Chronographed my loads oh no....

[JEREMY logan]

For starters i've never used a chronograph until the other day. I have what i call a good load @ 100 yrds you can cover up my three shot group with a dime. Not the best but good for me and my rifle . I shoot a 300 rum. Now that i've found what I call a good load i decided to set up the chronograph and shoot a 10 shot string. Here is what I come up with average muzzle velocity was 2964 E.S. 53.64 S.D. 16.27 from what i've read these numbers want shoot at extended range 800 to 1300 yrds will they? What do I do next?

 

[jmason]

Jeremy- read this thread again. Do all your testing with the chrono. You want an SD of 6fps or less. To get that you'll need an ES in the low teens. Some may argue with this but I'd consider it sound advice based on where I received it. You can do it. Load up some ammo, go shoot, and post your data. This place is a great resource and you'll get lots of help deciphering your results.

http://www.longrangehunting.com/forums/f28/sd-es-load-advice-42379/

 

[JEREMY logan]

Thanks for the help again jmason

 

[AJ Peacock]

What is your load?

I like to work up loads using a ladder over a chrony, so I know where my chosen load lays within the range of possible loads. You could shoot a ladder over the chrony and see how it looks.

OR, if you were happy about your load prior to using the chrony, you could put the chrony in the closet until you burn the barrel out and need to work up another load.

AJ

 

[JEREMY logan]

AJ my load is 88 grains of h-1000 fed. 215m primer topped with one sweeeet little 210 grain berger. JMASON will my chrony give me the average MV and ES /SD? shooting 3 shot groups or is it just 10 shot strings that it will do that.

 

[jmason]

Yes it will. What kind do you have? If you don't know how to get that info out of your chrony just write it down and use Excel. You should get 2 or more charge (powder) weights in a row that are uniform (good ES) depending on how big the steps in the charges are. The bigger the steps, the fewer individual charge weights(3 shot groups) that will be uniform.

Once you find a charge weight range that's giving you some uniformity, confirm it with a 5 or 10 shot string of the same charge weight. Once you get this far, If you really enjoy tinkering, you can change your seating depth or primers to try to make it better. This will likely force you to yet again adjust your charge weight.

Or simply call it a load and enjoy life. If you get to where you have an SD of 6 or less and you're getting decent accuracy I'd call it a load because if your like me the rifle/load combo will shoot better than you can.

BTW, AJ has also given you good advise but I would consider his methods "advanced" in that he can clearly and concisely interpret his own results. I still sometimes struggle with it. What I'm telling you to do will cause you more shooting but will leave less Grey area for interpretation. At the end of the day it really doesn't matter how you get there, as long as you're there.

 

[JEREMY logan]

(two or more uniform powder charges in a row) give me an example of what the numbers should look like say for example 3000 fps 3000 fps and 3000 fps would be perfect right. What should i see if i were watching the fps only?

 

[Varmint Hunter]

Probably a silly question but why shoot the 210's at less than 3,000 ft/sec? You could do that with a 300WBY and you would get better loading density and probably lower ES.

In my limited experience with the 300 RUM it seems that consistency is improved with loads that are at, or near, maximum in current reloading manuals.

 

[jmason]

Jeremy- these are hypothetical charges and velocities, but something like this. Just use excel for SD.It's in the "more functions" if you click the weird "E". For ES subtract the highest shot in the string from the lowest shot in the string. Record your data, post it, and let us help you. This thread might help someone in the future.


Charge 1 (75gr retumbo)
2775, 2742, 2758
ES 33 fps
SD 16.5 FPS

Charge 2 (75.5gr retumbo)
2781, 2759, 2799
ES 40 fps
SD 20 FPS

Charge 3 (80gr retumbo)
2801, 2779, 2824
ES 45 fps
SD 22.5 FPS

Charge 4 (80.5gr retumbo)
2830, 2849, 2849
ES 19 fps
SD 10.96 FPS

Charge 5 (81gr retumbo)
2850, 2849, 2866
ES 17 fps
SD 9.53 FPS

Charge 6 (81.5gr retumbo) ****
2870, 2875, 2879
ES 9 fps
SD 4.5 FPS

Charge 7 (82gr retumbo) ****
2886, 2889, 2897
ES 11 fps
SD 5.68 FPS

Charge 8 (82.5gr retumbo)
2919, 2916, 2897
ES 22 fps
SD 11.93 FPS


Charge 9 (83gr retumbo)
2925, 2932, 2945
ES 20 fps
SD 10.14 FPS

Charge 10 (83.5gr retumbo)**STICKY BOLT****STOP****
2951, 2975, 2948
ES 27 fps
SD 14.79 FPS

 

[Shawn Carlock]

Once you have the charge dialed in as good as possible you might consider these steps to lower ES:

1. Sort bullets by baring surface measurement (although this is usually a waste of time with the Berger's as they are very consistant)
2. Be sure to dry graphite the inside of the neck before putting a bullet in as this helps with consistant neck tention and release.
3. Measure your OAL with a bullet comparitor and use a micrometer seater to make them all the same length based on the foreward baring surface of the bullet.
4. Try different primers, simply changing primers has almost cut ES in half for me in the past.

If you can get low teens or single digits for ES, your in the game.

 

[milanuk]

2. Be sure to dry graphite the inside of the neck before putting a bullet in as this helps with consistent neck tension and release.

Hi Shawn,

I've heard of people doing something similar to this on a few occasions... I'll admit, I'm curious but have never got around to trying it. Would you mind expanding on your methods for this? I have a picture in my head of using some Lock-Eze or other fine dry graphite lube with a Q-tip and lightly swabbing the inside of the neck, but figured maybe I should ask first and avoid screwing it up

Thanks,

Monte

 

[A/C Guy]

.. Here is what I come up with average muzzle velocity was 2964 E.S. 53.64 S.D. 16.27 ...

That is not really bad. You could try a heavier crimp, more neck tension could reduce the E.S. and S.D.. Also try seating the bullet closer to the lands. Get under .030 off the lands and see how those numbers change.

You have a very good starting point with your existing load.

 

[A/C Guy]

Probably a silly question but why shoot the 210's at less than 3,000 ft/sec?

He said he just got a chronograph, so obviously, he did not know he was pushing "only" 2964 fps and not 3000+

 

[JEREMY logan]

Hi shawn and thanks everyone for the info. I've been away from the computer today I took a side job replacing someones roof (shingles) man thats real work ....I miss the office shawn could you tell me exactly what kind of dry graphite you use and how you apply it ? Thanks again everyone for the help as soon as I get a good load and go out to shoot some long range targets i'll post them I figure if yall are nice enough to help me out you should atleast see the end results . I'll post the bad shots togun)