kachunk" insures no bridging is occurring inside the powder measure, and helps insure a more consistent charge. My measure has not problems throwing consistent charges, even with the kachunk...

Huge +1

The springs or rubber bands are not necessary for consistent powder drops.

[Xfactor]

I would argue that the "kachunk" insures no bridging is occurring inside the powder measure, and helps insure a more consistent charge. My measure has not problems throwing consistent charges, even with the kachunk...

Huge +1

The springs or rubber bands are not necessary for consistent powder drops.

In another thread specifically about this topic, I posted some results of testing with my 550 with the anti-return cam system (the part that causes the "kachunk"... which is intended to mitigate powder bar double charges). For me, I have gotten *extremely* consistent throws (w/ VV N320 and Ramshot Silhouette) with the ant-return cam disabled and two Dillon powder bar return springs.

Interestingly, the worst consistency was with the cam disabled, and only one powder bar return spring... so there is definitely something to having substantial return tension.

[ChuckS]

For me, I have gotten *extremely* consistent throws (w/ VV N320 and Ramshot Silhouette) with the ant-return cam disabled and two Dillon powder bar return springs.

Interestingly, the worst consistency was with the cam disabled, and only one powder bar return spring... so there is definitely something to having substantial return tension.

Same here ...