7mm rifle build

[MagMan]

I've got a #4 Brux with a n 8 twist.

I recently used a Brux #5 with an 8 twist for my 280 Ackley. Only have 3 shots down the barrel with 183 SMK's and it shot 1/2" with forming loads.

 

[tim_w]

Guess a SWAG but......Grab some 6.5x284 norma lapua case run it thru a 7mm mandrel load and you are at 280 AI vel. Set the chamber to a 40 degree shoulder and .010 case taper and you have a simple AI fireform using a jammed bullet ideally. Now you have exceeded vel of 280AI and have equal powder capacity.

Even SAAMI shows the sharp AI shoulder and less tapered cases are good to almost 70K max mean pressure 65K max variable psi 69.1K. With lapua cases no issue at all from my experience with numerous loadings.

If it were me I would set throat for the 175-180 eld and bergers as you have lots of room with the short fatter 284 case even in a medium action. 24-26" barrel

Lapua cases easy forming or not... whats not to like.... I do like the longer case neck of the 280 better but not a deal breaker.

Unless factory loaded ammo is a must have that would be my choice. Tech you could shoot 284 win ammo in that chamber.

 

[codyadams]

my 280 rem needs to be 3.480 long and 4 more grains of powder to match the velocity and then it is single feed. the 284 win is only 3.210 long will mag feed with no extra work on action. 284 win also has lapua brass option. 280 ackley will be the better choice if velocity is a big concern and the 280 will be better if factory ammo is a concern. pick one and enjoy

Since he has a rem 700 long action, he can load as long as about 3.7", so OAL isn't an issue.

 

[MudRunner2005]

I've got a #4 Brux with a n 8 twist.

With the 8 twist, I really would recommend going with the .280 Sherman, 7mm RemMag or .28 Nosler to push the 175 to 195's to get the most of that 8" twist barrel.

 

[tim_w]

thats a good point. I assumed it was because he had 473 bolt he was looking at those two cartidges. If that is not a requirement.......

 

[Sinko]

I've decided I need a 280 Ackley

 

[lancetkenyon]

.280AI.
175 Berger, 58.0gr RL23, 2975fps
200 yards


921 yards

 

[Sinko]

It's at the smith. 4-8 weeks away. Decided to go 280 AI SAAMI length chamber with a free bore for 160+ class bullets.

 

[tim_w]

Give a report back once you get it in hand and do some load workup.