I realize the 24 inch bbl would be the more preferable one for hitting out to 1,000 yards but how much of a "penalty" would I incur with a 22 inch using 168 & 175 loads at this distance.
M14NM match rifles have won a lot of matches and set many records with .308 Win and 7.62 NATO cases stuffed with 172 to 185 grain match bullets shot from match grade 22" barrels. But they usually didn't shoot 168's out fast enough to keep them supersonic past 900 yards.
You'll probably be penalized using 168's but not with heavier ones. 168's have been used successfully with max +P loads in tight groove diameter (.3075" or smaller) barrels in higher elevations and hotter temperatures when the air is less dense.
Just remembered that Sierra's. .308 caliber 180-gr. HPMK bullet has the same boattail as the 168. It too, proved to go subsonic around 900 yards when shot from M14NM's 22" barrels. The longer boattail on their 175's lets them stay supersonic through 1000 yards. That's why it replaced the 168 in military match/sniper ammo. Sierra's earlier 180 HPMK had a long boattail and was the favorite long range target bullet for the M14NM rifles.
Every barrel is different. If you were to cut 2" off a barrel that you had previously tested for velocity you'd see about 10-25 fps for each inch you cut. That would vary depending on the individual load and gun of course. And there is a bigger penalty with heavier bullets.
You will see more variance than that between barrels of the same length. I've seen 22" barrels on individual guns shoot faster than 24" barrels on another gun.
It also varies by length. A 308 is in its sweet spot between 20-24". You see very little difference with any of those lengths. Once you start getting shorter than 20" you'll see speed drop off in bigger increments as you go shorter. Going longer than about 24" will see smaller increments in additional speed.
Generally 2" either way is more about how the gun looks and balances to you than speed. Once you start talking about 4"-8" differences then it does start adding up and making a difference.
The Berger 168 hybrid is a good bullet, doesn't have the boat tail issue the Sierra 168 has. The 168 VLD is seating depth finicky like most secant ogive bullets.
The 175s haven't proved to be more popular than the Sierras with the folks shooting F Class, but there are two flavors of 175gr bullet offered by Berger as target bullets too.
as someone with a howa GK 1500 in 308 with a 22" barrel (actually i really wanted this barrel size for easy of storing )
i can tell you its still bloody accurate, ive been putting bullets through the same hole on my stock howa GK, and its basically my designated tac driver now, only thing that comes close is my m1a with a Leopold and is modified to be a higher in accuracy than a stock m1a (civilian m14 if you dont know the m1a designation)
nutnfancy did a video on the howa giving it a 9/10
the only issue i had is i forgot to loctite my scope base down initially and that gave me odd groups , still was hitting in black at 300 so , just goes to show the rifles dependability in my book
