test results help: UPDATE 300 yard test

[emn83]

Got a chance to go to the range today, it was cold and pretty windy, but after being cooped up all winter, I took a chance and hit the range.

Conditions:
100 yard range
Sunny
Temp:22 degrees
Pressure 30.06
Humidity: 32%
wind 15 MPH from 9 o'clock

components:
Brass: Lapua .308 Win standard
Powder: IMR 4895
Bullets: Berger 155 Grain Target VLD
Primer Federal GM 210M

First target: 44.8 grains

Second target: Top 44.6 grains, bottom 44.9 grains

Third target: Top:45.0 grains, bottom: 44.7 grains

taking out some of the horizontal because of wind, it looks like 44.6 and 44.9 grains offered the best groups.

any thoughts and/or comments are appreciated

 

[BrentM]

Re: test results help

Horizontal IMO, as you mentioned, should be ruled out. That is lot of wind.

Verticle: I believe you are on the right track. However, in my experience powder amount is helpful but how far off the lands are you should be considered as well. My rifle shoots almost the exact same spot with 1 grain powder change. For example 56.5 and 57.6. 57 vertically strings the bullets. My rifle also likes .075 off the lands more than it did .050 for the same powder amount.

Perhaps you could load up some in the 44.6 to 44.9 with varying seating depths?

 

[emn83]

Re: test results help

Thanks for the reply. My next test, depending on what input I got, was going to be Berger's recommended test. All those loads were .010 off the lands, debating, since I use the gun for hunting, to try touching the lands, or just use .010 off the lands as my longest OAL...that was 2.200 base to ogive as it stands

 

[BrentM]

Re: test results help

I am sure an expert will chime in but I think you are headed the right direction. My LR rifle has a long throat and with the bullets .015 off I did not have enough bullet in the neck. I had the same issue with a couple of other rifles too. My 3006 has a short throat and is solid at .010 off.

Anyway, I happen to believe that for hunting, a repeater, and possibly someone else shooting/handling my rifle it was best to pull the bullets back and seat them deeper. It worked for me. I like the fact it seems to be fine with .075 off right now and the bullets are not knocked off center easily.

 

[emn83]

Re: test results help

looking at the data, 44.6, 44.8 and 44.9 had the smallest vertical spread, I'm thinking, I'll load each of those again, with loads .010, .050 and .090 off the lands and see how it goes

 

[MNbogboy]

Re: test results help

Hello emn83,
Was certainly a little nippy this morn...I shot a couple of groups at home with a new lot of bergers and some new brass in a couple of my 260s...I had a gusty 2:00 wind at about 5-10 definitely will spread out your groups....Both were wearing a different scope so after the sighters a .53 & .56 were very respectable for me (the SDs were bad but expected with new brass)...They should only get better after the new brass gets a couple more firings and I fine tune the seating (new dies at Berger make a whole new bullet)...

Your charges seem to be in a good node...Normally if you get to your sweet node the groups won't change too much plus or minus a couple of tenths...When you start your seating tests stick with one charge in your case
average out your best 4 and it looks like 44.7 or 44.8....Did you happen to shoot these over the chrono?

After the first seating test you can narrow that down even more with a couple more seating tests....I generally try .010, .020, .030, .040 .050, .060, .070, .080 &. 090 the first time....The second time I take the two or three best ones
and go in .005 increments in each direction from them....

Once I find what seems to be the best seating then I go back to the charge and work both ways from there....If accuracy picks up at another charge then I once again work the seating .003 in both directions...Usually you will find a home for both but sometimes it takes a couple of trys....Better than random chasing your tail.

BTW I sent you a PM with the rifle club info.

Good shooting,
Randy

 

[emn83]

Re: test results help

Randy,
That wind combined with the cold made for some unplesent shooting over 29 rounds and about an hour of somewhat hurried shooting.

I used my chronograph (shooting Chrony F-1) when I did my initial testing, 44.8 grains (with a statistically insignificant 3-shot group) averaged 2941FPS with an ES of 29 and SD of 14.53. That was also the best 3-shot group of the day at .539MOA with a .385 vertical.

Today I had chrony issues, a bunch of errors, and velocity readings that had a range of 1500 FPS (got what I paid for with a free chrony)

I'm thinking, I'll go with 44.8 grains, because it's had the best overall results. I'll rough in my load going .010, .050, .090, .120 off the lands, like in the Berger manual, for now...my seater die does not have a micrometer, so the real fin adjustments are very difficult.

Got your PM, gonna get my self organized and get that mailed out.

Erik

 

[emn83]

Re: test results help

loaded up 6 each at .010, 0050, .090 and .130 off the lands, so I can do 2 3 round groups with each. The 0.130 off the lands is short! only 2.085 base to ogive (2.77 OAL), I heard powder crunching when I loaded it...kind of hoping that one isn't the best shooter...and that the compressed load doesn't give me issues...first time I've had one

 

[MNbogboy]

Re: test results help

I have found that the F-1 is OK (I have had two of them) but in order to get consistent results you have to control the sunlight that it sees....The two sunscreens that come with them are next to worthless...My first one had cardboard ones...In those days I either shot on cloudy days or before the sun came over the trees....With my newer one I first built a shade out of pink styrofoam that was about 2' x 3'.....worked ok but when the suns rays could get a peak at the bullets they often reflected to create enough difference in the comparator circuits that start and stop the counter....Result wild readings(starting or stopping prematurely)....Also the errors caused by 3 fluctuations vs the two that it needs....

Early this winter I finally built the "box" that I got the idea from by somebody on this forum (I think)....The "box" is framed on the bottom with a standard 2x6 I think about 34 or 36 inches long above that is a compartment that just fits the chrony...It is closed at the target end....has two 1-1/2 or 2" diameter holes above the sensor ports....Then abve that is the bullet path compartment...About 14" tall, 5-1/2" wide andthe 34 or 36" long the rest of it is...The sidewalls are 1/4 plywood and the top is a std 1x6 x again the 32 or 34"....The bullet path compartment is open at both ends...The top also has two 2 1/2" holes directly over the chrony compartment holes.....I had two battery operated under the cabinet LED kitchen lights to use when on dark cloudy overcast late in the day shoots...The jury is still out on these because I haven't had enough opportunity to fully test them yet but the one time had good results....

The "box" so far has proven to work 95% of the time with few if any errors anymore....Bullet path alignment in darker conditions has been a little bit of a problem and sunlight towards sundown still causes unreliable results...(my target faces west) Shooting through the "box" has never been a problem...It is located about 12 feet in front of my bench on a homemade adjustable stand.....

I would guess that when yours worked it was on a cloudy/overcast day...The sunlight today would have given mine fits if I didn't have the "box"....The velocities I recorded today were definitely very close to what I have recorded in the past with that load and new brass....The only difference was the bullet lot and even though drastic changes are seen in the bullet specification the relative velocity and grouping appeared to be similar....

I have never owned a micrometer die (wish I had one more than once)...If the .308 bergers are anything like these .264 hunting VLDs both the 130s and 140s you will find up to and sometimes .015 differnces in bullet length and COALs.....However the base to ogive measuremnt is very consistent as well as nose profile....the excess length is carried towards the tip...A single setting with most dies will provide the oal that you are looking for regardless of the COAL....I suggest to setting your die for your longest ones first...Then depending on the thread size of your seater stem (mine are 28 tpi which equates to approx .036 per turn (ie: 1/4 turn in will shorten your oal by approx .009)..This should get you close if you then measure to your
land setting you should be close.....If you are measuring COAL on the bergers you will have a spread equal to the bullet lengths...If you sort all your bullets by length your average COAL difference will again approximate the bullet average length...You probably already know that you should not adjust the COALs on the Bergers (i have made that mistake)....For my hunting uses I find the Bergers still shoot great when mixing the bullet lengths...always under MOA and often under .5 and sometimes one ragged hole...But my bag manners don't let me do that very often...LOL

Good shooting,
Randy

 

[emn83]

Re: test results help

thanks for the advice Randy, gave me a lot to think about...going to have to come up with something short term, until I have the time after the school year to properly make a box for the chronograph.

I measured my base to ogive using 5 different Berger 155 VLDs, and measured each 4 times, 2 times using a dummy case I set up, and twice using the Hornady OAL gaue and comparator....got an average reading of 2.215, and went from there....wasn't too difficult getting the die set up for each base to ogive setting, just a little more tedious than I want...lol....I need to learn more patience...


Wednesday is "supposed" to be partly cloudy and 46, and Saturday overcast and 46, if the temps hold true, I should get some decent shooting in on one or both days

 

[MNbogboy]

Re: test results help

As far as compressed loads go a little crunching can be good...you know you have 100% case fill.....If there is a lot of crunching you can try filling the case with a long spouted funnel...This sometimes makes a lot of difference and can even eliminate the compression....On the other hand a compressed load will often affect your seating depth, just as neck tension and speed of seating can...
Often not enough to make a big difference but sometimes a little thing can be big....I set my neck tension as low as I dare for hunting loads and if I am running compressed loads often my COAL will vary because of it...Just another something to think about.

Later,
Randy

 

[BrentM]

Re: test results help

My guess is 130 is going to not be it. On another note you can cover the neck of the case with your finger and lightly tap the base in a circular motion on the table. This gently removes some of the air and packs the powder. It does fry up some room, perhaps enough to not hear the crunch.

 

[emn83]

Re: test results help

My guess is 130 is going to not be it. On another note you can cover the neck of the case with your finger and lightly tap the base in a circular motion on the table. This gently removes some of the air and packs the powder. It does fry up some room, perhaps enough to not hear the crunch.

cool.....going to try that next time....also looking at getting a funnel with a longer drop tube

 

[BrentM]

Re: test results help

Do you ever notice, after the fact, auto correct kicks in a does things FRY instead of Free? I have to turn that thing off I guess.