7MM - Need to make a choice

[MontanaRifleman]

I have a 270 Wby (Rem 700 long action) that I am not happy with, so have decided to rebarrel to a 7mm. I am looking for a long range hunting rifle with good horse-power. I am not looking for the most efficient round, because the rifle will only be used for some load development, then hunting. Bullets will be 170gn and up, VLD style. I am thinking an 8 twist barrel would be preferred to give me options with some of the newer high BC bullets.

I have considered the 7WSM, a 7mm/375 Ruger wildcat, or the 7mm Rem Ultra Mag. The 7/375 Ruger seems like a very good option ballistically and would be my first choice, BUT I am not sure that I want to go down the route of sourcing dies and forming brass.

The 7RUM solves a lot of these issues, but really is getting into big case "barrel burner" territory. However given that I am not too concerned about barrel life, and do want to run heavier bullets, the 7RUM may well be the "best" option for me.

At this stage of the process, is there anything I have overlooked? Or have I talked myself into the RUM chambering?

I would say either the 7 WSM, 7-375, 7-300 WM or 7 STW, in that order.

The 7 WSM is going to give the best barrel life with the availability of off the shelf dies and brass. Performance will be close to the 7 RM without the scabby belt.

The 7-375 will give you upgraded performance but a bit more expense in forming dies. You'll need custom sizing and seating dies as well, but that's the best route to go for any precision rifle project. The case capacity is essentially the same as the STW, but again, no scabby belt.... can you tell I don't like scabby belts? You can expect a little more barrel life than the STW because of the sharper shoulder and longer neck. My process for forming the 7-375 case would be...
Hornady 338 RCM FL
Hrnady 300 RCM FL
Custom 7-375 FL Bushing die based on reamer drawing, for final sizing
Ream and turn to .015 thickness
Fireform

I will not be as irresponsible as some to suggest what you will get 1500 rounds of good accuracy out of any of these cartridges let alone the STW with a .277 long neck and 25* shoulder. I think you can expect about half that with the STW, slightly more with 7-375 and 7-300 WM and a little more with the 7 WSM which should get maybe 1200 give or take depending....

The 7-300, will also require some forming and special dies with a little more horsepower than the WSM and less than the others.

The STW has off the shelf brass (not a very good selection) and dies. Expect the least barrel life out of the bunch with its 25* shoulder and .277 long neck.

 

[MontanaRifleman]

I've been called a liar saying the STW can get 1500 rounds of barrel life...

Who was it that called you a liar?

 

[Broz]

The 7-300, will also require some forming and special dies with a little more horsepower than the WSM and less than the others.

Not all that special as far as dies go. All we use is a set of 300 win bushing dies with a 7mm size bushing. Pretty easy and benefits from the availability of good brass for the 300 win. First round firings are on course with 2nd firing as far as fire forming it is null. Expect 3150 fps from a 28" tube with 180 gr bullets and more if you push it hard. Barrel life is looking pretty darn good as we have yet to wear one out and are well past 1000 rounds on a couple rifles now.

Jeff

 

[MontanaRifleman]

Not all that special as far as dies go. All we use is a set of 300 win bushing dies with a 7mm size bushing. Pretty easy and benefits from the availability of good brass for the 300 win. First round firings are on course with 2nd firing as far as fire forming it is null. Expect 3150 fps from a 28" tube with 180 gr bullets and more if you push it hard. Barrel life is looking pretty darn good as we have yet to wear one out and are well past 1000 rounds on a couple rifles now.

Jeff

I hadn't thought about using the 300 WM bushing die. I guess it seemed like a big step down to the .284 But if it's working for you it must alright.

That's great you're getting that kind of life out of your barrels. If you're using slow powder and heavy bullets, that helps. I burned out a 7RM in a little over 1000 rounds and I shot warm loads out of it for sure. When folks ask about barrel life, I try not to be too optimistic. Better they get a little more than expected than less IMO. No hard and fast rules on barrel life.

When I bought my used 25-06 Sendero I had no idea of the round count. The smith down here in Belgrade said it was one of the worse fire cracked barrels he had ever seen when he scoped it. I had just shot a .224" group @ 110 yds a few days before. The reason I took it to the smith for a bore scope is it took me a couple of days of cleaning with BTE and Wipeout to get all the carbon and copper out. I shot a lot of sub .5 MOA groups with that rifle after that and when i sold it this spring it was still close to .5 MOA after about 400 rounds I had put through it. I guess some rifles just don't know when they're burned out.

 

[cummin_un_glued]

Jeff,

before I decided on the 7x300 I loaded up some dummys to check them in my mag box. I used a 7mm rem mag FL die just raised up because I didnt have any 300win dies at the time. Any reason that dosnt work?

 

[Broz]

Jeff,

before I decided on the 7x300 I loaded up some dummys to check them in my mag box. I used a 7mm rem mag FL die just raised up because I didnt have any 300win dies at the time. Any reason that dosnt work?

No, until you want to full size the case. Then I prefer the redding 300 win body die. It works great. I use the 300 win bushing neck die for the neck and the body die foe case and shoulder control. These days I just leave them set up in my redding T-7 turret press and run them through both dies each firing. This way if they need bumped they get it. If they don't nothing happens. I find this keeps my brass more consistent each loading.

Jeff

 

[Broz]

I hadn't thought about using the 300 WM bushing die. I guess it seemed like a big step down to the .284 But if it's working for you it must alright.

I started using 3 bushings to step the neck down about .010" at a time. This is over kill but helps to keep the necks true. Two bushings work well and one will do it. But I prefer to step down brass slowly. Small steps will allow the case to be in a different rotational direction each step and less stress on the neck shoulder junction resulting in a truer neck. Plus you only need to do this once in the beginning. Once the necks are down sized you just use the final bushing for one trip to reload.

Jeff

 

[MontanaRifleman]

I started using 3 bushings to step the neck down about .010" at a time. This is over kill but helps to keep the necks true. Two bushings work well and one will do it. But I prefer to step down brass slowly. Small steps will allow the case to be in a different rotational direction each step and less stress on the neck shoulder junction resulting in a truer neck. Plus you only need to do this once in the beginning. Once the necks are down sized you just use the final bushing for one trip to reload.

Jeff

Yeah.... I was thinking the 308 shoulder on the bushing die would be a little loose for the 7mm. Guess it's not a big deal. I'm using a 270 WSM Type S die for my 6.5 WSM, but that's a little tighter.

 

[MontanaRifleman]

Jeff,

before I decided on the 7x300 I loaded up some dummys to check them in my mag box. I used a 7mm rem mag FL die just raised up because I didnt have any 300win dies at the time. Any reason that dosnt work?

Might that lead to stretching and thinning above the belt and possible case head separation after a few firings?

 

[cummin_un_glued]

that may be part of what jeff is talking about. I plan to go the 300win bushing die way with mine when it gets here.

 

[Lefty7mmstw]

I will not be as irresponsible as some to suggest what you will get 1500 rounds of good accuracy out of any of these cartridges let alone the STW with a .277 long neck and 25* shoulder. I think you can expect about half that with the STW, slightly more with 7-375 and 7-300 WM and a little more with the 7 WSM which should get maybe 1200 give or take depending....

QUOTE]

Irresponsible, eh. I've been there with my sendero 7stw, done that. I traded mine with around 1500 rounds on her(probably over but I didn't log book the rifle- only empty bullet boxes and bad brass to go by). The last group at 100 yards was .4" with a 140 sierra and rl25 when I was re-sighting with a 6x nikon I was thinking of trading along with the rifle. 750 rounds on an stw is a good break in unless you are a fool and running the **** out of it or shooting hot weather/barrel a lot. If you do either of those you are correct, otherwise you are pretty mistaken.

 

[MudRunner2005]

Yeah, I caught alot of crap for saying it could get 1500 accurately...Now you know! I pretty much getting called a bald-face liar, and asking was I (ME) gonna replace HIS barrel if he didn't make it to 1500 rounds. Why would I do that? I don't know how you treat a rifle? I could burn one out in 150 rounds, it's not hard to do when you get it glowing hot and keep shooting...

Thanks Lefty for solidifying what I said before.

 

[MontanaRifleman]

Irresponsible, eh. I've been there with my sendero 7stw, done that. I traded mine with around 1500 rounds on her(probably over but I didn't log book the rifle- only empty bullet boxes and bad brass to go by). The last group at 100 yards was .4" with a 140 sierra and rl25 when I was re-sighting with a 6x nikon I was thinking of trading along with the rifle. 750 rounds on an stw is a good break in unless you are a fool and running the **** out of it or shooting hot weather/barrel a lot. If you do either of those you are correct, otherwise you are pretty mistaken.

Yeah... I would say it's irresponsible to tell someone to expect an an unusually high barrel life from an overbore cartridge like the 7 STW.

As mentioned, I burned up a 7 RM barrel in a little over a 1000 rounds. about 300 of those were factory. The rest were from various loads I worked up from 110 gr bullets to 175 gr bullets. My pet load was 160 Partitions over a charge of IMR 4831 that pushed about 3000 out of a 24" barrel. A little warm, but not extreme. When my barrel burned out I started a thread in another shooting forum asking what the life expectancy was for a 7 RM. Average responses were about 1000 - 1200 rounds. That was quite a few years ago and what I've read since then is pretty much the same.

Let me ask you a couple of questions....

What are the factors in barrel life?

Light bullets vs heavy bullets?
Fast powders vs slow powders?
Rate of fire?
Heat and Pressure, i.e., hot load vs moderate load?
Case capacity?
Shoulder angle?
Length of neck?

So lets assume the 1st four being equal, Why would a 7 STW with the same shoulder angle and neck and about 12% more case capacity as the 7 RM, get 50% more barrel life? Is there some witch doctor waving a stick with a shrunken head on it, over the STW's?

Are you saying that an STW will get more barrel life on average than a 7 RM? or even a 7-300 WM which has a little less capacity than the STW and a longer neck?

One of the earlier posters here said he was getting 300-500 rounds of barrel life out of his 7 RUMs which has about 15% more capacity and a sharper shoulder and longer neck than the STW. The STW falls right between the 7 RUM and 7 RM. The average I hear most often for the RUM is about 500, which is why I shy'd away from it. I would just love to have a 7 RUM. But when you figue about $1.30 every time you pull the trigger just for the barrel on top of bullets, brass and powder... that adds up.

A couple of more questions...

Since you are so optimistic about the 7 STW barrel life are you willing to...

Guarantee the OP that he will get 1500 of good accuracy out of an STW should he choose it?

Are you willing to back up your guarantee by paying the $600-$700 it is going to cost him for a new barrel? Not to mention the PITA to ship his rifle and down time, etc.

So either walk it back or put your $$$ where your mouth is bub...

It's easy to spend someone else's $$$ on the internet...

 

[MontanaRifleman]

Yeah, I caught alot of crap for saying it could get 1500 accurately...Now you know! I pretty much getting called a bald-face liar, and asking was I (ME) gonna replace HIS barrel if he didn't make it to 1500 rounds. Why would I do that? I don't know how you treat a rifle? I could burn one out in 150 rounds, it's not hard to do when you get it glowing hot and keep shooting...

Thanks Lefty for solidifying what I said before.

So you finally got brave enough to say something... but of course you didn't answer my question... as usual

Who called you a liar and please show us your ref...

...and are you going to pay for a new barrel for the OP if he doesn't get what you're telling him he will get? Put your $$$ where your mouth is...