178 bthp,rl15

[browninghunter86]

Got out to the range this afternoon and sweated it out. Had some good results(I believe)
Savage 10 Action, Shilen Match 26" 1:10twist varmint contour barrel, BC A2 Medalist stock, Accu-Trigger, Nikon 4-12x-40mm scope
WW Brass 2x fired, weight sorted to 1%
178 BTHP Hornady
RL15
2.005" TTL
Flash holes deburred
Lee Collet Sized
Seated to 2.227"ogive ~2.879" tip
Distance: 200 yards
Temp: 94F, sunny slight breeze
Shot off Caldwell Lead Sled Plus
Load #1-42.0gr then increments of 0.3gr up to 45.0

***Shot 6&7 scattered then 8,9,10 settled back down***

[Wyoredman]

What rifle are you shooting? What Powder are you using? What distance?

Edit: got the powder RL 15! Sorry

[Unclenick]

He's running a .308 Savage action with a custom 26" replacement barrel.

[Jimro]

I'm sure Uncleknick can do the spreadsheet graphing, but it looks like #8 is promising. A darn near straight line between 7 and 9 with small vertical rise. Although the line goes 7 9 8 from bottom left to top right it seems like those shots might be close to a harmonic node.

Not enough data to know for sure, but that is where I'd start.

Jimro

[browninghunter86]

Jim 7 8 9 didn't shoot on horizontal line?

I was thining 1-5 shot on bassically the same horizontal line and with only 0.49" vertical dispersion at 200 yards?

[Jimro]

What follows is based only on my experience. With a 308 you normally get a "low node" and a "high node" of accuracy during load workup, the "low node" is usually between 2550 and 2650 fps and the "high node" is between 2700 and 2800 fps. There seems to be a transition point between the two nodes that is a "scatter node" where the bullet timing and barrel harmonics just don't work out right.

I assume that since you spent the money on a 26" barrel for your rig you would want the velocity advantage of the "high node" for long range shooting. Once you get past 600 yards, velocity matters more. I don't know if you plan on shooting that far, but normally a 178gr BTHP over a heavy charge of Re15 is a 1K load. If you were shooting 600 and under the 168 BTHPs are a lot cheaper.

Try loading up 5 shots of #4 to test the low node, and 5 shots of #8 or 9 to test the high node. Wait 5 minutes between shots if you can to keep your barrel cool.

Jimro

[browninghunter86]

Oh ok I see. Yes I was thinking #6 and #7 were scatter node then 8-10 settled back down.

I should have a chrony to measure velocity sometime next week

Yes am planning on taking that out far one day soon once i can afford some high quality optics with more power. 12x might not work so good at long range for me


Thanks

[Jimro]

Magnification isn't as important as glass quality/clarity and repeatable adjustments. The rule of thumb for "tactical" shooting is that 0.5x to 1x per 100 meters is perfect when it comes to magnification. There are a lot of snipers out there who like more magnification, but usually for the observation portion of their mission instead of the shooting portion.

With a 26" barrel shooting 308 you'll need around 40 moa of UP from from your 100 meter zero to get out to 1 kilometer depending on atmospherics. Off the top of my head it should actually be closer to 35 moa, but you'll want some padding. That limits your scope choices a bit.

Jimro

[Unclenick]

Here's what a plot looks like. I ran the horizontal and vertical separately on this one because there was less obvious flattening than before.

[browninghunter86]

Nick not sure if these were calculated assuming I was aimed at center of the big black 2" square but I was actually aiming at the small hole just under shot #4 that has some outlining with black sharpie around it.(Basically right under bottom edge of shot 4.

And this was shot @ 200 yards

[Unclenick]

It's arbitrary. I just put them where the flatter areas would be close. If I use the average values as the 0,0 points, the plot looks like below. The least change for horizontal is actually shots 6,7. and 8, while for vertical it is 8, 9, and 10. I would tend to favor vertical as it isn't affected by wind as much, but you can see how any of those are good candidates.

[browninghunter86]

Got out to range today and shot groups with 42.0-43.5gr. Weather was good

***43.5 was shot after final zero of scope***

[Jimro]

Looks like 42.3 is your low node for accuracy. I expect you will see groups open up between 43.5 and 44.2 and then settle down again between 44.5 and 45.0.

Your low node looks to be about the duplicate of M118LR (save the difference in bullets) in terms of velocity so it should get you to 1K if you want to stop load development now. With enough scope adjustment 1 to 2 MOA difference gained by finding the "high nod" isn't going to be a dealbreaker on making the shot.

Jimro

[browninghunter86]

well did a few seating depth loads with 43.2 gr RL 15 and rifle seemed to only like it about 0.020-0.025" off lands. Everything else opened up a lot. I believe shot 3 in group #3(bottom right) I rushed or something. Shots were fired round robin.

[browninghunter86]

what would I try next to get more accuracy out of load once I find seating depth? Go up and down in 0.1 gr to see if that tightens anything up or switch primers or swith brass?

I know more trigger time with load will help too

[tobnpr]

Seating depth (jump) should be the last thing you play with once you find the most accurate load...JMO...

"Trigger time" should be mostly irrelevant when doing load development. If you have doubts about your trigger control or handling, lock the rifle down in a shooting rest.

If you introduce any significant shooter error into the equation, your "load development" is useless since you can't tell that from variations due to the load.

[browninghunter86]

not please at all. I am not sure if it is my scope(since it has a preset 100 yard parallax) or the caldwell led sled rest I was using but load did not shoot worth crap at 200 yards especially after grouping well at 100. And bad thing is almost every shot felt extremely well when I squeezed it off

91F, 10 oclock wind @5-7mph

[Jimro]

Don't be disheartened, look at the vertical spread, it is still sub-MOA at 200.

A 5-7 mph bursting wind from left to right explains the horizontal spread. Shooting from a lead sled means that your technique was as good as it could be, except that you had a hard time accounting for conditions.

No worries mate, shooting in the wind is more art than science some days. Last time I shot at 500 yards the flag at the firing line was standing straight to the left, the 300 yard flag was straight to the right, and the flag at the target line was dead calm.

Jimro

[Unclenick]

Yes, if the wind is gusting it will spread you horizontally and, to a lesser degree, vertically, tending to create a diagonal line whose angle depends on the gyroscopic stability factor of your bullet.

[Jimro]

Looking at your target after further reflection, I'm of the opinion that even with the wind gusts you are meeting the base standard for M118LR accuracy, which is around 20 inches at 1000 yards, or right at 2 MOA extreme spread.

On the flip side, there are folks who can achieve very small groups at 200 yards, and they are either extremely good at reading the wind or they are shooting under very favorable conditions.

Jimro

[browninghunter86]

thanks to Nick who has been workin QL predicitons adjusted to my barrel/powder here is the groups I shot this morning. 5 rd groups at 100yards and middle target was sighters.

40.5 numbers looked like--- AVG=2453,ES=21.37,SD=10.39
42.5 numbers looked like---AVG=2586,ES=29.85,SD=12.76

After going back to initial groups shot at 100 I noticed 42.6 strung vertically at 100 and 42.5 did same thing today at 100


Thanks Jimro too for the input and advice

[tobnpr]

When we first moved beyond 100 yards in our shooting, the effects of wind drift became evident.

While wind effects are usually largely negligible at 100 yards, that isn't the case at 200....and become exponentially more influential to bullet flight as you stretch the bullet's legs...

http://www.6mmbr.com/winddrift.html

[browninghunter86]

this accuracy would work out but not to 1000 yards. Velocity is too slow according to JBM but accuracy looks like it is there

[Jimro]

If you bump up to the "higher node" you should get more velocity without a loss of accuracy, although 2580 fps is pretty darn close to M118LR ballistics (although that measurement is taken further from the muzzle).

I think you'll find good accuracy around 44.4 grains of powder based on your initial test.

Jimro

[browninghunter86]

Switched to Varget and CCI 200 primers. SHOT @100 yards

Here is target shot to detrmine optimal charge using OCW method



From that I picked middle load between #3 and #4.

Here is seating depth test #1


Seating depth verification, scope was adjusted from previous target