Resizing 30.378 weatherby down to 7mm or 8mm

[JamesWilson5]

Got low on brass for a 7mmstw and took 8 mm remington mag brass . Simply ran it through a 7mm stw resizing die worked like a champ and got plenty now . So I was wanting to take a 30 378 weatherby and neck it it 7mm or 8 mm . I have a 30 378 dies but how can I get it down to that caliber and what would I need . Got plenty of brass I know it's crazy but I have a 7 rum and stw also 7mm weatherby but I am looking for so serious horsepower powder or barrel life I'm not concerned with just want to take a Cadillac and turn it Into a top fuel dragster lol .the 8mm would be a very interesting idea especially cause I have 338 378 brass and dies also but how can I size them down. Any ideas would be much appreciated thanks in advance

 

[gearguywb]

I don't see how you would be gaining anything going to 8mm. Diameter difference is relatively small and bullet selection in 8mm is not very good.

 

[JamesWilson5]

I got plenty bullets stored up just trying to get alot more than 8mm rem

 

[Varmint Hunter]

If your 30-378 WBY isn't a "top fuel dragster", I don't know what is.

 

[BillLarson]

Be careful necking down.It can make too much neck tension....
I would anneal,neck down,trim to length,and ream throat of case.

 

[JamesWilson5]

Just shot a group with stw loaded last night 3/4 inch not to bad bout to order my chronograph see what I got going on

 

[Bghunter338]

@purpledragon

 

[Harry Knutz]

Necking down usually creates necks that are too thick, If you can't slide a bullet down the neck of a fired case with little to no resistance, Then your necks are too thick and need to be turned. Necks that are too tight will cause poor accuracy. Secondly, If you don't have a rifle that shoots 30-378, You will need an action with a Lapua bolt face or an action that was designed for 30-378, The head of the case measures 0.579 , The STW measures 0.532, So the bolt faces are much larger on the 30-378. Thirdly, The 30-378 is way overbore and a barrel burner already, Necking it to 7mm is not a worthwhile endeavor.

 

[purpledragon]

Have a die that sizes the 30/378 to 7mm, but has to be fire formed first, as it will become Ackley Improved in my chamber. It is a beast of a 7mm.

 

[JamesWilson5]

where can I get a die

Have a die that sizes the 30/378 to 7mm, but has to be fire formed first, as it will become Ackley Improved in my chamber. It is a beast of a 7mm.

Where can I get a die and what caliber is the die called and would u mind giving me a lil insight of ballistic

 

[jessej]

Got low on brass for a 7mmstw and took 8 mm remington mag brass . Simply ran it through a 7mm stw resizing die worked like a champ and got plenty now . So I was wanting to take a 30 378 weatherby and neck it it 7mm or 8 mm . I have a 30 378 dies but how can I get it down to that caliber and what would I need . Got plenty of brass I know it's crazy but I have a 7 rum and stw also 7mm weatherby but I am looking for so serious horsepower powder or barrel life I'm not concerned with just want to take a Cadillac and turn it Into a top fuel dragster lol .the 8mm would be a very interesting idea especially cause I have 338 378 brass and dies also but how can I size them down. Any ideas would be much appreciated thanks in advance

I like the way you think neighbor.

Would love to see a 284-378 wby propelling a light hammer up around 5k fps

 

[JamesWilson5]

Top it off with a 30 inch tube pound of powder look like a tracer round I mean realistic should bump 4k fps with right bullets. That thing would be a nightmare for deer with a Barnes or a hammer bullets

 

[jessej]

I ran 100 grain sierras over 4000 in my stw.

 

[JamesWilson5]

That's screaming