1st Load Workup - next step?

[Conaso]

Tikka T3x TAC A1 6.5 Creedmoor
New Lapua Brass (Lee collet NS), CCI BR4, H4350, 140 ELD-X

Tried to work up load while fire-forming brass

10 - 41.8gr, 2616fps, 31.67 ES/10.67 SD .62" group
10 - 41.9gr, 2639fps, 36.89 ES/10.04 SD .35"
10 - 42.0gr, 2651fps, 32.30 ES/11.35 SD, .55"

Obviously I need to improve ES/SD. Should I keep fire-forming the remaining 50 Lapuas at 41.9gr or try to workup load with fired brass?

What load on ff brass, 41.9gr plus 0.x +- to account for expanded case?

Do I need to do another load workup with ff brass?

 

[MtnCreek]

If I'm reading this right, it's not a load workup, it's 30 reds fired with 0.1 gr difference across the board. Start lower and work up in about 0.3 gr increments. You need to understand how to identify high pressure signs before hand.

 

[Shankin]

I agree with MtnCreek. Read up on what signs of pressure are, find pictures of them and whatnot.

What I will usually do for load development is take the max listed charge weight minus 10%, and start there. From there, go up +1% until you get to max listed charge weight. Once at max listed, load 2 more at +1% and +2% of max. When you go to the range to shoot these, you HAVE to be watching for pressure signs. As soon as you see one, stop.

From there, look at your data, and make your decision. If you chart your velocities, you’ll likely see flat spots (where velocity doesn’t increase or decrease much if at all), and there’s a pretty good chance that there’s an accuracy node within those flat spots.

 

[Conaso]

Well, it really wasn't the "first" shooting of the rifle. Weeks earlier, for the first time I fired 5 rounds (39.0grs), cleaning after each round. Then I fired groups of 3 rounds - I loaded 3 rds each of 41.1, 41.3, 41.5, 41.7, and 41.9, cleaning after each 3-group. 41.9 was the best group. Kind of breaking in and partial load development. So today I got out the chronograph with 10 each 41.8, 41.9, and 42.0.

 

[Conaso]

BTW - absolutely no pressure signs.

 

[Shankin]

I would keep working up. Just as an example, the load that I have settled on is 42.5 of H4350 with 130 Berger Hybrids. Sierra calls for a max of 42.0 of H4350 with 140’s. Not all bullets are created equally, but if you’ve already loaded 140’s to 42.0 and haven’t seen signs of pressure, bump it up .1-.2 at a time until you do see signs of pressure. Look back at your velocities looking for flat spots, and you’ll prolly find an accuracy node in there. You’ll likely find that your sd and es have dropped as well.

 

[Conaso]

I would keep working up. Just as an example, the load that I have settled on is 42.5 of H4350 with 130 Berger Hybrids. Sierra calls for a max of 42.0 of H4350 with 140’s. Not all bullets are created equally, but if you’ve already loaded 140’s to 42.0 and haven’t seen signs of pressure, bump it up .1-.2 at a time until you do see signs of pressure. Look back at your velocities looking for flat spots, and you’ll prolly find an accuracy node in there. You’ll likely find that your sd and es have dropped as well.

Most appreciated.

 

[MtnCreek]

ES in the 30's over 10 rds is high. Do you thrust your chrograph?

Couple places to look would be seating depth and lee collet die setup.

 

[Conaso]

Seating dept is .020 off landes. I'll double-check die or go to my Redding S die. Maybe being new brass reason for ES/SD? For next trip I'll reload once-fired.

 

[MtnCreek]

What chronograph are you using?

Were the groups listed in post 1 ten shot groups?

Edit: Fuck autocorrect.

 

[Conaso]

Shooting Chrony Beta Master
Yes, 10 shot groups for each

 

[MtnCreek]

I'd disregard the SD's and shoot at 400+ to look for vertical.

If you're putting 10 rds into <0.7, hard to beat that.