Biggest cartridge/caliber YOU can shoot comfortably?

When I was shooting a stock Remington Sendero in 300 WM (w/ a Gen II RAZOR & bipod) I was good for 30 - 40 rounds w/ no issues afterward. I was shooting 180 gr E-tips w/ 78 gr Ramshot. I actually haven't used that gun in like 2 years. For a stock rifle it shoots exceptionally well. I've just been using other rifles for range, hunting, etc. I think I've been spoiled by the short-action w/ a muzzle brake...

I too have good praise for the Rem sendero. I recall practicing for a buffalo hunt shooting my father's Sendero in 300 WM no brake with a leupold, no bipod on it about 7 years ago. I put at least 40 rounds through it per session for 3 sessions. This was when I was a junior in high school and weighed only about 170 lbs. It was a very manageable rifle to shoot. It kicks less than my 700 25-06 Mountain with a pencil barrel. I too have been spoiled by short actions. I have killed quite a few elk with my 243. Its all about shot placement.
 
I shoot a 300 H&H with 190 SMK with no brake. Weighs about 13 pounds but I load up 50 rounds for this rifle. I'm out of ammo in the same amount of time as my similar 25-06. Really, it as all about getting square behind the rifle just like the videos by LL and Rifles Only instructed.

.300 H&H.. what kinda rifle is it in? Cause Im picturing like a awesome pre war M70 or some sweet Griffin & Howe custom built 1903
 
300 win mag,is the upper end of My limit,just not real pleasant to shoot. Can shoot about 5 rounds before I start to flinch. My goto is a 7mm rem mag,can shoot it all day.
​​​​I'm 5'11,and 180ish.
 
300WM ~12lbs. I can shhot quite a bit accurately with no tendency towards flinching, but I can't say it's pleasant with 200gr bullets. If I back down to 125gr or 110gr screamers ar 3600-3800fps it's pleasant.

What I really enjoy, as the best balance between performance and shoot-all-day ability, is my 243AI. Pretty much same trajectory to 1000 just less energy.

Just finished my 338 Edge, yes it's braked and it is really a hoot and pleasant to shoot (1.1-1.3" groups at 300). Somw day if I have the brake off I'll have to try it.
 
If we are still talking unbraked guns, my rem 700 Classic 30-06, at 7.5 lbs it's still comfortable to shoot, maybe not for 40-50 rounds but for normal load development, sight-ins, etc, its just fine. Now, the 338 Winchester magnum, forget it already, lol.
 
In my youth for whitetails I would use a P64 70 loaded balls-to-the-wall with H4350 and a 165 Sierra. The 70 got sold, right shoulder had surgery and I got two plus decades older. These days it's a Belgian Mauser .270 with a very moderate load of H4831 and a Hornady 110 gr. SP. Prone rifle is a 12 # .308. That's all I want anymore.
 
Largest caliber I shoot consistently is a 300 RUM custom r700 that weighs about 13lb. I haven't run into anything, caliber wise, I wasn't comfortable shooting yet though. I have made it up to 338 RUM thus far, with a bunch of stuff in between.

I do have a Browning A Bolt microlite in 260Rem that has the most felt recoil of what's in my stable currently.

I did have an old Remington 721 in 30/06 that was downright painful to shoot due to the shitty ergonomics of the 1940 stock! That one is now a custom 280AI that I can, and do, shoot all day.

As has been stated previously, it's mostly about having proper form. You can't help things like metal buttplates and too much drop in stocks other than replacing them though.
 
Shot up to .50 in the AW 50 and .338 in the AI and blaser, definitely wouldn't want to shoot them all day. My unbraked 9.3 is tame by comparison to the .338. Saying that, my mate's browning maral in 9.3 has a lot sharper recoil than my tikka. Am keen to see how .300NM compares to the lot when it shows up.

I had the opportunity to shoot the 338L side by side with a 300NM, both had Surefire brakes and the Norma was a longer slower recoil impulse. The 300WM doesn't push as hard as the NM or the LM but has a noticeably sharper kick.
 
.308 un-braked is my limit, target gun weighing 12lbs or pencil thin tikka doesn't matter. I have a Gen 1 30-06 Remm 700 Ti that kicks like a mule without a brake at 5.5 or 6lbs, I sight that in and use it in the tree stand. Had a savage long range hunter that I sold, I couldn't tell the difference with the brake closed or open on a 300wm, that was too much recoil for me. I do have a rem 700 300wm in an AICS Chassis (MK13 clonish) and i can shoot that suppressed all day, even my Sako TRG in .338 suppressed can be shot until i run out of ammo-$$. To me the muzzle brake/concussion is what induces a flinch more than the recoil. Switching to suppressors has helped my shooting.