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7mm X .300 Weatherby vs. 7mm STW?

74K views 225 replies 32 participants last post by  Darkker 
#1 · (Edited)
CAUTION: This post discusses loads or load data that equals or exceeds published maximums for the cartridge(s) mentioned. Neither the writer, The Shooter's Forum, nor the staff of The Shooter's Forum assume any liability for damage or injury resulting from using this information. DO NOT ATTEMPT TO DUPLICATE THE DESCRIBED LOADS without first working them up from a published safe starting level charge while watching for pressure signs. If you don't know how to do that, don't try.

I have a Browning 1885 in 7mm Remington Magnum with a Leupold 4.5x14 50mm scope. When I bought this combination,
my intent was to have it re-chambered to 7mm X .300 Weatherby for more velocity.

I bought new .300 Weatherby cases and RCBS dies for the the wildcat and sized the cases. I don't have an outside neck turner,
so I haven't finished prepping the cases.

Upon developing loads for the standard 7mm magnum cartridge, however, I found that I could drive 175 gr. Sierra SBTs and
195 gr. Barnes SSPs to 3060 and 2850 fps from the rifle's 28" barrel, respectively. I also found the recoil as hard as I wanted it,
at least from shooting on a bench.

Those velocities are not far lower than the larger 7mm cartridge velocities, which almost invariably have 2" shorter barrels. Not long
after I bought all that, the new 7mm STW came out in factory rifles, and cases are available for loading.

I am reconsidering having the rifle re-chambered to one of the larger 7mm cartridges, now that I have a home-made lead sled. Do any
of you have experience with either of these longer cartridges and/or considerations I might not have thought of?

 

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#2 ·
To muddy the waters, you could also have your 'smith to chamber for the 7mm/375 Ruger and have the same 7mmx300Wby and 7STW peformance...
 
#3 ·
I've shot the old 8mm Rem mag for years and shoot a friends 7mm STW which is the 8mm mag case necked to 7mm. The 7mm Ultra-mag has a bigger case along with the 7mm by 378 Weatherby which has even a little bit bigger case.

The problem is bullets at the velocities your shooting these at don't usually perform well at closer ranges. Deer shot under a hundred yards tend to end up with lots of blood shot meat, even a 7mm Rem mag will do that at close ranges with 140 and 150 grain bullets though.

The only thing I'd say is go for the 7mm RUM, no case forming to do and maximum velocity from a factory case. Bullets and brass is available and it's really hot. It's a larger case than the 7mm STW and you can buy standard dies and brass.
 
#4 ·
Alaska Man, I once purchased a 7mm STW but was unimpressed with the velocity verses amount of powder I was burning etc. Why my model 70 Winchester .300 magnum was out shooting that rifle using 150 grain bullets. I traded off the 7mm STW for another rifle!

If you want more velocity pushing those larger 7mm bullets, I would look hard at getting yourself a much bigger case for starters. However, this is only going to increase the recoil to the upper torso, there is "no cigar" when it comes to shooting large bullets fast.:)
 
#5 · (Edited)
If you want more velocity pushing those larger 7mm bullets, I would look hard at getting yourself a much bigger
case for starters. However, this is only going to increase the recoil to the upper torso, there is "no cigar" when it comes to shooting
large bullets fast.:)
I believe that part of the reason the larger 7mm's fail to impress compared to the vanilla 7mags is due to the shorter barrels than
I have on the 1885 (28"). I realize, too, that there are other imperceptible differences in barrels that make identical barrels shoot differently.

On average, the full-length, blown-out .375 H&H case that the STW and .300 Weatherby use should produce about a 150 fps gain
over the standard length 7mags. In my barrel, that would probably give 3210 fps with the Sierra 175gr. SBT, and 3000 fps with the
Barnes 195 gr. SSP.

Those would be some smokin' velocities for those bullets! They would also generate more recoil than I want to tolerate shooting from
a bench. That's why I made a lead sled. Practicing from a standing or other off-hand shooting position would probably be alright.

I am not worried about recoil when actually shooting at an animal in the field. I don't notice even .388 recoil when I shoot at a living target.

I am primarily concerned with the relative merits of the two cartridges in question, or lack thereof.
 
#6 · (Edited)
I have finally decided to go ahead and have my 1885 re-chambered for 7mm X .300 Weatherby, as I already have the cases and can
get a neck turner. I plan to use Sierra 175 gr. Spt Bt's, 195 gr. Barnes SSpt's, and 180 gr. Berger Hp Bt Hunting.

Right now, the slowest powders I have are Reloader 25, Hodgdon H-1000, IMR 7828 and H-870. I also have some H-4831 and IMR-4831,
but I suspect they would be in the medium burn rate for this cartridge.

I intend to try even slower powders such as H-50BMG, Retumbo, H-US869, VV-N570, and VV-24n41. I have a very limited supply of H-870
and Barnes 195 SSP's, so I may just stick those two together as they are now in my standard 7mm Rem loads if they are still an accurate
combination.
 
#7 ·
Am I reading this right?! :)

Are you updating a thread that is 3.5 years old to let us know you're finally going to have your barrel rechambered? I've been known to be a little circumspect about spending money or having custom gun work performed, but 3.5 YEARS? :D
 
#8 · (Edited)
Am I reading this right?! :)

Are you updating a thread that is 3.5 years old to let us know you're finally going to have your barrel rechambered?
I've been known to be a little circumspect about spending money or having custom gun work performed, but 3.5 YEARS? :D
My apologies if I have offended some etiquette, but this is still an open topic for me, and I like to plan out my ideas well.
I have been planning this project since I first saw a Browning B-78 in a catalog in 1979. There was not one for sale then,
so I settled on a BBR in 7mm Rem mag.

I plan to finish the load development by next summer, so no one will have to hear about it anymore after that. :)
 
#11 · (Edited)
It's funny you mention the .35 Whelen, as it is what I would like to have as my "for everything" rifle in Alaska. I have thought of having
my left-handed, Ruger M77, 30-06 with a 24" Douglas barrel re-chambered for just that cartridge.

Or, perhaps I could simply buy another left-handed Ruger and have that one made into the .35. Any reason to have another rifle or handgun
is fine with me.

As you might notice, that dream of a long-range rifle was when I was 16. I no longer want to try my hand at wounding an animal at long range,
and having to carry it back either way.

I just came back from an unsuccessful caribou hunt North of my home town of Kotzebue near the Red Dog Port Site. Two nice size bulls came
to within 630 yards of my hunting partner and me, by my Wind River laser binoculars.

It was breezy, so even though I had my '06 with 180 gr. Light Magnums, and he had a .270 with 130 gr. bullets, we didn't attempt the shot,
and we could not get ahead of them later.

If I had had my 1885 7 mm mag and a steady rest, I might have attempted the shot, as have shot that load my whole life. On the other hand,
a steady rest is hard to find on the breezy tundra.

I just wanted to have fun target shooting at long range with this rig. I don't consider live animals merely targets.
 
#12 · (Edited)
A_M,

I have built, shot and owned rifles chambered in both the 7mmX300 Wby and the 7mm STW and have taken deer with both cartridges out to a measured 1,000 yds. and was quite impressed with the results...

The two cartridges mentioned though, are ballistic twins and one will not out do the other as either velocity or accuracy are concerned...

If you do plan on shooting game at long-range, make sure you use a bullet that will perform well on the intended game at the ranges you plan on shooting...

Above all - PRACTICE PRACTICE PRACTICE and then PRACTICE some more...

When all was said and done, shooting in the prone position, with a bi-pod and my best loads, this is the type of accuracy I expected from my rifles as well as my self before I would ever put the cross hairs on ANY animal at long range -

600 yds. 2" or less...

700 yds. 3" or less...

800 yds. 4" or less...

900 yds. 5" or less...

1,000 yds. 5" or less...

These are for 3- shot groups...

I would NOT shoot in a high wind situation nor when heat mirage was a major factor to contend with. As always, if you are not assured of a clean killing shot, DO NOT SHOOT! You will always get another chance. Any animal, even varmints deserve a humane kill...

Being a retired Military / Police Sniper, I firmly believe in our moto 1-SHOT 1-KILL....

A
 
#14 ·
Alaska..........

I have only shot lighter bullets (140's) through my STW thus far. They shoot so well to 600 yards, I just haven't tried anything else......yet. But 140's are on the light side for true long-range work.

I've found IMR-7828 to be the absolute berries for the 140's in my Model 70. Accuracy is superb and velocities are UNREAL. Your mileage may vary. I had a short fling with R22, but found it to be WAY up the hateful scale for temperature sensitivity. Far enough up the scale I deem it to be unsafe in my rifle.

Both 7828 and R22 are going to be on the fast side for you when you're talking the heavier-for-caliber bullets. H1000 should be a logical one to start with.
 
#16 ·
OK, the rifle is at the gunsmiths, and should be ready in a week or two. In the meantime,
I am dismantling my 7mm mag rounds and saving the powder and bullets for the new cambering:


I also bought an RCBS hand held neck turner to ensure the necks are not too thick after necking
down. I am using Remington brass I bought some 20 years ago, and the necks were just slightly
too thick, perhaps just a thousandth or two. They were, however, quite uneven. The tuner is set
to .013", and almost every case was cut thinner on just half of the neck.

I also found that the case holder uses standard sizes of thread, so I fabricated a way to attach a
cordless drill. It takes a few seconds to make the case rotate evenly, but turning is a snap after that;
much faster than by hand.

 
#17 · (Edited)
The rifle should be done today. I am about to go to the gunsmith's and check on it.
There was one thing that I forgot to mention, and that was the fact that my rifle has just 1-10" rifling. The manufacturer's
recommendations for the 180 gr. Berger bullet is 1-9".
I did some quick calculations in my head figured that the 7mm mag cartridges to which those recommendations refer can only push that
bullet to about 2900, fps. My rifle should be able to get that up near 3200 fps, thus achieving the needed revolutions per second.
Well, I'm off to the gun shop.
 
#18 ·
I hope it's done. Been a long time coming. How far do you have to travel to get to the gunsmith? Gotta take an airplane? I envy you guys up there in Alaska. You have millions of acres upon which to shoot, there is all kinds of game and your gun laws are amenable to the law-abiding. I have vast expanses of land upon which to shoot, too, but you also have that scenery. Nevada can't compare...
 
#19 · (Edited)
Unfortunately, the reamer had not made it to the Gunsmiths yet. Perhaps Monday. It is just a 25 minute drive there.
Yeah, I was born here, and when I was a young man, I thought that the world was passing me by while I wasted away my youth in a
village. By the time I finally went out of Alaska at age 36, I had two little daughters and my priorities had changed.
I enjoyed seeing the big cities, but I also realized I had not missed much. They are dirty and stink, and no one says hi to you
unless they want something from you.
Here there is not a dealer on every corner trying to sell to my kids, and later my grandson. There are not many drive-by shootings, because
you can almost guarantee they will get shot at right back.
I have seen some amazing sights. I have seen a goodly chunk of the Western Arctic Caribou herd in the Noatak river valley. I was on a hill
next to the Aggie river looking across the valley at hundreds of thousands of caribou, literally as far as the eye could see, 75 miles to the
horizon and 50 miles across. We filled our boat with meat that day.
I have been out in the ice floes at Spring looking for bearded seals, and heard the silence of the Earth with only the cracking ice to disturb
it as we sneak closer while the seals sleep for 7 seconds at a time.
 
#20 ·
. . . seals sleep for 7 seconds at a time.
What? Seals sleep for just seven seconds at a stretch? I'd wake up exhausted-- time and time again. I suppose it's because they are essentially pure prey animals. Everything eats 'em, 'cept for fish. Must be a miserable existence being a seal...
 
#22 · (Edited)
Yeah, I've played around with a few wildcats and they can take some time, particularly if they are very obscure. I'm considering several different options for Indiana's new silliness, including the 35 IHMSA that Elgin Gates created by pushing the shoulder back on a 300 Savage and then necking it up. That would be a long wait, I'm sure. Maybe I'll be back in another 2 years, saying I finally got MY next wildcat finished! :D
 
#23 ·
here is some info that I got from PaCowboy for my 7mm-300wby.

This my most accurate load
168gr Berger
IMR 7828 77.5 gr
Federal 210
3211 fps (chronographed)
Just shot this load at the range 2 weeks ago. 2.375" @ 300 yards.

168 Sierra Matchking
H-1000 76gr
Federal 215
200 yard 4 shot group 1.105" I pulled the 5th shot for an overall group of 1.95.

150 Nosler Ballistic Tip
RL-19 73gr
CCI 250
High Velocity 3173
Low Velocity 3161
Avearge Velocity 3167
Extreme Spread 12fps
Avg Deviation 3.28fps

140 Nosler Ballistic Tip
IMR 7828 77gr
Fed 215
3421 chronographed

I don't recommend shooting many of the 140's or 150's. You will burn your barrel out much faster than if you use 168's. I'm going to work on the Berger 180's to see what I can do with them. I think they will work better for long range shooting and hunting with the better BC.
 
#24 ·
Thanks for the info, Zorak, but I intend to use just the heaviest,
highest balistic coeficient bullets: Sierra 175 gr. BT, Barnes 195 br. SSP,
and the Berger 180 gr. VLD Hunting bullet.

I am still waiting on my gunsmith to put the ding dang rifle back together.
 
#26 · (Edited)
I had a look at Barnes' page, but too bad no picture of the bullets.
It sounds like those bullets will be great ones, too.

I also had a look at Lazzeroni's pages, and it looks like the
Firebird gets about 3400 with a 168 gr bullet. I am expecting about
3200 fps with 175 and 180 gr. bullets with this rifle. I was getting
3060 fps. with H-1000 and the 175 gr. Sierra SBT, and 2850 fps with
the Barnes 195 gr. and H-870. I am expecting around 3000 fps. with
the Barnes and H-870.

I just got back from the gunsmith's, and my rifle is finished! I inserted
one the re-sized .300 Wby cases, and it slid all the way to the belt.
Now I just need to determine throat depth and start working up some
loads. I picked up a pound of Retumbo, and a pound of US869 to
get started.
 
#27 · (Edited)
I finally was able to take a day to make some test loads for the
new chamber. I used just one powder and bullet for this inaugural test:
Hodgdon US869 and the Sierra 175 gr. Spt Bt. I expected good things
with this bullet and powder, and was not disappointed.

I started with a load some five percent below published maximum for
that powder and weight in a 7mm STW, and went by 1 grain increments until the unmistakable
sign of maximum pressure for this rifle appeared; a shiny,
gold colored ring around the striker indentation in the CCI 250 primer.

I discovered this interesting phenomenon some 20 years ago and called
the Sierra tech staff about it. The technician informed me that it was
not over pressure loads, but that the old CCI 250 primers are soft and
tend to flow into the striker hole and form a crater at the pressures of
a magnum cartridge. The 1885's falling block mills the top edge of the
crater flat, thus exposing the brass under the nickle plate.

As always, one must stay with published data and find one's
own firearm's characteristics. I also kept meticulous track of the
velocity and case-head expansion. Expansion was large, but not
unexpected, as the cases are new and also absorb a percentage
of the energy of the gunpowder in this first expansion.

I stopped at the powder load that had reached 3231 feet per second
by my chronograph. In my experience with new brass, 3300+ fps
should be there with once-fired brass. I will also switch to Winchester
WLRM primers, as they perform with identical velocities in this barrel,
but are harder and don't crater. Cartridge overall length was 3.703;
this chamber has a very long throat, significantly increasing capacity.

My Infinity app says that last load made 4055.8 foot-pounds of energy.
I messed up, though, at the range as I was hurrying to set my
target up to align with my chronograph.

I ended up having to shoot all my rounds at the shot-up target I
used to bore-site at 100 yards, due to many other shooters with high-capacity
rifles blasting away at nothing in general. At least I know that I had hit it
as the bullets knocked it askew. Accuracy was not my intention for this
first test, however. I will delve more into that when I have all 88 cases
fired at least once.

Next I want to try Retumbo with the same Sierra 175 gr Bt. I have use
this bullet for most of my life, and it is fun to finally get it moving the way
I wanted it to in 1979.

My camera took it's final dump this winter, so pictures will have to wait a bit.
 
#28 ·
OK, so I tested the Sierra 175 gr. Sbt. with H-Retumbo, and that powder was able to push the bullet to same velocity level as H-US869: the top load with signs of high pressure reached 3234 fps. with new cases.

I also tested the top US869 load with that bullet and once-fired cases. Five shots averaged 3319 fps., extreme spread was 44 fps. with a low standard deviation. The group was, however, a disappointing two inches.

I now will test those two loads with fired cases and one grain less than maximum for this rifle and the WLRM primers. Hopefully, that will tighten the groups, but if not, it just means more fun working up loads!
 
#29 ·
Keep us posted, please. I'll be wearin' the same underwear pretty soon, myself. My 'smith says he has all the stuff 'cept the barrel and that once he gets it, delivery is just a short wait from then. Then I'll drive 300 miles up and down I-80 to get it. Please Lord, let there be no mechanical failures when going either way...
 
#30 · (Edited)
Alright, there are definite signs of pressure with the 175 gr bullet and this charge of US869, even with the Winchester primers. The loads with US869 averaged 3230 fps. and four shots printed 1.57".

The shells loaded with Retumbo and same bullet averaged 3112 fps, but with a dismal 2.2" four-shot group, though pressure seemed ok, and the extreme spread was really small.

I also tested the Barnes 195 gr. Ssp. with H-870. The maximum velocity with cratered CCI 250 primers was 3090 fps. I will try backing off two grains and switching to the WLRM.

Grouping was hopeful for this old pair, though I don't have enough to test thoroughly; neither is made any longer.

This bullet, at 2850 fps, when this same rifle was a 7mm Rem Mag., is the only one I have ever seen completely penetrate a full grown Bearded Seal; not even a .338 Winchester Magnum 250 gr. Silver Tip could.
 
#31 ·
Yesterday, I tested 3-shot groups with the 175 Sp Bt and US869 at 3135 fps and the 195 gr SSP and H-870 at 3000 fps, both with once-fired case. The 175 gr load printed a ho-hum 2.5 inch group, but the 195 gr bullet printed one inch. Case head expansion with the 175 was 5-6 ten-thousandths; the 195 gr went just 2-3 ten-thousandths.

That will be my load for the 195 gr Barnes bullet, but the 175 gr bullet needs more TLC. I need to test groups with Retumbo, now that I have more once-fired cases. I also need to tweak the amount of US869 and see if I can get the velocity I want with the accuracy I need.

I also tested Berger's 180 gr. VLD Hunting bullet with US869. The top load showing extreme pressure on the primer, reached 3220 fps with new cases. I plan to try 1.5 gr less powder and new cases for a group. Overall cartridge length was a long tall looking 3.78 inches.

I will also test the Berger bullet with Retumbo; the range got rained out yesterday beiore I could test those loads.
 
#32 · (Edited)
I tested the rounds with the Berger 180 gr. VLD and the near maximum load of H-US869. Five rounds printed about 2.25". Lame.

I also tested that bullet with H-Retumbo, and the velocity reached 3167. Surprisingly, those bullets printed about 2.5" and all seven had different amounts of powder.

I am a little worried that this rifle seems so finicky now. It used to group maximum pressure loads in less than an inch. If I had not gotten a 1-inch group with the Barnes bullets, I might start wondering about scope mount security.

I might have to start playing with seating depth and other more detailed approaches. I have 'til mid September to sort this out. I suppose 195 grain bullets would work fine for caribou, but I'd hate use such a rare and special bullet and powder for fairly light game.
 
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