270 or 308

[jthyttin]

updated now for correct info , my bad ( i was hungry , i have eaten now!)


100m/200m/300m
270 - +1.8''/0.0''/ -8.3''
308 - +1.74''/0.0''/-8.03''

This is still cherrypicking. Actual numbers are vice versa, although the difference is just as small.

Look for e.g. Barnes VOR-TX ammo that has like for like bullets (130gr T-TSX). 270 has both better BC and slightly better MV. Their trajectory figures:

	100y	200y	300y
270	+1.3"	0	-6.3"
308	+1.4"	0	-6.6"

Velocity figures start to show the real thing, at 300y it's 2432fps for 270 and 2341fps for 308. 90fps is starting to make a difference in terminal velocity for Barnes (assuming both bullets designed for same expansion threshold, a figure that Barnes doesn't publish nowadays)

 

[sparrow123]

It’s all Horlicks designed to flog snow to the eskimos

For the golden oldies like us it works , for the young’uns you have to polish it to sell it, where you and I would take a grubby green shell case that’s probably 30 or 40 years old give it a tumble and make it

This is still cherrypicking. Actual numbers are vice versa, although the difference is just as small.

Look for e.g. Barnes VOR-TX ammo that has like for like bullets (130gr T-TSX). 270 has both better BC and slightly better MV. Their trajectory figures:

	100y	200y	300y
270	+1.3"	0	-6.3"
308	+1.4"	0	-6.6"

Velocity figures start to show the real thing, at 300y it's 2432fps for 270 and 2341fps for 308. 90fps is starting to make a difference in terminal velocity for Barnes (assuming both bullets designed for same expansion threshold, a figure that Barnes doesn't publish nowadays)

So out the two what do you prefer shooting cal ?

 

[tackb]

This is still cherrypicking. Actual numbers are vice versa, although the difference is just as small.

Look for e.g. Barnes VOR-TX ammo that has like for like bullets (130gr T-TSX). 270 has both better BC and slightly better MV. Their trajectory figures:

	100y	200y	300y
270	+1.3"	0	-6.3"
308	+1.4"	0	-6.6"

Velocity figures start to show the real thing, at 300y it's 2432fps for 270 and 2341fps for 308. 90fps is starting to make a difference in terminal velocity for Barnes (assuming both bullets designed for same expansion threshold, a figure that Barnes doesn't publish nowadays)

i think you may have missed my main point

the 270 is not any better than a 308 or vice versa , there was claims that the 308 was lobbing bullets (glittery brick and all that nonsense) but like for like there is nothing in it

and it still holds that the 308 is the more versatile round in my opinion

i intentionally didn't choose superformance and tried to match as best i can the rounds , i did however intentionally avoid lead free because i am not sold on it and think it's a load of nonsense.

maybe the 90fps difference (results may vary) could be made up by the 0.8mm larger bullet diameter (tongue in cheek before you furiously respond!)

 

[tackb]

Fair enough

I understood that Ackley was after increased ballistic performance, not necessarily improved accuracy.

i think you are correct but by trial and error and looking to advance ackley stumbled across other benefits

 

[kenbro]

Same with my .243 so I bought a Rem 700 in .270 then both .30cal cans in 1/2" unf fitted as the barrel OD profile was the same. I took the T8 off the .243 and checked it fitted as some people have no clue what thread is on the end lol

Did hear, there’s some with lefty threads as well! .
Ken.

 

[jthyttin]

i think you may have missed my main point

Not at all, the point is just biased and missing key factors.

In full house loads, with mainstream bullets containing lead (don't know the boutique market since it's not relevant to me), I wouldn't go to 125gr in 308 for general use load. It's just lacking at both short and longer (let's say over 200m) ranges.

For a given bullet construction, two things define the behaviour in (given) target: impact velocity and sectional density. Bullets of similar construction with higher sectional density tend to have also higher BC that further contributes to higher impact velocity (in addition to case capacity difference between the cartridges in question). Of course when these variables are matched, larger diameter bullet tends to be more "efficient", "destructive" or whatever you want to describe the terminal effects that lead to faster expiry.

If we take granted that 130gr 270 is suitable for reds, you really should be looking at 160gr bullets in 308 to match the SD. Give it a little leeway, and take 150gr 308.

In non-lead of suitable design, I'd happily use 130gr in 308. Thus it's obvious to compare e.g. T-TSX if you're fixed on 130gr 270. In 270 130gr still has adequate but not excessive speed, and many manufacturers won't even offer lower than that. Arguably you could also drop down to 110gr if available (T-TSX is).

For true like for like comparison in lead containing ammo, you should take a manufacture product line and pick the candidates there. Like Hornady American Whitetail, or Nosler Ballistic Tip Hunting. Or at least match the next weight up in 308, not next weight down.

 

[Tim.243]

Did hear, there’s some with lefty threads as well! .
Ken.

Lefty might be on your voting ballot X lol
No LH .303's lol

 

[south-nofolk-stalker]

Lefty might be on your voting ballot X lol
No LH .303's lol

I had a cack gander 270 shooting 130 Barnes since 2011 just to throw a spanner in the works

 

[tackb]

Not at all, the point is just biased and missing key factors.

In full house loads, with mainstream bullets containing lead (don't know the boutique market since it's not relevant to me), I wouldn't go to 125gr in 308 for general use load. It's just lacking at both short and longer (let's say over 200m) ranges.

For a given bullet construction, two things define the behaviour in (given) target: impact velocity and sectional density. Bullets of similar construction with higher sectional density tend to have also higher BC that further contributes to higher impact velocity (in addition to case capacity difference between the cartridges in question). Of course when these variables are matched, larger diameter bullet tends to be more "efficient", "destructive" or whatever you want to describe the terminal effects that lead to faster expiry.

If we take granted that 130gr 270 is suitable for reds, you really should be looking at 160gr bullets in 308 to match the SD. Give it a little leeway, and take 150gr 308.

In non-lead of suitable design, I'd happily use 130gr in 308. Thus it's obvious to compare e.g. T-TSX if you're fixed on 130gr 270. In 270 130gr still has adequate but not excessive speed, and many manufacturers won't even offer lower than that. Arguably you could also drop down to 110gr if available (T-TSX is).

For true like for like comparison in lead containing ammo, you should take a manufacture product line and pick the candidates there. Like Hornady American Whitetail, or Nosler Ballistic Tip Hunting. Or at least match the next weight up in 308, not next weight down.

ok , you're not completely wrong but you are wrong with a few assumptions

as i am sure i am on some details

but my point still stands despite all the tangents you introduce

130gr in 308 is entirely suitable for reds , all those i have shot have totally died as i am sure they would with a 130gr 270 load , and in fact when the range gets 'out there' a more fragile bullet behaves differently and is an advantage , all about picking the bullet for the job at hand

i'm sorry if you have a 270 and feel some kind of slight in anything i have said but i'm beginning to feel you are arguing for the sake of it now and together we are derailing the thread.

my point to the OP's question is either will not make a jot of difference but the 308 is more versatile

the other points about bullet drop are more in response to those who claim the 308 is a glittery brick and the 270 is a lazer , neither is true and from a purely ballistic point of view the drops are for all intents and purposes the same , and before you start on about bullet type again you can get many types of bullets in many weights.

 

[kenbro]

Lefty might be on your voting ballot X lol
No LH .303's lol

Was referring to a thread some time back when someone was struggling with undoing a “left” hand threaded mod!
Ken.

 

[Tim.243]

Was referring to a thread some time back when someone was struggling with undoing a “left” hand threaded mod!
Ken.

Oh good...

 

[Alhamander]

Yes!

I went out yesterday and for the first time shot an old Sako L61R .270. Unmoderated. I braced myself. Needlessly. Actually very enjoyable, and WHAT a noise rolling down the sides of the loch! Less loud than I'd thought and less recoil too. Who knew...and the beer can had a lovely hole in it...

 

[Scotty99]

The .270 is a necked down 30-06 (or 30-03 as some folks claim). So go for a 30-06 it has the benefit of the larger capacity case and a .30 calibre bullet. If you reload then you can reload from 110 grain bullet right up to 200 grain giving you a huge range of quarry to go for. If you don’t fancy that then a .308, very capable round with a lot of factory ammo availability.