.284 + 180g Hybrids + H4831sc velocities

[FTRinTexas]

Do these velocities seem to fit the normal range?
Dallas, TX
H4831sc Temp: 78
Humidity 79%
Charge - Average - SD: - ES:
53.0 - 2676.0
53.2 - 2685.0 - 9 - 17
53.4 - 2700.0 - 2 - 3
53.6 - 2721.0 - 9 - 15
53.8 - 2721.0 - 15 - 9
54.0 - 2725.0 - 5 9
54.2 - 2740.0 - 10 - 19
54.4 - 2751.3 - 6 - 10
54.6 - 2758.7 - 10 - 19
54.8 - 2756.7 - 7 - 14
55.0 - 2773.3 - 7 - 13
55.2 - 2773.0 - 8 - 14
55.4 - 2785.7 - 11 - 19
55.6 - 2796.3 - 7 - 13

30" Bartlein 1:8"
Lapua 6.5-284 necked up
CCI BR-2
4 shot groups
Formulas used:
'=STDEV(B9:E9)
'=MAX(B9:E9)-MIN(B9:E9)

This was my 1st time out using the LabRadar and just wrote doen the velocities. Setup was easy, but stopping and reviewing the series was a pain.

No pressure signs. Do I need to keep going up in powder?

 

[ShootDots]

"Generally" speaking 54.0grs of H4831SC will give you "about" 2815-2830.. If you are using a brand new barrel, you can expect a "speed-up" of approximately + / - 40-60 f.p.s. If you have a "looser" bore on the HIGH end of SAAMI specs, it would go a bit slower, conversely a tighter bore will produce higher velocities for the same charge weight. Finally, if you have a S-L-O-W lot of H4350sc, you will need more powder than you would with a faster lot. H4831sc can vary from lot to lot considerably..

 

[dskogman]

What Ben said. If you go much higher your going to start blowing primer pockets.

 

[Rogmay]

I'm shooting a 284 with a 30" Krieger, 8 twist, 180 bergers, 54.4 of H4831sc, 1000 rounds down the tube, getting a hair over 2800fps!

 

[Grimstod]

Just curious. How full is your case? Is powder up to the neck should junction?

 

[brxbrad]

I feel your numbers are spot on....I've been through 4-.284 barrels in the last 4 yrs. All Bartlein, 3 were 32" 1:9 and the one I'm shooting now is a 32" 1:8.25 twist. The 1:9's shot 2830 fps @ 54.5 gns of 4831SC with ES 9 and 4 SD and the 1:8.25 runs 2800 fps with 55gns of 4831sc with an ES of 11 and SD of 4.5.

 

[billlarson]

every barrel is different........... choose the fastest load that is the most accurate....
bill

 

[FTRinTexas]

Just curious. How full is your case? Is powder up to the neck should junction?

At 55.2g, powder appears to be the body/shoulder angle.
Will re-test this weekend.

 

[FTRinTexas]

Another weekend at the range
LabRadar
Dallas, TX
H4831sc Temp: 89
Humidity 46%
Charge - Average - SD: - ES:

54.6 - 2742 - 2.2 - 5
54.8 - 2757 - 9.5 - 20
55.0 - 2767 - 12.3 - 27
55.2 - 2779 - 8.5 - 18
55.4 - 2785 - 6.0 - 14
55.6 - 2789 - 6.4 - 15.0
55.8 - 2805 - 6.6 - 16.0
56.0 - 2818 - 1.7 - 3.0


30" Bartlein 1:8"
Lapua 6.5-284 necked up
CCI BR-2
5 shot groups

No pressure signs at 56.0. Felt recoil increases at 55.8. Appears that I just have a slow lot of H4831sc