Analysis paralysis: .270 vs 280AI vs 7 SAUM

[MHWASH]

I have a Remington 78 in .270 Win. I've been tossing around the idea of rebarreling to either 280 AI or 7 SAUM. Every time I get close to pulling the trigger, I run some balllistics and it appears there's no real difference between the 270 and either 7mm. I realize the AI & SAUM are ballistically the same.

This rifle currently wears a 21" barrel, if I rebarrel I will go with 22". Rifle will be threaded for use with my can. Intended use is bear and spike elk out to 800 yards eventually.

 

[BigStick]

Mechanically,the 270 is a rather POOR choice,due projectiles.

The 7 SAUM(I've had a few),is also a mechanical compromise,due brass selection.

The 280/280 AI is leaps and bounds ahead,due same.

78's are nice,due the fact they are typically scored for less than a 700,due their fit/finish. Metal is the same,though stocks are compromised. I've a few.

Distance isn't a function of headstamp. 78's/721's/700's wear an exceedingly forgiving COAL latitude,which arranges them to be PRIME Custom Candidates.

Opting 1-8" 280/280AI,grants 180gr .796 BC's,or better yet,190gr .838 BC's and both are capably housed in OEM mag confines.

I prefer the 280 Vanilla,though I shoot both. Lapua '06 brass abounds and is without peer. In a 22",it will offer a .796 BC at 2800fps+,which is simply sensational,in all avenues..................

 

[Bomberodevil]

Do you hand load? If you do not hand load, I would likely go to a 7mm RM. I also have a 270 Win and a 280 AI, and they are pretty close, with the 280 AI having an advantage with more efficient bullet selections. My understanding is like yours, that the 280 AI and the 7 SAUM are basically identica.

 

[BigStick]

The 270 is never within "the realm" of a .284",due projectiles. Such notions are contrived.

None of my 7 SAUM's would run with any of my 280/280AI's,due the HUGE concessions in COAL latitude.

Such things matter.............

 

[hereinaz]

What ballistics are you looking at?

Per SAAMI the .270 win, the 7 saum, the 7 Rem Mag all have slow twist barrels and light bullets. If you get a fast twist barrel, longer throat, and handload heavy for caliber bullets you can get the advantage of high BC. The 280 ai has a bit of the advantage there.

If you are going to a magnum get the 7 prc because your given range of 800 yards is going to need all the extra margins for error. It is designed with high BC bullets in factory loads.

Or, get the 6.8 Western if you want to stay .270 caliber. So, I second what was said about that above.

How far are you realistically looking to shoot?

Velocity matters for elevation drop in the first 500 or so yards. That’s why “flat shooting” .270 win was touted over the 30-06 before rangefinders became available.

After 500 ish the BC and weight of bullet matter after shedding the initial velocity. This is what really matters.

In the end, the wind will be the biggest factor at 800 yards, and so you need to look at wind drift as much or more than drop.

 

[BBob]

The easy button is the .280 or .280AI. No bolt face or feed rail changes necessary by going that route. The SAUM (or any magnum) has a larger case head which would require the bolt face to be opened up, a different extractor installed and likely the feed rails opened up.

 

[BigStick]

Any/all over the counter 721/700 280/7mm RemMag's will simply stabilize,feed and function a .796 BC Hornady 180 ELD M at Low Tide.

BC advantages start within the 50yd line and never pale............

 

[ResearchinStuff]

Bigstick is right, from the options listed,
based on bullets 7mm is the better bore size, and based on brass 280/280 ai is the better cartridge choice.

 

[MHWASH]

I'm using the Berger ballistic program for the comparisons.
I already have 250 pcs of Norma 7SAUM brass, and 100 Peterson 280 AI brass. Other than a bolt face change, there should be no issues using the 78 for the SAUM. This would eliminate any OAL concerns, I believe.