Teach me about overbore cartridges

[Bill Norton]

I have a Blaser R8, which is a multi-caliber rifle. I currently have a 30/06 and my next cartridge will be something fast and flat.
As I am researching calibers I'm learning more and more about overbore rifles and how they can blow through a barrel within 800 rounds or fewer. The question I have, as I try to pick a round, is what causes the rapid deterioration of the barrel? Is it velocity of the round or the shear amount of power that is ignited? In the long run I am looking for performance first but If I can have both then perfect because the barrels run about $1,200.
The calibers I have considered thus far is:
6.5x284
Nosler 28
Nosler 27 (new)
264 Win Mag
270 Weatherby

My shooting will mostly bee Midwest deer but want to be ready if an elk hunt comes up.

 

[Wolf76]

It's my understanding the over bored cartridges burn lots of powder relative to the size of the bore. This leads to excessive heat and unburnt powder acts like a sand blaster. Balanced cartridges like a 308 have an extremely long barrel life.
Add a 257 weatherby to your list of cartridges. It kills a lot bigger than it looks.

 

[Bill Norton]

It's my understanding the over bored cartridges burn lots of powder relative to the size of the bore. This leads to excessive heat and unburnt powder acts like a sand blaster. Balanced cartridges like a 308 have an extremely long barrel life.
Add a 257 weatherby to your list of cartridges. It kills a lot bigger than it looks.

I forgot to add 257WM to the list. Do you have one? I have always looked at that one too.

 

[Wolf76]

I forgot to add 257WM to the list. Do you have one? I have always looked at that one too.

Yes, I have one. Always amazes me how stuff just drops dead. Something about a 100 gr bullet going 3600 fps. But you'll only get 800-100 rounds before it's torched. Mines waiting on a new barrel right now.

 

[Bill Norton]

Yes, I have one. Always amazes me how stuff just drops dead. Something about a 100 gr bullet going 3600 fps. But you'll only get 800-100 rounds before it's torched. Mines waiting on a new barrel right now.

That's good to know. I am not a good tracker, maybe a little color blind with red. Wanting a minimum blood trail without launching a ballistic missile at it is always a plus.

 

[JMW67]

I have a Blaser R8, which is a multi-caliber rifle. I currently have a 30/06 and my next cartridge will be something fast and flat.
As I am researching calibers I'm learning more and more about overbore rifles and how they can blow through a barrel within 800 rounds or fewer. The question I have, as I try to pick a round, is what causes the rapid deterioration of the barrel? Is it velocity of the round or the shear amount of power that is ignited? In the long run I am looking for performance first but If I can have both then perfect because the barrels run about $1,200.
The calibers I have considered thus far is:
6.5x284
Nosler 28
Nosler 27 (new)
264 Win Mag
270 Weatherby

My shooting will mostly bee Midwest deer but want to be ready if an elk hunt comes up.

I am not familiar with the r-8 wont mag length and bolt face dictate what round you can change to This is a question as I do not know

 

[Bill Norton]

I am not familiar with the r-8 wont mag length and bolt face dictate what round you can change to This is a question as I do not know

Yes, It is a very complicated firearm. I can switch out bolt faces to accommodate everything from a 223 to a 338 Lapua.
This is a video that explains it:

 

[JMW67]

wow that is interesting learn some thing every day thanks I would add either 7mm rem mag or the 7mm weatherby to your list both flat shooting and not to hard on barrels

 

[Quintus]

The .270Wby will amaze you. It is the best kept secret in the shooting world right there in plain sight. It can go from lazer to thumper with minimal recoil like no other. You may not get quite the barrel life of the 7 mag, but it is far better than the .257Bee. I have both and while the 257 is that SUPER hot chick that pops your eyes out, the .270Wby is the one you want to marry. She still looks great at the ball, gracefull and elegant, but when times get tough you know she can handle that side of it too.

 

[Bill Norton]

The .270Wby will amaze you. It is the best kept secret in the shooting world right there in plain sight. It can go from lazer to thumper with minimal recoil like no other. You may not get quite the barrel life of the 7 mag, but it is far better than the .257Bee. I have both and while the 257 is that SUPER hot chick that pops your eyes out, the .270Wby is the one you want to marry. She still looks great at the ball, gracefull and elegant, but when times get tough you know she can handle that side of it too.

That was beautiful. I almost teared up!

 

[Aoudad shooter1975]

I have owned a blaser since the late 90s. And a R8 since 2009. Great guns but one thing to remember. They tend to like factory seating ...standard OAL. I had 8 barrels for my R93..most were fabulously accurate. The 257 especially a true one hole rifle. It loved 100 grain bullets. I also had a 264 win. It was awesome 3/4 MOA with **** near everything you fed it....now on the flip side. The 6.5-284 in my R-8...while fabulously accurate with 100-120s. It was 1/2 to 3/4 with 143 ELDs but 147 it was lackluster. The 9.3x62 barrel was quite possibly the most accurate barrel I ever owned. For a bigger bore--a true one hole rifle. Enjoy your R8. I gave up on blaser when they started poking my eyes out on scope mounts,the first set I bought were around $200 the last set was $500. Great accurate system that you do not have to tune that much--and they flat out work. The are also great to travel as they takedown--the first pic is of my first R8 in a 30-06 simi-weight and a last light Gemsbok , next is my wife with my R93 257 WBY in Africa . Out of the list you gave and my experience with Blaser I'd go 264 win mag. Again Enjoy!

 

[MagnumManiac]

The truth of the matter with serious overbore is the fact that you have to scrub the bore more frequently and slow fire. When you fire it fast, the throat wears so fast that it is elongating with every single shot. The haze cracking can be bad, but as long as the bullet is still engaging the lands without stripping, then accuracy will last, it's the slipping/stripping that causes accuracy to drop off.
The trick is to use cooler powders, double base powders generally have a higher joule number, but actually give more energy with less heat/flame.
I have had 6 264WM barrels, all of them have had 1500 rounds through them before the throat was so bad that the rifling was almost non existent for a good 4". Frequent bore scrubbing prolonged the life for each another 1000 rounds with just over MoA accuracy.
This is pretty good going in such a cartridge.

Cheers.

 

[shootallday]

Me being cheap, one thing I would consider is get the barrel in a cartridge that after you burn that very expensive barrel up you can have it rebored so it can have a second life.

 

[mike hunt]

That was beautiful. I almost teared up!

GOLD