I am thinking of rechambering my 7mag. to 7STW. the 7mag. shoots .5". Will rechambering change the accuracy. Anyone with an experienced opinion please weigh in. Thanks. fws

I had a 30/06 rechambered to the fire formed version and the 1.5 MOA stayed the same. If that rifle shot 1.0 MOA or better I would have left it alone.

Will the STW fit into your action/magazine?

toto--

There's no hard and fast rule either way, but convential wisdom has always been "the smaller the case the smaller the group". There're exceptions. It also depends a LOT on how good a job is done on it. A poor job is not likely to shoot well no matter what caliber it is.

The shape of the case is probably the least critical of all the things that make accuracy.

I assume you have an action long enough for the longer STW?

If it were me I'd be thinking about a 280 instead of anything with a belt, but that's just me.

Thanks JBelk and others. The rifle is a Rem.700 and yes the magazine is long enough. I have a STW built on a mauser action that will shoot 3 shots cover with a dime, but it weighs 12lb. A little too heavy to tote around. I would hate to mess up a good shooting rifle. I get a little over 3000' per sec. with a 160 nos.bt. I believe I get over 3300 with my custom STW. I have a 19" barreled 7x57 that I get over 2800 with a 160 which would be plenty out t o 300yrds. So I'm thinking if I could keep my accuracy it would be to my advantage to go to the STW with the 700. I have thought about building another STW on a mauser action. It sure gets expensive. I need to stop building guns where I can have the money to do some of the hunting that I keep reading about on this and other boards. fws

If you are thinking of rechambering the factory Remington 7mm Mag barrel to the Stw you probably won't achieve impressively greater performance. My experience says that if the barrel is presently shooting best at around 3000fps, it will perform the best at the same speed after rechambering. I have seen this too many times to think it is not so. If you want the STW your best bet is to rebarrel at 26" at a reasonable weight. Regards, Bill.

I'm with Bill. When you jack the velocity up by several hundred fps, it's a whole new ballgame with no guarantees.

The 7mm STW usually needs a 28 inch or longer barrel for best results as it's burning a whole lot more powder than the 7 mag. When the 7mm STW first came out a whole lot of guys went the rechamber route with their factory barrels and many were dissapointed in the accuracy. Frankly your not gaining much over your 7 mag in terms of real world capability.-Rob

I posted this same info in another thread, but if you intend to rechamber to 7STW.....

I'd be careful on just rechambering from 7 Rem Mag to 7 STW. I did this about 3 years ago and while the rifle shot great, the chamber didn't clean up completely. There was a small bright ring on every case I fired right where the 7 Rem Mag shoulder used to be. After I checked the case dimensions, I noticed that the diameter at the shoulder of the & Rem Mag is slightly larger than the shoulder to the 7 STW. If your 7 Rem Mag chamber is not a SAAMI minimum chamber or if the 7 STW reamer is for a SAAMI minimum chamber, it might not clean up completely.

I did this with a Rem 700 with a 24" barrel. I gained about 200fps over what I could get with the 7 Rem Mag and my accuracy was about the same, and inch or better at 100yds. About 1 1/2 years ago, I rebarreled the rifle with a 26" PacNor barrel and gained another honest 150 fps (about 3350 with 140gr, 3200 with 160gr).

I just wanted to thank all for the response again. After considering all info. that was presented I will keep the 7mag. as is, although I am considering to build another STW on a mauser action with a lesser weight barrel. Thanks again. fws