7mm STW--any thoughts/experience with?

[HiBC]

Different strokes for different folks.Enjoy doing it your way.

I spent many years as a fan of the 7mm Rem Mag. It IS a great cartridge.

I've hunted a lot of pronghorn. I like to eat them. The damage done by the 7mm Rem inspired me to build my .257 R AI. IMO,there is no doubt it was a good move.

Loading in general, there are few powders/loads for the 7mm Rem that permit better than 85% load density.Why on earth would I want more case capacity?

IMO,the 7x61 Sharpes and Hart hit closer to ideal,but the 280 AI comes pretty darn close to optimum for 7mm.

The chrono will tell you for all the thunder and belchfire not all that much real velocity increase occurs with the 7mm STW,

Is the point extended useful Max Point Blank Range? Run the numbers with a 280 AI . How much MPBR do you gain?

If you use the knobs and dial,what is the gain?

Given mag box length limits,I've heard bullets over 145 gr may not work out so well with the STW,
This might be particularly noticable with the bullets I would imagine I'd choose,myself....175 gr or heavier VLD type javelins.

At mag length COAL,at what point does the cylindrical portion of the bullet get seated deeper than the case mouth? The ogive into the neck? Or are STW's used as single shots? Just curious.

This is the same problem that eliminates the Hornady 75 gr AMAX from being loaded to mag length in an AR.

I must admit,I have never owned a 7mm STW. Considering these issues,along with barrel life....Nope. I'd go 280 AI.

I do not give any magical properties to the 6.5 bore. Its just a bore size

The bullet manufacturers have given a lot of attention to the bore diameter. More than the 7mm.

IMO,there are more long range projectile choices in 6.5, 30 cal, and 338.

And,for very long range shooting,I'd figure on having time to use the target knobs. Those make two or three hundred fps rather moot.

I just don't get it. Is it the looks of the cartridge and the OOOOW and AAAHHH factor?

 

[stagpanther]

I already have 280 AI and enjoy shooting it very much. Why the 7mm STW? Cause I want to--and I don't mind changing barrels.

 

[old roper]

stagpanther, Should be good barrel. I kind of put 28 Nolser on hold and with 280AI in mid 2900fps with Peterson brass/175gr ABLR. I tried to get some Berger 175gr and 180 VLD's but no luck. Good Luck

 

[stagpanther]

stagpanther, Should be good barrel. I kind of put 28 Nolser on hold and with 280AI in mid 2900fps with Peterson brass/175gr ABLR. I tried to get some Berger 175gr and 180 VLD's but no luck. Good Luck

Thanks OR--Sorry you can't find the bullets--I noticed all the way up until about this past winter 7mm bullets were still pretty available even when most others were long gone; I love the fact they aren't so popular, great ballistics performance. You might have noticed the 183 MK loads I did for my 280 AI turned out pretty well, I think they and 190 vld's will be OK in a 8 twist or better driven fast enough.

 

[reynolds357]

7mm is one of my favorites--but I see very little talk of this cartridge.

I have one. It's all it's supposed to be. 7 Rum and 28 Nosler kind of stole its thunder.

 

[stagpanther]

I've worked on and shot a rem 700 7mm RUM, a very nice rifle IMO --but the problem with it is that it is more than capable of over-driving smaller bullets at closer ranges. I warned the owner about that but a friend of his took a shot at a deer within 200 yds with a smallish bullet, I was told they were sure it was a good hit but the deer just ran off.

 

[old roper]

stagpanther, I'm hoping to use 280AI on bull elk hunt this year. I've been seeing lot more target bullets also.

 

[stagpanther]

stagpanther, I'm hoping to use 280AI on bull elk hunt this year. I've been seeing lot more target bullets also.

What are you using for bullet? I bought the new Berger 190's specifically for the 7mm STW but may try them out on the 280 AI.

 

[old roper]

I was going to use Nosler 175gr ABLR. I got 8lbs of R-26 this past spring and been shooting pretty good in that 280AI and I was looking for change.

I think 180gr be top for me on bullets in that rifle.

 

[stagpanther]

How about the 160 partition?

 

[reynolds357]

I've worked on and shot a rem 700 7mm RUM, a very nice rifle IMO --but the problem with it is that it is more than capable of over-driving smaller bullets at closer ranges. I warned the owner about that but a friend of his took a shot at a deer within 200 yds with a smallish bullet, I was told they were sure it was a good hit but the deer just ran off.

Only bullets I have ever shot in it are Barnex TSX and TTSX. Wouldn't trust anything less.

 

[Scorch]

How about the 160 partition?

In my experience, the Partition is a great bullet, just not a very accurate bullet. Granted, I haven't used Partitions for over 20 years, but I still hear this from others who have used them. If you want a tough bullet, any bonded bullet will be tough enough, maybe the Scirocco A-Frames will be a bit tougher, but I would stick with monolithic bullets (Barnes TTX, Cutting Edge, or similar) for the velocities you'll see out of that 7 STW. Make sure you condition the bore before shooting those solid copper bullets, though.

 

[stagpanther]

In my experience, the Partition is a great bullet, just not a very accurate bullet. Granted, I haven't used Partitions for over 20 years, but I still hear this from others who have used them. If you want a tough bullet, any bonded bullet will be tough enough, maybe the Scirocco A-Frames will be a bit tougher, but I would stick with monolithic bullets (Barnes TTX, Cutting Edge, or similar) for the velocities you'll see out of that 7 STW. Make sure you condition the bore before shooting those solid copper bullets, though.

What do you mean by conditioning? (I personally am shooting jacketed only).

 

[Scorch]

What do you mean by conditioning?

Start by breaking it in the old-fashioned way to burnish the bore (5 shots, clean, 5 shots, clean, 5 shots, clean, 10 shots, clean, 10 shots, clean, 10 shots, clean), then use a bore conditioner when you shoot (like Tetra or even Militec). Copper fouling with the solid copper bullets can get bad very quickly.

 

[reynolds357]

In my experience, the Partition is a great bullet, just not a very accurate bullet. Granted, I haven't used Partitions for over 20 years, but I still hear this from others who have used them. If you want a tough bullet, any bonded bullet will be tough enough, maybe the Scirocco A-Frames will be a bit tougher, but I would stick with monolithic bullets (Barnes TTX, Cutting Edge, or similar) for the velocities you'll see out of that 7 STW. Make sure you condition the bore before shooting those solid copper bullets, though.

I am not a huge Partition fan. I agree on your accuracy assessment. In my experiences, the faster you push them, the less accurate they become. I miss the Winchester Failsafe. IMO, it was a Partition done right.

 

[stagpanther]

For what it's worth, the hunters I know whose rifles I work on who use Weatherby's 270 and 300 wby mags with the factory partition ammo very often return from their hunts with one-shot kills. I myself haven't used them in a hunt, but I've shot a boatload of them and they would be at or near the top of my list for a medium to big game bullet.

 

[stagpanther]

Put her together this morning and took a few test shots after a millitech treatment to the bore. A bit like wildcatting since no gages for 7mm STW seem to be made anymore, though I did use the 375 H&H belted mag go and no-go gages for setting headspace. Other then that--you're on your own. I've always liked Khantrol brakes, and decided to try for the first time their HexMod CWES Muzzle Brake GEN 2. Jeremy says it's a piece of cake to set on his video--but try as I might there was no way I could get it to stay clocked--and it ended up rotating loose with the shots I took. More fussing ahead. Unfortunately, like the Weatherby cartridges, the 7mm STW will not work with any MDT magazines beyond 1 cartridge in the top of the magazine.

 

[stagpanther]

My patience ran out on the Rubick's cube machinations of getting the brake to lock in place, the inner collar simply kept spinning and I couldn't attain that magical balance of where it gripped "just enough" and still remain moveable by putting pressure on the brake itself. So I bubbatized it and put a crush washer on anyway. It's still an excellent brake and would recommend them without hesitation, though the this particular version is more challenging for me to install.

My patience also ran out on the Luth AR buttstock, the one little hex screw lock just isn't enough to keep it firmly in place, so I yanked it and put the rudimentary magpul rifle buttstock on, which at least locks solidly in place with no wobble. I also took the old large (thick) firing pin bolt out and replaced it with a new (thiner) small firing pin bolt.

This should be serviceable for now--I will probably replace the accutrigger at some point as well. Next tasks at hand are fire-forming brass and making a modified case gage from fired brass.

 

[stagpanther]

Additional bolt work--I found a PTG magnum bolt head which I decided to put on the bolt. This necessitated changing the firing pin spring setting to get proper firing pin protrusion from the bolt face--a major pain in the butt since it's under a lot of tension. I'm also going to reset headspace to be on the safe side (the head seems to have a different depth from the original). I also found a rifle basix trigger in my treasure chest which I think will fit.

 

[stagpanther]

I've had some teething problems with the new barrel which I haven't quite been able to figure out. After assembling and checking headspace, the first few charges I tested using virgin 7mm STW brass would jam in the chamber after firing. The bolt would rotate freely but I could not withdraw the fired case. I could get them out but only by giving a solid rap with a wood block on the bolt handle. These were relatively low end charges and there were no signs of pressure on the fired case. Despite resizing the new brass and taking the gun apart and reassembling it after resetting headspace--the case jamming would not go away. Bullet Impacts were random and grouping was something around 3 MOA+; not good. I've tried several variations in case trim lengths but that does not change the jamming.

When I first ordered the barrel--there were initially no options for brass or ammo for the 7mm STW--so I bought a bunch of 375 H&H magnum brass as a "last resort" back-up. Using a 300 H&H as an intermediate size and then the 7mm STW die I made a passable collection of brass. Before fire-forming, it retains a more tapered case body than the stock 7mm STW, so it fired and ejected no problem. After the first firing I decided to do a second test firing to see if after forming the chamber if it would jam. Happily, it does not--and morer importantly, the grouping radically improved; here's my first group of 4 shots using a moderate charge of 77.1 grs of H1000 driving a 150 GMX. Were it not for the flyer it would be a nice group.

An interesting side effect of putting this rifle together, I learned something new about the Burris XTR 2. I've always used it as a high power longer range scope, but have found the propensity for "mirage" shimmering at higher magnifications annoying. Today I discovered the scope's reticle excels at lower magnifications at intermediate ranges and remains exceptionally clear and sharp, I shot my group above at around between 6 and 7 x