Home Forums Hunting & Shooting Hunting Rifles 7.62x39 vs 6.5 Grendel vs 6mm ARC

But why not just use the most objective answer sd? Weight retention is a subjective way of saying same thing.

And yes, are gold dots not fusions? Bonded? So I ran accubonds a long time and they worked great but I run slower stuff with eldm type bullets now and get more drt’s and shorter recoveries but I choose a pretty high starting sd because it ensures the depth for game intended while the bullet does way more internal work and gives up more weight...you make that sound like a bad thing? It’s not, it’s actually a great thing but you have to get the formula right for game intended.

You lose sd as you go, the more you lose the more damage happening in critter. Many formulas work. Some like more insurance and poking holes for blood trailing, others like the more drt formulas. If you’re gonna play on the niche end you need to have a really solid handle on this stuff and most objective handle possible.

And yeah the fmj solids examples in Africa teach a lot about the subject. For dangerous game you need impacts at least 2200 with over .3 sd solids or you risk becoming grease spot. You can get there with a 6.5 man licker or 7x57 with the heavy for cal fmj or a 300 gr 375 h/h etc. The 6.5 has better formula than the 700 nitro express. Go math it yourself. There’s a line between the spear and the sledgehammer we play with the 700 nitro went too far to the sledgehammer and can’t reliably get deep enough, not enough sd for velocity or not enough velocity for sd...for game intended. However you wanna see that but you have to add either sd or fps to make it work.

We don’t need to push things to those extremes here as we shoot variable sd bullets. So you wanna dump all the work over 14” or 36”? How much work you wanna dump over that range? That’s where energy will make an arguable measure but we have to understand how it applies over distance traveled inside animal or more accurately per inch of travel. Ie; a 416 on a goat, can likely do 4’ of penetration so x ft/lbs per inch over 48” but goat only 14” wide meaning the hillside gets all the work, but a 130 gr bt from a 270 flattens said goat...more ft/lbs per inch over way less inches, in case of goat getting formula right for game intended. Or somewhere in between? You can match things up very nicely for game intended.

So anything burning 30 grains of powder for big game is niche end. So particular care in bullet choice required. Already this a slow speed cartidge and you’re fighting an uphill battle thinking mono’s or bonded as your already at tail end of performance window as soon as you get 100 yards down range. This screams for squishier bullets, the 6.5 123’s nothing will take those in the ribs at 400 yards, even from a 16” barrel you’re still around 1820 at 420. Bullet behaves like a bonded there, nice big mushrooms and high weight retention, the mono has pathetic bc and needs 2000 fps to think about doing decent work, so where does that land for distance? If you play at niche end you want max efficiency if you want more than 200 yard option. It’s nice that it’s available. Elk and moose in ribs at 400 is a real thing, deer to 658 and antelope at 752 recorded from Grendel 123’s, the 7.62 could never get close to these capabilities, it’s a different level below the Grendel and arc. If 200 is fine then most choices will work. For moose and elk size game I still want .25 sd or higher and enough bullet to shed and work well and not driven too fast to shorten its depth. If you want most efficient and versatile use of 30 grains of powder you go Grendel and 2nd best arc lol. Otherwise I’d go 30-30 over the 7.62. As twiggy says, bullets matter. Always start with bullet, then figure out what case will push it for game intended.

If I am forced to go monos one day I would compensate by going up a full powder class and get 6.5 Creedmoor to keep similar distances with my 123 Grendel. That’s how inefficient monos are. Would not waste time on monos from these little squirrel guns.

I won’t be nearly as windy: No, SD has nothing to do with weight retention or bullet construction or expansion. You just have some belief in BC on a target, re-badged as SD. There’s no ‘formula’ for it. Long for caliber is long for caliber. High BC is high BC. Heavier weight weighs more. Expansion is expansion. Velocity is velocity. Bullet construction varies. Target density varies.

SD? It’s visiting a palm reader.


SD is purely SUBJECTIVE.

EVERY projectile of like diameter and mass,share an IDENTICAL SD “value”,which is more than telling. Hint.

Aero form(BC) is the driver which factors drop,drift and impact velocity most. Not that Brokedick CLUELESS Droolers ain’t a fhuqking hoot,”explaining” her Google. Hint.

Fhuqking LAUGHING!……….

take a seat stick you bowed out of this long ago, I'll take it from here

whiskey, you can measure the final sd of a recovered bullet, an actual objective number to work with, you can measure distance travelled once the swimming started...another objective number, you can measure the energy dump along that travel...another objective number...just because we aren't doing that yet doesn't mean it isn't coming, sectional density reduction rate (sdrr) and energy reduction rate (err) should become things one day to help us get away from discussions just like this

try to imagine for a second that we had a terminal ballistics calculator and all the knowns were shot into gel and the sdrr/err factors known at a couple impact velocity points, imagine being able to predict terminal performance as well as we can with inflight performance, we're a little behind considering we're a quarter way through the 21st century lol, but at least nearing turn of century someone went down 'temp wound stretch permanent cavity' route and tried to make a more objective look by looking at actual wounds...it was at least a step in the right direction, but we've completely ignored the bullet, the finished bullet, it has measures, it actually tells the story, the 'rates' at certain impact velocities tell the story of all that temp/perm stretch wound cavity etc. lol

we will get this subject more objective one day and it start with discussions like these, zillions of them, I think I started banging on about what we're missing in about 2020 on Alberta forum, but may as well have it here too, Hornady...offer is still there to have me come develop this out for ya, don't be trying to steal my work

anyway, all the topics on terminal ballistics are mostly palm reading, and most guys choose from the knowns without really understanding or being able to visualize things and they don't have to, but you sure do if you're going to play on the niche end of the spectrum, and it's why I was able to take factory 123 gr grendel for 6 years exclusive on Alberta big game, 7 species, 10-420 wars, average shot distance around 160-165, average recovery distance around 10 yards, and we walked up to everything right after shooting, 20 animals, and only surprises pleasant ones, it is the most efficient choice for burning 30 grains of powder going

so I don't think you're ready to take this much further, you've got a formula that works for you but there's actual numbers behind it that are objective and are doing the work

one day we will have that calculator that will show you exactly why the 35 gr Berger is the top choice for fur guys on coyotes from a .204 ruger, and then everyone else wanting to shoot coyotes for fur can compare or even design new combo's against that formula to make sure they get it right, then one will be able to see why the 700 nitro would knock elephants out but the 6.5 man licker could reach the brain pan and turn out the lights despite some 7000 ft/lbs energy difference lol, or why the 416 goat was just an unimpressive hole vs the .270 win 130 bt lighting....we'd be able to see all the known winners, the 30 cal 180 grainers...and compare every single thing against them, then the rules of thumb would be so much more accurate, we'd know what a 20" combination is, we could plan for a 36-40" combo's for Alaska hunts perhaps, or Africa too, we could go see what our .243 55 gr bt is going to be like on a coyote vs a 35 gr Berger from a .204....and ALL these arguments online would be the same length as the inflight ballistics arguments now....really short discussions

so, since we aren't fully there yet, and we do still shoot variable sd bullets from rapid/maximum variable to slow/minimum variable and we already have our general rules of thumb for class 2 size game of around .2 sd and for class 3 size game .25 sd then those are the numbers to start with, it will allow you to understand why the twigster chose the 120 mono from the 7-08 vs the 120 bt for his 5 1-shot moose kills....see that's pretty niche end of spectrum to go after large AK moose, already starting with minimal bare sd and not a ton of velocity to compensate so you have to keep as much of that sd as possible for widest variety of shot angles, the 120 bt...we can feel that it's going to maybe only go 1/3rd as deep, so we can 'feel' that it would be a ribs only ideal shot opportunity option for big ole moose but the mono will punch through quartering shots and still get far enough, and a calculator looking at the right information would tell us this so stick didn't have to bail out on this conversation, glad you stuck around to find out

so yeah, you definitely want sd in your top 3 considerations for game intended, which are sd, construction, impact velocity.....that's the formula, full stop, it's dynamic subject and we can get off in the weeds discussing expansions or whatever but eventually we will be able to recommend a 30" combo that dumps 100 ft/lbs per inch etc.....the wound channel will be explained by that, the expansion will be explained by that, sd is a mandatory number for what we do

lol…you can measure ANYTHING before and ANYTHING after, but you have no idea what happens in between…..you can GUESS, based on bullet construction, impact velocity, medium, etc….enough to have expectations. We have varying weather, too….bit we don’t call that ‘’Weather Density’, just to plug a cool term that nobody can deduce a value for knowing or caring….without pages of mental gymnastics.

In my head I kinda see it as an integral. The change of SD of a bullet over path, ecompassing all mentioned so far. I don't think theres any constants to take outside of the integral to make it easier/simpler though lol. Limits/boundaries of the integration are zero to wherever it finally stops, of delta mass in pounds over delta diameter squared. Now that takes into account penetration depth, projectile expansion and protectile weight retention lol.

Now theres some overthinking

It’s funnier than fhuqk,how “REAL” her Imagination and Pretend are…to her. Hint.

Fhuqking LAUGHING!…………

And that’s what we do, is guess. We don’t measure, why? Too much work for manufacturers? Not enough budget for gel? We should measure it’s time, we can sink bullets into milk jugs at two miles because we have 21st century measures and calculators for inflight ballistics but we’re still in the just throw a 180 out of a 30 cal and yer good terminally...that’s a facking joke to me. Note: If we Google weight retention and sectional density...one of them relates to penetration, so let’s at least use that objective starting point.

And as we see, our own subjective internal interpretations and imagination of terminal ballistics playing out here and every other facking thread. It pains me to see this this far into the 21st while we have inflight down to milk jugs at two miles lol.

I’m doing my part to objectify it as much as possible. We all have our own interpretations from observations etc of what lower and higher sd combined with construction type bullets will do for animals we envision.

But let’s absorb this new perspective for a minute before arguing it. I happily ask for further dialogue, inputs and ideas to objectify things even further.

Been at this awhile though and haven’t seen a better formula yet to predict than sd/construction/impact velocity, for game intended. It’s the most complete and objective we have for a good long while now, we still have to do the imagining of what each choice will actually do to animals. Weight retention is just a more subjective way to explain retained sd (or deeper penetration due to higher sd). It is NOT an irrelevant figure but rather one of the top 3 most essential figures to start your math.

Stick you’re embarrassing yourself, take a seat, this is too much for you.

I use a Grendel Howa mini w/ 23” stainless bbl I chambered for it. I went with modified mono bullets. To offset the reduced velocity I shortened the 120 Etips in a precision collet setup in my lathe and ended up with an 87gr boattail Nosler Etip. These seem to be softer than most monos and also have a larger base plastic tip/hollow point. My impression so far is they have a lower velocity expansion window and out of the Howa and 8208 powder velocity is at 2930 fps. Still haven’t caught one in a deer but they have killed exceptionally well and I see no reason to change yet. I figure these are as good as anything to 300 with a good flat trajectory to boot (to 300). With the solid shank retaining weight it’s the best of both, quick full expansion and plenty of penetration for deer sized game. Anything bigger than whitetail and farther than 300 yards I use more gun.

I misspoke on the velocity, just looked at the box and I have written down 2982 fps…that’s impressive performance out of the little Grendel case IMO and does a good (great) job. No need to look further for me.

88 ELD’s in my 19” Mini Howie Carbon Wueen are fhuqking hammers and CRUSH all things 7.62x39 and 264 Grendel. Hint.

Pardon my simply shooting it all. Hint……….

That’s dedication msalm! Can’t get that off the shelf.

Great cartridge, worthy of all levels of engagement imo.👍

In a 23” tube factory Hornady black 123 eldm with .252 sd will still smash elk/moose in ribs with over 1800 fps at over 500 yards and it's got enough penetration for class 3 game. That's my draw, deer size game are almost too small for this combo. I rarely keep an eldm in deer size game, even out to 420 from a 16" barrel and 1820 fps impact, quartering exits. Need steep quartering and larger bodies to catch things in the offside. Internal damage is average broadside as half the work potential went out the other side, but steep quartering on larger critters its truly amazing.

Dang mslam that is cool!

so the thread is about 7.62x39, 6.5 grendel or 6-arc....3 factory available cartridges...none of them .22 cal lol, wtf are you doing here, seriously, take a seat, this just ain't a thread for you in several ways, beat it

I've killed plenty with the grendel and the arc, and I'm really taking a liking to the arc cartridge. It's a deadly little fellow. My howa mini is stupid accurate with hsm 95 gr sst. I hope to start load development for it and my AR this week.

I shoot 6 PPC too,also in wares that exist. Hint.

Pardon the 22 ARC,but Crying CLUELESS Kchunts will always find reason to Whine. Hint.

Fhuqking LAUGHING!………….

I currently have Howa minis in 20, 224, 6mm, 6.5, and 30 cal Grendel versions. The 30 is actually a .311 bore 7.62x39 factory barrel I opened the chamber with a Grendel reamer. Wanted to get the 125 class bullets up to the 2500 fps range or at least a little better than the x39 case. Haven’t shot that one too much to see if it played out as hoped. The 20 is great with BIB’s 40gr hp’s at 37-3800. Was hoping for 4000 and need to play with powders yet.

I shoot a fleet too and the 243 with 112’s has the most ass. My 7” 224 with 88’s, is the most fun. As diameter goes up,performances and BC goes down. Hint.

Cryote is obviously fhuqking CLUELESS. Hint……..

haha, Cryote is best thing you've said all thread, thanks for the laugh, and awesome projecting

did we figure out the best one for the OP yet? hint....haha

Well I like the Grendel and ARC better than the x39 no matter how you look at it. If I were hunting elk or moose I would pick a different rifle. If I expected to shoot game animals where shots were farther than 300 yards I would choose a different cartridge. That said I say own both an ARC and a Grendel. ARC for deer and varmints the Grendel for deer and hogs.