Mid/Big Bores?

Currently, my biggest caliber is the Marauder in .25. I have been taking a serious look at the .357 specifically in the Air Force line. Ballistics resembles a 9mm carbine, or just about. Targets will be pest control like nighttime fox and coyotes and maybe daytime long distance groundhogs.

The over bearing question is, dollar for dollar, am I gaining anything over the .25? Ammo suddenly triples in price plus another $1500 in the rifle with good glass. I'm conflicted with this purchase.
 
Don't own a big bore! but like you been considering one.. I have the condor ss in 25 that I do like & personally believe a NSA 55.5 gr would do the job on coyotes.

My reason for considering a big bore was for deer, it's the law in my state! nothing smaller than .357 cal.

I was thinking about the Benjamin bulldog if I was to get one .
 
Airguns and in particular big bores are really not a game of justifying dollars over xx... If it were purely a fiscal decision, a powderburner would be the best option.

That said... I'm full in. I've got a dozen or so mid and large bore airguns. 

With proper shot placement that Mrod should take care of what you described. Of note, too is that if you get into big bore, you may as well get into casting.
 
You have a Mrod .25 I've owned a few Mrods. Great airguns. 

What do you shoot? Distance groups, BR, FT, hunting bigger pests or game? I went with a .257 Scandalous with Lilja barrels.

I can send 62-92 grain .257's from a 1-14 & 88-110 from my 1:10.

72 grain @ 1080fps. Bc .212. That's some serious long range plinking.

Sub 1"moa is literally easy for this thing. I'm mainly a long range plinker but I pest house sparrows at 10-60 yards with my .177 EVO-10E Steyr and FWB300S. 
I hunt Whitetail with my traditional & compound.


 
I'm not sure how you have your marauder tuned or if you have any aftermarket parts in it, but you may not need to go up in caliber just in power. In stock form the marauder .25 is a 40 fpe gun. Usually pushing 25gr pellets at 850ish fps. This is what I started out with as well. Great gun for the money. If you decided to get something like a kalibrgun cricket, taipan veteran, fx wildcat or any number of guns that are capable of 60fpe. You would be able to push the 34gr pellets at 900fps for some serious power over your current setup. I currently have both a cricket and veteran setup one at 870 and the other at 910. I've taken something like a dozen foxes with this setup out to as far as 65 yards and its worked flawlessly. Two different times shooting doubles. This would allow you to stay in the same caliber and interchange ammo from one gun to another, while keeping your ammo cost down. Or you could be addicted like rest of us and go out and buy a totally unneeded fx maverick vp .30 cal like I did 😜. Just food for thought. 
 
My 257 that I got rid of was pushing 200 ftlbs but it was a Doug noblized valve with a long tj barrel on it 85 gr spitzer at over a 1000 fps I don't know what the Texan 257 will do. My 357 Samyang recluse is at 200 ftlbs with a valve upgrade but think 357 air force is around 300 ftlbs if you want longer range for coyote and fox hunting I would go the 257 route 200 to 300 yards people are taking coyotes with it 
 
I recently ordered an Ataman. 357, and my reasoning is for a bigger pellet. I enjoy big and slow rifles which produce a reasonable kick and a big thud! The Ataman will not be legal for deer in my state, but I'm not looking to deer hunt with an airgun. We only recently got away from shotguns to straight wall cartridges. 

I would decide what kind of lead you want to throw and go from there. The Ataman will produce 150 fpe, which is triple the energy of my .25.
 
 Before you purchase anything, look at your state game laws concerning airguns if you plan on hunting with them. In Tennessee for example, you can use up to a .25 caliber for most small game. Big game requires at least .35 caliber. So if you have a .30 caliber, it’s not legal to for either and you can’t hunt with it. Airforce makes a very good product and you will be happy with one. I own a .35 Benjamin Bulldog and like it so far. It’s a little more affordable than the Airforce and there seems to be several showing up for sale in the classified on a regular basis at a good price.