Best power/weight ratio in a repeater?

My keltec SU-16c weights 5 pounds and accepts a 30 round mag of 5.56 Nato giving it 10,500 foot pounds of energy per pound of rifle.

I would think one of the .30 cal or 8mm semi autos from post WWII would take the win here based on your strict parameters. I think the G3 carbine platforms, capable of firing 180 gr .308 from 20 round magazines would win on the weight per KE category excluding such specialty weapons as 50 BMG, 12.7 or 20mm anti-materiel weapons and some of the really wicked safari rounds where even a couple of rounds, or perhaps a single would eclipse 20 rounds of even .300 WM. There are probably some ARs in .308 that would be even lighter with the same 20 round magazines. Somebody has probably built one in .358 win.

How about a rossi 92 in .454? The 16” barrel holds 8+1 and can launch a 300 grain bullet 1900 fps.

AR with that weird drum mag would take the win.
In a non-ar, the 454 Rossi would be a top contender.
There's a reason it isn't made anymore. It was too much power for the strength of the action.

My Guide Gun is just over a yard long, weighs 7 lbs and holds 5 rounds of .458 caliber lovin’ that can fling a 540 gr hard cast with enough oomph to drop a Cape buffalo with one shot... and leave a bruise on my shoulder for a week.

I dunno if this is the most powerful small repeater out there, but it certainly brings the mail when hotrodded a touch.

Stay safe.

m1 garand in .458Win (should hold bout 5 rounds I think)

BAR .458 (3 in the mag)

rem 74/76 series .35 Whelen 10rnd mag

Smaller rounds that really sizzle usually have comparatively higher energies in general. The cartridges also weigh a lot less.

Rough estimates.

A loaded up Marlin SBL with hottish ammo (325gr @ 2000fps) would have around 18,000 total ft-lbs from a 6 round capacity whereas a loaded up AR with normal 55gr load would have 38,000 total from a 30 round capacity. A higher cap mag would be even more “powerful” and only marginally heavier.

Marlin probably weighs 8.5 lbs loaded with no optics and the AR probably close to 8 lbs based on typical builds with no optics.

That difference is quite staggering to look at only through numbers but it also illustrates how pure energy numbers don’t tell the whole story an sadly, how it is not a great way to compare power/weight ratio of firearms. It sets a standard but is misleading.

Things like what the rifle will be used for are not taken into account. Good for academic study and interesting to ponder but when it comes down to it, firearms that typically can be had in larger capacities are always going to win. AR-10s can be built so impractically light as to be unusable and as such could have a crazy ratio. Something like 52,000 ft-lb in a loaded up 7-7.5 lb rifle.

The Rossi 92 .454 would have about 22,000 total energy from 9 rounds. It must weight around 7-7.5 lbs loaded too I would think.

Since I have just now seen your post about about gun handling, I will say that a lightweight AR-10 would handle great but would have terrible recoil. So it would be impractical.

LoonWulf said:

rem 74/76 series .35 Whelen 10rnd mag

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This. I researched the subject a few years ago and this was pretty much the most firepower and stopping power I could reasonably find in a relatively lightweight, carbine-sized package. Rechambering one to 9.3x62 would up the ante even further, but only marginally.

hq said:

This. I researched the subject a few years ago and this was pretty much the most firepower and stopping power I could reasonably find in a relatively lightweight, carbine-sized package. Rechambering one to 9.3x62 would up the ante even further, but only marginally.

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A 35 Whelen AI can get a 300 gr bullet up to 2300 FPS and fire and eject reliably from a 7600. This would also be a formidable option.

earlthegoat2 said:

A 35 Whelen AI can get a 300 gr bullet up to 2300 FPS and fire and eject reliably from a 7600. This would also be a formidable option.

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Back in the day Bonnie and Clyde were confronted by lawmen using (among other guns) “police issue” Rem Model 8 .35 Remington and .25 Remington autoloading rifles, so the .35 Whelen - .35 WAI in a large mag auto like a 7400 is certainly a more powerful critter than the model 8 for sure .

As for the .458 BAR, I always wondered what a .416 Taylor would do in a BAR... if proven reliable one of those may be the ultimate heavy-cover Kodiak Island rifle

Stay safe.

Alaskan Ironworker said:

How about a rossi 92 in .454? The 16” barrel holds 8+1 and can launch a 300 grain bullet 1900 fps.

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That's what I was going to say. I don't know if its the most KE per lb or whatever, but it certainly is one of the most formidable little thumpers around.

Hmmm. My 1895 CB holds 9*1, and the buffalo bore 405 gr is clocked at 2000 FPS from a 22” barrel... out of the CB’s 26” barrel let’s assume it’s about 2150...for 4100 ft lbs... x 10 shots... ouch!

Despite its seven pound weight ( unloaded) the CB’s 7.5” longer barrel makes the rifle not as compact or tight-space handy as the Guide Gun is... and even that’s not as handy as the smaller 1892 style Rossi . I think the Rossi .454 wins in the most compact thumper category.

Stay safe.

A 12 gauge with Brenneke 3 inch black magic mags has got to be in the running? They kill at both ends!

1 3/8oz (602 grains) at 1500 fps for 3000+ foot/pounds at the muzzle

https://www.brennekeusa.com/hunting-ammunition/black-magicr-magnum

Edit: they make a more stout slug load! The magnum crush!

1.5 oz or 666 grains at 1600 for 3800 foot/pounds

https://www.brennekeusa.com/hunting-ammunition/magnum-crushtm/

Now I want to try some! (Or maybe just one...)

Didnt even think of shotguns. Yeah, a ksg loaded with brenneke in one tube, and buckshot in the other would make me feel pretty safe in my home or in bear country.

Capacity is a bit of a cheat, but I'd say that for a single bullet, the biggest power-to-weight ratio is probably the sporter-weight safari rifles. You can blast cartridges in the >5000 ft-lb "screw you" range like 458 Win Mags and 416 Rigbys from a 9 or 10 pound gun.

what about an AR10 in 308 with a 20 round mag? That is 2660 ft-lbs of energy per round TIMES 20 rounds. Thats 53,200 total.

I’m not sure what sense can be seen in multiplying by magazine capacity. You don’t take that magnitude of force in recoil and you can’t apply that magnitude of force downrange either. Hitting a steel plate with a full magazine of 5.56 doesn’t make a hole, while hitting it once with 338 Lapua can. Shooting an elephant at 50 yards with a a 500 rounds of 22 long rifle doesn’t create the same influence as one round from a 505 Gibbs. The formers in each case don’t separate shoulders or detach retinas, whereas these are real possibilities for the latter two.

At what range are we measuring KE?

What cartridge and rifle platform combination provides the best ratio of power (measured by total KE delivered from a full magazine) as compared to weight?

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A belt fed would likely win, at some point the number of rounds linked would marginalize the firearm weight to the point of insignificance.

Ft/Lbs of energy per pound might not tell the whole truth anyway.

A Calico 9mm with a loaded 100 round magazine is 8.8 lbs, using Winchester 115gn +p (455 ft/lb per) gives us 45,500 ft/lb total energy. Around 5170 ft/lb energy per pound of weight.

An M82 with 10 rounds is 32.7 lb, with say 14,000 ft lbs per shot would be 140,000 ft/lb total but only 4281ft/lb per pound of rifle.

If we divide 14,000 by 455 you would need to hit the intended target over 30 times with the 9mm to deliver the same energy as a single hit with the 50 BMG.

Fun to play with the math but useless beyond that...

I think a .308 Scout rifle at 7lbs with a 10 round magazine, or a Remington 760/7600 in 35 Whelen with a 10 round mag would both be respectable. 10 rounds of Whelen would give about 35,000.

I own neither a 35 Whelen, nor a 10 round magazine for a 760/7600. There was a thread back in 2008 here that spoke of Triple K, Eagle and D&E magazines (the D&E would hold 12) for the pump Remmy, but I can't speak of the reliability of any of them.