First time using a chronograph ... how did I do?

[MCMXI]

I used a friends chronograph today ... my first time using one and I can see how they become addictive. I shot a .300 Win Mag and a Marlin 1894 in .45 Colt. I've been working up loads for both so how does the data look? I can't explain the odd load in the 10-shot string of the .45 Colt ... could be a bad primer.

Anyway, thanks to ReloaderFred and Slamfire1 for their suggestions in setting up the chrony in another thread. I was able to set it up 15 feet away, level and aligned with the target. I shoot prone so I was happily surprised that my first attempt using a chrony and shooting at 100 yards went as well as it did. I managed not to shoot the tripod, chrony, rods or covers so that's a big plus.

 

[BFE]

Look like a heck of a good job to me, very nice increase in loads and easy for you to understand looking at speedsheet.

 

[lonewolf83]

what kind of group did you get with the 71.3gr in your 300 winmag

 

[33rowdy]

Looks good here!

 

[MCMXI]

what kind of group did you get with the 71.3gr in your 300 winmag

The 71.3gr load grouped at 0.578" (middle target, top row).

Here are the six targets (six different loads) that I shot yesterday. I'm using the OCW method shooting the targets in a "round-robin" system i.e. first load at target #1, second load at target #2, third load at target #3 until all six targets have one shot on each ... then I go back to the first load and first target and repeat this procedure five times. The other comment I should make is that I shoot prone with a bipod but I don't use a sandbag or anything else under the butt of the rifle ... just my shoulder which will introduce more error into the data compared to resting the butt on a support of some kind.

It looks like the sweet spot is around 71.6gr with 71.3gr and 71.9gr grouping in roughly the same area. I can't explain the flier on the 71.6gr target ... ... that was the first shot in the group and it felt ok. The other four shots grouped at 0.559". 71.3gr looks unstable but 72.2gr and 72.5gr aren't that bad either. I was interested to see that the velocity didn't change much if at all between 71.0gr and 71.9gr. There was an obvious increase in velocity at 72.2gr and 72.5gr.

 

[Walkalong]

71.3 to 71.9 looks like it is trying to shoot. Just throw out that one high one on 71.6.

Now, if it will repeat that a couple more times, then you may be on to something.

I have seen many folks, myself included, shoot 3 or 4 good groups and one or two bad ones with the same good load/rifle in the same conditions within a relatively short time span. The load did not go bad, the rifle did not go bad, we did. One good or bad group means almost nothing. (Although once in a great while, it means your scope just "took a s***" on you. :banghead

 

[The Bushmaster]

Looks like you need to tweek the loads between 71.3 to 71.9. They look promising...

 

[MCMXI]

I have seen many folks, myself included, shoot 3 or 4 good groups and one or two bad ones with the same good load/rifle in the same conditions within a relatively short time span. The load did not go bad, the rifle did not go bad, we did.

So TRUE!! When I first got to the range, I felt like I could hit a mosquito in flight, but 35 shots and four hours later I was struggling. I find "precision" shooting to be mentally and physically exhausting. The "round-robin" system is supposed to help in this regard since it averages the fatigue and conditions over all the loads.

Looks like you need to tweek the loads between 71.3 to 71.9. They look promising...

Next weekend I'll shoot 71.3gr, 71.6gr and 71.9gr with 10 of each load using the same system (and chronograph). Hopefully that'll be it since I need to get this figured out for a "long-range" match next month.

 

[Walkalong]

hours later I was struggling

I know the feeling.

When I first got to the range, I felt like I could hit a mosquito in flight

Not a Mosquito, but a fly at 100 yds is not bad.

 

[lonewolf83]

thats just awsome!