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Loading for the 300 WSM

I've been working up loads for the 300 wsm.

With the 150's I've been getting the best results with H4350
With the 165's. IMR 4831 has been giving the best results.
With the 180's and 200's. Reloader 19 is working the best.

I'm getting the best accuracy at or just short of maximum for my rifle.
The denser the load, the better the bullet flies.
It doesn't seem to matter whether I use CCI 250 primers or WLRM primers.

Of the bullets I've tried so far, the Hornady Interbonds, Nosler Accubonds and Partitions fly the best. I was going to try the Failsafes but, I chose not to shoot moly coated through the barrel.

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Loading for the 300 WSM

I don't really go by what the manuals say entirely. Their max load for the 30-06, for example, in the Hornady manual, gave me something like 2905 fps or something for a 150 grain bullet, it might have been a little higher, it chronographed at only 2810 fps out of my 30-06. For the 7mm Remington Magnum, on several websites I've found, they used 78.0 grains of powder behind a 160 grain Barnes X and got just over 3000 fps, my own 7mm Remington Magnum, not the ADL, chronographed at 3165 fps MV. Perhaps exactly what bullet is used plays a major part. One thing is for sure: with very stout loads, accuracy is excellent with heavier bullet weights, but damned if I should use stout loads with lighter bullets, those under 150 grains, and accuracy falls off noticeably. I wonder if those STW folks have that problem. Sooner or later, I'll have my own loads for my 7mm-08, I may power them down, considering the way I have things set up for this year's deer season, I figure I'll get those 140 grain ballistic tips at around 2500 fps, that should work like magic. Unfortunately, I can't offer much help with the 300's, my 300 is a 300 Weatherby Magnum, and I hate to shoot it, mainly because of the cost of ammo.

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Loading for the 300 WSM

This 300 wsm I'm using is going to be my primary hunting rifle.

I'm testing loads in all available hunting weight because I will probably be using this rifle for most of my hunting. The 200gr are a bit much for this round, but they sure fly nice. The 180's and 165's are the best performers. The 150's also fly well. I loaded some of the Hornady 150gr Interbonds up to 69gr of IMR 4350. According to the Hornady loading info. Thats a 1/2gr short of maximum. Other than the primers were looking a little flat they did well. I worked up to 70gr of H4350 and got 1/2 " groups and a slight flattening of the primers. Thats .9gr shy of maximum. I think I could push the H4350 to 71gr and still get good accuracy, but I would definitely be flattening primers. The little extra velocity gain isn't worth it.

When I get the loads I like in all weights I'm going to cronograph each one to see what I'm getting. I don't want to check as yet, because I don't want it to influence the out come. I'm looking for the densest most acurate load with each weight. I believe the denser the load. The better the accuracy. Once I get the velocity readings I'll make the final decision on loads.

So far it looks like I'm going to be shooting 165gr Interbonds, 180gr Accubonds and the 180gr Bear Claws for the heavy stuff in the thick forest. I'll also load some 200gr Accubonds for a heavy, just because they fly better than the Bear Claws.

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Loading for the 300 WSM

I think barrel length is important, too. For sandard calibers, they do all the ballistic tests with 24 inch barrels, even though they're frequently marketed as rifles with 22 inch barrels, like most model 700s. A lot of magnum rounds are tested through 26 inch barrels, but the rifles people usually buy for these rounds have 24 inch barrels. I've been able to get impressive velocities even with this shorter barrel, and great accuracy, but my preference is always toward slightly longer barrels, but not too long.

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Loading for the 300 WSM

Your absolutely right about barrel length and the stats they get. They vary from manual to manual.

One thing I have run across in loading the short cases (308 length) is the difference in velocity change is minimal from 20" to 24". The biggest advantage I've noticed in a short case and a long barrel, 24" and longer, is long barrels give the bullets better stability. Therefore better accuracy. This is why you see SWAT teams and long range varminters using the 308 with 24" and 26" barrels. My 270wsm has a 29" barrel. The rifle from recoil pad to crown is 48" long and has shot everything I've put through it, so far, into one hole. That's off the bench. Three shot groups.

The 7-08 is one of my favorite rounds and one of the most underloaded. It is capable of far greater performance than published. One thing I've noticed when gun enthusiasts talk about the shorter rounds is. They have a smaller capacity case therefore they can't get the same velocity. It's true that less powder is less velocity. The thing that isn't taken into consideration is they are loaded to higher working pressure. The 30-06 is loaded to a max pressure of 50,000 CUP. The 308win is loaded to a max pressure of 52,000 CUP. The new WSM's are loaded to even higher working pressure than the popular belted mags. That is what accounts for the velocity and energy they produce. The 300 wm is loaded to a max of 55,000 CUP (copper units of pressure), which is around 58,000 to 60,000 PSI (pounds per square inch). The 300 wsm is loaded to a max of 65,000 PSI (pounds per square inch). 5,000 PSI is a substancial difference.

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Loading for the 300 WSM

In a way, I disagree about the higher pressure and the short mags. With light bullets, yeah, but when it comes to longer, you get less room for powder, so then it's harder to get very high speeds. They don't load 175 grain bullets into 7mm WSM's because of this, you would get substandard velocity and they wouldn't sell. I have no trouble at all beating the 7 WSM's velocity with the 7Rem Mag firing 160's, 162's, and 165's. Now if I were loading a 300 Win. Mag, I would wait a while and get a feel for what it does with particular loads, but I could probably match most of your loads in the 300 WSM, or at least get right on your heels. It holds a lot of fuel, but big, monster cases are don't always mean super-speed. The 7mm Remington Ultra Mag is a good example. It's not efficient. I'm sorry, but it is the truth. By the time you get to its average level of performance in factory loads, you're in a tight jam. The reason for this is, as powder volume increases, you get less and less out of each increment. It takes more and more powder to get a small boost in velocity. Same with the 7 STW. So bigger cases for a given caliber don't necessarily amount to greater performance, since I would consider I round that has poor ''fuel economy'' to have lesser performance, due to lesser efficiency.One other thing worth mentioning, is that while you're jam-packing your case with powder, using considerable amounts to get less-than-considerable velocity gains, you're sure as hell blowing the recoil right off the charts. A small change in velocity can equate to a huge increase in recoil if your cartridge has less than ideal powder efficiency. In my own handloads for the 7mm Remington Magnum, I can tell the difference easily when firing a beefed-up handload from a regular factory load. A 160 grain Barnes X fired at 3165 fps produces, I would say, well over 25 ft-lbs of recoil energy. That's a pretty good kick, endure enough of it and a flinch will almost inevitably develop. Same with a 30-06. Same with a 270. In fact, even a minor increase in velocity for most 270 Winchester bullets will boost recoil to 30-06 levels. A 140 grain bullet at 3000 fps will top 20 ft-lbs, which is incidentally what a 30-06 shooter would take when firing with 180's in factory loads. Kinda takes away the charm of the 270, I would say. Same for the rest.

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Loading for the 300 WSM

I guess I didn't give a clear explanation. I was trying to explain how these short rounds are capable of producing the velocities and pressures that they are.

I've heard these tales about how the 300wsm can out perform the 300wm. I own a 300wsm and I know that's a bunch of hogwash. W ith bullets of 150gr or less the 300wsm can stay on the heels of a 300wm, there wouldn't be any noticable difference, but with the 165gr and larger. Especially 180gr and larger the 300wsm is going to fall short.
The 308win is capable of keeping up with the 30-06 with 150gr or less. Anything larger and the 308win falls short.

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Loading for the 300 WSM

Yeah, that's what I figured. The 308 is beautiful though, the way it shoots.

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Loading for the 300 WSM

What the 300wsm is capable of, is throwing the same weight bullet faster than the 30-06 in a shorter, lighter rifle. With the same length barrel.

Same goes for the 270win and the 270wsm. The 270wsm is capable of throwing the same weight bullet faster. in a shorter lighter rifle. With the same barrel length.

The two key reasons are more powder and higher working pressure.

Not to change the subject, but. I stopped at a gun shop today to pick up a few cartridge cases. While I was there I asked about the chances of getting a 7-08. They had about, a guess, 45 -50 bolt hunting guns on the rack. There were a few 30-06's, 270's, 308's, etc... The rest were 7mags, assorted 300mags and assorted 338mags. Get's a guy to wondering, I'd say.

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Loading for the 300 WSM

I had a similar experience when I bought my model 700 BDL (30-06). There were six other 700 BDLs there, one other was a 270. One 300 Winchester Magnum. Two 300 Remington Ultra Mags, and one 338 Remington Ultra Mag. I looked at BDL SS's. 300 and 338 Ultra Mags, and one 338 Winchester Magnum. All of the model Seven's were SAUM calibers. On the bright side, they did have two model 700 ADL's one a 30-06, the other a 7mm Remington Magnum. It makes me wonder also.

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