Help With .308 Win Data

[Squid556]

I’ve had a curiosity in my mind about how much faster .308 Win can push the heavy 178 grain class of bullets if they are single loaded, or used in a long action. Not being bound by short action magazine length.

Trouble is finding data on “max length” 308. I understand each rifle will be cut slightly different and OAL will vary on bullet selection. Im just wanting to get a rough idea if the gains by putting the bullet farther out are actually worth pursuing.


Thanks

 

[mcapo]

I would think the first piece of data you’ll need is your CBTO measurement to the lands of your specific LA rifle and selected bullet?

Then you can look at case capacity, compression, pressures, velocity etc?

Maybe search for “old” m24 308 max loads?

You can single load really long in a SA 308, only issue might be that you would have to remove the bolt to eject a loaded round.

Maybe just go for long action cartridge?

 

[Leo]

Moving the bullet out will not make significant performance difference, certainly not enough to make it worth building another rifle (not that there is anything wrong with a new rifle) Since a .308 is basically a short 30-06, you could always got to 30-06 in that long action. They are still pretty easy to find. If you just really want a wildcat caliber you can look into a .308 Ackley improved. There is always .308 WSM but you would need to change the bolt face.

Good Luck, have fun.

 

[Creedmoor]

You can single load really long in a SA 308, only issue might be that you would have to remove the bolt to eject a loaded round.

Maybe just go for long action cartridge?

sorta, I have a single shot 40X SA in 300WM.
If I eject a loaded round it just drops it in the action.

 

[gassprint1]

I would think by putting the bullet farther out you would lose a slight bit of pressure meaning there will be less time for pressure to build before the bullet exits the case neck. If you use a longer bullet but the same amount is seated in the case as a standard bullet, then i would think bullet weight increases. As @Leo said, your just looking more to 30-06 length and then comes the debate..which is better..308 or 30-06. I have shot a 308 but i own a Remington 742 30-06 rifle. I guess it depends on distance you're wanting to shoot out to.

 

[DadSmith]

I’ve had a curiosity in my mind about how much faster .308 Win can push the heavy 178 grain class of bullets if they are single loaded, or used in a long action. Not being bound by short action magazine length.

Trouble is finding data on “max length” 308. I understand each rifle will be cut slightly different and OAL will vary on bullet selection. Im just wanting to get a rough idea if the gains by putting the bullet farther out are actually worth pursuing.


Thanks

I say do a plunk test for maximum OAL then start loading mid charge of powder of your choice. If you want speed CFE 223 loves to be loaded to maximum charge it actually preforms better accuracy wise than its lower charge.
Then load up 50rds and jump 0.2gr for each 10rds.

CFE 223 maximum charge is 47.5gr for 175gr.
I'd start at say 46.5gr and work up 0.2gr from there. Reason for only 10rds of each is if you start noticing pressure signs you only have to pull a few. Once you get above recommended maximum powder charge.
Reason I think CFE 223 would be best to test for velocity is its one of the faster velocity for the 175gr but it isn't compressed like most of the other powders which will give you some room to increase over maximum recommended charge. Just be careful not to compress the load as that will raise pressure quickly.

I know 175gr is 3gr lighter than what you want 178gr. But you can lower the charge as mentioned and work a load up from scratch.

 

[Squid556]

I probably should have been more specific in the OP.

The interest is the additional case capacity gained, when a deep seated bullet is allowed to be loaded farther out than normal.



I figured I’d have people ask why not get a long action caliber. That’s missing the point of the question.

Leave it to ingo to try and convince me to buy more guns

 

[Leo]

Leave it to ingo to try and convince me to buy more guns

Not that there is anything wrong with that!

 

[Hawkeye7br]

As Leo said, merely seating the bullet farther out usually gains very little, especially if the powder in the case is already into the shoulder or near max.

If it was simply a matter of seating bullets farther out, all those Ackley Improved cartridge designs would never have been invented.