284 win ackley improved

[762 ULTRAMAGA]

I'm having an 18" 284 win barrel made up for my tikka for a suppressed hunting rifle, I want to send a 175 elite hunter around 2700-2750.
I know there's a shehane version available but I like the idea of going to a 40 degree shoulder.
Any thoughts about doing a 284 ai?

 

[B23]

Short of just having something different and a 284 with a 40° shoulder there isn't really much to be gained by improving the 284. The 284 is already a pretty straight case and comes with a 35° shoulder so I'm not sure it would be worth the extra time and money to blow it out to a 40.

I'd think throated properly and with the right powder, RL26 maybe, you'd be able to reach 2700 or more with just a straight 284.

You'd have to either replace the bolt or have it opened up but if you wanted more velocity than a straight 284 will give you I think you'd be money ahead to go 7 SAUM or WSM. Maybe even a 7-6.5PRC.

 

[jamesmc8]

What is the length of the suppressor? Could you get by extending the barrel to 20" for more velocity?

 

[fightthenoise]

Just a data point, not trying to sway you one way or another but I have a 20” 7 SAUM sending 180 ELD-M’s at 2780 with a charge of RL23 that was on the low end of my ladder, so a ways off from pressure. I’m not sure how the powder capacities compare between the two though. I ladder’d RL26 as well and velocities were appreciably higher. All that to say that your goal seems reasonable especially if you can find good brass. I know Lapua makes 284. I’ve pondered a 284 myself, seems like the Tikka actions were made for it.

 

[762 ULTRAMAGA]

Short of just having something different and a 284 with a 40° shoulder there isn't really much to be gained by improving the 284. The 284 is already a pretty straight case and comes with a 35° shoulder so I'm not sure it would be worth the extra time and money to blow it out to a 40.

I'd think throated properly and with the right powder, RL26 maybe, you'd be able to reach 2700 or more with just a straight 284.

You'd have to either replace the bolt or have it opened up but if you wanted more velocity than a straight 284 will give you I think you'd be money ahead to go 7 SAUM or WSM. Maybe even a 7-6.5PRC.

Definitely some good points but the saum is out because I have a 6.5 version already, plus I'm not a fan of the shoulder angle. I have to trim mine every 2-3 firings.
The wsm is awesome but brass does make it tough, plus it's more than I need with an 18" barrel.

I've done a bunch of reading on the 284 Shehane and it looks like there's a 2 grain usable powder increase just blowing out some of the taper. Looks like people are getting 75ish fps velocity gain over the straight 284.
By going with an ai version I'm thinking I could blow the shoulder out a bit and remove all case taper for a 4 grain increase??
I know that's not a ton but it has me intrigued, I'm going with the 284 case either way so it's just a matter of dealing with custom dies.
And the more I think about it the more I like the idea of having dies cut to my chamber

 

[B23]

I don't 100% remember but I think, some time back, Shawn Carlock w/Defensive Edge did a 6.5-284 Improved. It's been some time since I talked to him about it but if I recall he came to the conclusion the small gain wasn't worth the extra work and cost. For me, even if you gained 100fps, and at equal pressure that'd probably be stretching it, it wouldn't be worth it. That extra gain by improving a 284 case would be about exactly equal to what a 7-6.5PRC would be and that would be a whole lot easier way to go.

Don't get me wrong, I'm a big 284 fan. My 6-284 and 6.5-284 are two of my most favorite rifles but I've had my fill of "improved" cartridges and unless I can get formed brass from the smith that built it or there's a big gain by improving it like there is with say a 338 Lapua Improved it's just not worth the extra work. But that's just me and we all like and see things differently.

 

[wildcat33]

284win was basically AI’d from factory. With already straight walls your gains from 5 extra degrees on the shoulder seem very small.

280ai vs 284 win:

 

[762 ULTRAMAGA]

I don't 100% remember but I think, some time back, Shawn Carlock w/Defensive Edge did a 6.5-284 Improved. It's been some time since I talked to him about it but if I recall he came to the conclusion the small gain wasn't worth the extra work and cost. For me, even if you gained 100fps, and at equal pressure that'd probably be stretching it, it wouldn't be worth it. That extra gain by improving a 284 case would be about exactly equal to what a 7-6.5PRC would be and that would be a whole lot easier way to go.

Don't get me wrong, I'm a big 284 fan. My 6-284 and 6.5-284 are two of my most favorite rifles but I've had my fill of "improved" cartridges and unless I can get formed brass from the smith that built it or there's a big gain by improving it like there is with say a 338 Lapua Improved it's just not worth the extra work. But that's just me and we all like and see things differently.

I can't argue with you
Maybe I'd be smarter just selling my standard boltfaced tikka and getting a magnum to go 7-prc.
Another issue with that plan besides scraping what I've got is that 6.5 prc lapua brass is completely unobtainable.
It might be worth it though in the long run considering I could use a 6.5 prc bushing die vs waiting 4 months for expensive customs..
See what you did?
Now I'm trying to talk myself out of the 284
Edit:
I see the 6.5 prc holds 68 grains of h20
I measured a few 284 lapua cases tonight and they were right at 67 grains
That definitely makes me lean towards doing a blown out 40 degree 284

 

[B23]

Neck up the 6.5 PRC brass to .284 and that 68 number will go up a little. Are you looking for some Lapua 6.5PRC brass? I recently saw 200pcs for sale.

 

[762 ULTRAMAGA]

Neck up the 6.5 PRC brass to .284 and that 68 number will go up a little. Are you looking for some Lapua 6.5PRC brass? I recently saw 200pcs for sale.

Possibly
I'm definitely considering it
Let me know if you come across some

 

[HighUintas]

Possibly
I'm definitely considering it
Let me know if you come across some

I think your idea of going 40 shoulder and blowing the wall out (basically 40 degree shehane) is awesome.

I've got a 30-284 and was considering getting a reamer made for a 30-284 shehane ai... But I'd have to call it something else.

The only thing that has stopped me needing to use a hydroform die and having to get completely custom resize dies made. And I think doing that has the potential to shorten the neck a lot. I bet it wouldn't be an issue for a 284 though.

Do it!!