Does longer free bore reduce barrel life?

Hodmedod.one

Well-Known Member
If all goes well I should get the opportunity to do some Bear hunting in Canada in the near future. I have spoken to my FEO and he says I can have a .30 cal to use on Deer in the UK that is also suitable for Bear.

Looking at the muzzle energy of various .30 cal ammunition, I like the idea of having a .300 win mag or .300 Weatherby for Bear. I know that the Weatherby is going to be more expensive to reload ammo for.

I have seen that the Weatherby range of magnum barrels are produced with a long freebore (.361" for a .300WM) as this is how they achieve higher velocities than other makes.

Is this going to seriously reduce barrel life?

Is a stainless or blued barrel more susceptible to burning out?
 
I am struggling to think of a physical reason why a longer freebore would increase velocity.

You can use a load that would otherwise be overpressure. This may have been more true several decades ago, compared to new powders/loads like Reloder series, Superformance etc.
 
If all goes well I should get the opportunity to do some Bear hunting in Canada in the near future. I have spoken to my FEO and he says I can have a .30 cal to use on Deer in the UK that is also suitable for Bear.

Looking at the muzzle energy of various .30 cal ammunition, I like the idea of having a .300 win mag or .300 Weatherby for Bear. I know that the Weatherby is going to be more expensive to reload ammo for.

I have seen that the Weatherby range of magnum barrels are produced with a long freebore (.361" for a .300WM) as this is how they achieve higher velocities than other makes.

Is this going to seriously reduce barrel life?

Is a stainless or blued barrel more susceptible to burning out?

why not consider changing a 30-06 to 338-06?
 
I have a very nice and little used (less than 100 rounds) 300 Weatherby Mag I no longer require. if you're interested I can put some pictures up?

Once used brass and dies too if required.

Cheers

K
 
A taster of the "real deal":



IMG_3338_zps070adf80.jpg



IMG_3337_zpsd6dcd5b4.jpg
K
 
I know where there is a little used original mk5 .300 wetherby for little money with rings brass dies loaded rounds pm if you want details
 
I would say buy the rifle that you can get the ammunition for both species you intend to hunt here or Canada ,
If you intend to reload the free bore is not a problem , load to mag length and should you need a second round its there in the mag ,

Cheers
 

I wouldn't put much credence into that thread. "I think Sako has a lot [of freebore]". Well, he clearly has no experience of Sako, otherwise he would have said so. I have owned six Sako rifles (a mix 223, 243, 7-08, 30-06) and all of them had minimal freebore. What a long freebore does is lower peak pressure. Weatherby rifles deliver high velocity. If they have long freebore it isn't so that "the bullet to get a running start before hitting the lands", it's to reduce peak pressure. No doubt Weatherby factory ammo uses a slow burning powder, which maintains peak pressure for longer compared to a fast burning powder to achieve the high velocities. I have a Valmet combination gun, which has a break barrel shotgun type action. The rifle barrel has a lot of freebore (more than 1/4 inch). This reduces peak pressure, hence reduces back thrust on the cartridge and standing breech face which is weaker than a turn bolt action. The reduced back thrust resulting from the generous freebore means the Valmet can fire full power factory ammo without any concerns.

As for barrel life, lower peak pressures means less gas erosion. Therefore, all other factors being equal, a long throat should result in longer barrel life. But if barrel life concerns you, stay away from high velocity magnum rifles, stick with a 30-06 for example.

I presume you are going for black bear? I have hunted black bear twice in the mountains of Idaho (Selway Wilderness area). There were bear around, one trashed our spike camp while we were out looking for elk. I didn't get to shoot that bear - or any other - though my hunting partner did. She shot a barren sow, estimated at 12 years old. She used a 7mm Mag but her choice of rifle was steered by a) what she owened and b) we were primarily after bull elk. Had we been going for just bear, she would have taken a .308 or similar.

On my first trip I took a 30-06 loaded with 180gr Hornady Interbond, and on the second I took a 7-08 loaded with 154gr Hornady Interbond and in neither case was I undergunned. The guide uses a 30-30 on black bear, and he has plenty of evidence as to its effectiveness in the form of hides on the walls of his house. You don't need a 300 magnum to kill a black bear, just one good well placed shot. You might consider using a larger bullet (such as a .35 Whelen) instead of throwing a .308 bullet faster than necessary. But if you fancy owning a Weatherby, go ahead and get one. :)

-JMS
 
Sorry klenchblaize I didn't mean to p1ss on your bonfire or pinch your glory I can assure you ! I was just trying to helpful be to homedod .
 
I suppose you might limit the capacity to gradually seat the bullets longer to maintain consistent jump to the lands as the throat wears and so you might have to set the barrel back or replace it after a lower number of shots fired... But the factors that are said to cause throat wear are probably more important, i.e. neck length, shoulder angle, quantity of powder burned and if it is 'overbore'. I don't think I would really worry about any of them much for my hunting rifle as barrels are essentially a consumable item (like bullets and powder), unless it was very expensive or an irreplaceable classic that would be ruined if re-barrelled.
 
It should be mentioned that true 'freebore' is different than just having a long throated chamber. With real, engineered-into-the-equation freebore, rifling is reamed to the barrel's groove diameter which (we should hope) is very close to nominal bullet diameter. I have two rifles chambered in this fashion and both are extremely accurate despite having been shot regularly over the last 4 decades.

Some time back, when the International Handgun Metallic Silhouette Association was holding 200M pistol shoots all around the US, I build a 7mm Bench Rest for a guy on a Remington XP-100 pistol using a reamer he designed which had 1.5 calibers of freebore in a 15" barrel. The cylindrical section was .2855" IIRC. His hope was to increase his velocities without increasing pressures, ala Roy Weatherby. It really didn't pan out. His velocities were about comparable to his factory barrel XP 7mmBR with about all powders and bullet combos. Only when he started to push the pressure limits did he get any real gains. It was an accurate, sub MOA gun, but the freebore did nothing in the short run. ISHMA comps died out in favor of the NRA sponsored shoots and I lost track of the guy so I have no idea about longevity of that barrel.~Muir
 
Sorry klenchblaize I didn't mean to p1ss on your bonfire or pinch your glory I can assure you ! I was just trying to helpful be to homedod .

No problem and feel free to urinate on whoever's freebore you like!

Did anyone mention that to the less educated chap such as K a poor man's freebore is a nicely eroded throat??

Breakout the JB Bore Compound.

K
 
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