Gunsmithing Home built Tubegun Chassis

[mbrittan]

About eight months ago I started on a project to make a tubegun chassis for my Savage actions. I worked on it in my free time after work and some weekends. I started by looking at the few that are available commercially for other actions, and taking the features that I liked, designed my own version on AutoCAD software.

I ordered a piece of 1.5x3inch 6061 stock to make the lower receiver from. I machined a radius in the top of the lower to mate to the 2inch tube. The action screw holes, two locating dowel holes, and the dead center of the mag-well were reamed through the receiver. The action screw holes were opened up near the end of the build for clearance. The lower receiver was clearenced for the trigger assembly, and the mag-well was wire-EDM cut to accept Accuracy International magazines. I bought a five round 308mag, and a ten round 223mag. The opening of the mag-well was beveled just enough to make inserting mags easier.

Mag-catch being machined.

The outside profile was machined, and cut to take an AR style grip.

 

[mbrittan]

Re: Home built Tubegun Chassis

For the action tube and forend I ordered 2inch 6061 tubing. The action tube was bored out for a snug fit.

The front was threaded for the fore-end, and a tennon was turned down on the rear to accept the butt stock assembly. I machined a flat on the bottom of the tube to use as a reference. Then the ejection port, serial number window, bolt handle slot, and the trigger and magazine clearances were machined through the tube.

On top of the tube a flat for the scope rail was machined, and four tapped holes & two dowel holes were put in to hold the rail in place.
The scope rail was a 16inch blank from EGW that I cut to length. The bottom of the rail was set at 20minutes of angle and machined flat. Then the mounting holes were drilled & counter bored. The front of the rail was relieved to cantilever over the fore-end tube.

The fore-end was slotted to take an adjustable handstop/sling mount. It was also drilled and tapped for bi-pod studs in two spots at the tip.

For ventilation a series of radiused slots were machined through the sides, and the tip was cut with a matching radius.

 

[mbrittan]

Re: Home built Tubegun Chassis

All assembled, with the scope and bipod attached, it weighs 16.8 pounds on my scale. I still need to come up with an idea for a bag-rider to add to the butt. I plan to shoot it for a while to see if any changes need to be made, and will probably put on the .308 or .260 barrel, and see how it feels/shoots with them. Once I am happy with it I want to send it for hardcoat anodizing for durability and to knock the shine off of it.
The adjustable butt stock can be adjusted for Length Of Pull, Stock Offset, Stock Cant, Butt Pad Height, Butt Pad Cant, and Cheek Height. The cheek piece was formed from eighth inch Kydex, and is adjusted with the 3/8-16 threaded rod/wheel.

Accuracy before being put into the tube stock was very good. The picture on the top is six shots at 211yrds (just over 3/8 MOA). I have shot the tube assembly once using some of SouthWestAmmo’s 77gr Run N’ Gun, and was happy with the results at 104yds (picture on bottom, right at ½ MOA). After deer season is over I will take it out with some hand loads to see how everything turns out.

 

[Adam B]

Re: Home built Tubegun Chassis

wow that is very nice, I am amazed all the time at the skill many of the members have on here, nice work!

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[jura1976]

Re: Home built Tubegun Chassis

that is very nice work!

 

[toygunner]

Re: Home built Tubegun Chassis

Nice works. I've been wanting to make one, but never find the time.

 

[SJshooter]

Re: Home built Tubegun Chassis

Beautiful!

 

[3-0-hate]

Re: Home built Tubegun Chassis

That is amazing.. Great work!

 

[sawman556]

Re: Home built Tubegun Chassis

That is very nice!!! You going to sell any?

 

[HotrRod308]

Re: Home built Tubegun Chassis

That is nice work..... Very impressive!

 

[GHall1971]

Re: Home built Tubegun Chassis

After this I have decided I have no skill..lol... Wow what a build. I like the finish.... Are you going to have it coated?

 

[Greg Langelius *]

Re: Home built Tubegun Chassis

That rifle is a work of art. Such self indulgence is well worthy of praise. It's also worthy of some dedicated load development.

Keep us informed.

Greg

 

[jrm850]

Re: Home built Tubegun Chassis

I agree... Work of art! I absolutely love the forearm!

I'm in the process of doing the same thing for a rimfire trainer for my kid. This is definitely a huge batch of inspiration. Thanks for sharing.

 

[LRI]

Re: Home built Tubegun Chassis

very nice

 

[pm04z71]

Re: Home built Tubegun Chassis

Damn....... that is sweet

 

[scythefwd]

Re: Home built Tubegun Chassis

ok, i'm not usually a fan of tatical looking crap, but that sir, is badass.

 

[BigBlue&Goldie]

Re: Home built Tubegun Chassis

This is nicer than 99% of the commercial offerings I have seen! You need to either start manufacturing these or sell the rights to someone who will!

 

[rlr]

Re: Home built Tubegun Chassis

Very Very Nice! Great Job!

 

[mbrittan]

Re: Home built Tubegun Chassis

Thanks for the positive feedback everybody. I plan to shoot it as it is for a while, and make any changes if needed. Then I want to get it hard coat anodized. Then if I want something instead of the black finish, I could spray some camo at it.
Not planning to sell any of these, would take to long to make for other people.

 

[deadeye]

Re: Home built Tubegun Chassis


Very nice.

How did you handle the recoil lug and the safety?

 

[SPfeiffer]

Re: Home built Tubegun Chassis

THAT IS AWESOME!!!!!! i would love to learn to do that.

 

[mbrittan]

Re: Home built Tubegun Chassis

The recoil lug is made from S-7 tool steel. It is a round disk that bears on the full diameter of the upper receiver tube. After heat-treat the disk was surface ground on both sides to be parallel. You can see the recoil disk in this pic...

I'm not running a safety on this build.

 

[mbrittan]

Re: Home built Tubegun Chassis

Also, if anyone knows of / uses someone for hardcoat anodizing let me know. So far the only one that looks promising to me is US Anodizing.

thanks

 

[PowerstrokeOBX]

Re: Home built Tubegun Chassis

 

[Hennig]

Re: Home built Tubegun Chassis

Some awesome work there mate. Colour me impressed!

 

[csdilligaf]

Re: Home built Tubegun Chassis

That is an awesome job. I am not at all familiar with the concept of tube chassis and its benefits. I have seen some of the Tubb's and others but never really got into the design untill I saw yours. What are the key things that someone goes this way? Is the action a press fit in the tube? Or maybe epoxy? Warm the tube, shrink fit it in? Or maybe this is not what is trying to be accomplished?
Great job on the build. Building does make everything more special when you do it yourself.

 

[Bubb]

Re: Home built Tubegun Chassis

I'd get a Patton cause savage will be calling! Awesome!

 

[SPfeiffer]

Re: Home built Tubegun Chassis

looks alot like an XLR

 

[TrapperT]

Re: Home built Tubegun Chassis

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mbrittan308</div><div class="ubbcode-body">Also, if anyone knows of / uses someone for hardcoat anodizing let me know. So far the only one that looks promising to me is US Anodizing.

thanks
</div></div>

One of the largest anodzing companies in the US is Pioneer Metal Finishing. Here are a couple things to keep in mind:

- Anodizing causes growth. Thus if your parts fit "snugly" now, they will not fit together after anodize
- The same applies to threads. If your threads are cut to standard class 2 sizes, they will grow and you'll have a hard time (if not impossible) assembling the components
- The surface finish after anodize will depend on how the parts are treated prior. So if you want a "flat" finish, your parts need to be sandblasted or beadblasted. But even these two types of media will produce two slightly different sheen's. If you leave them machined, the parts will have more of a glossy look to them.

- Also, if you have different materials (i.e. 6061 or 7075) they will need to know this as it takes a slightly different anodize process

Hope this helps

 

[Jedi]

Re: Home built Tubegun Chassis

Very nice
fully enclosed action, 360' recoil lug
Very much like my RTS, especially the receiver and stock

You got the savage crowd drooling, i would seriously think about marketing it

 

[Andy Warhog]

Re: Home built Tubegun Chassis

Very nice craftsmanship. I would at least consider marketing these. Definitely study up on metallurgy and anodizing process effects before you jump in. How did you attach the buttstock and what is the adjustment range for cheek and lop? What's the overall weight and the weight of individual components? Dimensions? Mill time?

 

[mbrittan]

Re: Home built Tubegun Chassis

csdilligaf - The action fits with a slight resistance for 360degrees of support. It gets seated firmly against the recoil disk, then the action screws lock it in solid. Here are some of the benefits, except of course number 3 http://www.tubegun.net/TubegunBenfits.htm

SlowNoisyDeadly - The buttstock slip fits on the rear of the receiver tube, with a locating slot for a dowel pin that mates to all three parts (upper tube, lower receiver, and buttstock). It is then locked in place with two screws on each side of the stock.
The cheek piece can go from about even with the receiver tube to an inch taller. One full turn on the adjuster moves it .062 inches. Length of Pull can be as short as 12.5 inches, to about 15 inches. Over-all length with the LOP set for me, and the 26inch barrel is 46.25 inches.

Thanks for looking everybody.

 

[S1erra1]

Re: Home built Tubegun Chassis

Absolutely outstanding work mate, well done.

 

[mbrittan]

Re: Home built Tubegun Chassis

I got to run a few rounds through it today. Went out at 100 & 200 yards with some of SWA's 77gr Run N Gun, some handloaded 69gr SMK over 25.3gr Varget at three different OAL, and some 75gr A-Max over 24gr Varget.

SWA 77gr Run N Gun

69gr SMK

75gr A-Max

69gr SMK at 200

Five, five shot groups at 100 yards averaged .51MOA with various loads.
Four, five shot groups at 200 yards averaged .686MOA with various loads.
It was very nice to shoot, and I'm happy with the results so far.

 

[Jedi]

Re: Home built Tubegun Chassis

holy crap that is a lot of offset
http://riflemansjournal.blogspot.com/2009/11/equipment-adjusting-tubegun-stock.html

not saying you got it setup wrong but that will tell you correct way if you have not already ref material

 

[derrekmorehead]

Re: Home built Tubegun Chassis

When I win the lottery I am going to hire you to build me cool toys like that! VERY IMPRESSIVE! Reminiscant of an Eliseo chassis. Nice work sir....

 

[ranger1183]

Re: Home built Tubegun Chassis

Excellent job! If you have CAD files you are willing to share, please let me know. Thanks!

 

[bentbolt308]

Re: Home built Tubegun Chassis

looks great very nice craftmanship

 

[PBRACEGUNS]

Re: Home built Tubegun Chassis

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ranger1183</div><div class="ubbcode-body">Excellent job! If you have CAD files you are willing to share, please let me know. Thanks! </div></div>
I would be interested in the CAD files too.

 

[Killshot44]

Re: Home built Tubegun Chassis

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jedi</div><div class="ubbcode-body">holy crap that is a lot of offset
http://riflemansjournal.blogspot.com/2009/11/equipment-adjusting-tubegun-stock.html

not saying you got it setup wrong but that will tell you correct way if you have not already ref material </div></div>

I don't know if Michael is a large dude or not but I've seen more offset on the line. Some guys just like that thing right in the middle of their set-up when prone strong side.

 

[Mike0341]

Re: Home built Tubegun Chassis

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SASSdriver</div><div class="ubbcode-body">looks alot like an XLR</div></div>

except the XLR is a chassis. the receiver drops into it and can be taken out and put into another weapon.

legally this isn't a chassis to my understanding because the barrel screws into the upper and everything attaches to it.

basically he built an action (upper receiver) and a lower receiver that allows him to attach a savage barrel and use a savage barrel. very impressive yes but he would need a license in order to produce them for others.

might be a good idea to put a serial number on the upper receiver (technically an action because it hold the bolt and the barrel screws into it) just to keep the ATF off your back. your legally allowed to produce a certain amount of weapons a year for your own personal use. I'm to sure how many though but i know your allowed to.


awesome work. just be careful if you decide to do this for other because legally you just made a weapon and did not make a chassis as you called it in your description.

EDIT" you should definitely patent it because the only parts you are using from SAVAGE is their bolt and you could easily make it so it uses someone else's if they have a problem with it.

check to see if their bolt design is patented, as well as the way they install their barrels with the locking nut design.

if they are then you could get a manufacturers license from the ATF and sell the action and the rest of the system separately and people will then be able to go from there.

 

[dinc]

Re: Home built Tubegun Chassis

Mike, he built a tube chassis. There is a Savage action inside the aluminum chassis. Maybe look at some commercial tube guns to get a better idea of the concept.

 

[Mike0341]

Re: Home built Tubegun Chassis

ah so the action is shoved into the main tube... i see now. i completely missed that when i read/looked over it the first time.

i would just hate to see the feds show up and arrest someone over something like that so thats why i expressed my concern. in this day and age it seems they are always trying to get someone for something.

 

[vvillium3]

Re: Home built Tubegun Chassis

Great build, always love to see home builds. What software did you design in? Gotta love when your own designs turn into reality. It must be a great feeling every time you shoot it or if someone asks you where you bought it.

 

[Chiller]

Re: Home built Tubegun Chassis

Very well done. Have two CSS and like what you did there

 

[JFComfort]

Re: Home built Tubegun Chassis

Well done! I really enjoyed this thread!

 

[mbrittan]

Re: Home built Tubegun Chassis

This is basically just a stock for the Savage actions that I have. I did consider someone at the range or whatever getting excited about not being able to view the S/N, and have a window machined through the tube so it is visible. You can see it in this pic just below the rear scope ring.

Have enjoyed shooting it with the .223Rem barrel in it so far. Very accurate, and basically does not move any more than a 22 does. The offset in the butt really only measures about one inch. With me straight behind the rifle, the butt pad is in a good shoulder pocket and off of my collar bone. I can rest my head almost straight down onto the cheek piece and be ready to go. If I were to sling up for AROS or something I do think it would need to come back in line a little, as I would be coming up into the rifle with more of an angle to my body.

Thanks for the good feedback.

 

[digitalshooter]

Re: Home built Tubegun Chassis

I love it. That's a very nice setup you made.

 

[HK MaNiaK]

Re: Home built Tubegun Chassis

Thats real nice hopefully ill be able to make something like that after I take all my classes.

 

[matthias]

Re: Home built Tubegun Chassis

Nice job, when you think about it home built on snipershide means world class everywhere else .