160 Flatlines and IMR 8208 XBR

[JZimm9mm]

I am attempting to work up a 160 grain Flatline load for my LRP-07 using IMR 8208 powder and Lapua brass. I started at 43.6 grains and noticed some powder crunching seating to 2.800" COAL. That doesn't seem like a huge charge and that's the Warner recommended length. I tried a drop tube and seating them to 2.860" and still got a bit of crunching. I fired 3 rounds over my MagnetoSpeed and got 2795 fps. I have a feeling this is fine, just wondering if some powder crunching is typical with these bullets. Anybody else tried this combo yet?

 

[AZgeek]

Not with that combo, but I've done some load development with this bullet. I elected to use CFE223 as it allows for a larger powder charge due to its spherical structure. My max load ended up at 48.2 gr which pushed the WT160 at 2896 fps out of a 24" barrel. Seating depth is 2.827. Not happy with the groups at 100 yards. Need to first try and back down the powder charge to see if that tighten things up then if necessary play with a shorter seating depth.

 

[agbm]

Here you go, not sure if you already looked at this. 160gr flat lines/lapua brass /H4895 best combo
https://www.snipershide.com/warner-tool-160gr-flat-line-projectiles/

 

[JZimm9mm]

As the OP I wanted to post some results since there seems to be very little info on this combination. I used Lapua brass, Federal 210M primers, 160 grain .308 Flatline bullets, and 8208 XBR powder. Seated to 2.860" COAL. Fired from a JP Rifles LRP-07 with 22" barrel. MV measured with a LabRadar.

43.6 grains = 2796 fps
43.9 grains = 2801 fps
44.2 grains = 2824 fps
44.5 grains = 2837 fps

44.2 grains gave the best precision. 43.9 grains had the best chrono statistics.

 

[wapiti16b]

What was the bullet jump on the loads you tested and twist rate of your barrel ?
Not sure of your magazine oal or if it's possible for you to jam the lands , do not if you can 8208XBR spikes pressure pretty quick in my experience .
I load it for .556 and .308 it has become one of my favorite powders .

 

[JZimm9mm]

I'm not sure of the jump because I have never gotten a good measurement of where the lands are. Being a semi-auto I have just been working within mag length, which with my LaRue mags is about 2.865" maximum. Twist is 1:10. But thanks for the heads up about pressure spikes with 8208. I was pleased with the velocity I was able to achieve with it.

 

[wapiti16b]

I'm shooting a 20" barreled FN SPR ( 1n12 ) and getting 2720 fps with Berger 168 Hybrids ( 35 rounds on a magnetospeed ) single digit SDs and 25 fps ES . I have found 8208 to be temp insensitive and very easy to meter out of my powder charger ( Hornady ) for my plinkers . I do however trickle and beam scale all my loads for long range .