Throating a 270 Wby

[tbrice23]

I have an 8 twist 270 wby barrel for the 170gr EOL. My barrel arrived without the standard. .375" freebore.
I have .097" room in the magazine when the 170s are at the lands.
I my experience with the EOL bullets is they usually like around .100" jump.
My question is should I throat it .030", .100" or the full .375" freebore PAST my max magazine length?
Thanks.

 

[just country]

morning, smithy will use a standard 7wbee reamer on the barrel.
this will set the free bore, unless u want longer throating. this also
can b done. justme gbot tum

 

[tbrice23]

????
No one is going to put anything 7wby in this chamber.

 

[can1010]

have read on here to many times of people having terrible pressure problems when short throating weatherby chambers. some people are having success jumping .300. in my 270s I have had good luck with between .060-.090 jump. will your smith slowly add freebore until it shoots best without adding to your oal. leaving room to grow and stay mag feed

 

[tbrice23]

have read on here to many times of people having terrible pressure problems when short throating weatherby chambers. some people are having success jumping .300. in my 270s I have had good luck with between .060-.090 jump. will your smith slowly add freebore until it shoots best without adding to your oal. leaving room to grow and stay mag feed

So you are shooting 170s in a 270wby and have best accuracy at .060 to .090 jump?

 

[can1010]

not a 270wby I have 270-338 rum imp and had a 270 wsm for a while both liked to have some jump never had any luck close to lands.

 

[tbrice23]

Thanks.
I bet that 270-338 is a hot rod for sure!

 

[can1010]

99 gr RL-50 170 Berger or 165 Matrix 3350 27 inch rock creek and there is more to go but best accuracy is 3280. you have to see it with the 126 Hammer Hunters 3700 fps and it is accurate

 

[J E Custom]

The Weatherby's have lots of freebore because they are loaded hot to get velocity. If you short throat a Weatherby Mag, you may not be able to shoot factory loads or get the velocity you can otherwise. My recommendation would be to buy or borrow a SAMMI 270 Weatherby reamer and let the reamer set the throat correctly.

J E CUSTOM

 

[just country]

morning, sorry I meant 270WBEE. I have a custom
7mmBWee. my smithy told me free bore can b good.
I shoot the barnes 145gr. LRX. COL is critical when shooting
barnes bullets. u push them hard. justme bgot tum

 

[MagnumManiac]

So you are shooting 170s in a 270wby and have best accuracy at .060 to .090 jump?

Having done this myself, I would NOT go shorter than .375" on the throat.
Regardless of how much jump you have or not, it will be a fruitless endeavor if you short throat the 270 Bee. Pressure will run sky high and you will NOT get any where near the velocity you expect.
Mine is at .375", I have no trouble getting ragged hole groups with plenty of jump at 100mtrs.

In my opinion, the standard .375" freebore length should work well even if your mag allows more bullet to protrude.
.097" is quite a bit of room, is your mag length around 3.620"?
My rifle (Win Model 70) has only 3.400" of mag length.

Cheers.

 

[tbrice23]

My mag is 3.555"