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Hi guys...I use a 284 and send the 162 eldm off at about 2770. I was just running the numbers on the 147 eldm and launched at 2700 it has slightly more velocity and about 100 foot pounds less getting out there, about 2000fps at 600 yards.
Question is, two frangible projectiles about the same velocity and energy, how much difference to killing power does the smaller hole make?
I think the difference is immaterial so long as you stick the bullet in the right place. But a 6.5mm projectile has an area of 0.35cm2 whilst 7mm is 0.41cm2. That's a 17% increase in the size of the hole that the 7 makes. Not sure how else you could quantify the difference. Standby for many anecdotes.
shit loads of difference....you can shoot animal with your 7mm projectiles but you cant buy any 6.5mm ones to use.
Best thing to do is ask the deer. Those that were shot and ran and died with the 6.5mm compared to the the ones hit with the 7mm. The ones who say they died quicker the are the ones to listen too and get the caliber the that caused it. Or look at each caliber and see what one can't do what the other does. Using 140/150 gn projectiles, there's not much in it in real life. Only on paper. 7mm gets you into tge 180/190 class if you think you need it.
Me 7mm. It can load down to 6.5 performance and up in weight if needed. And very common. Really you cant go wrong with either.
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If you're researching buying one or the other the real option is to split the difference and get the mighty .270, the king of calibres for almost 100 years.
And you would think a 17% wider wound channel, I wonder if that's less important with frangible projectiles.Quote:
Originally Posted by Pommy
mate......the size of the hole will be stuff all diferent...unless it pencils and even then it will still be the same... frangible is what it is,explody and fly apart... too long and both will tumble at times,too slow and both will not open properly,too fast and both MIGHT be too explody .
and there is such a huge variety of cases to poke them out of,its not apples with apples unless same parent case eg .260 and 7mm/08 nothing is relevant if yo ucant get projectiles in first place...there is the 6 and a bit .257 and the only TRUE 7mm the .277 to also consider....
I’ve been back and forth about a 100 times and now back at 7mm and still don’t know , watching with interest cheers
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The for sale threads prove it.... I'd be going with what projectiles you can get your hands on, if you have a stash of both (lucky bastard) second hand rifles of both calibres will start showing up as folks run out of their own projectilesQuote:
Originally Posted by buzzman
It not the size of the hole, it's the temporary wound channel where the difference is. The 7mm will kill faster
You know you really want a 6.5Quote:
Originally Posted by buzzman
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Looking at Reloaders website at the moment. 6.5mm projectiles basically spoilt for choice. 7mm different story.
Its academic really, there is no degree of dead....
Haha don’t get me thinking [emoji23]Quote:
Originally Posted by 25/08 IMP
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I've reached the conclusion that the differences when shooting similar bullets of similar energy and velocity, of either 6.5mm or 7mm, are inconsequential.... a zero noticeable difference in the hunting field.Quote:
Originally Posted by Fisherman
Yes, the .284 has 17 percent more cross-sectional area than the .264. That’s not insignificant... but against the surface area of a deer, I’m having trouble seeing how this is going to make a significant difference, especially when you consider the bullet’s frangible expansion, tearing, break-up, and tumbling in game.
Were we discussing solid bullets, the larger diameter of the 7mm would probably start to matter, but even then, a 0.5mm wider one? 0.5mm is so close that this difference in changing the outcome of a shot even with a solid bullet is rather unlikely.
It's bullet placement and bullet design (classic, bonded, partition), that are more important than diameter. Shot placement and bullet design are the keys, not some 0.5mm wider bullets.
I have the 284 for hunting and a 6.5x55 for paper (and the eldms for both), I've always been skeptical about the 6.5 at distance but I was surprised by the numbers. Outside the size of the wound channel, they are pretty much equal on paper out to a long way (assuming similar expansion) and the 6.5 does it with about 30% less recoil.Quote:
Originally Posted by Micky Duck
Don't tell everyone about 6.5!Quote:
Originally Posted by Fisherman
Must say the 168eldm 308 do the trick as well.
When I went to buy my first rifle I quizzed my guru hunting mate and his advice was if your going to put a hole in it make it a big one.
So bought an old Mauser Fiberglass stock 30-06 and no cans in those days!
Talk about recoil!
To be fair shot placement is the big one and not over stepping the chambering and your ability.
It takes years to master the above 3!
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@andyanimal31 is right about shot placement. For many years when I started hunting deer I just aimed at the chest area. As I gained experience I've learnt to pick the exact spot on the animal I want to hit. I was sighting in on paper and shooting MOA or less then going out and aiming at the big bit on animals.
I imagine that part of the 6.5 thing at distance is at what point it stops being frangible, then you would expect considerably slower killing. The PRC would move that distance quite a way out from the 450 yards I've seen the 6.5x55 being effective (shooting at the big bits).
Shoot to kill and the animals won’t know the difference. Since I bought my PRC earlier this year, I’ve shot 27 deer from 31 shots, from ranges 80m to 560m. The furthest any ran after being shot was 30m. My 7mm results were not much different if I recall correctly, although the hit/miss ratio has increased over the last 12 years of using it [emoji23]
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Just got a message from a mate who put down a Sika at 700 yards with PRC (147eldm), be bloody cold up there this morning.Quote:
Originally Posted by JoshC
Other way around Micky. There's plenty of 6.5 140 & 147 ELDM on the shelf, its the 7mm that's suffering the most.Quote:
Originally Posted by Micky Duck
Anyway to the OP, 6.5 all the way....just coz, rest is all academic
Shot placement, shot placement, shot placement. 17% bigger hole 100mm off target makes 50% longer kill time. Of cause my stats mean nothing.
First consideration has to be can you shoot it accurately?
Currently having a 6.5 built, looking forward to it
First point is that in general cases for the 6.5 cal are smaller because grain for grain of powder they generate more pressure and more barrel erosion. So powder charge and kinetic energy are less than with the equivalent 7mm. Eg 260 Rem vs 7mm08. Its easier to build an accurate rifle in a lower power cartridge and easier to shoot it well.
The main thing is that for the same bullet weight you get better BC in. 6.5 which improves your probability for shot placement ( but only noticeable at > 300 m and if you use a rangefinder well).
Recoil is massive for me for some reason, I get good results but it makes the preparation harder, zeroing, practice etc. I shot a sika hind at about 400 yards a while back with my mates 6.5x55 (143eldx @2700fps) and my only thought after letting it go was "no recoil", dropped the hind on the spot, I might work up a load and see where it goes.Quote:
Originally Posted by Bagheera
They punch above their weightQuote:
Originally Posted by Fisherman
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I shot the 147 and 156 in my 6.5 saum and the 168 in my 7saum I get far more bang flops with the 168 but it’s considerably heavier so it’s apples for oranges .260 and 7-08 with 143 eldx and 140 NBT would probably be as close in weight as you could get for a decent comparison I find my 7 kills faster but same thing heavier pill so it’s a little more forgiving . I had endless bangflops on Tahr with my 6.5x55 with 139gn sp probably more than any other rifle iv had
With the absolute non existent supply of 7mm projectiles its a fairly easy choice to go for something that actually has projectiles available. So with that you've got 6.5, .277 and 30 cal. Put the rightly constructed bullet in the right place and I'm sure they won't tell the difference.
( I own 2 7mms and It's a shit to shoot them as every projectile counts)
Berger the worldQuote:
Originally Posted by Rock river arms hunter
I see youre using a 284.
Maybe you could get a used 6.5-284 barrel brass and dyes from an F Class shooter and make an exact comparison with all the same gear but different bore size.
Only use 10mm and up, because more is better! :ORLY:
Attachment 208688
@Micky Duck can you expand on this?Quote:
Originally Posted by Micky Duck
Wondering what you were talking about as I had always taken the box figures for granted e.g. 7mm/.284 I took a look at my wall conversion chart. And what do you know, 7mm is 0.2756". SO measuring a 7mm/.284 ELDX with the verniers comes in at 7.17mm/.2820 and a .270 NBT is exactly 7mm/0.2755. So now that my mind is blown, what is up with the naming? or measuring system seeing as they don't actually convert? Also, by the chart 5.56 is not 0.223" yet 7.62 matches 0.300".
I'm not sure but could be to do with barrel diameters, either inner or outer rifling measurement.
Curiosity got the better of me and I had to know.
https://en.m.wikipedia.org/wiki/Caliber
So it's not bullet diameter like all the reloading manuals list but approximations and there abouts of the barrel diameter. Except for the exceptions. Well I think I have learned something :wtfsmilie:
But it still doesn't explain why a approximate 7mm projectile is also named 7mm at .284 and not 7.2mm. probably confusing myself now.
Yeah I have learnt a bit too. If you google it there's a lot of info.
Way more 6.5mm aroundQuote:
Originally Posted by Micky Duck
Same over here, 7mm are hard to source should you need them. 6.5 not so much except for the 143 eldx.
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Greetings All,
The calibre controversy has been going on for a long time. Up until WW2 smokeless rifle cartridges were mostly named for the bore dia (land to land measurement) hence .270 or 27 calibre, 7mm or 276 calibre. Post war some US cartridges started being named for groove dia .243 for 6mm or 236 calibre and .308 for 30 calibre. All this has got hopefully confused and the table in Wikipedia mentioned above is worse than useless in adding any clarity. With pistol and small rifle cartridges that were developed in the black powder era the situation is even worse and I wont even go there.
So sorry Micky your beloved .270 falls about 0.02mm shy of being a true 7mm calibre. It probably owes its existence to the US reluctance to use anything metric (softening lately) and Winchester picking the next calibre down from 7mm as .280 was already in use.
Regards Grandpamac.
