Re-barreling .308 to something big?

[marksman1941]

I appreciate all of the great suggestions folks! I knew y'all would have some ideas.

I think my top three currently are
1) 45 raptor, although there's not a ton of info out there on it
2) 375-08. I don't mind expensive bullets, as long as I can get some that expand in the right velocity range for a 16" barrel
3) 338 federal, and probably hot rod it some to get some decent velocities. Putting this in a bolt gun I should be able to in above published pressures that are most likely set for a lever gun.

 

[Ark. Trapper]

I did a 375 Raptor. I'm pushing a 270 grain Speer BTSP at 2450 fps in my 22" bbl. That's 3500 ft-lbs at the muzzle, 3000 ft-lbs at 100, and 2500 ft-lbs at 200 yards. I wanted a hard hitting thumper that I could also reach out to 300+ with if need be. I looked at all the options you listed but when you run the numbers the 375 wins out in my opinion.

 

[Dean2]

I did a 375 Raptor. I'm pushing a 270 grain Speer BTSP at 2450 fps in my 22" bbl. That's 3500 ft-lbs at the muzzle, 3000 ft-lbs at 100, and 2500 ft-lbs at 200 yards. I wanted a hard hitting thumper that I could also reach out to 300+ with if need be. I looked at all the options you listed but when you run the numbers the 375 wins out in my opinion.

Agreed. That is GREAT performance out of a 308 case. Within 350 FPS of the375 Ruger with a 270 grain bullet and with about half the powder. Fits right in with my earlier suggestion of the 9.3/08.

 

[Wolf76]

How does it feed from the bottom metal?

I'm in a similar place, I've got a couple donor guns (kimber and a seven) in 308 for building a bigger bore small thumper for my wife. The easy button is jes for 358 or 338, but the minimal bore gains doesn't offset the decrease in Bullet selection.

The 45 raptor looks good but when I talk to various builders they all end up with an aic mag to keep the 250 grain projectiles from nose diving.

Big bore 308 bolt face is a quandary.

The nose dive did happen wth the savage mag. 2 things really helped it. Adding springs to the the Z metal under the slide plate and pointed bullets. Bear creek ballistics and Maker T Rex bullets make great bullets with pointy tips. I shoot the non tipped bullets just fine, but it isn't perfect. Never had an issue in the field though, but I've only once shot at a running deer with it...and it worked like it should.
I'm working on a 44 cal belted cartridge that will beat all the other straight walled stuff right now, but it has a mag bolt face.

 

[marksman1941]

I did a 375 Raptor. I'm pushing a 270 grain Speer BTSP at 2450 fps in my 22" bbl. That's 3500 ft-lbs at the muzzle, 3000 ft-lbs at 100, and 2500 ft-lbs at 200 yards. I wanted a hard hitting thumper that I could also reach out to 300+ with if need be. I looked at all the options you listed but when you run the numbers the 375 wins out in my opinion.

Running those numbers, and adjusting to a 16" barrel (assuming a loss of 30fps per inch) that puts me right at 3000ftlbs muzzle energy. Which is substantial to say the least. Was that in an ar10 platform or a bolt gun?

 

[Ark. Trapper]

Bolt gun. I don't do AR's. I don't believe you're gonna loose as much as you think by dropping to 16", which is why I may chop mine down before deer season.

 

[marksman1941]

Bolt gun. I don't do AR's. I don't believe you're gonna loose as much as you think by dropping to 16", which is why I may chop mine down before deer season.

The more i research the 375 raptor the more it seems like it is indeed the biggest I'm going to be able to make here. Seems very close to the 375-08 (or identical). Surprising how much velocity they're getting with heavy bullets

 

[Ark. Trapper]

The more i research the 375 raptor the more it seems like it is indeed the biggest I'm going to be able to make here. Seems very close to the 375-08 (or identical). Surprising how much velocity they're getting with heavy bullets

It really is a ballistic anomaly. It is a very, very efficient cartridge. It's a versatile little **** too.

 

[marksman1941]

It really is a ballistic anomaly. It is a very, very efficient cartridge. It's a versatile little **** too.

I briefly looked at it a while ago when checking out some oddball ar15 uppers but dismissed it before doing too much research. But it really does seem versatile as heck. Whether I end up suppressing it or not, it still looks to be an absolute hammer inside 250 yards.

 

[Dean2]

It really is a ballistic anomaly. It is a very, very efficient cartridge. It's a versatile little **** too.

It is not actually an anomaly. The reason it works so well is large bore, fairly heavy bullet and relatively fast powder. Good initial pressure but the large bore means you don't get the same high pressure to produce velocity you do trying to drive a heavy bullet down a smaller bore. Remember your high school math, area of a circle is pie x r squared so the area expands a lot with a .075 increase in bore diameter.

Applies to ordering pizza too.

 

[Ark. Trapper]

It is not actually an anomaly. The reason it works so well is large bore, fairly heavy bullet and relatively fast powder. Good initial pressure but the large bore means you don't get the same high pressure you do trying to drive a heavy bullet down a smaller bore. Remember your high school math, area of a circle is pie x r squared so the area expands a lot with a .75 increase in bore diameter.

Applies to ordering pizza too.

It may not be an anomaly but it's sure as h**l rare in the ballistic world. Lol

 

[Ark. Trapper]

I briefly looked at it a while ago when checking out some oddball ar15 uppers but dismissed it before doing too much research. But it really does seem versatile as heck. Whether I end up suppressing it or not, it still looks to be an absolute hammer inside 250 yards.

Suppressed with 325 grain Makers is absolutely Hollywood quiet. I wanted to do 350's or 400's but Paul said my 12 twist wouldn't stabilize em. The 325's hit like a freight train tho!

 

[comfisherman]

Bore helps a lot. Having played with wsm and rum variations its rather substantial the gain for equal weigh as bore increases. My 375 ruger gets the 270class bullets right near 2900, and single digits e.s in the mid 2800s. I do wonder how the tough jacket Bullet options will do with a 2400 launch speed.

How the bullet performance for those lower bullet speeds?

 

[Ark. Trapper]

Bore helps a lot. Having played with wsm and rum variations its rather substantial the gain for equal weigh as bore increases. My 375 ruger gets the 270class bullets right near 2900, and single digits e.s in the mid 2800s. I do wonder how the tough jacket Bullet options will do with a 2400 launch speed.

How the bullet performance for those lower bullet speeds?

So far all I've shot with it is a 100lb whitetail doe at 125 yards and the 270 Speer BTSP made a 1" exit wound and turned the lungs to mush. I plan on shooting a few more with it this fall with the 235 Speers and the 325 grain Maker subs