8208XBR for .223?

[Morphling]

I was wondering if anyone has tried 8208 XBR with the 69gr.Sierra MK?
Also wondering if anyone has tried out the AR Comp yet with the same bullet?
I will be using them in a RRA NM AR15 with a 1-8" barrel.
Thanks..

 

[biner626]

Re: 8208XBR for .223?

Bottom of page
Cant remember if he shot the 69.

 

[308sako]

Re: 8208XBR for .223?

Working with an accurate rifle is both a joy and a challenge. I am at a stage where I am trying to make the last few adjustments and narrowing down the powder type and charge. Today's results were gratifying in that they illustrate very well how small charges can make a big difference in performance. The powder is IMR 8208 XBR, the bullet was Sierra's 69 matchking, Lake City cases and Tula small rifle magnum primers. The charge increment was 2/10ths of a grain.

Rifle is a Colt 6724, the "accurized" 24" SS 1 in 9 twist model, optic a Leupold Mark4 16X with a dot reticle, trigger is a Jewell .

Velocity top, was recorded as 2935 uncorrected standard deviation was 4 ft/secs.
middle group velocity was 2965 with standard deviation of 3
bottom was 2995, standard deviation of 5.

The top group was fired at 100 yards in winds to 25 mph, but spilling over a berm and rolling... the winds diminished as time went by and the last group at the bottom was probably only in 15 mph.

 

[Morphling]

Re: 8208XBR for .223?

What did your charge weight end up as on the top target?You went 2/10 incr. but what was the charge?Any signs of stress on the brass?I started out with 23.0 and worked up from there.So far I am at 23.5 and grouping decently at 200yds.Just want to make sure I am not pushing the pressures up to high as this is a Service rifle Match gun..and dont really want to replace a barrel after only 2000rds.
F.Y.I. brass is WCC 07,CCI BR4 primer,seated to 2.260
And thanks for the replies guys...

 

[TRAAV]

Re: 8208XBR for .223?

23.5 seems to be the sweet spot for me. I have used this powder bullet combo for a few rifles and the all seem to like this weight.