Jeff686 Posted June 28, 2008 Share Posted June 28, 2008 I shot the chrony stage at Area 1 today. I made major by the skin of my teeth, 165.3 pf. Here's what I did in prep work: Using 124 Ranier RN: sampled 18 times, with an average of 123.4gr Using Longshot: 8.4 gr of longshot gave me an average of 1386.4 fps (5 samples) Average power factor was: 171 Used a Shooters Chrony to measure speed Tests done around 5/2008 Loaded for match with 8.5gr of longshot (same lot number but different purchase date from testing, I think) Used bullets from same batch/box as above. At the match: Used an Ohler chrony, usual procedure. The 3-shots averaged 1343 fps and the bullet weighed 123.1, for a PF of 165.3. Could my chrony be off that much? Link to comment Share on other sites More sharing options...
yoshidaex Posted June 28, 2008 Share Posted June 28, 2008 temp, humidity and altitude can affect chrono readings also. Link to comment Share on other sites More sharing options...
Johann the Horrible Posted June 28, 2008 Share Posted June 28, 2008 All Chrono`s are not equal. We used to have one at National that constantly read lower than that of the different provinces. At the last Nats it got killed though and we are hoping that the replacement would be more similar to that of the provinces. It is of course quite possible that the provinces Chronographs are inaccurate though. Link to comment Share on other sites More sharing options...
dfwmiket Posted June 28, 2008 Share Posted June 28, 2008 Yes, your chrony can be............ trust me, I know. My best advice is chrono your loads on a couple of different chronos, assuming you can, and then take a good average. Around here, I try and test mine on the shooting chrony, the Oehler, and on the CED, and then average them out to get a pretty good idea. Sometimes chorno can be voodoo, really. -Mike Link to comment Share on other sites More sharing options...
Resjudicata Posted June 28, 2008 Share Posted June 28, 2008 Also, how far away from your chrono were you when testing. It seems a lot of people get higher readings because they are too close to the chrono when testing. You should be at least 10 feet away. When I develop my load that I want to make major I make sure that all shots run over major. In other words, I make sure that if I just have bad luck and take all of the slowest loads from a box at the chrono will they all still make major? Just my suggestion. Chris Link to comment Share on other sites More sharing options...
kframe_mike Posted June 28, 2008 Share Posted June 28, 2008 I know my Shooting Chrony sure seems a bit optimistic.I think it has to do with the fact that they fold in half.While its kind of a neat feature for storage and transport,I think it can also make the distance between the skyscreens change enough to throw it off.When this one gets ventilated,I'll replace it with a CED.-Mike Link to comment Share on other sites More sharing options...
open17 Posted June 28, 2008 Share Posted June 28, 2008 Dang it Jeff, now you have me nervous! I changed powder and load just before the A1 match, and my load is averaging about 1360. Hope my little F1 Chrony is more accurate than yours. I won't hit the chrono stage until Sunday morning. Bill Link to comment Share on other sites More sharing options...
LPatterson Posted June 28, 2008 Share Posted June 28, 2008 I too had an optimistic Shooting Chrony that died after inaccuracies almost had me minor at an Area 1. I originally blamed the snow but after a 165 at a local match and a thread on here about the differences in accuracy with wider distances between the sky screens, I SHOT it. Link to comment Share on other sites More sharing options...
Jeff686 Posted June 28, 2008 Author Share Posted June 28, 2008 Oh, one thing I didn't do yet, is run the ammo from the match over my chrony. Maybe I should have sampled the EXACT batch of ammo I made, just to be sure. I'll be interested to see my chrony results from the left-over match ammo. Link to comment Share on other sites More sharing options...
Rabe Posted June 28, 2008 Share Posted June 28, 2008 Oh, one thing I didn't do yet, is run the ammo from the match over my chrony. Maybe I should have sampled the EXACT batch of ammo I made, just to be sure.I'll be interested to see my chrony results from the left-over match ammo. May be moot now but, is there a difference in the number of times your brass was reloaded, or are they all once fired for the match. I know there are some of us who will load "old" brass for a lost brass match since we are "frugal" ie cheap Please update us after you chrono your left over rounds. also was there a difference in temp. from your may chrono and at the match? Link to comment Share on other sites More sharing options...
BSeevers Posted June 28, 2008 Share Posted June 28, 2008 (edited) My Chrony was consistant but read high. Increase your load a little and check it with a friends different brand and your Chrony to get a baseline of where your Chrony reads. In otherwards shoot the same rd over both chronos in a line Edited June 28, 2008 by BSeevers Link to comment Share on other sites More sharing options...
Loves2Shoot Posted June 28, 2008 Share Posted June 28, 2008 My minor .40 ammo made 156 PF, but then again I knew the chrono I was using is garbage and didn't want to take a chance as I didn't have time to work a load up right. The 10 feet thing does get some folks. Link to comment Share on other sites More sharing options...
steveknapp Posted June 28, 2008 Share Posted June 28, 2008 The manual doesn't mention it, but it appears that the angle at which the chrony opens can be adjusted. Mine has a metal bracket that looks intended for that purpose. If yours reads a bit high, open it up a wee bit perhaps? Link to comment Share on other sites More sharing options...
G-ManBart Posted June 28, 2008 Share Posted June 28, 2008 A bunch of things could be going on there really. One, you didn't test the sample that they tested at the match. The temp, pressure, altitude etc are all going t to be different and that changes things. You got a light bullet weighed at the match (that's half a point right there). Every chrono is a little different. Add all those up and it's easy to get a significant difference. One comment about changing powder charges and not sampling the lot you're going to take to the match. Most people's scales only go to .1 accuracy so unless you weigh ten charges, average them and do that four or five times, you're really only in the ballpark with your charge. Last time when you thought you had 8.4 it might have really averaged out higher and then when you made the change to 8.5 it might have actually really been lighter than that. Best bet is to test a load and then when you're happy with the PF, don't change anything at all...nothing....then crank out everything you need for a match. R, Link to comment Share on other sites More sharing options...
XRe Posted June 29, 2008 Share Posted June 29, 2008 Used a Shooters Chrony to measure speed This was your mistake Only half kidding... I haven't sampled a wide number of Shooting Chronys but the ones that I have sampled generally show a higher velocity than the ones we showing up at matches. They seem to be pretty consistent - that is, you can line them up with other chronos and get an idea about what the "offset" is, and use it from there to get the right ballpark velocity. Tests done around 5/2008Loaded for match with 8.5gr of longshot (same lot number but different purchase date from testing, I think) Used bullets from same batch/box as above. ALWAYS shoot a sample from the ammo you loaded for the match over the chronograph - you never know what might've changed on the press, in the powder, primers, or bullets, etc. If anything, this just gives you a last confirmation that your ammo is good to go... Used an Ohler chrony, usual procedure. Dual CEDs in a chrono coffin, not an Oehler Link to comment Share on other sites More sharing options...
kframe_mike Posted July 1, 2008 Share Posted July 1, 2008 The manual doesn't mention it, but it appears that the angle at which the chrony opens can be adjusted. Mine has a metal bracket that looks intended for that purpose. If yours reads a bit high, open it up a wee bit perhaps? You might have something there.If I get a chance to check mine against my bud's CED,I'll see if theres any tweeking that can be done.Otherwise,I figure mine to be at least 30fps high?Not a big deal unless you're looking for 38 Spec Minor in the Wife's K-frame,then it can be a pretty big deal. Link to comment Share on other sites More sharing options...
n2ipsc Posted July 1, 2008 Share Posted July 1, 2008 ...Yes, your chrony can be............ trust me... A not-uncommon lament heard frequently whilst wringing hands and beseeching the Chrono Gods is... "But...it made major over my Chrony!" Link to comment Share on other sites More sharing options...
larry cazes Posted July 1, 2008 Share Posted July 1, 2008 Used a Shooters Chrony to measure speed This was your mistake Only half kidding... I haven't sampled a wide number of Shooting Chronys but the ones that I have sampled generally show a higher velocity than the ones we showing up at matches. They seem to be pretty consistent - that is, you can line them up with other chronos and get an idea about what the "offset" is, and use it from there to get the right ballpark velocity. I have two shooting chrony betas gathering dust in my garage. When they are working They BOTH consistently read significantly higher than the CED that I rely on. Link to comment Share on other sites More sharing options...
UW Mitch Posted July 1, 2008 Share Posted July 1, 2008 Last year I almost didn't make major in L10 shooting a single stack 45. Sue and Joe used up ALL my ammo and I squeaked by just over 165. This year my squad was the last one to chrono on Sunday afternoon. So we shot the whole match hearing how people's readings were between dead on and low by as many as 5pf (at least from what I heard). I measured my loads up here at 181pf (lots of room to spare) and went 176pf at the match. Glad I didn't dial back any on the load. To echo what David said. I loaded a bunch of ammo and shot a local match, then chronoed afterwards. Got my reading of 181. I'm comfortable shooting that, so I came home and loaded more rounds without any adjustment to the machine and checking the powder charge. Then put those in an ammo can on the side as my Area 1 ammo that I didn't touch. Week before the match I took a sample of 50 of those rounds and shot them during a local match to make sure everything was still good to go. JPL gave me that you should make sure that your slowest still makes PF with a margin for error. You want to be prepared for the fluke that the 8 rounds you give up for chrono are the 8 slowest rounds you brought to match. ~Mitch Link to comment Share on other sites More sharing options...
al503 Posted July 2, 2008 Share Posted July 2, 2008 JPL gave me that you should make sure that your slowest still makes PF with a margin for error. You want to be prepared for the fluke that the 8 rounds you give up for chrono are the 8 slowest rounds you brought to match. I was given the same advice by someone else. Get the average around 170-171 and if none of them chrono below 1320 (using a 125 gr bullet), you're good to go. My CED read 170.6 before and it was 171.6 at the match. Link to comment Share on other sites More sharing options...
n2ipsc Posted July 2, 2008 Share Posted July 2, 2008 ...So we shot the whole match hearing how people's readings were between dead on and low by as many as 5pf (at least from what I heard)... Mine chrono'd WAY hot - usually squirt 115's out at ~1460-1470fps (Oehler 35P); registered ~1510 (!) fps over the match chrono(s). Makes me wonder if Silhouette isn't more temperature sensitive than I thought...hmmmm... Link to comment Share on other sites More sharing options...
XRe Posted July 2, 2008 Share Posted July 2, 2008 registered ~1510 (!) fps over the match chrono(s). Almost old major! Yowza... Link to comment Share on other sites More sharing options...
HuskySig Posted July 2, 2008 Share Posted July 2, 2008 The few weeks leading up to Area 1 I was a bit concerned with my loads making minor when it counted. So every time I saw someone pull a chronograph out at the range I asked to shoot a few rounds through it. I was able to shoot through four different chronographs: Oehler 35P, PACT Professional XP, CED M2, and CED Millennium. All of which consistently put my loads in the 128.0-128.5 PF range. Match day I was at 130.3 PF. mattk Link to comment Share on other sites More sharing options...
bberkley Posted July 2, 2008 Share Posted July 2, 2008 I heard a few people went sub-Minor. I shot the same load as 2 years ago which was 7.4gr N340 under a 124gr MG FMJ. It was 40fps slower this year. Same batch of powder, primers, and bullets. Link to comment Share on other sites More sharing options...
bgary Posted July 2, 2008 Share Posted July 2, 2008 I heard a few people went sub-Minor. Just one. And, lemme tell you, it is heart-breaking to have to pull someone out of the results like that. B Link to comment Share on other sites More sharing options...
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