The books list as high as 77 grs of imr 4350 for a 165gr 30 cal 300 win mag.
At 3300fps.

I also have a 28" barrel, your 300 may be a 24" barrel- i dont know.

When i had a 7stw- i couldnt get 3550 and a 140 with a 26" barrel, im not calling you a liar, it just wasnt achievable in my rifle.

The laws of ballistics, would state that the 300 would push the same weight bullet faster at the same pressures, with the same powder charge the 7mm option would have a higher pressure and higher velocity.

My loads are all chrono'ed. With two systems. It isnt bs.

The calibers that ive seen that have a tendency to be hard on a throat are usually significantly over bored. Massive amounts of powder and a very tight burning cylinder. I think the 257-6.5-270stw-rum or even larger could fit this category. The 300 win mag capacity is quite efficient for 277 and 7mm bullets. The 7mm Jarret, an awesome round is a 300 win mag necked down to 7mm. According to several gunsmiths i have used, throat erosion is highly determined by the operating temperatures. Meaning long strings of successive shots do more damage than a few high powered shots.

Hey this isnt for everyone, i was replying to the op with real world experience on his question.

my point is, your claiming the MV which you say you chronied, the win mag has just over 90 gr capacity, its 92% of the STW, but your getting 97% of the MV of the STW with 69 gr. of powder (or 82% of a full power stw load, which is only 76% of the case capacity, my friend I've been stuffing powder and bullets in cases since 1978, what your describing just isn't possible. burning powder gases make pressure, pressure makes velocity, you can't use less powder in a large case and make more pressure.
there are things you can do to delay throat erosion, but even a 223 will burn the throat out in about 6,000 rounds (I know this, I've probably shot out as many barrels as anyone, my 6.5 is on its third barrel and its a 270 necked down) and the 300 winny is overbore at .284, heck the 7 mag is overbore
RR

The powder speed difference between h1000 and imr4350 is dramatic. I use over 73gr of h1000 for several loads, 75 gr of retumbo for the 165-170 class. I use 83 gr of us869 on the 150s. I use far less 4350 on a much lighter bullet. I get 3425 on a 140 cutting edge with imr4350. You responded with a different caliber and different weight. Nowonder there is a difference.

I am not sure of your requirements to call a cartridge overbore. There is a series of diminishing returns with the addition of powder not resulting in an equal improvement in velocity. That makes sense to me, but with ultra slow powders like 869, what was overbore is now more efficient.

I shot this rifle at he Avenal Practical Rifle match. It was my first time using this gun at distances to 900 yards. Had my speed been off i would not have hit anything shooting 2 moa targets 1 shot only at each. So it is that fast, the bc is 590 on a 140, and i sold my 7stw when i realized this rifles potential. I thought about creating it in a 6.5, but then you hit the overbore/efficiency issue.

As for the 223, most people shoot DI guns that bring gas back into the action and shoot them quickly for multiple mags! Very few shoot three rounds and let it cool!

I have the rifle you are telling me - cant do what it does. I am enjoying it and i will smoke a big elk and deer with it this year, as long as nobody tells the elk i cant do it, that is. :-)

I don't give a rats rear about how much difference there is in burn rates, you do not hear this, do not shoot above max MV in and magnum case using a powder charge that only uses 76% of case capacity, I've loaded many, many thousands of rounds, the difference in burn rates isn't that dramatic, I shoot a lot of powder designed for the 20 MM Vulcan cannon, no magnum load that I have ever saw used a less than 85% fill rate to achive max velocity at acceptable pressures, and its a well published fact that your most efficient loads are those using a powder that fills the case to 90% or more, that is in every manual out there. keep insisting that your correct, I'll agree to write it off as more internet hype.
RR

Well there you go again- dont foam all over your keyboard and stroke out.

Try to have a nice weekend.

James (ridge runner) knows a bit about this stuff...he's one of the originals from LRH (I've been following your thread there). He's been shooting LR before anyone knew what LR was, he even has some stuff from Kirby Allen, Mark Bansner, etc before anyone knew who they were. I'd listen to him...

Jake, one more chance
the speer #11 manual lists the max load for a 270 BEE with a 140 and IMR 4350 at 69 gr. to run 3200 fps so the 270 Bee has an H20 capacity of 85.3 gr, so how can a larger case make almost 250 fps more with the same charge? yeah you have a 28" barrel vs the 26" on the BEE, that will gain you approx. 60-80 fps so???
RR

We have a reamer ready for a .270 based on the .338 Norma case...should be chambered up within a few weeks, I'll report back with results.

Also have .257, .264, and .284 on the .300 Winny case...

Ya want I should stand behind ya to catch yer shoulder Jeep?? That bugger is gonna have one hell of a sharp and fast recoil pulse buddy! Just thought i'd give ya a little heads up there. That way you won't get that awful SURPRISE I hate them!!!

And now to address the illustrious Jake. Most of us on this forum have learned through vast experience how to sniff out horse pucky on the net. RR and myself have been reloading since before you were born more than likely. I was wildcatting before RR was out of his diapers and still listen to his advise at times. The scrawny redneck knows a pretty good bit about this here shootin stuff. Now, as for what he has been telling you, and he has been rather nice about it for him actually, I will put in some pretty plain and easy to understand terms for ya. He has been callin BS on your claims because it is, under the laws of physics as well as gas expansion and propulsion laws, impossible to do what you are claiming. Now, if you would like me to provide the math formulas to show you why this is impossible I would be happy to do so. Unlike what we have seen so far from you, we would both be happy to show our work, so to speak, in providing you the clear and unadulterated truth.