vertical stringing a good load to work on?

[Brummy Mark]

Hi all, shot on a hot day 27c with fresh winds 15mph

.223

60gr Berger match varmints.

coal as 2.260- reloading manual length rather than using QL initially, max to my lands is 2.293 (averaged)

bartlein 1.725 twist heavy target 22"

 

H335

23gr grouped at 1.75 inch first 5 shots through new barrel

23.5 all 5 shots on top of each other, no horizontal dispersion, vertical was 1/2" ish

24gr opened back up to 1.5"

24.5gr I shot at faster rate, 1st 2 shots touching on the bull, second 2 shots about 1/2" away from the first 2 located at 7 oclock from the 1st 2. Last shot I pulled and was 1/2" below and right of the 1st 2 shots.

 

No signs of pressure at 23.5g and only slight crater round firing pin mark on the 24.5gr rounds primer wasnt flat and not spread either, so would have carried on to 24.7 and 25gr, but ran out of bullet heads.

 

Now is it worth loading some more at 23.5gr as they were the tightest group? or carry on till signs of pressure or come across another tight group? didnt have chrono to hand, however the start load of 23 was recoil free, but the 23.5gr load and above had the expected felt recoil

[AckImp]

We've often found that you'll happen across an accurate load at a point well below maximum (and well below the cartridges capabilities) and see a deterioration after this as charges increase. If you persevere I wouldn't be surprised if you find that your groups start to shrink again as you approach maximum. Dig around the 'net and you'll find lots of references to people finding a couple of different "nodes" when working up a load.

[jcampbellsmith]

One comment, 0.5 gr increments are big steps for a small cartridge. Have you considered trying 0.2 gr increments when you feel you are getting close to the ideal powder weight? Regards JCS

[Brummy Mark]

Thanks both, JC yes I do go up in smaller amounts, H335 QL data suggested that the pressures and the FPS change for loading in 0.1 increments showed very very small changes, I loades some N140 with 75gr amax today and they have gone in 0.1gr increments due to the very big changes that QL predicts with this powder.

 

I was just after thoughts on the vertical stringing, was it worth loading the same charge again or is the stringing due to some other influence.

[jcampbellsmith]

Sometimes if my load test is inconclusive, I just load it up the same loads again and try again. On some loads, I've on occasion just given up as I couldn't get to a satisfactory conclusion. Regards JCS

[DaveT]

Thanks both, JC yes I do go up in smaller amounts, H335 QL data suggested that the pressures and the FPS change for loading in 0.1 increments showed very very small changes, I loades some N140 with 75gr amax today and they have gone in 0.1gr increments due to the very big changes that QL predicts with this powder.

 

I was just after thoughts on the vertical stringing, was it worth loading the same charge again or is the stringing due to some other influence.

15 MPH is a fair wind for a lightish bullet and will cause some vertical deflection either up or down depending upon whether the wind is coming from right or left respectively.

 

Not saying this was the cause of your vertical stringing but it may have contributed.

[Brummy Mark]

Hi Dave, yes wind gust 15,mph max right to left 2pm near full value, timed shots for the lul

[gun nut]

Brummy,

vertical stringing is usually an indicator of too little powder, but with a new barrel settling in and only .5" stringing I would load some more of the same and chrono them. If it's too slow move up to 24.5.

With your 24.5gr load rushing the groups could cause the 2 distinct 2 shot "group" but it can also indicate you're too close to the lands, try another 5 but load 10thou further off the lands.

In the photo below the top group was at 2.040" at ogive, the middle at 2.060" and the third at 2.080". This nicely illustrates the effect on group size by finding that sweet spot. In the middle group I pulled the last shot, think I lifted my head too quick! In the bottom group you have 2 distinct 2 shot groups cause I was too close to the lands. The first group was 3 shots which exhibit the classic even spred about the aim point of being too far off the lands, the other 2 are 4 shot groups. Cal was 6.5x47 and Amax 123's over 37.5gr Varget and Rem7.5 primer. Chrono said 2930fps but range test points to about 2850fps , either that or Hornady's BC for the bullet is wrong!

 

 

AG0698_zpsaacd5cb9.jpg.html][/url]