308 -Ftr speeds?

BELOWaverageIQ

I am just wondering ( for any of you who have chronographed) what speeds are being achieved in .308 with the 30''-32'' barrels.

Thanks in advance.



Don't all rush in at once lads ha ha :-)

Cass

Sorry.

Don't know how this sneaked pass me. Anyway i got to try some ammo today, and instead of taking readings of the box i brought the Chrony. I only had 200gr and 190gr with me. I'll get around to the rest at some stage.

200gr

Average velocity of 2564fps. ES = 26. SD = 35.

190gr

Average velocity of 2717fps. ES = 24. SD = 15.


Savage action, TruFlite 32" barrel. 1:10 twist. Chrony at 5 feet. HPS ammo. HPS brass. SMK heads.

ranger4

Anyone had good results with the 208g amax with their 308, Heard some shooters gaining good accuracy with the 208g amax with re17 or n550 with shorter 308 barrels.

Tackleberrywho

Ezridax wrote: »

Sorry.

Don't know how this sneaked pass me. Anyway i got to try some ammo today, and instead of taking readings of the box i brought the Chrony. I only had 200gr and 190gr with me. I'll get around to the rest at some stage.

200gr

Average velocity of 2564fps. ES = 26. SD = 35.

190gr

Average velocity of 2717fps. ES = 24. SD = 15.


Savage action, TruFlite 32" barrel. 1:10 twist. Chrony at 5 feet. HPS ammo. HPS brass. SMK heads.

That seems like a large standard deviation?
Or is that 3.5 and 1.5 which would be Excellent?

I had HPS .308 1/12" Standard deviation 12
SD for Hornady Tap 155 Grain was 9 which I was well pleased with for factory ammo.

Cass

Tackleberrywho wrote: »

That seems like a large standard deviation?
Or is that 3.5 and 1.5 which would be Excellent?

Nope. Its 35, and 15. Thing is do not get too hung up on numbers. Just back from the range and the 190gr shot excellently in the wind and were extremely consistant. I remember reading an article by John Whiddon. He said during his load development he had an ES of 9 and SD of 1 (or something to that effect). Went out to range and shot 1,000 yards. The shots were all over the place and the group was poor. Now remember he is a world class shooter so his idea of bad and ours could be slightly different.

Anyway he stayed on the range and tweaked the loads, and went out and shot the new ammo at 1,000yds. No chrono, ES/SD measurements, etc. Just excellent groups and high consistancy. When he went back in he then took out the chrono and got the ES/SD. Results were somwhere in the region of ES-22, SD - 14. So according to the numbers they should have been a poorer round yet they shot better.


As he said himself, if you have access to a 1,000 yard range forget the chrono at the start of the load developement and concentrate on the grouping. Then chrono and measure after if you want.

I had HPS .308 1/12" Standard deviation 12
SD for Hornady Tap 155 Grain was 9 which I was well pleased with for factory ammo.

Did you do this yourself with a chrono? How many rounds did you use to get this figure?