Please help with this ladder test- new 2nd ladder

[TroyMN]

I will just post the 3 pictures with all the data instead of retyping all the chrono and weight numbers. First off this is only my 3rd ladder test, 1st with this gun. Shot at 300 yards, less than 3mph wind,53-58F degrees. 90 -120 seconds between shots with a couple other longer rests. The shots are numbered by taking video and replaying and numbering the target. My trouble is the 44.0 grains started walking DOWN the target not up????? :-\
40.1-45.8 Varget .3 increments 168 gr Hornady bthp. Why would it walk down?

 

[jbpmidas]

Re: Please help with this ladder test

Elevation on 9-13 looks really good.

 

[jcampbellsmith]

Re: Please help with this ladder test

.... Why would it walk down?....

I would suggest that the barrel is waving up and down and at this load (44.0) it is on a downer when the bullet exits. As the load increases it is pointing further down. There's a 50/50 chance that the barrel is pointing down as the bullet exits. By down I mean below the line of sight. I don't think it matters a jot where the barrel is pointing when the bullet exits as long as it is consistent. As already pointed out, shots 9 - 13 look promising and very worthwhile exploring further.

I have tried plotting the relative vertical elevations as attached to get a clearer picture of what might be going on.

Good luck. JCS

 

[FroggyOne2]

Re: Please help with this ladder test

Start at .2 below number 10 and go in one tenth incriments to .2 above number 11 and see which one may shoot.. I have a feeling there is a node right there.

 

[TroyMN]

Re: Please help with this ladder test

The velocity for 9-13 are 2389,2424,2419,2455,2478. That seems quite slow for a Hornday 168 grain hpbt out of 20" .308 winchester. I was hoping to use this round for possible 1000 yard purpose. I am visiting my brother-in-law in Scottsdale AZ this winter and might be able to shoot during a practice session at Ben Avery facility. I have a accurate load with SMK 168 and different brass, however the internet says that is a POOR 1000 yard bullet.

 

[Preacher]

Re: Please help with this ladder test

Don't believe everything you hear on the internet !!!!!!
The heavier weights may buck the wind better, but a ton of folks shoot the 160ish weights at 1000 yards with out problems... If your rifle likes em, shoot em....

 

[Alex Wheeler]

Re: Please help with this ladder test

I would not use this ladder to make any assumptions. It is erratic. If thats a 1 moa gun each round could be 1.5 from poa. I am not trying to insult, I'm just saying in a 3mph wind the total grouping should be a lot smaller. I would re shoot the ladder, using wind flags and see if it duplicates.

My advise is to pull back to 100 or 200 yards and shoot 3 shot groups untill you see pressure, at some point you will see your groups shrink. And lately I have been noticing my best groups happen when the barrels pointing down. Any how, go back the the area when you had the best groups and work .2 gr increments above and below. Then shoot a ladder with those at 600 yards, color your bullets and shoot 3 of each.

 

[TroyMN]

Re: Please help with this ladder test

Other than shot 4 the bullets start on the right and walk to the left each charge staying with in .66 MOA of the last shot. The 14,15 and 16-20 dropping vs climbing really threw me. I understand now a little more about the bullet exiting on a down vibration. I thought 300 yards would be long enough to see the velocity make the bullet climb the target despite the harmonics. I understood they climb, stop, climb again, stop ect, and you nodes are on the stops. Thank you jcampbellsmith for the excel sheet, to me that showed your groups went up and down with increasing charges.
The top of my ladder test almost looks like a 1.5 MOA group but the charge changed from 40.1-43.7 grains Velocity 2168-2478.
I also attached a target from previous day of (same Load) 44.0 grains #14, this was with a tighter neck that my current dies can not duplicate.

I was hope to still use the 168 Hornaday for the 1000 yards. The 168 SMK are the bullets that had a funny reaction to going transonic. I have a nice .5 MOA load for my SMK's. Reports are they start to keyhole, get erratic near 1000 yards.

 

[FroggyOne2]

Re: Please help with this ladder test

A lot of folks try to shoot the SIE 168's at 1K.. that was the bullet and being shot from a 20" bbl that hurt that young man at Tullahoma. Yeah, he should have not stepped off the catwalk.. but the bullet was keyholing too.. This past month, there was a guy that was trying to do the same thing.. shoot the SIE 168's at 1K.. you couldn't even hear the bullet come over the berm! I don't advicate it.. it was designed to be shot at 300 meters.. and in my opinion, should not be shot past 800 yards.. but then that is my opinion..

 

[jonbearman]

Re: Please help with this ladder test

What weight would be a good alternative to the 168's froggy? I would like to know myself as I want to join in on long range shooting.

 

[300 RUM]

Re: Please help with this ladder test

Reading some of the posts, my next comments may be warranted, if not just ignore them.

I have tested the SMK's (155gr to 175gr) my rifle don't like any of them

Lapua 155gr rifle eats them like M&M's loves them

Berger 155gr hybirds and 185gr juggernaut love them also

Hornday 178gr BTHP ok.

All shot to 1K just fine if you can keep the speed up there.

Like all the wise folks always say, it's what the rifle likes not you.

Any ways I tested the Lapua 155's against the Berger 185's at 1K and found maybe MAYBE a 1/2 moa difference between the two weights. The reason being in my case is that the 155's were at a MZ of 2,956fps avg and the 185's were at a MZ of 2630 fps avg.

Conclusion: If you can not shot the 185's at the same speed as the 155's you are not going to get a difference in moa that shins over the other.

Check it out yourself generate a graph that shows the difference between the to out to 1K and over lay them. Also go and shot the too and see for your self.

The 185 will retain more vel then the 155 but doesn't show much on paper


At least for me

Just my opinion

 

[TroyMN]

Re: Please help with this ladder test

2nd ladder this time starting at #9 (42.5grains) up to #27(47.9grains) I think it looks promising 20,21,22 due to velocities 2650,2656,2650 and .5MOA point of impacts. The velocities are all I can hope for out of a 20" barrel and should keep me supersonic until 1000yards. #25,#26,#27 started extractor marks on the head. I was going to load up 10-15 rounds of the 46.1 and try some groups. Any other thoughts? Thanks for your input.

 

[savageshooter86]

#24-27 look like there is a definate node there but like you said if seeing ejector swipes better take it down to the next node which appears to be there at 46.1 gr. I would reshoot those 20-22 again in atleast 5 shot groups to see if they repeat. Then if they do play with seating depth some to finalize the load. With that bullet 46.0 gr Varget is usually a good load.

At what distance was this ladder shot at?

 

[TroyMN]

Thanks for the reply. Shot at 50 feet why? ;D

No this one was 200 yards, could not see the bullet holes good enought at 300 just incase the camera messed up again. I was just thinking about loading up 20 or so 46.1 and see what a 5 or 10 round group does. My gun is a stock sps 700 so the lands are aprox 2.342, then the OAL is 2.934 I think the box can take 2.850. I thought I was stuck jumping the bullet. Maybe I will seat it longer this load is mainly for long range target, I will single feed each any way. Right now I am at .087 off, what is recommended? I just started to sort brass, this last ladder was shot using only the middle 2/3, I only removed the odd balls, heavy and light.

 

[savageshooter86]

only speaking for myself here but I would load those 3 charges one more time and shoot to see if they group same POI again. Then from there I would work up in 0.005" OAL until I found best group size all while watching for pressure signs very closely. I started using intial 0.020 jump to begin load development and working up to max safe pressure. Then from there I know my OAL will only be shorter until my best load is found.

My best group with 168 Amax with little work was 0.338MOA @100 and I have switched to the 178 BTHP and best group on paper so far was 0.200 MOA@ 100 yards. Hornady makes a good "cheap" match bullet

Right now I am at .087 off, what is recommended?

Every rifle is different so no set standard to go buy. Play with seating depth until you find one your gun likes

 

[FroggyOne2]

Jon, either the 155's or the 185's and I like the 155's better. Due to that they are easier on the brass.

Troy, I like 20-22. Due to the fact that there is no elevation shift. I would be looking there.. shooting five shot groups for elevation at 600 yards.

 

[normmatzen]

I know you have gotten all kinds of comments, But!!

YOU GOT IT!

If you plot the change in point of impact vs powder charge, you will have a down pointing parabola.

The correct charge for this barrel is the powder charge just before the POI started down. Or at the tip of the curve you have drawn with POI vs charge.

YOU HAVE TUNED YOUR CHARGE! DON'T CHANGE ANYTHING!

 

[TroyMN]

I just found a flaw in my plan, NECK TENSION. How important is it? I messed up the consitency consitency consitency plan reloaders strive for. In my goal to get the case weight similar, remove the heaviest and lightest 30%. Now I mixed up my cases that have been sized by different methods.
I used a Hornady FL sizer on most
I am now trying a Lee Collet die, to keep the fire formed case matching my chamber better.
I also have some that have been sized by a previous die must be without the expander ball .301(i.d.)
So my inside neck diameter varies from .310 my resizing with collet to .308 running the .301(i.d.) brass through the collet die to open up neck some.
This started to worry me when I noticed some of my bullets seated VERY easy compared to others.
I do not know what my neck tension is because I have not measured OD before and after seating.

***Big question is this going to mess up my NODES or are they still in the same spots/ powder charge? Should I pull all the bullets and Full lenght resize?( I do not have a bullet puller and I want to get my collet die to be my main resizing die in the future.)

I have loaded 46.1 grains in .020, .040, .060 and (.080 ladder shot at) off the lands. I also loaded 5 each of 45.9 and 46.3 seated at .020 off. This whole lot does not have the same neck tension..........

 

[Webster]

On your target you state that the rifle is a REM 700 SPS. Factory barrels are not as good as custom barrels. Did you have it glass bedded. Why did you get a 20" barrel if you want to shoot long distance?

 

[FroggyOne2]

Prob got talked into it over on the Hide..