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Critique my custom (planned components for a 7WSM)

stiletto raggio

Sergeant
Full Member
Minuteman
Apr 14, 2010
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Colorado Springs, CO
I have been convinced by people far more experienced than me that the 7mm WSM give the most bang for your buck in terms of long range ballistics versus recoil and ammunition cost. I already have a good .308 and, while I may rebarrel it to .260 when the time comes, I see no sense in buying another non-magnum precision rifle for the time being.

Since none of the big foreign or domestic makers seem to see the value in the 7WSM as a long-range cartridge, this means I have to go either custom or semi-custom. A lot of the rifles I have seen on this forum and others have given me ideas about what I might like and, after comparing many options form many companies, here is my tentative plan for my first custom precision rifle:

Stock: Manners T5A. I like the versatility of having the stock built to my specs (flush mounts, railed points, LOP and color) and I think the thumbhole will make the rifle easier to manipulate with one hand (not shoot, just hold on to and move with) than a more traditional stock. The Mini Chassis eliminates the need for bedding and, installed when the stock is built, I think will have the performance edge over separate pillars and bottom metal. Weight: 4.5 lbs

Action: Big Horn Arms. I have read nothing but stellar reviews of this action and, as many people have pointed out, the action will likely outlast every other component of the rifle. I like the design and the ability to experiment with different mounts. Still, the Surgeon, Stiller and other actions are attractive. Weight: ~2 lbs.

Barrel: Bartlein has a waiting list, but since I will be deployed when this rifle is pieced together, I can afford to get in line. I am leaning toward their Medium Palma contour with fluting and their gain-twist rifling. They will install it on my action. Does anyone have experience with barrels of this type? I can't imagine the contour degrades accuracy or it wouldn't be in use by some of the best shooters in the world. Do you think the 30" barrel will provide a useful velocity advantage over a 26" heavy? Weight: ~4.75 lbs

Trigger: Timney 510. It seems to be the standard for custom rifles, but I can be convinced to go elsewhere. Weight: negligible.

Base and rings: Badger Ordnance. The exact models, of course, depend on optics. Again, they seem to be the industry leader. Weight: 1 lb.

Bipod: Atlas. At $220, it is more than I would have thought of spending six months ago, but compared to some high-end OEM (Sako!), the price seems reasonable. They seem to be the most sturdily constructed rifle bipods available. Any reason not to? Weight: .75 lb

Sling: Tab Biathlon Sling. This design seems to be well thought out and versatile, with advantages in shooting as well as carrying the rifle compared to a standard 2- or 3-point sling. Weight: ~.75 lb

Optics have yet to be decided, but I think that is a subject that requires some more research as well as testing the limitations of my Leupold Mk 4.

So far, the rifle (as described) would weigh approximately 13.75 lbs. That is not light, but my Steyr .308 weighs 11 lbs and carries just fine. I am a big guy so the long barrel and somewhat heavy weight aren't major deterrents, and I would rather not resort to a muzzle brake just yet (though I can be convinced it is a wise investment).

Running cost estimate: $3400 before scope or magazines. That puts me about $1k under a top-notch GAP rifle and, hopefully, still within the same performance window.

As I said, I would like your input, feedback, criticism, experience, and whatever else you want to throw at me. Any experience with these components or, even better, comparative experience with these components and others in their respective classes, would be greatly appreciated. I promise not to get my feelings hurt.

 
Re: Critique my custom

I would go with a different action. Although you may have heard "good" reviews from owners of Bighorns, why not go with one of the many builders with a long standing reputation of incredible, reliable actions. These include GAP Templar, Surgeon, Badger Ordnance, etc.
 
Re: Critique my custom

The bighorn kicks ass, mine is accurate as hell.

I am huge bartlien fan too, but also talk to AJ about his barrels from Mark, the rifle I have from Bighorn is an absolute tackdriver
 
Re: Critique my custom

I know the Big Horn is new-ish but, with the reviews I have read and the recommendations I have received from extremely knowledgeable people, I don't think I will regret going that route. I mean, I can't see it performing measurably worse than any of the aforementioned actions and it will certainly be more precise than I am. I haven't heard any horror stories...

Any experience with Palma contour barrels? Not just the Bartlein. I've never handled a Palma-barreled gun. Perhaps I should hit up the Olympic Training Center...
 
Re: Critique my custom

Man your going to love the 7WSM. I think its the best cal. out there. Here is what I am shooting, so I think you have made some good chooses.

GAP 7WSM
Remington 700 SA
Jewell trigger
Badger bolt knob
Badger lug
Bartlein 1-8.7 twist #4 bull 26' fluted barrel
Badger Thruster brake
Mcmillan A3-5 thumbwheel desert camo
Badger detachable mag alloy
Badger 20MOA base alloy
Badger medium rings alloy
Superior shooting systems speedlock
NightForce NXS 5.5 X 22 x 50
Gun was less then 3900.00
Gun weights less then 11 LBS

When I do it again think i would go with Seekins precision bottom metal. You get a 3.14 OAL over a 2.94 so you can seat those Berger 180's out just a bit longer. Have your throat cut for the 180's. The Big Horn action looks sweet. I would for sure go with the Badger Thruster brake. I love mine and will never shoot again without one. I really don't think you need a 30" barrel. If you look at some of my other post, you can see what accuracy my GAP has.

That's going to be a sweet set up. Keep us up to date.
 
Re: Critique my custom

Parts list looks good. You don't need a 30" barrel. Most people here run a 22-26" barrel and have no issues. If I had to build my 7WSM all over again with what I now know, the only thing I would probably change is the action and go Bighorn.
 
Re: Critique my custom

i like some of the bighorn features for sure however i would look into underground skunkworks actions. true drop in fit plus they take aw mags which is a plus for me maybe not the wsm. his actions are made by defiance who also makes the GAP templar action. this is funny because i am also using a t5a on my current build with chassis system but mine is in 7mm-08, obviously drastically different but just ironic to me. either way you will love it just make sure you pick a good smith!!!
 
Re: Critique my custom

I am about to build a 7WSM and have a parts list similar to yours. I am now vacillating over a 24" or 26" barrel.
 
Re: Critique my custom

I would really like to avoid putting a muzzle brake on the barrel if necessary. I've been talking to Frank at Bartlein and he said that guys have been getting 3150 out of the 30" barrels and that the Palma barrels don't give up anything to a fluted heavy barrel in terms of accuracy. I'm 6'3" and 260, so a few inches and a few ounces don't mean as much to me as high velocity and lower perceived muzzle blast.

Has anyone worked with RW Snyder? I may be having him piece everything together, install the trigger and CeraKote the barreled action. He is also the vendor of purpose-built 10 round WSM magazines, so I figure he will be able to ensure proper fit and function with heavy bullets (I know it is something about re-profiling the feed ramp).
 
Re: Critique my custom

Also, I did the math and, assuming the .300 WSM and 7WSM have the same or very similar case capacities, I would need a 31" barrel on a 7 to match the overall barrel volume on a 26" .300. That means that, for a given bullet weight (say, 180s) I should be able to get the same velocity on a 7mm as on a .300. To me, the +/- 150 FPS is worth the barrel length.
 
Re: Critique my custom

I really think you should recheck your math. I just don't see the need to run that long of a barrel on a tactical build. And another thing, speed isn't everything. If you want speed, then build a 7RUM or a 7STW. Which looks like that is what you are trying to do.
 
Re: Critique my custom

Volume of a cylinder= pi(r^2)h where h= barrel length and r= bore radius (1/2 bore diameter)

3.1417(.142^2)h=3.1417(.154^2)26

h=30.58

Assuming similar bullet weights and propellants, a barrel with a bore diameter of .284 must be 30.58 inches long to have the same volume as a barrel with a bore diameter of .308. I made an assumption about the size of the cartridge itself, but as long as the volume of the cartridge is pretty close, the results of the calculation are pretty accurate.

I don't want a 7RUM or 7STW, though with the longer barrel, the 7WSM certainly approaches the STW. The 7RUM uses a lot (about 30%) more powder to get a moderate (10%) velocity advantage out of a "standard" 26" barrel when compared to a 24" 7WSM. Rather than burn more powder (and chew up my barrel faster) I want to maximize performance of the WSM. OAL won't be any longer than a short-ish barreled rifle with a suppressor and, given the difference in action length, should be very close to a Sako or AI magnum-action rifle.

I apologize that my ballistic data is somewhat incomplete; these comparisons were made based on the Lyman reloading handbook.
 
Re: Critique my custom

I think you are looking at it the wrong way. What are you after? Energy down range? Down range velocity? Knowing the ballistic coefficient and speed of the bullet is a better way to figure out what barrel length you are going to need. You are putting way too much thought into this. There are a lot of 7WSMs out there. And pretty much no one runs that long of a barrel on one because we don't need to.
 
Re: Critique my custom

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hill billy</div><div class="ubbcode-body">I am about to build a 7WSM and have a parts list similar to yours. I am now vacillating over a 24" or 26" barrel. </div></div> <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hill billy</div><div class="ubbcode-body">I am about to build a 7WSM and have a parts list similar to yours. I am now vacillating over a 24" or 26" barrel. </div></div>

That's why I went with 25"
 
Re: Critique my custom (planned components for a 7WSM)

Stiletto raggio,

Critique:

Stock Manners T5a: Check

Action Big Horn: Check

Barrel Bartlein: Check; contour Light Palma; Length 26" Max
Equal accuracy to medium Palma, and less weight. For length see below.

Trigger Timney 510: Check

Base and Rings: Seekins Precision
Rational: equal build quality to Badger, less weight than steel Badgers. Weight you don't need.

Cartridge: 7mm SAUM

Rational:

7mm SAUM case capacity 73.6 gr. 7mm WSM 81 grains. Velocity difference, negligible. Source: 6mmBR 7mm Cartridge guide

link: 7mm Cartridge Guide

In short the 7mm SAUM will give better barrel life, due to less powder burned to achieve similar velocities.

Barrel length:

Both the 7mm SAUM and the 7mm WSM can reach 3000 FPS with a 180 gr Berger. Max range while still supersonic is 1700 yds for both. Going to a 30" barrel will yield an extra 150 FPS, and extends max range by only 100 yds to 1800 yds.

Law of diminishing returns applies.

IMHO and YMMV.

Good luck with your build,

Bob
 
Re: Critique my custom

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: stiletto raggio</div><div class="ubbcode-body">

Any experience with Palma contour barrels? Not just the Bartlein. I've never handled a Palma-barreled gun. Perhaps I should hit up the Olympic Training Center... </div></div>

We can fix that. PM edited.
 
Re: Critique my custom

I see what OP is trying to do, I belive he is trying to find the optimum barrel length to verify mathmaticly that all of his cartridge capacity is.

I belive Quickload can do that with different powders, calibers, case capacity, and barrel lenght.

I do not have QUickload but maybe someone with it will help you out.



As the build list.....looks good, big guys can run the bigger rifles better and the extra weight isn't always an issue. But I would have a Badger Thruster mounted to it, and have it profiled to the barrel contour, less effective because of the surface area reduction.....but it can be spun off by hand and a thread protector spun on for quiet....but any help is great when long days of 100 rounds fired are had, and the next day your shoulder doesn't hurt but is still all purple!!!

I have a Badger Thruster on my 7mm-08 18" and it is abrasive to say the least, I double up for all day shooting, and other shooters with AI 300Win Brakes say it is annoying. I think that has alot to do with the barrel length and powder, I am getting:

2600FPS
18" Barrel (factory rechambered/trued)
41.3gr IMR4064----OVER MAX SO DO NOT TRY WITHOUT COMING UP TO IT-----
CCI250 Magnum Primers
RP Brass
7mm-08
162gr Amax

Sierra's book lists a 26" barrel and 205M primer and 39.7gr of IMR4064 as maximum and 2700FPS for the 160gr 7mm-08. Sierra's SSP for the 7mm-08 is 15",the 210M primer, and 39.1gr IMR4064 gets 2400FPS.....that tells me that the IMR4064, gets another 11" barrel length and goes 300FPS faster with .5gr.


Follow my logic if you can....the .5 gr added you gain a bit but I was able to up my charge in my 18" barrel and saw a point of deminishing returns....the velocity quit changing as much with an equal increase in charge weight. I had found the complete burn length of a set charge weight, meaning I was finding the point where I would get complete burn of the powder to a point only slightly higher than the book. Quickload and the quickload manual could help you alot on selecting your barrel length.


Sometimes my idea's arent relayed sometimes
shocked.gif
But this is what I did with my 7mm-08Rem 18" barrel and it works better than I do and I belive that is why my Badger Thruster (not profiled to barrel contour, I wanted it to be that way but the smith forgot), is so obnoxious, is I just got 41.3gr of powder to burn completly is 18" and 3 feet away from your head!!!!