Asking this as narrowly and specifically as I possibly can. From people who have actually owned, fired, and better yet reloaded for the Remington 8's or 81's in .30 Remington chambering, which bullet weight was more consistently accurate - 150 or 170 grain?

I've been around over 6 decades and shooting 5.5 of those and already know all rifles are different. I'm looking for actual results people with actual experience have attained.

Roger

I like the 150gr Flat nose bullet (30-30) and 3031 powder.
I reload just barely up from minimum loads published in old Lyman manuals.
Action function fine and accuracy is more than acceptable out to 100yds which is what my Shooting Range is limited too.

I'm not an accuracy fanatic, but it's a comfortable load to shoot in the Model 8
(I don't have a Mod 81 in 30, just in 35)

I load similarly for Mod 8's in 25, 32 and 35 Remington.

They are just range toys for me. But the 32 Model 8 took deer in the hands of a family member for several yrs in a row with reloads. A couple were single round kills out to (estimated) ranges of 80 to 100yrds.
Those bullets were 170gr (IIRC) 32 Winchester Special FN SP jacketed bullet reloads in 30Remington reformed brass. 3031 powder once again.

The groove dia usually runs a couple .000 small on the Model 8 rifles from what standard 'spec' is.
30 Rem will likely measure out at .306d
32 Rem at .320

Maybe the thin jacketed 30-30/32Spec bullets aren't bothered by that.
I've shot cast lead in them as well and they seem to shoot just as well.
The 32Rem was very accurate at 50yrs with a reduced load of Bullseye and a .320d cast lead 8mm Nambu pistol bullet. IIRC they were 85grweight.
Manual action operation of course.

Fun rifles as are the Winchester SelfLoaders

I have a Remington 141 in 30 Remington, I use the 170 grain and load with IMR-3031. I get around 2 inch groups at 100 yards, but honestly, that is more my old eyes than anything else.

I admit that I do not meet your criteria of owning a 30, so stop reading here.
I have, however, owned two 35 81s, (and still have three 141s) and a friend had a 30 81. These rifles are not made for accuracy, as we know it today; the entire barrel and barrel extension assembly moves, a Browning feature, so they will never be MOA rifles. They were made for hunting.
Bullet weigts mean nothing, and the only way to see is try for yourself. As you said (Ok, for anyone else who might read this) each rifle is different.

My model 8 has never been very accurate. I worked up a load with cast bullets that is reliable, doesn't foul the bore, and is fun to blast cans and bang steel. I have a red dot sight on it (fastfire 3) that is good enough for this.

I've owned a lot of 8's and 81's i already know how they work. i've taken them apart all the way down the last screw and put them back together and they worked fine. I also know what kind of accuracy i can get personally with open sights. my last 81 in 35 would hold an inch at 50 yds and when i can get that with open sights i'm quite content. why do people always assume the other guy is ignorant. rhetorical question.

All i wanted to know - call it a survey if it makes you happy - is what results people got out of the rifles in the 30 remington chambering. And it appears a few people actually knew what they were talking about.

All i wanted to get a feel for is if there's a great disparity in the accuracy one can expect between the 2 weights.

Thanks!

Roger

I'll be interested to see if anyone can share any actual experience, although I doubt that what is true with one M8/M81 will necessarily be true with another.

I recently acquired three old Remingtons as a package, an 81 in .300 Savage, and M14's in .30 Rem and .35 Rem. The two M14's go nicely with the .25 Rem which came from my wife's father and grandfather. Haven't fired any of the three latest, but got enough factory ammo in the deal that I'll never need to load anything for them.

Ive owned a 8 in 30 cal. and a 300 Savage in the 81, fun gun to shoot and hunt deer with back in the day I used 30-30 starting loads and worked up loads based on feed and function in my 30 rem. Thats been a number of years ago, those big heavy rifles were all but recoilless...and factory ammo was abundant..

I'll add a data point or two when I get my circa February of 1923 8 to the range here shortly, but I am afraid that I am shooting cast, gas-checked and powder-coated boolits of 180 grains.

Id venture to say based on having both at one time or another that ballistically the 30 rem and 30-30 win are equal in all respects as to the 150 and 170 gr. bullets effect game and accuracy and all that depends on the individual gun..