Home Forums Hunting & Shooting Hunting Rifles Tissue Damage - .270 vs. 6.5x55

In my 6.5 Swede (M-70 trued, Bartlein 5 R)I load a charge of 48 gr of H-4350 with the 123 Nosler CC or the 120 NBT. Both 2880- 2915 and both work well on game up to a small 6 X bull elk. Mostly deer and goats.

140 Hornady SST is a sleeper also.

FWIW the only real study I've heard of on whether twist affects expansion is from Nosler where they said they checked expansion & penetration with rifled and unrifled barrels and saw no difference. Everything else I've seen is anecdotal, however, the monometals may be different. If you are breaking more bones with the swede, I would say that is why you are getting more damage. There is more collateral damage from bone fragments, etc.. and possibly loosing petals. The other thing is it looks like you are comparing untipped vs tipped bullets. I would guess, all else being equal the untipped versions would penetrate more deeply since the tips tend to aid in expansion.

Lou

I have definitely seen the effect of twist with varmint bullets, in fact Nosler Varmageddons. When they first introduced them I went on a prairie dog shoot with several rifles, including a "tanger" Ruger 77 .220 Swift with the 55-grain tipped Varmageddon loaded to 3800 fps.

Anybody who's shot a Swift much knows it tends to perform some serious lift and separation on PD's, and this one was no different. But the results still were noticeably less violent than the same bullet at 3100 fps from a Nosler/Noveske AR-15--which had a 1-8 twist. The ranges were the same, from around 50 yards out to 300+, and the .223 definitely and repeatedly did more damage than the Swift.

Totally unscientific observation: I've killed a lot of deer with the 6.5x55. I've killed a good handful with the with the 7x57, a bunch with with the '06 and a handful with the 270. The 6.5x55 has dropped deer as well as or better than any other cartridge, either from an original fast twist Swede barrel or a 9 twist. The 7x57 and '06 are good but not better than the Swede. It just drops 'em. It sets up some kind of shock that I don't understand. The 270 is the least effective cartridge I've hunted with. Yeh, I know I'll get flamed for that but that was my experience. With good placement it did not kill as effectively as the 6.5. It has a reputation for some serious mojo that is well deserved. It does not need to run at 2900 or 3000, it doesn't need explosive tipped bullets. I started out 20 years ago with PMCs and graduated to Interlocks and Gamekings when I began reloading. It's been wicked with both. No deer has gone more than 10 or 15 yards max. If I were hunting in more open country I'd have kept my 6.5-06. Or maybe not.
As for meat damage, probably less than anything else I've used.

This.

I can't imagine that the caliber has anything much to do with it.

And Dwayne is shooting pretty tough bullets. Faster twist facilitates greater expansion.In BG bullets the effect may not be as apparent as it is with varmint bullets but it's still there nevertheless.

Someone pointed out the differences could also be the plastic tips which is also valid since they help expansion.

When using very tough hunting bullets, faster twist is better.

Bob, I 'm sure you're right. But the 6.5 has mojo, man, mojo.

Bob;
Top of the morning to you sir, I trust this finds you and yours well on this Canuck Thanksgiving Monday.

I'll agree with you that the GMX/TTSX are a tough bullet and perhaps not the optimum projectile for this 22" barreled .270.

Beyond being curious to see what they will do in a particular rifle, my main reason behind using stout bullets is that we have overlapping seasons up here - so for instance I've got from Sept. 10 to Oct. 20 to sneak up on a bull elk with 6 points on one side - and at the same time will be packing a mulie buck, whitetail buck and black bear tag. After that there's a bit of a lull until the moose season kicks in for two weeks - so again one might want a tougher projectile than if the intended quarry was only going to weigh in at under 200lbs.

The Swede round does seem to be quite hard on projectiles too and until the monometals came along, either 140 Partitions or Hornady Interlock pushed not very fast were the champion performers.

If memory serves the 120 Pro Hunter and Solid Base would come unglued in spectacular fashion to the degree of only taking out the lung on the entry side for instance.

Anyway sir, again I'll state that I meant it only as a topic of pleasant conversation round our cyber 'Fire and nothing more. Before leaving that thought though I'd like to send my most sincere tip of the hat to all participants for keeping their decorum. Well done gentlemen.

All the best to you and your fine family Bob and good luck on your remaining hunts this fall.

Dwayne

OldRooster;
Thanks for your input here sir, I appreciate your candor and reading your experiences with the different cartridges.

As a bit of back fill for you or anyone else reading this morning, the rifle in question was a 1903 built Carl Gustav that I purchased for something under $60 from Century Arms in Montreal in 1984. We'd moved out here to BC where my folks lived at the time and my father had expressed interest in hunting with me but no longer had a rifle.

Though $60 was a lot of money for us then, my understanding wife supported the project and allowed me the time and leeway in our busy schedules to cobble this rifle together for my father.

This is him on the day I completed it - might be '85 by then I can't recall.


Back in those pre-internet days there wasn't much information on the Swede and we were both pleasantly surprised with how it performed on the local whitetail and mulie bucks we chased. I recall Dad's comment when I hit a meat mulie buck with my new .338 Win Mag and it didn't knock it off it's feet or for that matter seem to change it's leisurely gait much at all.... it wasn't a compliment to my new rifle anyway.......

In the fullness of time Dad's health no longer permitted him to hunt and he gave the little carbine back to me, requesting that I give it to one of his grandchildren someday. As it turned out it was our eldest daughter who spotted it in the safe one day and claimed it.

I believe she's taken at least 8 local mulie and whitetail bucks with it - each taking exactly one shot each.

This is her last year's buck which turned out to be one of the fattest carcasses I've ever handled in a lifetime of hunting. It went 149lb into the cooler so I'd guess at least a 3rd rack buck.


We've yet to get a range finder, but lets just say I asked her twice if she was confident in hitting this buck as it was across a fairly wide draw from us. The bullet hit a rib on entry, then traversed the lower lungs and top aorta, took out another rib and then completely smashed the big joint between the scapula and ulna before hitting the mountainside beyond.

I just shook my head as we were walking over to it and had to agree with her assessment when she said, "Man does this thing ever work!"

Thanks for reading sir, thanks again for your input and all the best to you this fall in your remaining hunts.

Dwayne

There is no doubt that twist is a mean MOFO on critters. That folks are still so afraid of twist is funny to me.

Steelhead, I've wondered about that too. I don 't know as much as a lot of you guys do about the subject but observed that the fast original twist was sure not a detriment.

BC - that's the kind of performance I'm talking about.

Dwayne: Top of the morning!

I'm a fan (not a detractor) of tough bullets in the 270 for BG hunting....and most any high velocity cartridge for that matter.

You chose the tougher bullets for about the same reason I did many years ago.....multiple hunts for various sized critters and wanting (it seems) to use one load rather than switch back and forth between different bullets for (say) elk,bear, and deer, which personally I think is silly but to each his own...

I have noticed that tough bullets benefit from more twist. The differences you are seeing, I think,aren't due to caliber (they are too close),velocity (the 270 is generally faster but not by a huge margin),or bullet weight(they are too close in weight). Maybe there are minor differences in the way the manufacturers engineer and construct those bullets for expansion from one caliber to the other but I doubt they vary that much.

The only factor left is twist and with that we are left to the same old, "same old" that the 270 is generally a 10 twist and the 6.5 is twisted faster.

I think the same forces that work to pull a very lightly constructed bullet to disintegrate in mid air from high velocity and fast twist in mid air, are at work with expanding bullets on BG animals, although the effect may not be so apparent. You'd have to shoot quite a few animals with both (which you have) to start to notice these differences. You'd also have to be paying attention, which you clearly are....

A pal of mine used to load 90 HP's in a 264 Win Mag (for fun)so we could watch them turn to a blue/white haze halfway to a 100 yard target(never make it there)...we thought it was a riot. and maybe why Berger target bullets(for example) have tougher jackets than the hunting bullets because under the stresses of fast twist to stabilize long heavy bullets,a thin jacket will pull apart in mid air.

If we see this with a bullet traveling in mid air, why would we think the same thing would not occur when a bullet impacts a game animal and starts to rupture and tear itself apart?

This is why those of us who started using Bitterroot bullets 30-40 years ago, used faster than normal twists...the bullets were unique for the day with very heavy copper jackets and pure lead cores....we built 270's and 30 calibers with 9 twists, 7mm's with 8.5-9 twists, and 375's with 10 twists, to help expansion based on the makers recommendation because he had done the testing already and seen the results with his bullets.Even at the same impact velocities the faster twist would show in the expanding bullet...we threw a lot of the old rules regarding twist out the windows....but the bullets had to be built to withstand the extreme rotational forces and high velocity impact. Bitterroots were made to do that and I think the same applies to today's mono's.

IMHO it isn't just "speed" although that's clearly a factor as well.If I were a mono shooter I would follow the same recipe and build a 270 with a twist no slower than 9". I have a hunch that some of the "failures to expand" noted early on with Barnes X bullets was due to guys using conventional weights, pushed them to conventional speeds,in standard twist barrels. I think the bullets will handle as much velocity and twist as we can give them.

As further evidence we could look back to some articles Dave Scovill did a few years back in Rifle Magazine, noting the effect of high speed, light weight monos from a 7mm WSM on African game....the skinners commented they had never seen so much damage from a 7mm bullet.Speed no doubt was a factor but so too was the higher rpm's.


I know Old Rooster thinks it's 6.5 MoJo but I think there is something else at work.

Bob;
Thanks for the reply and for taking the time to share your thoughts and experiences.

As always you've articulated them in a most excellent and readable format - well done sir.

The more I cogitate on the subject Bob the more I'm leaning towards your conclusion.

The monos do seem to thrive on high initial velocities and fast twist rates don't seem to bother them one iota either.

A 1:9 .270 would be the way to fly for sure for me I'm thinking - the barrel on mine is an old school Parker Hale and though I can't say if I've ever measured it, I'm guessing it's at least as slow as 1:10.

Thanks again for your well worded reply sir, I always enjoy reading what you write.

All the best to you folks again and good luck on any remaining hunts as well Bob.

Dwayne

Or just rebarrel your .270 to 6.5x55....

Don't laugh. That's what I did after shooting out my FN .270 several years ago.

Not a comparison of those two but with other X-bullets. It seems that some at higher velocity end up with the petals laid back on the shank of the bullet based on wound channels and a very few recovered bullets. Once it does this it acts more like a wad cutter bullet.

I suspect that at more moderate velocities the interval when the petals are in "full flower" is longer. That the slower bullets have a slightly longer interval at maximum diameter. Purely speculative but I believe there was some high speed photography done by Barnes in clear ballistic gelatin that could support this theory.

WDM Bell also thought that bullet rotation was a factor in lethality. This is what he attributed the effectiveness of the Swift on Red Stag at longer ranges after velocity had dropped off. Some of the military testing would tend to support this as well.

There was a Cooper for sale at Cabelas a couple years ago, .22-250AI with a 1 in 8 twist. That would have been real interesting, but I just could not swing it at the time

The physics for twist having some major impact on expansion/damage are just not adding up to me though intuitively it makes sense. My understanding is very little of the energy used to push a bullet out the barrel is used up in spinning the bullet, else we would see substantially lower mv with fast twist barrels. In turn, does not seem there would be a whole lot of energy to do anything with expansion since not much is used to spin. Did some quick searching on net and came up with following from longrangehutning forum (the intent is to show how little energy there is in spin):

I'd like to point out some calculations regarding translational and rotational kinetic energy that are completely open for interpretation.

barrel/bullet:
A typical .30 caliber 155 grain bullet at a muzzle velocity of 3000 fps from a 1:13" twist barrel.

At the muzzle, this bullet will have 3095 ft-lb of translational kinetic energy.
At the muzzle, this bullet will have 7.7 ft-lb of rotational kinetic energy.

When the bullet has slowed to 1/2 it's original muzzle velocity, it will have 1/4 of it's original translational kinetic energy. This will happen somewhere around ~800 yards. At that distance, the rotational speed of the bullet will have decayed as well, but not as much as the forward velocity. The rotational velocity at this point will be about 80% of it's original value. So the numbers after the bullet has slowed to 1500 fps are:

Near 800 yards, the bullet will have 774 ft-lb of translational kinetic energy remaining.
Near 800 yards, the bullet will have 4.9 ft-lb of rotational kinetic energy remaining.

As I said, these numbers are open for interpretation. I can tell you what I think about them, but it's just speculation.

At the muzzle, the rotational KE is only 0.2% of the translational KE. This tell me that practically all of the damage done will be due to the bullet's forward motion, the spin being of little consequence to terminal performance.

At around 800 yards, the rotational KE has grown to 0.6% of the translational KE. This is 3X higher % than at the muzzle, but still an insignificant amount compared to the translational KE.

I am of the opinion that the rotational speed, and rotational KE of a bullet are of very little issue to that bullets ability to do damage on a target. I could be wrong (I've never done the test), but the numbers suggest that there is very little energy in rotation compared to forward motion.

-Bryan

__________________
Bryan Litz
Ballistician

I am not disagreeing with results of Dwayne, just looking at other possibilities. I think MD wrote in the past about Barnes having a propeller effect due to the petals. I wonder if this is not because of original twist, but because of the bullet pushing through flesh - for ex, if you push a propeller through air or wind it will start spinning. Maybe there is some characteristic of the 6.5 in this case that does a better job with this effect (i.e. moving slower/less expansion, but spinning faster) where the .270 expands wider and slows down spinning more quickly (like a skater sticking arms out to stop spin). Otherwise more splash with the faster wider bullet, but less of a longer more cleanly cut type hole you would get from a spinning/cutting effect (for lack of better description).

Lou

Mule Deer;
Good evening to you John, I hope the day was a good one for you folks.

I'm not laughing at all...... in fact I ran 5 of our daughter's 6.5x55 rounds into the magazine of my .270 this very afternoon and they fed like proverbial butter - soft butter at that.....

Man this place can be hard on the pocket book sometimes.

Thanks for the "inspiration" to keep the local economy going John, I'm sure they'll appreciate it!

All the best to you and Eileen this fall.

Dwayne

Lou 270;
Thanks for the reply and copied information from Bryan Litz, it's an interesting read to be sure.

Initially I was somewhat reluctant to post this thread - as I've said a couple times it's counter intuitive to say the least.

Anyway I'm not exactly looking to make a .270 work "better" per se as its resulted in dead bucks every time so in that respect its doing what its been asked to.

The results on game were just interesting to me and I thought I'd share them here to see if anyone else around our cyber 'Fire had seen anything like it as well.

It could be that the bullets - maybe only this batch - combined with the twist and bore of our daughter's rifle are sort of "really good fit" that result in better outcomes than I was expecting.

Again its just a fun exercise and I very much appreciate everyone's decorum in their responses.

All the best to you this fall sir and good luck on your remaining hunts.

Dwayne

I'm betting Bryan ain't sent many Barnes in soft tissue, spun hard.

I'm getting ready to send some 55 grain ttsx spun with an 8 twist 223 into several deer this season so assuming the spin theory is correct I just may witness some spectacular results.

Shod