6.5 PRC - Berger 156 EOL - Seekins Havak Element

[Megalodon]

Didn't find a whole lot of info when I was deciding on a cartridge/gun for a lightweight hunting rig so figured I'd post up my results. I had really wanted to push the 156 as close to 3000 fps as possible and was worried about the 21" barrel on the Seekins.

Environmentals:
85*
4700'
35% humidity
25.3 inHg

Load:
Virgin ADG Brass
Fed 210M
RL-26 - 58.0 gn (moderate pressure signs at 58.5 gn)
Berger 156 EOL
CBTO - 2.340

Everything was shot with a TBAC Ultra 7. These rounds were in the 200-250 round count area for the barrel. Accuracy for a 5 shot group hovered right around 0.7 MOA, which on such a light gun shooting a big(ger) cartridge is probably the max for my skill level. Over 10 shots the avg velocity was 2988, ES 25, SD 8.75. Which I can probably tighten up a little going through a full prep and reload process on the second firings.

Overall very excited and happy with the velo and accuracy. Trued ballistic data at 400, 500, and 1000 yards. BC was close enough for hits on 1-2 MOA targets. I'll do a little more fine tuning and get more time behind the gun before my deer tag rolls around, but sitting in a pretty good place.

 

[wildwilderness]

That seem fast for a 21” barrel. Do you think it’s the R26?

 

[Megalodon]

I think it's probably a combo of the R26, being at 5k', suppressor may add 10 or so fps, and the mag/chamber on the seekins.

I expected to hit pressure well below 58.0 gn judging by what I'd found from other people posting. But the bullet is loaded way out there, I think COAL is damn near 3.10. Started at 54.0 and worked up 0.5 gn increments and everything looked/felt the same until 58.5. Who knows, I may be over pressure though....

It shot some factory ammo with the (I think) 140 Berger Hybrids at just over 3K.

 

[ID_Matt]

I was about to say that seems like a pretty stout load of RL26 and to watch for it in warmer temps but it looks like you already tested in the heat! The guns I have loaded for settled around 54-56 grains. 3K in a 26" and 2920 in a 22". Same components

 

[Megalodon]

I was figuring I'd have to "live with" about 2900 fps. Totally open to the possibility that I'm over pressure and just not seeing the typical signs. 58 gn pushing it ~3k out of a 21" barrel doesn't see too far off, just that 58 gn seems (like you're saying) 2-3 more grains than most people are loading.

 

[BigAl!]

This is helpful - thanks for sharing.

 

[ID_Matt]

I was figuring I'd have to "live with" about 2900 fps. Totally open to the possibility that I'm over pressure and just not seeing the typical signs. 58 gn pushing it ~3k out of a 21" barrel doesn't see too far off, just that 58 gn seems (like you're saying) 2-3 more grains than most people are loading.

It could be that you got a slower lot of RL26 or it could be that you are a bit over pressure and it may show up after a few firings when the primer pockets start to loosen up. If you are comfortable with it, then let it rip. If it were me, I would back it down to 2900 ish and preserve brass/barrel life. Extra 100 FPS won't be noticed anywhere.