Burned throat

Thanks for the information guys.
My rifle is a 10 twist and I have tried 139, 150, 154, 160, 162 and 175 of 4 diff. brands. The 139's opened up to about 6" so wont use them much. I don't want a diff.. case as I have all reloading equip for the Weatherby mag. so want to stick with it.
Who makes barrels for the 7mm WBY with shorter free bore?
AIRBORNE

PDRENNER said:

Thanks for the information guys.
My rifle is a 10 twist and I have tried 139, 150, 154, 160, 162 and 175 of 4 diff. brands. The 139's opened up to about 6" so wont use them much. I don't want a diff.. case as I have all reloading equip for the Weatherby mag. so want to stick with it.
Who makes barrels for the 7mm WBY with shorter free bore?
AIRBORNE

Click to expand...

The problem is not with the Weatherby case... It's with just about every Weatherby cartridge reamer... They were all designed to SAAMI spec, which includes that massive freebore. Unless you find someone who has a custom spec'd reamer, you will never eliminate the freebore issue. That is just one of the main reasons I recommend folks go with a 7mmRM over a 7mm Wby. They are also nearly identical ballistically (real world), despite some of the biased reloading manuals.

PDRENNER said:

Thanks for the information guys.
My rifle is a 10 twist and I have tried 139, 150, 154, 160, 162 and 175 of 4 diff. brands. The 139's opened up to about 6" so wont use them much. I don't want a diff.. case as I have all reloading equip for the Weatherby mag. so want to stick with it.
Who makes barrels for the 7mm WBY with shorter free bore?
AIRBORNE

Click to expand...

Maybe some of the other Weatherby aficionados will chime in. I've only had one Weatherby that would not shoot under an inch without any work whatsoever. That would include three .340, one 7 mm, a .257, a .270 Winchester in a 6 lug ultra light, and a .25 caliber and a 6.5 caliber Wildcat on a 6 lug Weatherby. So you shouldn't have trouble getting one set up that's really going to work with your 7mm Weatherby.

As I stated in another thread I own 4 Weatherby's and find that I get good accuracy with them. My 257 shoots .7 with it's best load , my 270 WM groups .7-.8 and my 30/378 is MOA at 100 yds. My best is my 7mm Wea mag which groups ..6-.7 at 100 yds with the 145 Barnes LRX and max loads of MRP. For all guns I began to load at max magazine length (OAL) and went from there.

If you really want to get past the long Throat on a Weatherby cartridge you'll need to define your own reamer and have it made. Then have a barrel chambered with that new reamer.

Thanks to all for the information.
What about the 7mm on a 300Win Mag case, will that fit in my mag well which is 3.368? But that would require new brass, dies and a new barrel oh well just a thought!
Mudrunner, why do you say the 7 Rem mag and the WBY mag are, "nearly identical ballistically" ?
AIRBORNE

PDRENNER said:

Thanks to all for the information.
What about the 7mm on a 300Win Mag case, will that fit in my mag well which is 3.368? But that would require new brass, dies and a new barrel oh well just a thought!
Mudrunner, why do you say the 7 Rem mag and the WBY mag are, "nearly identical ballistically" ?
AIRBORNE

Click to expand...

Unfortunately the .257, .270, & 7mm Wby rifles have a magazine block plate in them, which limits the OAL length. If you had started with a .300 Wby rifle, it would not have the shorter mag box and follower, and would be a better donor for anything longer/larger than the 7mm Wby & 7mm RM.

As for the ballistic comment... I say that because I have heard my whole life people touting that the 7mm Wby is supreme in velocity to the 7 Rem Mag because of biased reloading manuals and some magical properties bestowed on it by the Weatherby supporters, but in real-world testing where chronographs are relatively affordable for the common man, this has proven to be a misconception. The 7mm RemMag has proven that despite the slightly higher case capacity of the 7mm Wby, they are nearly ballistic twins. So, in the name of trying to dispel ancient myths, I like people to know that if they are looking for a cheaper and more common alternative with a better designed SAAMI reamer (less freebore), they won't be giving up anything by going to the 7mm RemMag.

I had bob hart do my last wby. Left the freebies in and it shoots great very little load work up.

Who is Bob Hart?
AIRBORNE

I've had good luck getting SubMOA accuracy in a 240,257, and 300wby. Best results have been with heavy for caliber bullets, my theory is the long bullets resist yawing as they enter the lands. It could be as simple as a poor barrel and there is no good load.
If you're considering a custom barrel and plan on reloading, choose the bullet you want to shoot, the amount of freebore can be made to suit a particular bullet, whether it's a 7mmwby or 7rem mag.

Thanks to all for the good information.
AIRBORNE

I too have noticed that Wby velocities are a bit overblown. I had a 300 Wby many years ago and used it extensively for hunting everything from small deer to very large moose. Accuracy was great until the throat began burning out. I put a new barrel on the rifle in 300 Win with a long throat so I could seat long bullets out and use the full length of the mag. and found I lost nothing in velocity.

Factory Weatherby ammo is the only ammo I chronoed that matches the claimed velocity.

Canhunter35 probably just revealed one of the biggest secrets in reloading! Long bearing surfaces on heavy for caliber bullets will line up better in the freebore, leading into the rifling, when compared to a shorter bearing surface in the same gun, period!

Think about it this way, if the freebore has a diameter that is usually .0005" over the diameter of the bullet the bullet is at maximum yaw when the front of the bullet is touching the bottom of the barrel and the rear of the bullet is touching the top of the barrel. The bullet can not yaw any more than this. If that bearing surface is elongated, for example a 195gr. 7mm EOL, vs. a 162 gr. VLD (Both Bergers), then the maximum amount the bullet can yaw is far less. When you solve for degrees off axis of the bore.

I believe this is why the SMK has such a reputation for accuracy. It has NOTHING to do with the radius of the ogive. The SMK has a comparatively, very long, bearing surface which aligns the bullets in the FREEBORE, almost immediately.

Long story short, I would look hard at a new barrel (sounds like your's is probably shot, or just have it set back if you can), keep it 7Wby. since you have all the equipment and make it a 1:8 twist, then shoot the 195's or if you really don't like bullets that big run a 160 Accubond or something similar. You really won't give up much in trajectory with the increase in velocity until you are probably past 500 yards. And let's be honest, shots past that distance are definitely the exception for 90% of us, even in this forum.

Just my thoughts, good discussion!