7mm Wsm For Long-range ?

Status
Not open for further replies.
Zak Smith

Zak Smith

Member
Joined
Dec 24, 2002
Messages
9,174
Location
Fort Collins, CO, USA.
I am interested in getting a rifle built for long-range "action" competition, the ITRC in Gilette in particular. This is the DLSports match run my Dave Lauck.

A friend of mine who has shot this match for several years has settled on a custom Rem700 with a 28" bbl in 7 Rem Mag. The 168gr Berger has a BC of 0.648 and it can apparently be launched at about 3100-3150fps. This is an excellent long-range setup.

I was looking at the 7mm WSM (Win Short Mag) data in the Hornady book and noticed that it matches 7RM in every bullet weight and beats it in velocity in some. The 7WSM max loads are typically 2-3gr more of the same powder as compared to 7RM.

This would indicate to me that the 7WSM has a little more powder volume available than the 7RM. The shoter 7WSM case is preferrable to me as long as it can meet the accuracy and power of 7RM.

Has anyone here built a precision rifle in 7WSM?

thanks
Zak
 
I know nothing of the 7mm WSM but my friend who owns a range near my home loves the 7mm SAUM. He has built two rifles just alike in the last six months. Savage actions, 26" straight taper barrels, and McMillan stocks. I was quizzing the smith who built the guns at our last match and he sounded convinced the the SAUM rounds where a better design than the WSMs. He said that although the WSM could be faster the SAUM would be more efficient and accurate.

I was going to buy a new rifle (12BVSS) with a factory barrel in 300 WSM but now I'm considering just getting a custom rifle built on a Savage action in the 7mm SAUM. Almost no recoil with the straight barrel and great bullet availability. This will be my first 1000 yard rifle.

Sorry for straying from the WSM but my opinion would be to go with either the WSM or SAUM over the RM just because of the short action and lack of the belt. Both would be make an excellent 1000 yard round.
 
How would the 7mm. WSM/SAUM compare to the full-size 7mm. Rem. Ultra Mag in terms of long-range performance? I know the latter round will have a few hundred fps extra velocity, but how would this affect downrange trajectory - enough to make a difference, or simply of academic interest? Would the higher velocity of the 7UM allow one to use heavier bullets at long range while retaining adequate velocity/trajectory?
 
For the following data, I'm assuming the 7WSM can reach 3100fps with a 26-28" barrel, and that the 7RUM has 250fps on it.

Code: 
 _BC_ _MV_         0     200     400     600     800    1000 | YARDS
0.648 3100 >   -1.56   -2.41  -21.01  -61.57 -129.45 -231.69 | > 7RM 168gr VLD
                        1.15    5.02    9.80   15.45   22.12 MOA
                3098    2804    2525    2264    2019    1792 | fps, velocity

0.648 3350 >   -1.57   -1.83  -17.22  -51.21 -108.15 -193.74 | > 7RUM 168gr VLD
                        0.87    4.11    8.15   12.91   18.50 MOA
                3348    3036    2744    2469    2211    1970 | fps, velocity

Are there any 7mm bullets with a higher BC than the 168gr Berger VLD (0.648) ?

The concern I've heard about the RUM is that it will have less barrel life than the 7RM.

-z
 
yes, there are higher bc's than berger's available... lost river goes over .7 for the heavier 7mm bullets.

back to the original question...
how far is the shooting in this match? how serious the competition? if i was building a rifle for long range competition, i would start w/ a rem 700 action, and chamber to either 338 rum, 7wsm, or 7 rum (in no particular order), barrel by shilen at 30", stock by mcmillan, and scope would depend on the rules of the competition, but i'm sure it would be a leupold of some sort.
 
I run a 7mm Rem Mag, and am switching to a 280AI(similar capacity to 7RUSM) for 1000yd comp. The 7WSM will work fine, you pick up a few gns capacity, which would be good to lower pressures at the same vel as 7Rem Mag, which will extend barrel life(a priority).

I'd go 7WSM simply because Win brass has tended to be better than Rem brass, and both are rather limited in selection right now. I know Norma is making 300WSM cases, but the 7WSM moves the shoulder forward, so you really don't want to form from 300WSM cases.

The 180gn JLK's and 180gn Bergers have better BC's than the 168's, the Carteruccis(sic) are also higher, but all will be awesome for LR shooting.

I'd go 7WSM, Winchester M70 push action(although nothing wrong with the controlled feed, my pre-64 shoots in the .3's), 30inch Kreiger, McMillan stock, smithed by George Gardner or Randy Gregory. You want a sniper rifle, go to George, you want a target rifle talk to Randy. I have rifles from both and they work extremely well. E-mail or PM if you want more info. Semper Fidelis...Ken M
 
re: 6.5x284

The 7 with 168gr VLD's has a slight edge on trajectory over the 6.5.

I've heard from a couple people that 6.5 barrels would burn out sooner, also. Is this true?

-z
 
I don't know about that...I don't have practical experience with the WSMs, but it seems to me that the throat wear on a 7mm WSM is going to be pretty high. For a hunter this doesn't matter, but for a competition shooter, it matters a lot because he shoots a lot more.
 
Why not 6.5x284?

I like being obstinate!:D

The 7mm bullets are slightly better, and you should be getting slightly more barrel life with something in the 280AI/7RUSM capacity area compared to 6.5/284. 7WSM has another 6-8gns capacity over the 280AI/7mmRUSM and is actually 2 gns ahead of the 7mmRemMag, so it should have a barrel life about the same as the 7mm Rem Mag, which is about 1500-1800rds, slow fire prone, plus one setback for another 1200rds or so. S/F...Ken M
 
No 7WSM for me for at least 2 more years. I just got a brand new 280AI for 1000yd. 26" heavy Kreiger on a pre-64 in a McMil prone stock. Was shooting fireform loads the other day off a bipod into the .4's using bulk Speer 110gn TNT bullets and IMR 4895. I might very well take it out to SD and shoot P dogs with it to form brass, it's a fun rifle. S/F...Ken M
 
In the various gunzine discussions of the Short Magnums, it is commented that there is some 20% less powder, but only a 10% reduction in muzzle velocity. (Roughly) This should result in a bit less burning of the throat during shooting, and thus extend barrel life. Since the weight of the powder contributes to recoil, there would be a reduction here, as well...

We've had numerous discussions here about the benefits of a short action as regards stiffness and therefore accuracy.

To me, this all adds up to the SMs being a Good Thing for a handloader.

:), Art
 
I know the reduction in powder is true to 300WSM, but I'm not so sure about 7WSM. The published max loads for the 7WSM are a couple grains above the 7RM.

Does anyone know the actual powder volume of 7RM vs. 7WSM?

-z
 
The 7WSM has slightly greater capacity than the 7 RM. The 7WSM is a necked down 300WSM ,which duplicates the 300Win Mag. The Win Mag is a longer case than the 7Rem Mag. A 7-300Win Mag would be more comparable to the 7WSM, in theory anyways. S/F...Ken M
 
Hey Zak if you are still interested in 7mm WSM as a long range cartridge. Give mac tilton at www.mtguns.com a holler. He built me a target rifle in .223 on a tikka action, but he also has experience building super accurate target rifles in 7mm WSM. (BTW the tikka shoots 0.25 MOA groups)
from his page (regarding true-flight barrels):
7mm x 1-8†twist; introduced during 2002 to cater for the growing 7mm 1000-yard target/ long-range hunting fraternities. Feed-back indicates extremely high accuracy levels from 7mm Rem Mag and 7mm WSM, particularly with Hornady’s excellent high-BC 162 grain A-Max, which co-incidentally has proven to be an excellent game bullet as well as a top choice for long-range paper groups. Obviously a great all-rounder.

One of his rifles took a top score in a NC 1000 yd BR competition.

atek3
 
I'm building a 6.5-284, myself.

The 7mm bullets are slightly better, and you should be getting slightly more barrel life with something in the 280AI/7RUSM capacity area compared to 6.5/284.
Click to expand...

Because I've been working with the 139gr Lapua Scenar bullets, BC of 0.615, in my 6.5-06 1000-yard rifle. A 6.5-284 is really no more overbore than the 6.5-06, and the 6.5-06 is more efficient than the popular .25-06, which doesn't seem to have much of a problem with short barrel life. I find the 6.5-284 to be a win-win situation, short action, less recoil and throat erosion than the magnums with their big boiler rooms blasting powder through small throats.
 
atek3,

Thanks very much for that link. It so happens I might have the funds to have a real nice 7 built soon. My main purpose for such a rifle would be to shoot the DLSports "Internat'l Tactical Riflemans' Championship" match.

With regard to the 162 AMAX, I will probably avoid it. A friend of mine was shooting hot 7RM loads through a 28" bbl for the DLSports match last year. His chrono'd muzzle velocity was around 3150fps. When the barrel heated up after about 10 rounds, they would vaporize between 10' and 100yards from the muzzle. This was reproduced in controlled conditions in an indoor shooting tube. A call to Hornady revealed that the 162 AMax basically can't be driven that fast without coming apart. He's switching to a similar bullet from Berger - apparently he was not the first to have this problem.

-z
 
Hah, exploding bullets, never seen it myself (but I was amused by the scene in Unintended consequences, wasn't that 6mm-348 win?).


Good luck on the LR rifle.



atek3
 
Steve,

I did buy a JP AR10 (in 308) last year, I think before I posted this thread. It shoots 0.5 - 0.75 MOA with FGMM 168gr. You can't really get 308 to the class I'm looking for in a LR bolt rifle, though, in terms of MV and BC.

-z
 
Status
Not open for further replies.

Similar threads

Zak Smith
  • Locked
Finally a 7mm: AI-AWSM in 7mm Remington Magnum
Replies
5
Views
6K
240SX
2
S
  • Locked
6.5x.284 versus 7mm Rem Mag for multi-gun matches
2
Replies
29
Views
6K
Flatbush Harry
F
I
  • Locked
Am I figuring this right? .300 WSM freebore
Replies
11
Views
713
robin banks
R
B
  • Locked
Rechambering a Savage for long range match work.
Replies
12
Views
2K
brass shower
B
T
  • Locked
Long range targets and 7mm rem. mag.
2
Replies
25
Views
3K
Zak Smith
Zak Smith
Back
Top