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October 14, 2008

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Petzal: The Great Overbore Conundrum

Once upon a time, the worst thing you could say to a rifleman was that his cartridge of choice was overbore. Today this would be the equivalent of calling him a Clintonista, or slapping him. Overbore meant that his 7mm Thunderf***er Magnum burned more powder than it could efficiently use, and was therefore less worthy in the great pantheon of cartridges than, say, a 7x57, or a .280, or for all I know, a 7x64. It also, by extension, meant that the person who shot a 7mm Thunderf***er magnum was unworthy to enter the Kingdom of Heaven, or was just a squirrelheaded son of a bitch.

There were other concerns. Huge cartridges that used gobs of powder burned out their barrels quicker, cost more to shoot, and were more difficult to shoot than non-overbore rounds. This is all quite true. But there's another side. Sometimes, you want a bullet to go much faster than a standard cartridge can manage, and the only way you can do it is by burning lots and lots of powder. It's the same in automobiles; if you want more speed, you need proportionately huge increases in horsepower.

An example: My favorite .338 load right now is a 225-grain Barnes XXX backed by 72 grains of RelodeR 19*. This gives me 2,750 fps, which is enough for any shot inside 300 yards. If I anticipate a longer shot than that, I can go to a .338 Remington Ultra Mag, which will gulp down 93 grains of RelodeR 22*, which drives the same bullet at 3,020, making hitting at long range somewhat easier. It is, as even the dullest among you can see, a whopping increase in powder for a comparatively small increase in velocity. But there you are.

Overbore, who cares? They are very useful cartridges under some conditions, and even now, as you read this, people are making RelodeR powder and new barrels whether we want them to or not.

*These loads are safe in my guns, but they may blow you into the next world. That is your concern. I assume no liability from now until the end of recorded time.


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Dr. Ralph

First you tell us the .338 or reasonable facsimile is the perfect all around gun... now you're pretty much advocating shooting at ranges beyond 300 yards. You might as well just go ahead and become the new spokesmodel for the .338 Lapua Magnum. Hell it penetrates body armour at over 1,000 yards. No wonder I didn't see your picture at Winchester's web site where they invited a group of so called gun writers to tour their new factory. Of course Bodinson and Carmichel were the only one's I recognized and you were probably in Africa... love you Dave.


Does anybody know where I can pick up a 7mm Thunderf***er Magnum?



The 7mm Thunderf***er Magnum is a creation of AssBlaster Arms. It is a smaller version of the .300 Lightning Sh***er. I'd suggest you google "thunderf***er" and see what comes up.


Nobody is gonna call me a Clintonista, or a squirrelheaded son of a bitch. A .30-'06 with a 165 gr. Nosler, zeroed at 200 yds.
has a nine inch drop and plenty of
stuff left at 300 yds. to kill anything short of a moose or the big bears. For moose, or big bears, the .338 Win. Mag. or .375 H&H Mag. are more than adaquate, possibly a bit "overbore", but who cares with something big and mean enough to put you in a world of hurt? Who needs a 7mm Thunderf***er Magnum, the animal will be just as dead if the shooter places the bullet right. BTW, a .338 Win Mag with a 215 gr. SBT zeroed at 200 yds. also has a 9" drop at 300 yds. IMHO, anyone who cannot get within 300 yds.of their chosen quarry is not a hunter, he is an optimistic artilaryman!

Blue Ox

Is the thunderf***er chambered for the same rounds as the earsplitten loudenboomer?


Blue Ox,
The earsplitten loudenboomer was developed to drive squirt gun shooters off the benchrest range. It really has no practical balistics past 600 yards. The 7mm Thunderf***er Magnum, as previously stated,is a creation of AssBlaster Arms, and is not only viable into the next zip code, will reliably knock the unfortunate shooter off his shooting stool, and at least across one county line. Advocates of the 7mm Thunderf***er Magnum, also developed the "one shot zero technique."


No, since the Thunderf***er drops 0.0002 less than the 30-06 at 300, it is more "accurate". Well worth shoulder surgury and Belltone hearing aids later in life. When you shoot the deer in the ass at 900 yards(as your shot will be off from the recoil), its guts will fly out at the speed of light. Also, when your retinas fall off it will have been worth it. I mean, if you had shot 0.0002 inches higher with your 06 the deer would have laughed at you then farted in your face right?

I'm going to go kill Bambi's dad with my 7mm-08 and a heart/lung shot now. Excuse me.


At least Dave has his head on straight in this respect; you up velocity for the purpose of achieving flatter trajectory and less wind drift so that you can shoot animals more easily at somewhat longer ranges. If he had said, "But there are times when a 225 grain bullet out of a .338 just ain't POWERFUL enough to kill something as dead as it needs to be. THEN I load up the same bullet 250 fps faster, and the animals fall down DRT," we could have had a real good debate. If you want greater range, go faster. If you want greater killing power, go bigger.


I just ate a big plate of beans so I can show off my Thunderf***er magnum...but when it lets loose it opens up a lot bigger than 7mm...!

Dr. Ralph

Yeah eyeball I just don't go along with the BS about pushing tiny bullets faster to kill bigger game. Bigger is what works up close. Just ask your wife...

jersey pig

i'm very interested in seeing the promotional material and the advertsing graphics on the boxes of 7mm thunderf****r magnum. the potential is almost unlimited.

Jim in Mo.

Dave I don't think your loading data for the 338 is out of line at all unless the Triple X's bearing surface is that much greater than the partition.

Rod McPhee

Dave, this was a very irresponsible article for you to write. You created a sweet name for a cartridge which does not exist. Now a bunch of people are going to build custom 7mm Thunderf***er Magnums with non standard chambers and its only a matter of time before someone blows his head clean off with a sloppy chambered thunderf***ker. Next time please have the courtesy to include chamber specs. ;)

Dick Mcplenty

Without the 7mm rem mag,there wouldn't be any magnums for those who can't handle real magnums.

With the advent of range finders turrets and dot reticles,I could care less about magnum anything. I've yet to see a barnes x stay inside an elk inside of 750 yards,using the various 06 based cartridges..

Clay Cooper

.338 Remington Ultra Mag, which will gulp down 93 grains of RelodeR 22*, which drives the same bullet at 3,020?

You got to be kidding!
I’m shooting a 225 grain Hornady out of my 338 Win Mag with 72 grains of IMR4350 and doing that and it knocks any Moose’s $ick in the dirt just fine!

Overbore .338 Remington Ultra Mag?

How about over cartridge!

Clay Cooper

.338 Remington Ultra Mag, which will gulp down 93 grains of RelodeR 22*, which drives the same bullet at 3,020?

David, I can do that with my 338 Win Mag, 72 grains IMR4350 behind a Hornady 225 grain soft point @ 3083fps. And yes, I’ve watched a many including my Bullwinkle’s bight the dust as if they were hit by a 460 Weatherby Mag.

Is the .338 Remington Ultra Mag over bore, no.

Just over cartridge!

Clay Cooper

Dick Mcplenty

The best Moose kill I ever witnessed was a kid with a 30-06 shooting 180 grain Remington’s!

Clay Cooper

7mm Rem Mag is best with light weight bullets for open country. Whatever you can do with bullet weights over 162, I can do better with my 30-06!

Clay Cooper

The best thing and only good thing about the 7mm Rem Mag is its empty brass? It makes darn good 338 Win Mag cases, just punch the neck out and I also use 300 Win Mag cases also! Now a 264 Win Mag? O’so sweet out before its time, just needs a better barrel!

You want to really try something? Try a Ruger #3 loaded at 458 Win Mag velocities!!! Nothing kicks harder than a 3½ 12 gauge!

Clay Cooper

Ruger #3 45-70 that is!


Unless something better than smokeless powder is invented, the 7mm Thunder****** has pretty much been invented. Check out this link.


I admit to never having held a Lazzeroni rifle in my hands, let alone firing one. But I think we've just about hit the max here. Anything that shoots faster than these will need fire-and-forget technology. A .416 that shoots almost point blank to 400 yards? You'd have to buy your Lead Sled a Lead Sled!

Scott in Southern Illinois

This is an awesome thread! I can see the commercial now on Wednesday Night at the Range: (cue heavy metal/Sly Stone Funk music, irritatingly typical in today's hunting video) AssBlaster Technologies introduces the 7mm ThunderF****r Magnum (cue hot chick holding and firing the rifle in a bikini ala Sarah Palin). Jim Scoutten's voice states "the all-new ThunderF****r Magnum is ideal for taking extremely dangerous game at any distance. Just point and shoot. As your PH lases your bull, the AssBlaster Technologies laser-guided bullet will seek and destroy its target post haste. Get yours today! Shoot straight, shoot often, and, share your sport!"


C'mon Dave, REALLY go for it! Cram a full hundred grains of the aforementioned powder into your case, add 4" to the barrel and get up to Mach 3! Imagine the boys' faces when they see that Chrony register almost 3400fps for a .338! A true half-mile shooting rifle for sure! Mach (bleepin) 3 or bust! We don't need no ScentBlocker clothes, no stinkin camouflage, no we don't need none of that stuff! Just give us the Mach 3 version of the ThunderF***r Magnum and point us to the nearest high-fence elk ranch! No stalking, no treestands, no problem! Mach 3 baby!

Oh, just one little request? Don't call what you do with one of those damnable things 'Hunting' because it isn't!


Putting the right bullet in the right spot is far more important than speed or size of bullets. Match your bullet to the speed of your round, barrel twist and the size of the game. Big and magnums are not always the answer.



I'll one up you on recoil. Try a 45/70 round in a New England Arms Handi-Rifle. Ouch! I will give you style points for the steel buttplate on the #3. Used to have a #3 in .375 Winchester. Using the 235 grain Speer Semi Spitzer in hunting loads it would get your attention from the bench.

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