Lenght of barrel and its effect on velocity

duke1

duke1

CGN frequent flyer
EE Expired
Rating - 100%
87   0   0
Location
Ottawa Area (Quebec side - <5 km from Parliament H
I have a very important decision to make regarding a barrel on a Weatherby 300 WBY Magnum with a length of 26" plus a muzzle break extending the barrel by about 1.5 inches.

I would like to hear your comments on what reduction in bullet velocity could one expect by reducing the barrel length by about 5 inches. I realize that powder, bullet weight, etc, would all be factors in addition to the final length of the barrel.

In my case, because of a damage to the barrel, I either need to cut it down by about 5 inches or replace the barrel with a new one at a cost of around $500. This gun is a show piece and will probably never hunt but if it does, the biggest game that it will ever encounter is an eastern moose.

Also, I want to make sure that the gun retains its value and I'm afraid that a shorter barrel (final overall length with muzzle break being around 23") on a gun like this might bring the price down considerably. The gun is a Weatherby Mark V Lasermark retailing between $2k and $2.4k.

All comments are welcome.

Duke1
 
depends what the case-capacity to bore ratio is. A hugely overbore cartridge like a 22-250 will gain a lot more from a longer barrel than a Hornet, for example. There are no rules of thumb here that apply to all cartridges. My 'rules' say that I will not get a rifle magnum less than 24" (preferably 26") to avoid excessive muzzle blast and performance hit. Something like a 44 mag in a lever gun wouldn't gain much going beyond an 18.5" barrel, whereas a 7 mag would see a HUGE gain between 18.5" and 24"


In your case, if it were MY rifle, I'd consider that barrel to be a write off, and replace it or maybe consider re-boring it to a .358 or .375 of some sort (to reduce the over-bore ratio)
 
^ I'd say he's lose even more than that. 23" WITH the brake, which is ~4" long maybe? So pressure is basically lost at just 19"

It'd be fun to watch the massive fireball, if nothing else. I'd wager than an '06 in a 24" bbl could hold its own against a 300wby in a 19"
 
Yeah, if it was a .308 I'd say cut it, but that's an overbore cartridge, not going to be terribly pretty in the shorter pipe, though light bullets would certainly still fly fast. I'd have to say rebarrel, but might as well pick a better cartridge when you do :) Bonus. Look at it as an upgrade. :)

What kind of damage by the way?
 
Ardent said:
Yeah, if it was a .308 I'd say cut it, but that's an overbore cartridge, not going to be terribly pretty in the shorter pipe, though light bullets would certainly still fly fast. I'd have to say rebarrel, but might as well pick a better cartridge when you do :) Bonus. Look at it as an upgrade. :)

What kind of damage by the way?
Click to expand...

It's a minor bulge in the barrel approx 5 inches from the end of the rifling. An area of the bore approx 1/4 to 1/2 in length is somewhat enlarged and the bulge is visible on the outside. It has been suggested that I should try shooting it like that and see how it performs.

I bought the gun recently for less than $800 (gun retails new at over $2k)and can easily justify any kind of appropriate repairs. I will be going to the Eganville gun show and will look for a barrel there as you have convinced me to re-barrel.

As far as the caliber, I would like to keep it a 300 WBY magnum as I already have a number of 300 WM, a 7MM, a 7MM WBY magnum, a 270, a couple of 358s and a 35 Whelen.

Thanks again for all your valuable input,

Duke1

PS. This is one of my sharpest looking gun with the Lasermark features.
 
duke1 said:
It's a minor bulge in the barrel approx 5 inches from the end of the rifling. An area of the bore approx 1/4 to 1/2 in length is somewhat enlarged and the bulge is visible on the outside. It has been suggested that I should try shooting it like that and see how it performs.

I bought the gun recently for less than $800 (gun retails new at over $2k)and can easily justify any kind of appropriate repairs. I will be going to the Eganville gun show and will look for a barrel there as you have convinced me to re-barrel.

As far as the caliber, I would like to keep it a 300 WBY magnum as I already have a number of 300 WM, a 7MM, a 7MM WBY magnum, a 270, a couple of 358s and a 35 Whelen.

Thanks again for all your valuable input,

Duke1

PS. This is one of my sharpest looking gun with the Lasermark features.
Click to expand...
Why not a 358 Norma mag? If you've already got some 300WM's, you're not gaining much going to wby. The Norma is much more potent than the 358 and Whelen, bordering on 375h&h territory. I also perceive a lack of .338 bore goodness in that list ;) If you want to stick to a wby cartridge, the 340 is a good one
 
prosper said:
Why not a 358 Norma mag? If you've already got some 300WM's, you're not gaining much going to wby. The Norma is much more potent than the 358 and Whelen, bordering on 375h&h territory. I also perceive a lack of .338 bore goodness in that list ;) If you want to stick to a wby cartridge, the 340 is a good one
Click to expand...

Thanks for the suggestions.

I do have a 338 WM but will definitely consider the 340 Wby Mag as a possibility. It is slightly more more powerful than the 338 WM.

Duke1
 
See your ad on the EE :D

As mentioned above, you can also use a Remington bbl, the thread is the same pattern (IIRC), so will only require timing. And the wby cartridges mentioned all use the same case head as their winchester brothers, so you could get by with a Remington barrel in 300WM or 338WM, and running a wby reamer into it :D

Cheers!
 
You must log in or register to reply here.
Back
Top Bottom