46 grs 8208!

[scorpion168]

Loaded 155 gr Sierra hpbt's(2155) and tried a round robin ocw. Started at 42 and up to 46 gr IMR8208XBR. 3 shots of each load, 1/2 gr increments. When I finished I had one hole in the 46 gr target! I was curious if I should try 46.3 or more, but why mess with perfection? Was seated at 2.807 in my Savage bolt .308. The other loads were all somewhat scattered.

 

[TacticalBoltKnob]

If you made one ragged hole, I don't think you are going to get better than that. I would load more at 45.9, 46.0 and 46.1, shoot several 5-shot groups of each, and see which one is best.

 

[rangeryo]

It's my understanding that the 8208 is fairly dirty powder. Might want to clean your barrel a little more often when shooting it. It does yield some excellent velocities though. Did you happen to Chrono your loads?

The reason I ask, is that I was getting 3050 fps out of 45.5gr of 8208 in my 24" rem barrel. I'm betting your running much less jump than I am on your loads, so in theory you should be seeing higher pressures/velocities.

 

[scorpion168]

Thanks for the input. I do not have a chrono. Did not see any pressure signs. Bolt never got tight. Was a good shoot.

 

[Boogie]

Reread the objectives of a OCW test. Your not looking for the smallest group. Your looking 2 and even better 3 groups in succession that hit the target in the same area. The only way your going to know if 46gr is your node is to shoot a group with 45.7, 46 and 46.3 gr and see where they hit on the target. If they all hit in the same area then you might be good to go but if one hits low left the next center and the next scatters then you haven't found the node.

I know. I've done it several times. Get a bug hole group and think I'm dialed in. Then I try to shoot at 300 yds and the bullet holes are all over the target. Scroll down in this forum and look at other ppls tests and read what is said about the groupings. It'll give you an idea of what I'm talking about.

 

[scorpion168]

Thanks Boogie.

 

[bruddah]

I've wondered how IMR8208XBR would work in the 308. It's been my go to load for heavy bullets in .223. Very accurate and supposedly temp stable.

 

[Boogie]

I shoot 155gr SMKs out of my 308 and it works great. I'm getting ~3000 fps with 44.2 gr (30" barrel) and half moa groups at 300 yds. And as you've already discovered it's great in 223 too.

 

[Grumulkin]

This is the best 3 shot group I've ever shot. Before you get too excited, I have to tell you it was shot with a rifle I couldn't depend on to do better than 1.5 to 2 inch groups at 100 yards. It taught me the very valuable lesson of not trusting a single 3 shot group.

As for IMR 8208 XBR, I have found it to be an excellent powder in my 270 Winchester. I found metering to be excellent and, in fact, it's one of the very few powders that I'll throw charges from the powder measure with rather than weighing every charge. I've also not found it to be a dirty burning powder.

I've never tried IMR 8208 XBR in a 308 Winchester. Maybe I should.

 

[Engine 22]

8208XBR is a great powder for the .308! My LMT MWS does really well with this powder and the 168 & 175SMK, as well as the 168 A-max. I have not found it to be any dirtier than other powders. Btw- XBR is and acronym for eXtreme Bench Rest. It is not temp sensitive and as stated earlier, meters very well with the small kernels.

 

[zulu1delta]

46gr seems abit warm.... Any issues with brass or tight bolt opening?