Today's 308 ladder tests

[thermaler]

Just back from the range and it was a tough one--winds were blowing 20-25 and temps were below freezing. Shots are at 100yds. Some ladder groups were less than 10 shots because manufacturer's recommendations for best load were at/near either min or max--or I was getting into compressed loads where I'm very conservative at this point.

Happily, there were no signs of over-pressure with any loads, and the bullets I seated long with cannelures beyond the case neck seem to do just fine. Due to strong winds and the target flapping a lot the groups could have probably been a bit tighter--but they all give me a good starting point for reload efforts. The one bullet results that confounds me a bit is the Hornady SST--which seemed to happily group well regardless of the load driving it. : )

[shootz]

Is it all 4895?

[thermaler]

None. Forgive me for not listing the recipes:

The Hornady 165 gr SST's were backed by Varget; the Berger 168 VLD, Accubond 180 and 168 TTSX were all propelled by IMR 4064.

[acemisser]

yeah..I went as well to test some Speer 190 gr bullets in the 308---also cold and windy and shooting only at 100 yds..
The way I do is load 5 with the bullet into the lands...another 5 backed off .020 and another backed off at .040 used 3 different
3/4 inch bulls eyes as well...all loads had the same powder charge of reloader 15......But with the weather I did not consider it a fair
test..What with the wind and frozen fingers,so I am going to do it over again and then decide.But I have to say from what I seen that the load with the bullet touch the lands was the most accurate,having 4 in 1/2 inch and 1 out,which may have been the cold fingers...I have never tried Speer bullets until to day.....I notice there is no much said about them?

[tiny68]

Distance? 100 yards? My 100 yards was hard to even repeat. 300 yards made things every clear with the ILDM. Tim


Sorry - didn't read your first few sentences.... duh...

[tiny68]

42.4 gr with TTSX looks pretty darn sweet... :)

[thermaler]

42.4 gr with TTSX looks pretty darn sweet... :)

Yeah--I'm going to load to that weight range when I work up the final set of loads.

[tiny68]

I didn't want to watch anything on TV tonight. I was curious about using the ILDM at 100 yds..... so plotted your data. When I see these in graphic form things are much easier for me to read. Looks pretty darn good. I would be interested to see if you repeated one of the bullets if you get the same trend. I have went to 300 yrds only in order to get much wider swings in the vertical deviation. Looks like you have a good choice for most bullets.

Luck, Tim

[thermaler]

Thanks for doing some analysis--yeah, I know it was a bit half rear-ended approach since 100yds is too close, but I really have no choice at this point and as long as I get a load in the consistent MOA or less ballpark for conventional hunting ranges (it is an axis, after all) I'll be happy. This is my first go at a ladder-type work-up, so I know I have lots of room for learning improvement.

PS--Just to be on the safe side--I did mention above the SST's were driven by Varget.

[thermaler]

I didn't want to watch anything on TV tonight. I was curious about using the ILDM at 100 yds..... so plotted your data. When I see these in graphic form things are much easier for me to read. Looks pretty darn good. I would be interested to see if you repeated one of the bullets if you get the same trend. I have went to 300 yrds only in order to get much wider swings in the vertical deviation. Looks like you have a good choice for most bullets.

Luck, Tim

Just out of curiousity--how do you interpret results from graph(s)...I have a hunch but would like to hear from someone knowledgeable.

[tiny68]

The flat spots are your nodes. I usually pick the center (if their is a clear center charge) and fine tune from there. If it is a hunting load, I then adjust the seating depth and I am done. For example, I would 33.6 gr with the SST. I would then try seating at 3-4 different (+0.005, 0.010, 0.015, and 0.020" from the lands). Once I set seating depth, I go back and shoot 5 shot groups at the center charge plus/minus 0.2 gr. It would be 33.2, 33.4, 33.6, 33.8, 34.0 gr for the SST. What shoot the best there is what I would go with.

If you don't want to mess with seating depth, call if 33.6 gr and go have fun.

I am shooting a 223 ladder this afternoon. I will see what it looks like and post resu

[thermaler]

The flat spots are your nodes. I usually pick the center (if their is a clear center charge) and fine tune from there. If it is a hunting load, I then adjust the seating depth and I am done. For example, I would 33.6 gr with the SST. I would then try seating at 3-4 different (+0.005, 0.010, 0.015, and 0.020" from the lands). Once I set seating depth, I go back and shoot 5 shot groups at the center charge plus/minus 0.2 gr. It would be 33.2, 33.4, 33.6, 33.8, 34.0 gr for the SST. What shoot the best there is what I would go with.

If you don't want to mess with seating depth, call if 33.6 gr and go have fun.

I am shooting a 223 ladder this afternoon. I will see what it looks like and post resu

Flat node you mean the line flattens on the graph showing similar close POI's? My plan was to find a few fine-tuned loads within that range, and once I selected the final powder load play a bit with seating depth. What fun!

I found some guru on the net who claims the audette ladder method is not scientifically sound--argues harmonics and sound-wave stuff in the chamber and at barrel end is what matters--though I have no clue what he's talking about.

[tiny68]

This method is tuning for the harmonics at the end of barrel. Think of the end of the barrel whipping up and down like a wave. You want the bullet to exit at the top or bottom of the wave. That is what the flat spots represent. We call these the nodes.

[thermaler]

If I understand correctly, those ideal harmonics are evidenced by the closeness of the groupings of similar (yet different loads) and the ones further apart would be "less harmonically stable?" Also--how were your 223 results today? : )

[tiny68]

Got the rifle sighted. Didn't get to the 300 yard range to shoot the ladder. Maybe later in the week. Tim

[seanhagerty]

If you only have 100 yds to play with, try the OCW load development template. It helped me figure out what was what.

Sean

[thermaler]

I think I was able to get 50% good results from my ladder tests--I worked up some load groups which were 3 sets of 3 weights bracketing the nodes. On the other hand, I felt that somehow I could do better with both the SST and TTSX, and the distance/shot sample group was insufficient in my initial ladder.

[tiny68]

If you want smaller groups it is time to invest in some wings flags. I would stay you pretty dialed in with those loads. Did you notice any strong wind or breeze when you shot the TTSXs? Almost no vertical.

Tim

[thermaler]

Fairly moderate day wind-wise--I'd say winds were 5-7 mph from about 8:00 position...a quartering tailwind. I'm thinking I must have pulled the shots somehow, I was shooting off a bipod and buttpod which moved around a lot during the shots--and the axis tupperware stock is very sensitive to any pressure from a cheekweld. I may also have not let the barrel cool enough--I put about 40 rounds through in the space of 2 hours--though a touch test of barrel muzzle and chamber, while warm, was never uncomfortably hot.

[thermaler]

I know there was a difference in load weights so it may be difficult to make conclusions like this: but it seems to me that the Varget-based loads developed a bit less "recoil wallop" than the loads based on 4064. Am I imagining this?

[seanhagerty]

No, you are not imagining. Different powders (and different burn rates) will develop a different recoil

[thermaler]

I just double-checked my loads against the initial ladder tests--the best groupings seemed to line up well with the nodes I got. Also, the VLD load I misprinted--should be 39.617, not 29.617. Sorry bout that.

[thermaler]

problem fixed