codyhuntsaz Report post Posted October 20, 2021 Obviously the more precise the better, but my question is… I put six rounds through a chronograph and five of the six were within 30 ft/s of each other and one was a little over 50 ft/s slower than the other five. If I average out the six I get 3241 ft/s if I throw out the odd one that was quite a bit more off I get 3251 ft/s. When I put this into my ballistic rangefinder which number should I go with? Or should I split the difference? Or is that not a big enough difference to really matter? Share this post Link to post Share on other sites
oz31p Report post Posted October 20, 2021 If you’re not going to work a smaller sd…. Take the first one. For a hunting gun, first shot cold more is the only one that matter. ideally a sd in the single digit 1 Share this post Link to post Share on other sites
codyhuntsaz Report post Posted October 20, 2021 2 minutes ago, oz31p said: If you’re not going to work a smaller sd…. Take the first one. For a hunting gun, first shot cold more is the only one that matters I’m shooting factory ammo. I’m not sure what you mean, take the first one? The first average of all 6 shots? Share this post Link to post Share on other sites
oz31p Report post Posted October 20, 2021 The first round down the tube with a cold barrel 1 Share this post Link to post Share on other sites
codyhuntsaz Report post Posted October 20, 2021 15 minutes ago, oz31p said: The first round down the tube with a cold barrel I get that, but I need an average for my G7 rangefinder. By that logic I could have only shot 2 rounds and one would have been 3246 and the other 3190. Big difference there. Share this post Link to post Share on other sites
oz31p Report post Posted October 20, 2021 I understand, the sd with your ammo/rifle combo is too much. 1 Share this post Link to post Share on other sites
muledeerarea33? Report post Posted October 20, 2021 Shoot one round an hour or one round when the barrel cools. It may take a day or a week but if your shooting factory ammo and the cold bore shot is what counts, you’ll want an average of cold bore shots. 2 Share this post Link to post Share on other sites
CouesPursuit Report post Posted October 20, 2021 A cheap chrono will only further complicate your conundrum, just something to consider, not sure what you're using. 1 Share this post Link to post Share on other sites
AZAV8ER Report post Posted October 20, 2021 How far are you planning to shoot? Out to 400 yards I would drop the odd velocity and use that average of four shots that are more typical. The idea of averaging cold bore shots is a very good idea. 1 Share this post Link to post Share on other sites
codyhuntsaz Report post Posted October 20, 2021 Shots 1-4 were all within 20 fps of each other. Shot 5 was 50 fps slower, shot 6 was the same fps as shot 2. 3245 fps. Seems to me with 1 odd round, it would make the most sense to throw it out and average the other 5, but I’m new to all this so that’s why I’m asking. I like the idea of averaging 5 cold bore shots over the course of 5 hours, but I just don’t have the time or ammo to spare. It took me forever to acquire the ammo and my hunt is too close. If I keep all 6 shots in and average them, I get 3241….3246 was the cold bore fps. If I throw out the “flyer” it averages at 3251. If I split the difference of the 6 shot group with the oddball (3241 and without the oddball 3251) I would get 3246. Which is the cold bore first shot fps. If any of that makes sense. Haha i would like to shoot less than 500 yards. It’s a Colorado mule deer hunt and I’ve yet to see the terrain, except on google earth. Share this post Link to post Share on other sites
CouesPursuit Report post Posted October 20, 2021 Have you put those velocities in with your BC to get a drop chart yet? I bet you aren't more than a few clicks off at 500 yards among them. Share this post Link to post Share on other sites
codyhuntsaz Report post Posted October 20, 2021 19 minutes ago, CouesPursuit said: Have you put those velocities in with your BC to get a drop chart yet? I bet you aren't more than a few clicks off at 500 yards among them. I did put them into my Gunwerks rangefinder, and tested from 100 to 200…farthest I could shoot and it was about 1” high at 200 with a 100 yard zero. Share this post Link to post Share on other sites
AZAV8ER Report post Posted October 20, 2021 9 hours ago, codyhuntsaz said: I did put them into my Gunwerks rangefinder, and tested from 100 to 200…farthest I could shoot and it was about 1” high at 200 with a 100 yard zero. I just ran my 270 using Berger 140 grain bullets, the difference between 2959fps and 2950 at 500 yards was .06 MOA and dial up was was the same 8 2/4 up. I do not think it is an issue out to500 yards. 2 Share this post Link to post Share on other sites
CouesPursuit Report post Posted October 20, 2021 9 hours ago, codyhuntsaz said: I did put them into my Gunwerks rangefinder, and tested from 100 to 200…farthest I could shoot and it was about 1” high at 200 with a 100 yard zero. I lowered my 7mm 160 Accubond velocity by 25 FPS and it is < .1MOA difference at 500 yards. Any particular reason you are using a 100 yard zero for a hunting rifle instead of 200? 1 Share this post Link to post Share on other sites
codyhuntsaz Report post Posted October 20, 2021 58 minutes ago, AZAV8ER said: I just ran my 270 using Berger 140 grain bullets, the difference between 2959fps and 2950 at 500 yards was .06 MOA and dial up was was the same 8 2/4 up. I do not think it is an issue out to500 yards. Thanks for checking that for me. Share this post Link to post Share on other sites
