http://www.2joutfitters.com/sizzlers.htm

Here is a site I found the other day. I have an &mm stw and I don't think I am getting those kind of speeds. Is this possible and to not show prssure signs. I shoot 140gr and I think I am just over 3400 fps. How can I get mine to go the 3600fps+ like this guys? Anyone get those kind of speeds?
Phil

Well my first thought would be to say sure you can have those velocities. But then again I bet you "really" want your bullet to move that fast. I used to hunt on a ranch in West Texas the owner claimed he got 4000fps from his 264Wm (factory) Since I wanted to hunt there again I never set him straight. I have a 26" 7STW. I have broken 3600 with a nosler 140. However case life was 2 firings at best. I question what pressure they are loading to for 3600. I get 3400 with a 140 and 3600 with a 120 and toss the brass after 5 loading. Loads for these two velocities are a couple grains above Nosler's max.

My personal experience with 7MM STW has been 3550 with 140's using H1000 and 3380 with 160's using H5010.

I shoot a model 70 classic factory chamberd for the 7mmSTW. I prefer the 160 grain bullets. I can't tell you why but I don't shoot it much. It is an abslute tack driver with a 160 grain Nosler acubond or sierra HP game king Using RL-25 or H-1000.
I one got 3350 with a 160 grain, but I did not like the way the primers looked. Brought the rifle home pulled a bullet and discoverd I had a 5 grain overcharge, scale slipped a notch.
I question franky the use of most bullets at such a speed. Mabye an X bullet. What are you hunting ? Mabye open country mule deer or speed goats. its easy to convince your self that a couple inches less drop at 400 yards has
some big value but I don't see it. Settle for what you can get safly , and practice a little more. And even at 3400 I would go for a premium bullet...tj3006

Having loaded for five 7mmstw's,three of which I owned,I found that only one rifle would exceed 3500fps and still have good brass life and show no pressure signs.One would top out just short of 3500fps and the other three rifles would top out much closer to 3400fps.I do know people that claim velocities of around 3600fps with 140gr bullets,but the fact that they are experiencing short brass life due to primer pocket expansion,indicates that they are loading at pressures that are above acceptable standards.When the weather warms up,these rifles also display resistance opening the bolt,which confirms that they are simply loading too hot.Of course ,I am talking rifles with a 26" barrel,as a 28" barrel would allow velocities approaching or possibly even excedding 3600fps in some rifles.

I think someon needs to buy a chronograph. I agree w/ stubble, maybe in a 28"bbl. but I doubt in 26" I shoot a 26" 7mmDakota & can get 3500fps w/o bending anything but accuracy isn't as good as 160gr @ 3250fps.

Just checked the Lazzoroni site. Their claimed velocity for the long magnum 7.21 with a 140 "lubed" bullet and a 27" barrel is 3750fps. That case has 20% more capacity than the STW.

Yep I think someone need a Chrono or a the very least needs to check their loads in a pressure barrel.

I found that site a year ago .He won't sell the ammo out right only if you buy his Rifle.
I know speed is good but don't sacrafice accracy
for speed . You have to look at what twist the barrel is so you know what weight bullet to shoot. The longer barrels will make more FPS but always watch pressure. In long range shooting most shooter prefer heavyer Bullets.
There is a Smith in montana that makes a 7mm AM
that is faster than the STW and is very accurate with heavyer bullets and has a longer 28-30" barrels.
My gun has a 26" barrel and a 1-9.5 twist it will shoot 140's but the 150 or 160 would be better. I currently shoot 150 Swifts.

My original load in my STW (70 Stainless Classic 26") was IMR-7828 under a 140 gr. Accu-bond at 3605 fps......chronographed. Primers were good, butter-smooth bolt lift, good primer pockets, cases are still in use. It was a 1 MOA load and no better. I have since switched to a 140 gr. TSX and gotten waaay better groups. I have no idea what the speed is running now.

quote:

My original load in my STW (70 Stainless Classic 26") was IMR-7828 under a 140 gr. Accu-bond at 3605 fps.

I load my 140s with 82 grs of 7828 that is several over Nosler max and I get about 3425 with a 26" sendero.

By the sounds of it, it all depends on the rifle of what speed you get. Personally if I only get a couple loadings out of a case I would be fine with it. It sounds like getting 3600 fps is possible but you just have to watch it. One question I have is how does cold weather play into the factor with pressures? Do you get a higher pressure?

quote:

I have is how does cold weather play into the factor with pressures

Normally lower. Heat raises the pressure.

It's a sizzler alright, better keep a spare barrel handy!

quote:

Personally if I only get a couple loadings out of a case I would be fine with it.

Just curious why you are willing to run at 70,000psi+ for an extra 150FPS. What does it get you?

quote:

Personally if I only get a couple loadings out of a case I would be fine with it.

The problem is that to get 3600fps from 3400fps,you are going to increase the pressure from the 65,000 range into the 80,000 range.That would be at the temperature that you develop the load at,say 70F.You will normally see pressure signs at that pressure but the bolt may still function,and you may not have any case failures.Now let's say that you decide to go sheep hunting and the temperature climbs to 90F.The pressure will climb even higher and you may find that the bolt locks up after firing,or that a case ruptures on firing.The result being that either your gun will be useless to you,or even that you may get a face full of hot gases and metal particles.
Of course we are only looking at the short term risks,but there are also long term risks,such as metal fatigue from operation continuously at above design pressures.You may fire that load for years without a problem,then sudddenly,without warning, something breaks and the result could be very unpleasant.
Another factor to consider is that pressure tests have shown that visual pressure signs often do not appear until the 70,000psi to 80,000 psi,on most rifles.As such if you increase the charge until they appear and then only back off of the charge until they disappear,you may very well still be operating above design pressure.My own practise is to increase the charge until I see the first sign of pressure and then reduce the charge by a full two grains with the larger cases,and a full grain with the small cases.Using this method,I can be reasonably sure that I am operating at safe pressures,even if the temperature climbs.
Now let's look at velocity readings,reported by everyone.If you use an oehler,the results will usually be spot on,but most of us use the shooting chrony which can produce erronous readings depending on light conditions,especially with the earlier units.I went out once and my readings were consistantly above 3600fps which surprised me,as they had always been 3500fps.I did some more shooting with other guns,then cleaned some barrels,and then fired a few more rounds over the chronograph which now registered 3500fps.The only difference was in that time,the sun had changed position.I have since bought a second unit and I always use both when developing loads,and always use the screens reguardless of the lighting conditions.It has happened a few times that due to light conditions,the one unit will read almost exactly 100fps high.I have talked to several other chrony owners and apparently this is a common issue with the unit that you need to watch out for.If your velocity seems about 100fps high or suddenly changes by about 100fps,it could be due to the lighting conditions.
I wonder just how many people are reporting 3600fps because of high chrony readings?

quote:

Originally posted by stubblejumper:

I wonder just how many people are reporting 3600fps because of high chrony readings?

I had often wondered that, too. I use a newre Beta Master Chrony (or Master Beta, as I like to call it ). Anyhoo...... I developed a load for my .220 Swift and using the Chrony numbers, ran it through ballistics software to get a 300 yard sight in. Using that info I sighted in at 25 yards and then moved straight to 300. The group printed DEAD NUTS where the ballistics program called for. So, I use that case to assume that the Chrony is probably pretty much right on. Dunno how else to test it barring buying a second chrono.

quote:

Dunno how else to test it barring buying a second chrono.

I went as far as buying a second unit,but before that,I just tested each load a few times under different light conditions,but a similat temperature.If the results were close,I accepted the values.However some people only chrony a load once or twice,and sometimes not even after changing powder lot#s,which can really make a difference.My last batch of imr is much milder than my old batch,so much,that I increased the charge weight by two grains with the new powder.

quote:

I developed a load for my .220 Swift and using the Chrony numbers, ran it through ballistics software to get a 300 yard sight in. Using that info I sighted in at 25 yards and then moved straight to 300. The group printed DEAD NUTS where the ballistics program called for

I would say that there is also a little luck involved.I have zeroed a load at 100 yards,and by 300 yards it was off by a few inches according to the ballistics calculations.By 500 yards it was off about 7".I find it normal that a load varies from the tables or calculations by at least an inch or more out to 300 yards,and more yet as the distance increases.
Just one more reason to actually shoot your loads rather than trust the tables or calculations.

Ramrod, I plan on using this gun on the prairies next year for antelope, I shot my last one at 507 yards and was inpressed with just factory shells with that. Where I hunt the antelope are wild and they are hard to get within 500 yards. I would rather practice and get a flat shooting gun and shooting at a longet distance.

You are far better off to use loads that are within design pressure and use a few inches more holdover at 500 yards.

The difference between 34 & 3600 is maybe 20yds Max Point blank and 2-3 in at 500yd with a Max Point Blank center. With a 400Yd zero the drop difference is less than 2". At that range if you have a good yardage tool the wind will cause you far more trouble.

Hey you can load up to the point that you get one loading. That is your option. I don't push things that far. My option. Like you say practice but get a good Yardage tool you will never miss the 200FPS.

quote:

Originally posted by ramrod340:

quote:

My original load in my STW (70 Stainless Classic 26") was IMR-7828 under a 140 gr. Accu-bond at 3605 fps.

I load my 140s with 82 grs of 7828 that is several over Nosler max and I get about 3425 with a 26" sendero.

EXACT same recipe I'm using....... 1 gr. under Layne Simpson data. Does seem awfully odd that it's appearing to give me 180 fps more than it is giving you.

Such is life.

Some say I've always been a touch slow.

I sight mine in +2-3/4 at 100 yards
+3-1/2 at 200 yards
+1/2 at 300 yards
-6 at 400 yards
-18 at 500 yards.

Since there's a real issue of pressure in this topic, I did something for a shit & a giggle. There's an online calculator for CUP. I ran my STW numbers and came in at 54.4K CUP. I put a post in the Reloading Forum for anyone who has a load with mechanically determined CUP value to run their numbers through. Wonder how valid the calculator really is???

Well for what its worth if you cross reference using cartridges that have both PSI and CUP I would guess between 64 & 65,000.

If I use Denton Bramwell's little formula that was built by cross plotting cartridges cup to PSI numbers PSI=1.516*CUP-17902. Or in this case 64,568PSI. Key issue is there is no direct conversion. These two numbers are measuring different things. But if you take the relationship between the two you get this formula for comparison.

you guys are totaly right about the difference in speed to what difference it has in drop. 2 inches at 500 yards isn't anything to worry about for sure and I don't think I will bother trying to push it too much. One other question I have is what does seating depth have to do with pressure? Does it really matter where it is seated as long as it is shootting good groups?
As you can tell I have a lot to learn but it is sure fun.

Bullet seating dept has a very small impact on a case the size of the STW. Key problem happens when someone is close the upper limit the either seats the bullet out longer or switches the bullet and now they are in the lands. That can result in a huge pressure spike.

Why do you want to push you bullet speed so fast? I simply don't understand how it helps much. If you are getting 3400 or so with a 140 grain bullet you are doing about all you can expect from a 7mmSTW. its a great round, but squeezing another 200 fps out of the bullet will not give you much of an advantage for hunting. And the risk is real.
A 160 grain bullet will usually have a little better BC, and if you can get 3250 or so with a a good solid bullet Barnes , accubond , partition, swift you have about all the killing power one could hope for from the cartridge. A 175 might be a better way to go.
bullets drop no matter how fast you push them
you need to know the distance and you need to shoot alot if you want to go over about 350 yards, no matter what you are shooting. One mans opinion. ...tj3006

I have been shooting the STW for about 10 years now and have been waiting for someone to finally figure out the real benefit to the STW and James just posted it. I have tried various bullet weights from 120 to 175 and by far the most interesting is the 175. If you do your homework and check the ballistics you will find the 175 shoots almost has flat as the 140 and arrives at a distant target with better energy. You really have not seen what a STW can do until you load a premium 175 (nolser partition or Barnes) full power. A 175 will penetrate a big bull elk stem to stern. From what I have seen a 175 is a much better killer than the 140. A 160 is not a bad compromise but I still like the 175 when you are talking the size of elk.

Winchester Classic 7mm STW 26" bbl., 82 gr. IMR 7828, 140 gr. Accubond @ 3530fps (chronographed) no pressure signs. 3 shots, 5/8" , I like it.
I might try the 150 Swift Scirocco just for grins.
sbsmith

quote:

Originally posted by sbsmith:
Winchester Classic 7mm STW 26" bbl., 82 gr. IMR 7828, 140 gr. Accubond @ 3530fps (chronographed) no pressure signs. 3 shots, 5/8" , I like it.
I might try the 150 Swift Scirocco just for grins.
sbsmith

Same gun, same charge, same bullet that I started with. Was giving me (so sez my chrono??) 3605 fps and 1". Am in the process of switching to the 140 gr. TSX and so far have seen groups tighten dramatically at 77, 78 & 79 gr. of the same 7828. Maybe try some of the TSX's for yourself.

quote:

From what I have seen a 175 is a much better killer than the 140. A 160 is not a bad compromise but I still like the 175 when you are talking the size of elk.

Having seen the 140gr tsx,the 160gr x and the 175gr partition used on elk and moose,both the 140gr tsx and 160gr x out penetrated the 175gr partition the majority of the time.The 140gr tsx showed more consistant expansion than the 160gr x.Overall,I was most impressed with the 140gr tsx.

stubblejumper
I have used 140's 160's and 175's in both tsx and partition and have recovered several 140's one 160 and no 175's. The 140's worked well but I saw a few that changed course (deflected) in the animal when they hit a bone at an angle. It did not make a difference if it was a tsx or partition they both did it. The 160's traced a straighter line and the 175's punched perfectly straight.

Having never recovered a 175 (partition or tsx) from an elk (I haven't seen any moose shot with any STW's yet) and having recovered several 140 my experiance has been that the 175's have better penetration than the 140's, however, we have to remember that there are alot of variables (distance, angle, size of animal etc) that go into the equation and we each have a limited sample of data to work on. I don't think you can go wrong with any of the good bullets I just like the heavyer weights.

My comment was that most people who shoot the STW use 140 or 150 grain bullets and overlook the 160 and 175 grain bullets because they want all the speed they can get. It not that speed is bad it is just not the cure all for everything.

quote:

Having never recovered a 175 (partition or tsx) from an elk (I haven't seen any moose shot with any STW's yet) and having recovered several 140 my experiance has been that the 175's have better penetration than the 140's,

I have recovered a few 175gr partitions and one 140gr tsx from moose and elk shot by myself and my partners.The recovered 175gr partitions weighed less than the 140gr tsx,and both tracked equally well through the animal.

quote:

Originally posted by MtElkHunter:
I have been shooting the STW for about 10 years now and have been waiting for someone to finally figure out the real benefit to the STW and James just posted it. I have tried various bullet weights from 120 to 175 and by far the most interesting is the 175. If you do your homework and check the ballistics you will find the 175 shoots almost has flat as the 140 and arrives at a distant target with better energy. You really have not seen what a STW can do until you load a premium 175 (nolser partition or Barnes) full power. A 175 will penetrate a big bull elk stem to stern. From what I have seen a 175 is a much better killer than the 140. A 160 is not a bad compromise but I still like the 175 when you are talking the size of elk.

I figured this out after I had my 7remmag rechambered to the 7mm Dakota. It easily reaches 3250fps w/ a 160grNP & has been more than adequate for any game I have taken up to elk size. I have complete faith in the 160grNP as I put one through a spike elk's spine & it exited out the front of his chest @ about 120yds or so. I have played w/ the light weights, but I always hunt w/ the 160grNP.