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Frankengun. yours? Let's see em.

I definitely remember this article from way back when and was inspired by his approach and his success. I thought the barrel lug plate design was brilliant, and the fact that he won matches with no changes to original design was super impressive as well. 1st iteration success is pretty rare for most inventors. I am surprised we haven't seen more from his magnetic damping experiments. Maybe I have just been out of the loop.
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Shelley was a very good shooter- that had alot to do with his success. He could make it shoot no matter what. As far as that magnetic tuner it only opposes the barrel from going down. Its not really for tuning as much as it was to oppose the flex of the forend. He was going to design a 360deg version before he died to do more tuner functions but never made it that far.
 
Well, if we're talking guns that started as one thing and now are totally another.

It started out like this, a basic bone stock Mossberg MVP Varmint in .223.
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Then I replaced everything except the receiver. LSS stock, PSG-1 grip from DPMS, XLR butt stock, PTG lug and barrel nut, Columbia River Arms 26" barrel with Sonoran coral snake cerakote, A2 flash hider, whatever brand rail, Timney and Jard trigger (depending on what I'm doing), BipodeXt and a USO B17 which is now a USO 3.8-22x44 and a 20 round P-mag because why not.
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Shelley was a very good shooter- that had alot to do with his success. He could make it shoot no matter what. As far as that magnetic tuner it only opposes the barrel from going down. Its not really for tuning as much as it was to oppose the flex of the forend. He was going to design a 360deg version before he died to do more tuner functions but never made it that far.
How did he die, if you don't mind me asking? He seems pretty vibrant in the article photos.
 
LSS stock, PSG-1 grip from DPMS, XLR butt stock, PTG lug and barrel nut, Columbia River Arms 26" barrel with Sonoran coral snake cerakote, A2 flash hider, whatever brand rail, Timney and Jard trigger (depending on what I'm doing), BipodeXt and a USO B17 which is now a USO 3.8-22x44 and a 20 round P-mag because why not.
img_2552-e1526186488701.jpg
Mine is not going to be that crazy, but close.
 
I am hesitant to post this but I hope some find the origins of my ugly gun interesting…


I started shooting F Class around 2013 and got stuck on the idea that we were going about trying to control barrel harmonics the wrong way. We create an explosion with every shot that changes the barrel diameter and action a couple of thousandths of an inch, and set in motion a 10lb 30" long whip that is screwed into a 2lb action with only .7" of threaded tenon. We try to control all of that with two small 1/4-28 screws and bedding that has to be immaculate and clean for everything to return to rest the exact same way after each shot. In addition, we have our sighting device mount spanning that same action, and held in place by a couple of even tinier screws. The thought occurred to me that nothing should be more repeatable than the natural frequency of the steel, and that there would be less chance for distortion if we supported the heaviest part of the barreled action instead of the lightest. Not original thoughts but my nature is to take a stab at it anyway. A plan was devised; wheels were set in motion.

Design goals…

· Eliminate the action screws and bedding.

· Find a way attach the barreled action to the stock that would impart major control over the barreled action yet still allowing vibrations and pressure waves to occur as close to their natural frequency as possible.

· Have a strong forend that moved the bag bearing surfaces closer to the axis of the bore.

· Be highly configurable for all bolt actions.

· Be affordable.

I had 100lbs of Bayer Texin Thermoset Polyurethane that I had procured for another project. This stuff is a seriously tough elastomer and I knew it was tough enough and flexible enough to handle the job I had in mind. My initial thought was to make a lightweight one piece barrel block with three bore holes, one large enough for the barrel and the other two for the forend rods. I was going to slide this block over the barrel and lock it into place by injecting the TPU between the barrel and block. The negatives were the amount of wasted material and the machining time involved in building the block. I thought the two rod forend would be too bouncy as well. The next thought was to use two narrow blocks tied together by four rods that would span the rifle from butt to the forend tip. I could not make the configuration work well with a bolt handle so I ended up with the current configuration of the EXO, a six rod exoskeleton of sorts. The design also inherited the attributes of better barrel cooling by having more exposed surface, and a great mirage shield mount.

Each block has two machined O-ring grooves inside the barrel channel located near the external surfaces. These O-Rings locate the barrel concentrically inside the blocks and contain the injected elastomer to the designed area. Between these two O-Rings inside the block, are machined features located adjacent to matching features machined in the barrel. These features, when filled with elastomer, form a single urethane shape that controls both torque and recoil. This system has proven to be reliable, repeatable, and a heck of a lot faster for a gunsmith to assemble than traditional bedding. As of yet, I have only tried the thermoset urethane that I inject with a machine, but I hope to find a suitable two component cross linking polymer that can be used with a conventional, inexpensive 3m or Loctite adhesive dispenser.
YYLSJCQ.jpg

YYLSJCQ

rest of the assembly is straightforward. I used high modulus carbon fiber rods for the forend for stiffness and reduced weight. 304 Stainless was used for the main stock rods for rigidity in the bedding area, and to add weight to the rear for balance. I tried carbon rods in the rear but I felt it shot and tracked better with the steel. The bedding blocks and forend tip also just happened to make a perfect mirage shield holder. I have not built a mirage shield yet but will have it mounted before the next match.
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DyeeA3j

First impressions were mostly great. I did a “shoot clean shoot” routine for a few rounds, then a few foulers and proceeded to the initial pressure ladder. Groups were tight and trends easy to spot.
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0nViGRn

What was not great was the rear bad riding surface was too short to allow much recoil. The pistol grip would contact the rear bag, which negated any tracking benefits the lower recoil moment provided. I lived with that until this week when I made a new straighter grip profile, which gave me more bag travel. I actually made a rubber grip mold this time too. I will eventually make a clamp on rear bag rider with an option of profiles. As of this writing, I have not shot the new configuration yet. You can see the old style grip hitting the rear bag in this video. (Not me. My face is made for radio)
The other not so great feature was that I needed a modified front bag that would support the forend rails without touching the barrel. I quick call to Protektor and they built what I needed without breaking a sweat. The Protektor bag has worked great but I do have to redistribute the sand to the correct places every now and then. The Bryan Blake / Fclassproducts 4 piece NEO bags will also work perfectly but they were not available at the time.

New Grip and my first attempt at anodizing.
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lIL5e9v

I have shot the EXO in two matches so far. I shot poorly at 1k with it when I did not have enough rest elevation for the shooting position at Camp Blanding Fl. My rest was sitting on a folded up towel. It was ugly. I shot a 600 match last month and tied for first out of 17 shooters, but was crushed in X count by my friend and fellow Accurate shooter member, Andrew with his Weil, Blake, Borden .284. (savageshooter86). It was good for a 595 but completely allergic to Xs. The lack of Xs is more of an indictment on my shooting ability than the rifle though. A couple of clicks on the turrets would have done wonders for my X count.
XIICn0P.jpg

XIICn0P

It is a work in progress. Plans include an adjustable cheek piece, bipod mounts, and modifying the rear stock plate to make it easier to drop the grip and service the trigger.

Anyway... Thanks for reading.
 
"Thanks for reading."

Thanks for sharing. Keep us posted.

Shot next to a fellow in a highpower match 35+ years ago wh was shooting a nosel 70 Winchester in '06 that had an exoskeleton type stock fabricated from 1/4 and 3/8 black iron pipe. Not as warm and fuzzy as walnut and blued or parked steel but if it works who cares.
 
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not as exotic as some of the builds here, but it is a shooter. put it together myself.

Savage Target Action with a little tweaking of the Accutrigger
Brux 6BR barrel, 1 in 12 twist. barrel smithed by SkeetLee
XLR Industries Element chassis. drop it in, bolt it down, shoot crazy good.
Vortex Golden Eagle glass

all 80 Bergers, jamed 15 thou, with N135

all 5 shots at 100 yds

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Here is mine. Sorry the photo isn't that good.
Remington 700 action .308 Winchester Trued and Blueprinted by Benchmark
Timney Trigger 8oz
Benchmark Barrel 30" 1:10 Twist
Duplin Rorer Bipod
XLR Evolution Chassis with Extreme Butt Stock
Vortex Golden Eagle
Burris Xtreme Rings
NF Steel Rail with Recoil Lug

Rifle 2.jpg

Here is 500 yards 20+2 rounds, last relay of my last F-TR match.

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I admit that mine doesn't look "bad" but it does have humble origins from a $250 used budget model Savage, a $200 clearance price discontinued chassis and coming soon a 35% off pre-fit barrel.

I am going to have to do some machining to use a Remington 700 style recoil lug and also hack the Accu-trigger to get the pull lower than the 3lbs it is now. The extended forend/bag rider is also kind of a hack, using an extrusion meant for something entirely different.
 
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Rem M-7, PTG bolt, SS PacNor - 6SLR , MDT with a delrin fore end I whittled in the mill, folder.
etc..... leftover parts made usefull
That looks like one of those 300 blackout receivers with the fireball boltface?

If it is one, does the case and brass feed/eject properly with the fireball bolt face instead of standard?

I was always curious about that. Thanks.
 
I started down a Frankengun path in a quest to learn something and prove a theory. A friend had bought a barrel for a 6mm-223 ar15. He had purchased a 1-8t barrel . he could not get it to shoot and did manage to find only 1 load that worked. He was using heaver bullets and keeping them mag length. Well i was looking at his ammo and a bullet and thought that the issue was the bullet was way to deep in the case and that was the issue. He had a fit and took the barrel off. I bought the barrel and came up with a plan. I found a old savage 110 in a LGS in 270. I took the barrel off with the help of @DirtySteve Steve. I removed the ar15 barrel extension. I made a adapter that had internal threads to fit where the extension threaded on. I did pay very close attention to not change the original headspace. I then placed the barrel between centers and turned the outside of the adapter down and threaded to fit in the savage action. Then i closed up the gas port with my mig welder and turned it down and polished it in the late. I had made some dummy rnds where i thought the oal should be using vld type bullets. Had a local smith throat the original chamber for the long combination which ended up the same length as a 270. In the end with a pos scope. I placed the barrel and action back into the Tupperware stock with a little jb weld bedding using @DirtySteve headspace gauges. The the gun would shoot anything you fed it into the same group. I thought that was weird. The group was about 1/2 in in diameter and did not mater charge weight of bullet. Ammo that was loaded to the OAL for a ar mag the friend gave me. All went into the same group. Why i have no clue. I feel it was definitely minute of deer.
LOL but I learned something.
 

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