223 Chrono test 2nd try.

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kmw1954

kmw1954

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First would like to thank everyone that contributed to my edification on the 1st try; https://www.thehighroad.org/index.php?threads/1st-223-chrono-test.891332/

Got to run a short test today on some of the same original loads with the only change being the weather and the brass. In the original test I was shooting loads that had all been loaded for the first time in LC brass instead of the PMC or GFL I had been using and did all the load development with.

Recap the gun is a Savage Model 10, barrel 22", 1:9 twist all shot on a bi-pod and rear bag. Shots were measured with a Magneto Speed Chronograph. All loads tested have been shot many times before for accuracy but w/o the aid of the chrono. There accuracy was the reason for this testing.

So I sadly did not get as much testing done as I wanted because I got volunteered to work the 200/300yd range because the unexpectedly got busy.

I did get to test 2 loads with a 62gr bullet and TAC powder; 4 shots each numbers I received from the chrono were, 23.7gr load 31SD - 67ES, 23.8gr load 13SD - 26ES... 2 Loads Benchmark powder and 69gr RMR bullet, 22.0gr 30ES - 74SD, 22.2gr load 27SD - 60ES.

Not sure what happened with the 22.0gr load because the numbers do not add up, actual numbers; in order 2699, 2705, 2734, 2669 so the ES was really only 44 and not 74. Don't know what that does to SD.

Last tested was a Benchmark load of 22.0 gr with the 62gr bullet... SD 20- ES47

Numbers where a good bit better all around and shot for groups as well as I could with the bayo on the barrel and even the groups all look well.
 
Just spent some time going over the numbers and targets and a couple quick observations.

Seems the Hornady 62gr FMJBT bullet in my rifle likes a speed of between 2730 and 2766 fps with any of the four powders I shot it with.
Next the RMR 69gr HPBT has consistently shot the smallest groups even though the chrono numbers are not the best and 2700 fps
 
Thanks for the range report and sticking with the chrono. While it can be frustrating a bit and has a learning curve, eventually the data will pay for itself.
Your 22gr numbers, with the string you gave, should be 65ES, 26.7SD. In your OP it looks like they were off and twiddled.
Also remember 4 shot groups for stats, not so good, but at least it’s a ballpark number so you know what the V range is. Good luck.
 
Blue68f100 said:
ES is the difference between 2734 - 2669 = 65 Not sure where you got 44 or 74
Click to expand...
Went back and looked again, found two mistakes! Numbers should be in order fired; 2699, 2705, 2743, 2669 =74
Transposed the 2743 and mistakenly used the the 2740 - 2699 instead of the 2669.

Mysteriously though this string produced the best group of the day!
 
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Once again I know that three or four group numbers are statistically weak and don't give a good picture but it does show a ballpark range. After a couple of tests with similar results shows me at least that there is something going on that I am getting those one shot extreme spreads in most every group.

My friend/mentor was also present and as was mentioned in the last thread he stated , Don't get too caught up in the numbers as the groups look very good. We both agreed that there are many possibilities for the dispersion such as brass, bullets, reloading technique, the gun heating up.

murf everything shot yesterday was at 200yds and were holding together pretty good. As you and my friend say, now it's time to see how they hold at 300yds! The to determine if it's the ammunition's or the shooter. I've only shot to 300yds a couple times to see if I could hit paper.
 
hope you have an ao (adjustable objective) on that scope. you will need it @ 300 yards.

luck,

murf
 
Scope is an Athlon Argos BTR Gen2, 8-34X56 with 30mm tube. So far has been working very well. Yesterday at 200yds I had it turned down to 24. Then will add that one of my other Enablers provided me with a nice Harris Bi-pod that has been even more stable than the Caldwell front rest. Not sure when but I hope to get back and finish up shooting those test loads thru the chrono and may even load a few more.
 
Is your model 10 chambered in .223? Or are you able to use 5.56 data for it? I've found that the RMR bullet shoots really good with 5.56 data and only shoots okay with .223 data. I should say, the ES for the 3gh is in the single digits when when I use 24.6 grains of TAC but when I slow it down the ES goes up.
 
Loading it at 223 levels.. When doing load workup when I got to 23.9gr of TAC the groups started to open up and I was happy with the 23.7gr load. Maybe I should readdress this and look a bit higher. But again I am getting even better results using the Benchmark powder with the 69gr RMR.
 
kmw1954 said:
Loading it at 223 levels.. When doing load workup when I got to 23.9gr of TAC the groups started to open up and I was happy with the 23.7gr load. Maybe I should readdress this and look a bit higher. But again I am getting even better results using the Benchmark powder with the 69gr RMR.
Click to expand...
For us, the 3gh really started to shine when it got close to 3000 fps. Out of my 28" barrel I was getting an ES of 7 using pulled lake city cases with 0 prep and just under 1/2" groups at 100. Was also getting 3160 fps.
 
When I loaded for this testing I only loaded 8 loads with the 69gr bullet and that was with TAC, 23.7-.8 -.9gr, Varget, 23.6 - .8 - 24.0gr and then just 2 loads with Benchmark. They were low starting levels but still shot the best group at 200yds. Those were at 22.2 and 22.2gr and was getting around 2720 fps.avg. Next round I am going to bump those up a few.
 
Got out to actually shoot these today before the sky's broke open. This was all done at 200yds.

Everything shot today was loaded with Benchmark. Some with the 62gr Hornady and most with the 69gr RMR. Also shot loads with PMC brass and Norma brass. Had 12 loaded the same using PMC and 12 the same with Norma brass and overall the Norma shot much better, more consistent numbers and better groups. Norma groups had ES of 35/36 and the PMC had ES of 68/85

The 62gr Hornady with Benchmark powder and PMC brass shot much better than with the LC brass from the last time. Of the 4 loads shot all but one had single digit SD and low teen ES.

The loads with the 69gr RMR still need some work as I don't think I found a stable node for them yest. I did also try a couple longer lengths. One was .010" longer and was interesting and another was .015 longer and it fell apart. Groups openned to over 5"..
 
Nice! Welcome to permutation hell. I would recommend you find your node first, and then play with COL. Good luck.
 
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