Low velocity #'s for 308

[rifleman1]

Hello all,
I have a custom rifle with a 22" kreiger barrel chambered in 308. I am shooting 155 Lapua scenars, I placed the chrono at exactly ten feet in front of the muzzle. I run pretty hot loads in my rifle but the chrony shows I am getting 2720fps. I feel the reading is good because I used our other chrony and got almost the same numbers. I see numbers from others saying they are getting 2950 out of their rifles with 155 scenars. What gives? TIA
mike

 

[Dans40X]

Sounds correct for a 22" 308 w/ 155's.
You didn't mention twist rate-

Try another powder besides Varget or RL15!!

46-47gr of 4064 out of a steel can, loaded in URBR cases is my go to load w/ 155's.

 

[Forum Boss]

The guys I know getting 2950 from a .308 with 155s are using long 30-32" Palma barrels. Keep in mind that two barrels the same bore diam. and length can vary by up to 160 fps or so.

 

[MrMajestic]

Sounds about right to me also. I won't embarrass myself by telling you what I get from a 20" barrel or embarrass you telling you what I get from a 26" 13tw! You could try 3031 which will give you 100% burn(according to QL) and heavier bullets, depending on twist. I would think 4064 should be a pretty good fit in a 22". Your barrel and accuracy will dictate your choice. In the end, unless your shooting 1K, fps won't win matches or transform poor shot placement into "Hammer of Thor" terminal results!

 

[Keith Glasscock]

For 22" that sounds a little slow for a max load. On the other hand, component choices can really hurt the velocity. For example, running Federal brass reduces the velocity a little compared to Winchester due to differences in case capacity. Primers can also affect things more than a little.

If you are running short of powder room, Moly, HbN, and WS2 can be a detriment.

Questions:

When you say that you are running a pretty hot load, how are you defining that? It could be that you are looking at a false pressure sign.

Likewise, what powder are you using? You might need to change to a different powder to get the results you want. I think 8208XBR might be worth trying in a shorter barrel.

Lastly, how many rounds through the tube? If you are less than 200, don't sweat it. Stainless barrels have a defined velocity increase after 200 or so (sometimes 100, sometimes 300) rounds. If you haven't gotten there yet, you might well see the velocity jump up 100-150 fps.