My Pierce 7 WSM build, now with a new barrel!

[Capt Academy]

Very nice shooting mcfred!

 

[mcfred]

I went to my first Raton Sporting Rifle Match and had a great time. I got a 48/60 in the FNG class. Reading the wind was fun and different. There was ample time for each stage which is very different than the local matches where you've limited time to get off your shots and there's no "coaching" or feedback from spotters on where your shots go.

It's a fantastic venue in scenic terrain with lots of wildlife including turkeys and antelope just walking around with shots going off all around them.

My buddy caught an interesting phenomenon of my rifle on camera. Spotters have commented on it before and I've managed to see it through my own scope before too, though I have never seen it happen with anyone else's rifle.

<iframe src="http://player.vimeo.com/video/69919372?title=0&byline=0&portrait=0" width="640" height="360" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe> <p><a href="http://vimeo.com/69919372">Peculiar Ballistic Trace, Raton SRM 7/13</a> </p>
It's like the bullet drags a bunch of burning powder with it as it goes down range. It's not your normal trace as you can see it sticks around after the bullet and drifts with the wind. Maybe it's water condensation, but it's inconsistent if it's just atmospheric condtions.

Neat stuff.

 

[mcfred]

I've been bored and have a little more money burning a hole in my pocket so I've been playing and designing/tooling up for more fun and games.

Last weekend I had a spare 26" .50 cal barrel I recontoured to a stubby ~18" and chambered to 510 WSM. I'm looking forward to mashing some pigs with it sometime:

Range report sorta:
http://www.snipershide.com/shooting...-go-another-route-big-bore-switch-barrel.html
505gr PP at 1850fps! ;D

Next I've been looking into creating an NFA trust and making a 'run' of Form 1 suppressors. I figure for a couple hundred dollars of material and a $200 tax per item I can cover the calibers I shoot from .50 all the way down for the price of a single top-of-the-line OTC titanium can.

Here's the current iteration of my mono-core design. Serviceable and just 3 parts:

I guess it's just money and you can't take it with you; might as well have some fun. Might make all this fit into a mag-fed aluminum bullpup chassis while I'm bored and have access to a shop and discount materials. Just looking at the rifle I can see a way to make it 10" shorter...

 

[long range newbie]

cool project wish I had access to that much of a shop I only have a lathe and milling machine

 

[D_TROS]

Cool thread mcf, I enjoy these reads.

Glad you made a Raton match. They are a ton of fun. You heading to the one this weekend?
I also was at the Scopre Hi match, man was it a blast. The temp on that convex box was over 135*F for our group. Good times.

As to the homemade suppressors, your bottom design looks decent. There is tons of homemade suppressors designs and tips over on silencertalk. Remember for magnums, stepped cones (like stairs) are more effective than cones (like parking cone), but if you do cones, and they will work fine, just make sure they are 60*
There is a fine line between volume for better suppression, and smaller to save weight. Good luck, I have 3 form 1 suppressors. Lots of fun.


Regards,
DT

 

[mcfred]

Yes, I intend to make the SRM this weekend, the format is great: just go hang out with some buddies and shoot some steel in a beautiful place. What's not to like?

RE the 2013 SHTRC, I can live with the 135˚F connex, it was only 10 minute stage. I do pity Neal T. for RO-ing up there all day though. What I could have done without was the 40mph gusting sideways dirt. Actions with loose tolerances seemed to keep operating though. All in all still a good experience.

Are your cans all the same caliber, general dimesnions and design? How would you rate them in dB reduction?

I've been loitering at silencer talk. The above pic is with one view rotated 90˚ about the bore. The core will likely be wire EDMed and as such the 'cones' are really 60˚ wedges. I am ignorant on the efficacy of the stepped vs. straight cone on a magnum though. Currently the design is ~6.5" OAL at Ø1.5" to be made entirely of titanium which hopefully will be light enough when stuck way out there. Mostly, I'm thinking long-term about my hearing. I don't need the ultimate in dB reduction, just something a lot quieter than the brake I have that will allow me to spot my own impacts.

 

[mcfred]

Time for an update.

Last month was the last 2013 Sporting Rifle Match so I'll be doing more of the local matches again.

I really enjoyed the Raton format. Good scenery and a casual pace. I placed alright but I had some issues that complicated things. One was a hang-fire that seems to be associated with a batch of Tula Mag primers. I've switched primers, adjusted the load and it works fine now. Another issue is that I've swapped out to a different reticle NXS scope and I didn't tighten the turrets very well. So I ended up cranking windage that moved the cap but not the POI. so I was off 2.25MOA for nearly an entire day chasing wind that wasn't there. The last issue was an improperly adjsuted trigger overtravel that caused a delay in firing. That's now been fixed too.

Here's some pics:

Last weekend at the local match, I managed another podium finish. We had a new match director and he introduced a couple stages I've not yet had. The weirdest one was a platform suspended on chains that would rock around in the wind and recoil. Another stage that was modeled after the Raton SRM Stage 7 where you had to shoot steel plates off sticks the difference being that Raton only goes out to 390 yards, we had to shoot 200, 300 430 and 500 yard steel. I did well at that one since I've been practicing for the Raton match... Had lots of fun. Seems the barrel can still group alright, even when in a hurry (too bad I was off .5MOA on the windage):

Some things on the rifle might change again after the New Year. I just can't stop tinkering with it. lol.

 

[Shanerbanner10]

Why tinker if its shooting so well? Great shooting. Very cool and interesting stuff!

 

[mcfred]

I'm helping a couple friends get into the LR shooting by building them a couple 7mm-08 rigs. One of them's going to inherit my receiver and I'll upgrade to a lighter SA clone. I'm not sure how much life's left in the barrel anyway. I keep hearing that 1200 rounds is 'good' for a WSM barrel and I'm at about 1000 now. It might last a little longer since I'm not hotrodding it much. The original factory Remington chromoly sporter contour didn't last 800 rounds.

Once the paperwork goes through, I'll be adding a suppressor and I don't know what that will do to the accuracy either. So tinkering's just the nature of the game.

I went back to the first page and rehosted some of the failed Tinypic-based images.

 

[Khavic]

This thread has me drooling down my chin. I'm taking my 300WSM to be worked over next week and was considering converting it to 7WSM.

Thanks for the great write up.

 

[mcfred]

McFred,
Would you share a few details on your 7WSM?

Were you feeding/shooting them from a mag in a short action?
What bullets?
Lead angle & freebore?
Tight neck/neck clearance?

Looking to have a tight necked 7WSM reamer cut for myself to run 180VLD's at mag length.
...

Yes, it's a short action using Alpha Industries 10-round magazines.
I've been using 180SMKs as they're less expensive and group .3moa at 200yds and have a substantially shorter OAL than the other heavy 7mms.
Lead angle's 1.5˚; freebore is .050" but should prolly be a little shorter for the heavy VLDs/Hybrids/Amaxes.
It's a "no turn neck" at Ø.317" with brass cut to give .003" clearance. FWIW turning brass to get consistent neck wall thickness and remove donuts is required with lots of bullet shank past the neck/shoulder junction for use with magazines in a short action.

 

[Wheres-Waldo]

Thankyou for the details...

I have a .312" nk, 0 freebore 7WSM being ground at PTG now, .012 neck wall thickness should easily clean up all the factory 300wsm cases and be running .002" clearance per side in the chamber.

Have yet to order a barrel... Id like to get a 3 groove with at least .010 land height with hopes of a little longer barrel life, and plenty of flat portion on the chamber end for setting it back a few times.

Also, I may have missed it, but are you using Win brass or Norma/Nosler? If Norma or Nosler, are you necking up or down?

 

[mcfred]

I'm using Win 7WSM brass, prepped, turned, weighed... Back when you could find inexpensive components and get more than 100 pieces to pick and choose from. It worked well enough I didn't need the Norma/Nosler stuff.

If I were using the Norma/Nosler and I wanted to be anal about the brass, then I'd 7WSM FL size the 300WSM, anneal, fireform/hydroform the shoulder, neck size, then push them over an oversized mandrel, turn the OD for neck thickness and try to get rid of any donut, trim to length, deburr case mouths and flash holes, uniform primper pockets, then weight-sort them. The tight-neck stuff is a PITA though if you're trying to save wear and tear on the necks. After thousands of rounds I've never split a neck.

I think a uniform neck wall thickness is more important than the .002" clearance. If I only neck-size I can get more than 10 reloads on a set of brass with a couple annealings inbetween, if I FL size and bump the should back a little for easy feeding and bolt-feel then I get 6+ reloads before the web starts to show signs of a case-head sepraration.

 

[Wheres-Waldo]

Uniform thickness is deffinately a must, but at nearly 2$ a case Ill happily be turning for a tight neck chamber.

In other cartridges I've only had to neck size for dozens of firing, no split necks at all... First time I used a body die was after setting back the barrel and putting in a fresh chamber... The less movement & sizing the brass goes through + frequent annealing = great case life... In a 40° shoulder its, for all intensive purposes, infinite. I have over 40 firing per case in my mild tight necked 6.5x47 Lapua Improved.

I plan on necking down 300WSM to a false shoulder, fire form then uniform the brass from there.

 

[mcfred]

If you do the false do-nut thing, it might not be a bad idea to remove the spring-loaded extractor plunger to keep it from pushing the case off the boltface. It helped with an 6mmAI I played with a while back. Just for that extra insurance. $2 a case is not pocket change when you buy a couple hundred.

 

[Wheres-Waldo]

You mean the ejector? That's a good idea...

 

[mcfred]

Haha, yeah that.

 

[mcfred]

Just came back from the Raton Sporting Rifle Match and finished top 10 of 50-60 competitors. Had a great time. It's been 6 months since the last SRM after which I sent off parts of my rifle as part of my weight loss program. So this was the first 70 rounds out of my post-op rifle. The new dope sheet was a good guess.

I swapped receivers and remanufactured a scope base from 7075 aluminum to be shorter height and a steeper cant to 45MOA up from 30MOA in stainless steel. Now I can keep my 200yd zero and still dial past 2000 yards without hold over. All in all I figure I lost about a pound, but I've not put it on a scale. It's not heavy, but it's not light either. I figure I'll add that pound back whenever the ATF gets around to finishing that paperwork.

 

[mcfred]

I plan on necking down 300WSM to a false shoulder, fire form then uniform the brass from there.

You might also try running the reamer in short to match the brass. This would be sort of like a 7mm-300WSM, but you might have to trim the case length slightly, depending on your reamer dimensions. You'd also need to trim a bit off the bottom of the dies, but this might be easier than fire-forming and messing around with a bunch of brass. With barrel steel being more available than brass, making the gun match whatever brass you can get starts to make more sense. Good luck with the project and let us know how it goes!

 

[mcfred]

I've seen this discussion crop up several times, so I thought I'd comment on it here for reference. I'm using the Alpha magazines to get slightly more room for longer loaded rounds. This is compared to the AICS magazines that have a spacer in the front of the magazine. There is a potential issue with using magazines that don't have this spacer. Without the spacer the tip of the bullet can be further forward relative to the rest of the rifle, assuming no other changes. This means the tip might catch on the bottom edge of the receiver if it has not been positioned to account for this. Many people simply notch out the receiver to let the round come up through the loading port. In my opinion, this is not a good idea.

This picture from Varmint Al shows a simplified finite element analysis (FEA) of a 243 round being fired. You can see where the stress is in the steel to contain the pressure. Now cut out some steel behind the lower lug abutment for a loading port and feed ramp. Now instead of a 0.473" diameter medium rifle round, make it a 0.555" WSM round. Now notch it out even more to use a different magazine...

For me I think it's a bad idea to cut that part of a receiver. That is a piece of high grade steel responsible, in part, for containing several tons of white hot fire a few inches from my face. I'd prefer to cut the rear part of the receiver that's holding much less force with much lower consequences if it fails.

Most disasters are a chain of factors that happen to combine in just the wrong way. Personally, I'd like to have as many links there as are easy and reasonable. Like safety glasses. I've never needed them, but I still wear them because it's an easy link to add to the chain. You could probably take 2 lug nuts off of each wheel on your car and have no problems. But I don't think this makes it a good idea, especially when there is no reason to do it. Why not just cut the rear of the receiver? This could be a feature and selling point for a brand of DBM (that moves the mag back to take advantage of longer COL) and would be another product to slightly enhance our hobby.

This picture shows what is, in my opinion, the proper way to use Alpha magazines, particularly with magnum rounds. Basically, the magazine was moved back relative to the receiver with a few modifications: the bottom metal was moved back by opening up the bolt holes off-center and filling with a steel washer/bushing, the REAR of the receiver was cut to give the clearance needed, the bolt stop was modified, and the inletting adjusted. The front of the receiver was NOT cut (green oval). This particular bottom metal (not naming names) was so far forward that even AICS magazines with spacers would hang rounds up under the receiver. You can see part of the original inletting. I would like to see manufacturers offer a bottom metal that fits like this to begin with. I've only ever seen one brand talk about this, but I would not recommend them for other reasons. Yes this is more work (particularly when starting with an improper bottom metal), but I believe it is a better solution.

 

[mcfred]

I had access to some software that can model this kind of stuff, so out of curiosity I mocked up a representative bolt and receiver ring, applied pressure to the bolt face and ran a FEA stress analysis. I don't trust the results enough to post numbers, but I think this shows what the situation is. This is a side cutaway of the model with colors showing stress:

You can see how the stress on the lower lug abutment is closer to the corner (compare with top lug) because the ramp is deflecting slightly. This shows the bolt lug stress, where you can see the slightly uneven distribution:

Looking at the feed ramp with the top half of the receiver cut away:

Receiver ring from the front:

This is looking at the bottom of the receiver, without being cut and with a cut made to the feed ramp:

 

[siscoe308]

Great thread, informative read top to bottom

 

[29aholic]

Any updates??

 

[mcfred]

Updates? Sorta, but not really.

• The ATF still has not returned my suppressor stamp yet (imagine that).
• My 7WSM barrel's not shot-out yet so I don't need a rebarreling.
• Components are hard to find and my stash is dwindling.
• There's a couple local matches that will use 60-100 rounds this month
• Raton's July 6th that will burn another 70 rounds.
• I found a retail brick of .22LR ammo (for the first time in 2 years)
• I got a Burris FistFire III for my .22 and beer cans everywhere are suffering.
• I built two 7mm-08 rifles and sent them off to their owners who will prolly show up at Raton next month.
• I learned that I will not have anything to do with Rock Solid Chassis anymore. Their customer service is shit and I can't get replacement parts for stuff when it breaks.
• A SH member pointed me to someplace that had Federal WSSM brass for my 7WSSM and I blew a paycheck on brass. I'd like to think I'm now set for life regarding WSSM brass.
• I've modified some reloading dies for tipping bullets. Hopefully the additional BC and the more uniform meplats will help bullets reach out a little further.
• A month ago I played hooky from work and took advantage of some relatively calm conditions to go shoot at a 22" plate at 2000 yards. I confirmed that Sierra LIES about their 180SMK's .660 BC, at least in my gun. At the same time I tested out my 45MOA scope base. At my elevation, with my 'slow' short-range competition load I can dial past 2000 yards without holdover with room to spare. I might have to develop a long range load for the Berger Hybrids. Either way, I only got 30% hit ratio in the boiling mirage:

That's about it.