280ai load development (continues)

[JD Jones]

Rifle- FFT/280 AI/7.2#
Brass- Petersons 1x
Bullet- Berger 168
Powder- RL26
Primer- BR2

Last week I did a rough seating depth test in 10 thou increments working back from 20 thou off jam. At 40 thou off I got:

At 50 thou off I got:

Today I did a 6 shot string. I just about split the diff on seating depth, loaded up charges 57.9-59.4 in .3grain increments.
Results:

These groups suck and there was an element of rushing and some called fliers.

Based on the targets, what direction would you recommend I go?

Play with seating depth?
Change my bullet?
Change my powder?
Other opinions?

The string 3 communicated to me that my perception of feeling rushed and a flier I called as soon as the trigger broke… was spot on since a near identical load (seating depth change) was half that group size just last week.

I feel like the target also indicates at least the vertical between say 58.2-58.8 is close?

Taking opinions!

 

[VinceMule]

JD, there are a lot of ways to skin a cat, and I am certainly not the last word.

I will share this system that I use, and I am sure that there is room for improvement.

With a little search, I will see what are the seating depth characteristics that a particular bullet likes, if I do not have any personal experience.

With the 168g vld hunting, I started .020 off the lands with my new 27", 9T barrel

Then I worked upwards in my powder charges, shooting two shot groups, I was seeking to find pressure. This "finding pressure" gives me some critical insight in brass life, and also, most rifles will shoot their most accurate within 2.0g of their max load.

OK, now that I have worked up the loads and found pressure, I may have some keen idea of the proper powder charges or a spread to work with. Now I go to 3 shot groups.

Once I have the most accurate powder charge, I will start tweaking the seating depth.

I start with a solid "touch" on the lands, and it is amazing how many times this depth is the most accurate, but you never know till you try, and every barrel you ever own will be different...humbling to say the least.

I will shoot two or three shot groups, and I will vary seating dept in .003-.005 increments back from firm contact with the lands. This will often try your patience, be patient and keep solid notes. Be methodical in your efforts and record-keeping. Once you find the "jump" a particular bullet likes, you can maintain that jump, and at the same time, you are doing your testing, you will also discover a spread in distances so that your load may stay in tune.

I am looking for small groups on my custom hunting rifles less than 3/8", and Stock Rem 700's bedded, free-floated, good triggers and scopes more often than not will shoot tiny groups!''

Finally, after powder charge and seating depth have been established, If I am not satisfied by getting bug hole groups, then I will switch out primers. As long as I have been using this method, I am humbled by what Primer I thought was best to find out that I really had no clue. Primers can make a HUGE difference in groups when you are looking to get groups that simply open up a bullet hole.

This method was taught to me by Joe Wagner, an old German Gunsmith, and it has proved to be spot on.

We all have to deal with the wind. When you have wind blowing in your face, this condition presents some changes in shot placement as it switches from left to right.

Shooting of a cheap bi pod can also give skewed results, depending on the accuracy you are looking for.

JD, may I suggest that you go to a cci 250 vs the BR2 if you have them.

Also, in my 280 AI, 9T,168g I am shooting very close to a max charge of IMR 7828, and the Federal 210 has the bullets all touching at 100 yards. I have the 168's, .003 off the lands. I also form my brass from Lapua 30/06 brass, leaving me with a shortish neck, and clean the carbon build up out of the neck of the chamber with a 38 cal pistol brush when I clean.

Also, hold down the forearm when you shoot, do not let a finger touch the barrel, and this is a tremendous issue...hard lesson learned.

Best of luck to you! Love to follow your results!

 

[manitou]

I tried 20, 30, 40 and 50 thou and had to back up and ended up at 5 thousandths of the lands for best results in my .280ai.
This is with the 168 Bergers.

 

[HSmithTX]

I would keep going shorter and shorter, to at least .100" off the lands and if it were me I would go back to .120" off the lands, and I would do it in .020" increments. I have about 80% bought into the theory that group width is seating dependent and vertical is powder charge dependent. I have only done this with a few rifles and a couple different bullets in those rifles but so far it's working. Find a seating depth that looks good or at least promising and go plus and minus 5 from there, see which direction it's leading you, if it isn't clear go another 5 plus and minus. You will find a depth that works better. Then do powder workup. If the whole thing doesn't satisfy you when done swap powder and do it again. I find my best loads near max, and using powders that fill the case completely or very close to completely.

 

[59FLH]

Whats the charge weight on the two sight in target groups?

If I understand you did a test with various charge weights at .02" jam, and a test with various seating depth and undisclosed charge weight?

Id recommend you pick a seating depth and then vary your charge weight.

 

[Mikecr]

What load did you do your seating test with, and why?

 

[JD Jones]

Whats the charge weight on the two sight in target groups?

58.5 grain was the charge weight. I did 4 groups starting at 20 thou off. Those were 40 and 50 respectively. I split that down the middle for the OCW

If I understand you did a test with various charge weights at .02" jam, and a test with various seating depth and undisclosed charge weight?

I did a ladder test at 200 yards at 20 thou off before the seating depth test. I landed on 58.5 because the vertical dispersion I interpreted from the target between 58 and 59

What load did you do your seating test with, and why?

See above: I did a ladder test first. The way I interpreted the test 58.5 seemed a middle point between two loads showing the least vertical dispersion. I'll admit tho the test was only at 200 and I was trying my best to move forward vs starting at a greater distance to show the results in dispersion at the various charges. That's how I landed on doing the OCW… I don't have a distance range I can drive to without a larger commitment to the day

 

[just_jon]

I would reshoot the test based on your statement re: rushing and called fliers. I have learned the hard way not to rely on data when I was not shooting my best.

 

[Mikecr]

I'll suggest that you're officially tail chasing.
You chose 20thou OTL (I guess, a guess) and worked up powder to 58.5gr.
Then, at 58.5gr, changed seating from where you worked up a load.
Then, changed seating again, and at the same time started over with powder changes.
Full circle, back to nowhere..

If your brass is fully fire formed, I would go back to around 57.0, and do full coarse seating testing again.
Then with best seating from that testing, do incremental load testing with powder.
Then with best of coarse seating, and best powder with that best coarse seating, fine tweak seating in it's window for tightest grouping.
If it doesn't shoot well with this, there is likely a different problem to work out still. You may have to go back to primer testing, or improve some attribute of reloading.

 

[VinceMule]

JD, I am shooting IMR 7828, NOT R#26

 

[jsthntn247]

Try them touching to .015 off in .005 increments and they will shoot.

 

[slickyboyboo]

Get you some Hammers, they are stupid easy to develop loads for. It took me 12 rounds in my 280 AI to develop a 1/4 MOA load, and they aren't sensitive to seating depth.

 

[JD Jones]

Get you some Hammers, they are stupid easy to develop loads for. It took me 12 rounds in my 280 AI to develop a 1/4 MOA load, and they aren't sensitive to seating depth.

Monos are next!

 

[JD Jones]

Cleaned barrel, Went back to the range fouled the barrel then Retested **only Slowed down this time**

Thanks for the opinions and conversations. I'm more than happy with my results. 3 was a little out but acceptable and likely me anyways.

Gonna work a mono up next. Thinking 150 cx (I have 100), LRX, maybe hammer hunter 143.

To those who hunt with monos, what Would you play with first? This would be for elk. 280ai and I would like to have a round capable of 500-600