77smk 8208xbr what velocities to expect?

[Djstorm100]

Out of a 18" rifle? Going to do a load development test this weekend, if the weather holds out.

[markm]

I get 2700 out of a 20" barrel. XBR is moody and can vary by lot. My current load is 23.4 gr. Work up carefully.

[rjacobs]

I want to say I chrono'd right around 2600 with 23.2g out of my 18" krieger barrel. I cant remember the exactly number, but it was 26 something, which matches what Mark is getting out of a 20".

[markm]

Yeah. XBR will shoot awesome with 77s. But if high velocity is critical, a powder like TAC is going to get you closer to Mk262 velocities.

[Djstorm100]

I did a quick load development because 8208 is just easy to load for. My older barrel (rainier arms) was at 2750 at 23.6 grain. I was expecting at least 2700 but dumbfounded when it was 2660.

[markm]

I did a quick load development because 8208 is just easy to load for. My older barrel (rainier arms) was at 2750 at 23.6 grain. I was expecting at least 2700 but dumbfounded when it was 2660.

Same lot of powder? I've had lot changes where I started getting a lot of popped primers all of the sudden... with the same old 23.8 grains. That's why I just dropped my load to 23.4.

[Djstorm100]

Same lot of powder? I've had lot changes where I started getting a lot of popped primers all of the sudden... with the same old 23.8 grains. That's why I just dropped my load to 23.4.

You know what. I just remember I cracked open the 8lb jug and didn't use what was left of my 1lber out of fear of not having enough for the match.

I remember you load and the sudden pressure spike you can get from the burn rate. Sorry Markm but I did stalk your post when I researching it..77smk and 8208xbr.lol Where is a good place to get Lake City brass?

[P2000]

This is with tmk's

https://www.m4carbine.net/showthread.php?t=184967

Sent from my XT1565 using Tapatalk

[markm]

Where is a good place to get Lake City brass?

We just scoop it up at the range during the summer when it's too hot to shoot in the desert.

[Kansaswoodguy]

http://brassbombers.com/223-556-Clea...e-City_c48.htm

Out of my 20" barrel with IMR 8208 22.1gr I get 2515fps at 23.1gr I get 2636fps at 23.5gr I get 2745fps this last one is above book and not really one I use, but it was in my notes so I included it for you and if you notice the fps gain is not linear wich also worried me with that one. I mostly shoot the 22.1gr load it's slightly more accurate out of my gun than the 23.1gr load good to about 700yds but I sometimes need more speed for the distances I'm shooting. These are all with the 75gr bthp match Hornadys they should be very close to the 77gr. You will obviously need to work up what's best in your gun looking for pressure signs.