I have a 7mm STW Win 70 SS with a 26" barrel. It shoots just OK (1.5" at 100)on a good day with the right load.

I was thinking of having it rebored and chambered to a 300 Weatherby. So will a 300 clean up a 7 STW chamber? From the drawings it looks close. And is a 300 bore enough of a jump from 7 MM?

Thanks

How about just doing a 300 stw? I believe all you have to do is run 7 stw case through a 300 stw sizing die.

Why not just rebarrel and be done with it?

Thanks, I hadn't heard of it but the cost of a custom reamer, reloading dies and the reboring turns this into a $1000 project.

I'm thinking reboring would be cheaper and take less than 4-6 months for a new barrel.

Question is why is your base barrel only a 1.5". I'd bet you a your rebore would be in the same situation.

Normally rebores tend to shoot about as good as the donor (at least the ones I've been around)

Why not ream the barrel to .323" groove diameter and rechamber to 8mmRemMag. You can buy the brass, when available, and standard dies. No barrel set-back involved.

Who would you have re-bore the barrel?

Multiple barrel makes and no waiting for a new tube Here

Or buy a takeoff barrel...300 Wbys show up fairly often. And I think there are a couple STW barrels on ebay right now.

Still be at the mercy of some moody gunsmith but that would be the cheapest route.

Personally, I'd rebarrel with a Lilja! Lol!

speaking of lilja barrels-- I got one for sale in 7mm. PM me if your interested in the details. im not home or I would look and post the details now.

Thanks for all of the options-

The new or take off barrel contours may not match the existing one and there is only one 7mm sporting weight listed on the site suggested.

The ebay barrels are blued not SS.

And nobody has offered an answer to my original questions.

I sure wouldn't think the .300 Wby would clean up a 7 STW chamber without setting it back. The STW shoulder begins .091" past where the Wby shoulder starts with only .003" less in diameter. I think you'd have to set it back, which doesn't seem like it would be too much extra expense considering you're having it bored and rifled.

The short answers to your original questions are yes to all. 7mm to .30 is enough. The chamber will clean up if the barrel is set back when it is rebored/rechambered.

That said, you should consult a rebore specialist like Cutrifle, Clearwater or JES.

My two cents are that if you really want it to shoot, have it rebarreled with a quality barrel contoured to match your factory profile. Have the action trued at the same time.

If you rebore, and it doesn't shoot, you have a $1000 project since you get to rebarrel it anyway. Or sell it at a loss.

A new barrel has a much higher percentage chance of shooting well. I think that is what my fellow members are trying to say.

Jeremy

Have to agree with Jon.

Here is what ammo guide has to say

Sorry, but based on your settings, you cannot ReChamber your 7mm Shooting Times Westerner firearm to .300 Weatherby Magnum because the .300 Weatherby Magnum employs a different case/rim construction than the 7mm Shooting Times Westerner.
Also, the case of the .300 Weatherby Magnum is too narrow at the top of shoulder.

Also, the case of the 7mm Shooting Times Westerner is too wide at the bottom of shoulder.

If that is what Ammo Guide conveys about the case & rim construction of the two cases than it is flat out wrong. The 7mm STW & 300 Bee are both based on the same belted (0.532") H&H head size.

The shoulder difference is real and you would need to set back the barrel since as others have pointed out since the 300 Bee is about 0.100" shorter where the shoulder radius begins compared to the shoulder juncture of the STW. However, my references show the 300 Bee to be ~0.005" larger in diameter at the shoulder, 0.492" for the Bee vs. 0.487" for the STW.

Yes, you can do it But you are looking at setting the barrel back about 0.250" to make sure you clean up the entire chamber.

I looked into reboring a barrel once and came to the conclusion that unless the intent is to rebore something that has a unique profile/contour that it is money better spent to get a new barrel. The cost at the time would have been a wash to rebore, set back and rechamber vs. a new barrel chambered and installed.

quote:

Originally posted by DavidReed: However, my references show the 300 Bee to be ~0.005" larger in diameter at the shoulder, 0.492" for the Bee vs. 0.487" for the STW.

I should have been clearer. The Weatherby is larger at the shoulder, though my reference lists it at 0.490", for a difference of only .003", which is what I was trying to say earlier. You said it much more clearly, sir.

quote:

If that is what Ammo Guide conveys about the case & rim construction of the two cases than it is flat out wrong. The 7mm STW & 300 Bee are both based on the same belted (0.532") H&H head size.

I've found many case head issues with ammo guide. Saying there are not the same. Most were probably in std but the dimensions they have in their data system don't match to the .0001 so you get an won't work.

I always take the head issue with a grain of salt. Shoulder that is another thing all together.

I re-read my post and didn't mention barrel set back to clean up the chamber. An important omission. It has been corrected. My assumption being the rebore specialist would do that, or recommend it.

Jeremy

Why not go to www.saami.org when comparing the dimentions?

quote:

Why not go to www.saami.org when comparing the dimensions?

Couple reasons I could never find the saami site when I needed it and then I had to compare the dimension. Heck for years I would use my drafting program and overlay the drawings.

Now I guess you can call it lazy. Taken with a grain of salt Ammoguide can give me the 98% answer what will work.

If I'm still interested I go the extra steps.

As to the OP. If you are going to rebore, rechamber and now setback a factory barrel that only shoots 1.5" on a good day. I sure wouldn't waste my $$. Just put the $$ to a new barrel. If the bottom-line is the issue you can get a stainless Douglas installed in the $400 range last I checked.

quote:

Originally posted by DavidReed:
If that is what Ammo Guide conveys about the case & rim construction of the two cases than it is flat out wrong. The 7mm STW & 300 Bee are both based on the same belted (0.532") H&H head size.

Yes. I have been converting and shooting 7STW cases in my .300 Weatherby for years by simply necking the 7 STW case up to .30 with a long tapered expander, then size the case in a FL .300 Wby size die, then load and freeform.

The only difference in the cases is the names stamped on them.

Guys as I said don't get worked up about ammoguide and the head. Ammoguide and saami has the 7 STW as .532" just like the parent H&H.

For whatever reason Roy set the 300Wby up with a head of .5315. Both Ammoguide and saami show that number.

Ammoguide doesn't think that "close" will work it is simply a program to it the head on the Wby to be smaller than the 7STW so it kicks it out.

Yes in the real world there is far more slop in head di that the saami .0005.

As in all data and answers from the net research.