Down range difference

[ajvigs]

If one was looking at a 18" barreled 308 versus a 7-08 sporting a 20-22" barrel, what would the down range difference be considering velocity and energy? Would it depend on the type of bullet used in each rifle?

May have another project on the fire [emoji6]

 

[Dwh7271]

I would think you're right on bullets.
The 7 would probably be a little faster w barrel advantage, probably a hair higher BC bullet.
It's the same case so a smaller bullet =a little more speed generally.
Although out to maybe 300, probably not a huge difference. And though it's done all the time w short barrels, if you need to stretch it out farther, I'd want more barrel.

 

[SJB358]

The 7-08 with a 20-22" barrel is just right, I think an 18" 308 is sorta on the short side. Just my opinion, but the 7 is going to win across the board to my mind.

 

[wildgene]

...Nosler actually shows a slight advantage in MV w/ the .308 (165gr./ 24") over the 7-08 (160gr./ 26"), but you would probably loose a significant amount of MV going to an 18" barrel. Energies & velocities of both bullets are neck & neck out to 500yds., started @ similar MV's, but the higher BC & SD of the 160gr. 7mm start to give it an advantage past 400yds.

 

[Ridgerunner665]

There is a formula for calculating the surface area of the base of a bullet....the larger base of the 308 bullet means the pressure is acting on a larger area, pushing harder if you will....same reason the Whelen can sling 200 grain bullets faster than the 30-06.

Downrange....BC comes into play, and always wins, past 500 yards at least.

I could explain that all a whole lot better, and I intended to but something came up, don't have time right now.

 

[Elkman]

Probably not enough to worry about. Sometimes I worry to much about "small" things like group size.

 

[Guy Miner]

Out to 300 yards, I don't think there's much of a difference between anything from the .243 Win up to the .30-06 for a "down range difference."

Yeah, there are differences, but I'd take a mule deer at 300 yards with any of them. Happily.

Regards, Guy

 

[Anonymous]

I've done a fair amount of shooting with carbine barrels.

My .308 Steyr with a 19" took a fairly large caribou at 300 and change. The bullet didn't perform great at that range...but I doubt 2 or 3 more inches of barrel would have made the difference there. I can't complain too loud- we ate well that winter.... I've rang steel and plunked groundhogs further than that...short barrels are no detriment to about any reasonable range but you may want a slighty softer or lighter bullet than you otherwise would choose.

My son took a nice caribou this year with a 20" barreled 7-08 at 150yds...again, not such stellar bullet performance that i doubt another 2" of barrel would solve that either.

 

[PJGunner]

My Ruger M77 RSI in .308 has an 18.5" barrel. The rifle is a one trick pony as it will only shoot one bullet and one specific powder charge and even with that is a 1.5" gun at best. Velocity is 2550 FPS with a 165 gr. Speer Hot Core. Switch to a 165 gr. Sierra Game King and it's back to shotgun patterns. That same load will do 2610FPS from a 2" Winchester M70 but the load is too hot for a custom Mauser. Dunno if the velocity difference between the two rifles is any help but that's what the chronograph told me. The load does shoot .80" groups average from the M70.
Paul B.

 

[Silent Sam]

I have a MKII RSI in 308. It shoots the Rem 150gr Corelokt load so well I haven't even bothered loading for it.

 

[lcq]

I have a Savage 10fp 20" 308. It shoots hot, cold, clean dirty and the cold barrel shot is no different than hot. I have run Barnes ttsx 150gr to 2800 but the BC is pathetic. 180 accubonds at 2570 nets me 0.5" groups and retains 1500 lbf out to 400 yds. you lose about 25fps for every inch with a 308