Today's 308 ladder tests

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. : )

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Is it all 4895?

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.

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?

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...

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

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Originally Posted by tiny68

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

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

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

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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.

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Originally Posted by 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

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

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

Quote:

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Originally Posted by 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

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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.

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.

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? : )

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

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

Sean

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.

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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

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.

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?

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

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.

problem fixed