Anyone have ballistic profiles to compare these 2?
Cheers
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Anyone have ballistic profiles to compare these 2?
Cheers
.270 calibre is 6.858 mm
.284 calibre is 7.12359 mm
So a .270 is closer to 7mm than what a 7saum is
If both are firing the same weight projectile with the same BC then they are for all intents and purposes identical.
Put a 145 eldx in the 270 and a 162 eldm in the saum and the differences increase.
Run them both on 2217 and fed 210 primers and both can be 900 yard machines
Pointing shit out helps sometimes :)
Attachment 287978
Much greater range of options in high bc pills in 7mm than 270. Both will provide terminal performance way out there.
Made a typo in first post
.284 is 7.21359
First the calibre for the 7mm is .275 to .276" or bore dia. .2755" if you are being pedantic. The bore dia for the .270 is .270" or 6.86mm so you have compared apples with oranges. Further 5 decimal places in mm? Really? Conversions need to rounded to significant figures, 2 in the case of mm for handloading. The 7mm is spot on 7mm when bore dia is measured and the .270 is significantly smaller.Quote:
Originally Posted by 7mmsaum
GPM.
No difference, bang its dead
The real difference only will become apparent at long range. That’s where the 270wsm suffers. Slow 1:10 twist and a poor selection of higher bc bullets. I’ve got one myself but there’s not really anything that’s in .277 that will stand up beside a 7mm 162 or 180 grain eldm way down range.
Ive tried a lot of shit. The .270wsm is a nice balance between being too brutish and not enough. You will never meet an inaccurate one. I would stand mine up with a 145/150 grn against anything out to the 600 yards Ive shot it to. I accept that at some stage the heavier 7mm projectile will take over but thats for the exception.
I’ve shot plenty of animals with a 22” barrelled .270wsm and either the 150ABLR or 150 Berger and it has always killed very convincingly out to 800m.
Beyond that the lower bc of the .270 cal bullets starts to take its toll and velocity drops below the 1800fps that those bullets require for reliable expansion.
I still own mine and have done the comparisons on the 7 saum, if you are hand loading then either of the two are great options.
Both cartridges kill very well out to a long way out.
But if you measure PROJECTILES the .277 is pretty much bang on 7mm,unlike the larger imposter.Quote:
Originally Posted by grandpamac
Oh but there is.... You need to custom build to take advantage of it...faster twists and you can run the heavier projectiles of .277 , the Berger's and the oft forgotten 160grn partition.Quote:
Originally Posted by Mararoa
Greetings,
No one has mentioned the 6.8mm Western. It came out a few years back and is basically a .270 WSM shortened to allow longer projectiles without the ogive inside the case neck and with a 1 in 8 or faster twist to stabilise them. Handloader did a load report on the cartridge recently.
GPM.
270 norma/nosler magnum??...... A certain Dairy cocky built one up a year or five back,be interesting to know how that's going now.
