7mm STW / 175gr. Sierra Gamekings

[STW Newcommer]

Shooters, I need some help. I am going on an Affrican plains hunt this September and want to be able to be effective out to 600 yds on antelope size game. I am learning how to shoot this distance as I have never done this before.

I have an older model Rem 700 BDL with DM, Zeiss Conquest RapidZ 4.5-15X50mm, and Brake. I measured the barrel from throat to end and got 23.5". It has a 1/9.0 twist. The barrel has no more than 200 rounds through it. The chamber and throat will fit a 3.653 cartridge to touch the rifling. My current load is a conservative 65grs of Vn-165 with a Remmington 9 1/2M Mag Rifle Primer. Grouping 1 MOA with 3 shots then that occasional flyer, always up and rt. about 2" @ 100 yds.

I have selected a 175gr. Sierra Gameking bullet and need advise about powder, bullet jump, primer and if anyone has a favorite load to share.

If there is a better bullet out there I an all ears. I selected the Gameking because I have used them for years very successfully, boattail design, reletively high BC and good availability.

I'm looking at RL-25, H-1000, IMR 7828 and have used Vn-165 but got some flyers with it. Not saying It wasn't my fault.

Also, how cold should the barrel be allowed to get between shots?? ie. room temp, warm, hot but not too hot to hold.....

I appreciate any help, Thanks!

 

[eshorebwhntr]

Welcome to the forum.

Everyone has their favorite bullet or load combination. I have nothing bad to say about the SGK but there are plenty of other options out there for sure if that bullet doesn't ever work the way you want it to. I've also never used Viht powders but haven't heard anything bad about them either.

I typically only shoot 3, 4, or 5 shot groups and wait until the barrel cools between groups. With the STW, it's mostly 2 --> 3-shot groups.

If you like that bullet and have some more of that powder I would first try a full ladder test with the powder to find the max and what the gun might like the best. Then possibly play with seating depth. COAL you listed to be at the lands seems a little short for a factory chambering. You might want to double check that number or consult with another member on here that has a factory chambering, mine is custom so I can't help much there.

Having played with various other rifles and Sierra Match King bullets (work very well on game too) I have never found one that wouldn't shoot really well (about .5moa) from .010-.070 jump. Some rifles had a wider range, some narrower. I would think the SGK would be similar and you should be able to achieve slightly better groups than what you've experienced so far. Sierra's and Berger's are my preference nowadays. Both will shoot very well. Sierra tends to have slightly lower BC's but are easier to tune a load with. Berger's have very good BC's but can be finicky in some rifles to load for. Like I said, everyone has their favorite, I'm sure they work fine, this is just my experience.

In my rifle I've only ever used F215 primers, H-1000, and Retumbo. All have shot well for me with 168 SMK, 168 Berger VLD, 168 Berger Classic Hybrid, 180 VLD, 180 Target Hybrid, and 160 Nosler AB (not ABLR). I usually end up somewhere toward the bottom 1/3 to middle of the powder charge range and .010 off the lands with all my best loads but there are exceptions.

Good luck. Hope you get a load figured out that will shoot the way you like.

 

[roninflag]

I harvested 4 bull elk with 175 sierras they worked great out of my 7mm rem mag.

 

[Lefty7mmstw]

If you have an older 7mmstw rem700 ss dm-b you likely have a 9.5" twist (looks like 9" on a rough measurement but that .5" matters with the heavies), which will not like the 175 grain pills too much at all unless they are flat base. My Pops has that rifle and it thrives on 140-150 grain bullets. He especially likes 150 grain pills and rl25 in rem brass lit by a 215...

Rl50 or h50bmg may be your friend with a 175 flat base, but those are getting harder to find these days as everyone wants the highest bc they can get (and boat tail bullets become the rage), regardless of whether the bullet is actually accurate in their rifle or not.

Personally, I'd buy a box of 140 nosler accubonds, a # of rl25, and some wlrm or 215 primers. Run those up at 20 to 50 thou. below max oal., and go kill some stuff. I've used the 140 ab in most of the 7stw rifles I've owned and it will usually be 1/2 moa or lower in a decent barrel if the shooter can hand on for the ride.

 

[STW Newcommer]

Thanks to everyone for all the info. This has really helped, but when I try to put it to work I found I was also limited by what is currently available. So I found some rl25, 7828ssc and F215 primers. Lefty7mmstw I had already purchased a bunch of 175 GK but do have some 140-150 still on the shelf for my .280. So I will try them too. As I read your posts and other posts in this site I see that the bullet type, jump and load require some work and lots of range time to see what works best for my rifle. Now my question is in what order of these variables should I experiment? How do you approach tuning your rounds?

Thanks again for your advise. This site is awesome. It's like going to school.

 

[Lefty7mmstw]

Thanks to everyone for all the info. This has really helped, but when I try to put it to work I found I was also limited by what is currently available. So I found some rl25, 7828ssc and F215 primers. Lefty7mmstw I had already purchased a bunch of 175 GK but do have some 140-150 still on the shelf for my .280. So I will try them too. As I read your posts and other posts in this site I see that the bullet type, jump and load require some work and lots of range time to see what works best for my rifle. Now my question is in what order of these variables should I experiment? How do you approach tuning your rounds?

Thanks again for your advise. This site is awesome. It's like going to school.

The sweet spot seems to be either 20 to 50 thou. off the origin, or max. magazine length... I'll let a pill run (off the lands a bit more, that is) to keep them in the magazine.
I would not waste a box of bullets playing with slightly different cartridge lengths; I've never needed to. Three lengths; 1 at 20-50 thou off.,. one at mag length, and one with the pill at max length with the bullet jammed... I'd only use the max. length (jammed) if the others do not work- watch your pressures if you do this. I also would work the load up in 1 grain (or slightly coarser at lower charges) and refrain from the couple of tenths at a time crap that some do; it simply does not matter in a cartridge of this size.

 

[roninflag]

or antelope size game out to 600 yards ..... lighter faster bullets are flatter and kick less. a 140 berger, a 140 cbt.

 

[STW Newcommer]

I have put about 50 rounds through it. I did 3 ladder tests from 71.0 to 74.5 grs (RL-25) at 0.5 gr. intervals, jump at .010 off the lands, 175 gr SGK and it shot all over the target. Slower loads shot hi and lo. Faster loads were a little more consistant but all over. Overall shot about a 8" circle at 300 yds. I did a second ladder from 74.0 to 77.0 grains of RL-15, I pulled the bullets back to .030 jump. It shot a little better but I did not get the clasic ladder, they were all over from right to left but pretty close up and down. It seamed to favor 76.5grs. But 76 and 77 were close up/dn but 6" wide l/R. 77.5grs was max in my gun. I've done ladder tests before with my .280 REM and never had this difficulty.

This is all making me wonder if something is wrong with the gun. It is not bedded nor has any pillars. The stock in synthetic and has some barrel pressure. But everything is factory stock. I assembled the stock and scope mounting with a torque driver. Any suggestions?

 

[Lefty7mmstw]

I have put about 50 rounds through it. I did 3 ladder tests from 71.0 to 74.5 grs (RL-25) at 0.5 gr. intervals, jump at .010 off the lands, 175 gr SGK and it shot all over the target. Slower loads shot hi and lo. Faster loads were a little more consistant but all over. Overall shot about a 8" circle at 300 yds. I did a second ladder from 74.0 to 77.0 grains of RL-15, I pulled the bullets back to .030 jump. It shot a little better but I did not get the clasic ladder, they were all over from right to left but pretty close up and down. It seamed to favor 76.5grs. But 76 and 77 were close up/dn but 6" wide l/R. 77.5grs was max in my gun. I've done ladder tests before with my .280 REM and never had this difficulty.

This is all making me wonder if something is wrong with the gun. It is not bedded nor has any pillars. The stock in synthetic and has some barrel pressure. But everything is factory stock. I assembled the stock and scope mounting with a torque driver. Any suggestions?

Change your bullet weight to a lighter one... you are marginal on your spin with the 175 sierra at 9.5" twist and she is showing it by puking on the target.
Assuming that everything is tight, your barrel is clean, and your scope is good that is. The design of the rifle works; my Pop's rifle is a solid 1/2 moa performer and is the same rifle you have.

 

[STW Newcommer]

Thanks Lefty7mmSTW!!! Your recipe solved my problem. I loaded 80.5 gr of Reloader 25 behind a 140gr Nosler Acubond. Two sessions at 0.5 MOA.

Thanks again, I really appreciate your advise!

 

[Sully2]

or antelope size game out to 600 yards ..... lighter faster bullets are flatter and kick less. a 140 berger, a 140 cbt.

Im with you. My own choice of slug weights for antelope would be in the 140 category.
after all I see guys on here preaching that a 243 makes a fine antelope gun and I dont intend on firing anything even that heavy out of a .243

 

[Sully2]

175 gr slugs in that caliber are elk rounds IMHO..!

 

[STW Newcommer]

Thanks Sully2.

I thought they would work as well. But my barrel didn't like them to much. It was like throwing knuckle balls. Could not figure out the ladder at all. Since I'll be hunting small antelope in Africa, the 140 will be fine. I'll just need to be very careful with any wind.

Appreciate your comments.