Ladder test interpetation

[4xforfun]

I did a ladder test last night. Just wondering what you who are experianced with them think.

My test consisted of 8 fouler/sighter shots. The first four got me started, firing 12 loads on the way up ...lowest charge to highest.( RED) . A cleaning followed by four more sighters/foulers and then I shot the next 12 from highest charge to lowest (GREEN). My chrono was DOA, so no chrono data. Test was at 750 yards. Although I waited 90 seconds between shots, things got fairly warm in the middle of my upward string (RED). I did a quick clean job, and the temps were high for the trip back down...300 WBY...lots of powder...lots of heat!!!

Now, I usualy look at the clusters ....RED 2, 3, and 4. GREEN 4,5, and 6. Green 8, 9, and 10.

But I see that shot #9 was below # 8 both times....A bunch low on the way up (RED) and slightly on the way down (GREEN). Would you (should I) be looking at load 8 and 9? Or stick to the "clusters"?

 

[Shynloco]

Since there doesn't seem to be much response to your post, hope you don't mind if I chime in with a couple of thoughts. First off, I'm not a real big fan of trying to use the ladder test by shooting one shot per load. That shows me nothing because there is an absence of the possibility of any consistency or pattern. I like using 5 shots per load, although sometimes 3 shots might work for some. I know that can be a pain, but is also a necessary piece of information to my way of thinking. And given the distance you are testing at (which is something I've never done BTW) the variables in your loads and conditions have increased (as compared to say 300 yds) which might actually validate a good group when you shoot it. That's why to me, group shooting is necessary to determine that sweet load that you rifle likes the best and will perform the best. Just my thoughts. Good luck and have fun.

 

[4xforfun]

Anyone??/

Normaly I would just simply shoot and figure it out, but I am shooting the PLATINUM JACKETED, GOLD CORE, BIB BULLETS....and don't have very many of them.


Anyone.....Buler...Buler....Buler.....................

 

[queen_stick]

Here's my .02...

You have a couple loads that had very close poi (in terms of vertical) when the barrel was cool, and when it was hot (Sounds like it got pretty damn hot!). If this is a match rifle, which I'm assuming it is based on your bullet choice, then I would choose the loads that had the the least vertical when the barrel was cool AND when it was hot. 7 and 8 have almost no vertical... I'd definitely retest those two.

I'd redo the test with 3 rnd groups. I'd load up some of 2, 7, 8, and 12, and shoot the 3 rounds of each load at their own target. Pic the best from that test, and continue on from there.

Being on limited supply of bullets sucks... you might want to consider a different bullet until you can get enough to get it dialed in, and still have enough to use the load you find for that bullet

 

[4xforfun]

Well. I went out and did some more shooting tonight. Had great conditions....right up till I got to the range. :-\ I had a 11:00 - 1:00 wind...about 6 knots. I shot anyway. Anyway, I had 14 brass prepped, so I loaded 9 at 83G (load #8...4 for sighters/warmup and a 5 shot group) and 5 at 84 gr (load #9 plus .2 grains.) The 84 gr load was about 5 inches with 2 1/2 vert. The 83 grain shot fairly well....2.55 inches....about 1" vert. Range again is 750 yards.

Again...no chrono data.

QUEEN_STICK,

This is actually an older tube I had done up a few years ago in a hurry and on the cheap. 1-11 Krieger. Only 27" (thats all that was in stock at the time), no flutes. Anyway...I had it shooting good with 210 Bergers...but it really let me down at a 2 day shoot...kind of lost interest in it and put it in the rack of WTF tubes!! Now has 761 rounds through it. I think I will be shooting this gun at the next matches...let my 13 year old JR PETA member and future SEAL TEAM SIX member shoot my Dasher. I have about 6 tubes for this gun...four in 300 WBY, one in 300 WSM ...1-12 made for the BIB.... and a 6.5 WSSM.


I know that this is only one group...but it will have to do for now.

 

[queen_stick]

an inch of vertical at 750... not too shabby

 

[DougMH]

I agree with Shynloco that one round of each load going up and down is not going to give you an accurate picture.

If you are shooting consistent 1" vertical at 700yds, I'd stop wasting bullets on ladder testing and go find a match to shoot in... or test in a windy place and hone those skills.

Twelve loads also seems excessive. If you can get a chrony hooked up, I'd find the minimum load that keeps the bullet supersonic at the distance(s) you want to shoot. That would be my absolute minimum load. Then I might do a minimum of 5 and a maximum of 8 loads in .3 grain increments (http://www.6mmbr.com/laddertest.html). I'd perform the test 5 times in load rotation. From top to bottom or bottom to top wouldn't make much difference to me as long as I had a consistent barrel temp for all shots (http://www.tiptemp.com/products/2302/reversible-temperature-label-16-level-vertical-pack-of-10). If you use these, I'd start with the 77 deg F to 212 deg F range.

Hope this helps.