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AMR-1

Posted: Tue Apr 24, 2007 6:43 am
by bboymatty
Bboymatty Presents:

AMR-1, Anti Materiel Rifle One

Competition section: realism

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For this competition I built a accuracy-based rifle inspired by the much loved and heavily replicated Barrett M82A1 .50cal “Light Fifty”; designed and built using the best of common hardware and household parts. I have personally invested over $250 AUD, and 15+ hours on this interesting and challenging gun. The reason I call it the Anti-Materiel Rifle is because when it is used to fire its specialty ammo, Nail Darts, it can deeply penetrate most targets including hardwood, thick plastic, brick, sheet metal, limestone, plus many more.

Characteristics

- Inline Design (1.3m length) Blowgun actuated solenoid
- 40mm chamber, 25mm outer barrel
- Breech Loaded, completely incorporated into the receiver
- 15mm stainless steel barrel, fused to 20mm class 12 pvc
- Removable bi-pod
- Removable 3-9x56mm scope (Yes I know its “overkill” but its great fun and it improves accuracy, not to mention it looks killer!)

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[youtube][/youtube]

The 1 metre long barrel is actually the amalgamation of 3 separate tubes (25mm PVC outer tube, 20mm pvc Inner tube, 15mm stainless steel Inner barrel), connected together using grinded couplers. This was one of the harder sections of the design but I’m happy with how it has turned out. The reason for using a steel barrel is not only its aesthetic appeal but also because it is DEAD STRAIGHT, which I have found it something very hard to achieve using regular class 18 or sch 40 pvc pipe. It works extremely well (as you can tell in the video) and there is no leaking whatsoever around the seals.

The chamber was designed to also be the rifle butt stock. Because of the extremely small barrel it did not need to be overly large. Currently I fire at 120psi and there is a significant amount of excess pressure as shown in the demonstration video. The design of the stock, (being back to front) is such only because I wanted to try something that deviates from standard aesthetic practice and I think I have achieved a rather unique look. It works well and is a good handgrip too. The valve is inside the stock and so doesn’t get in the way when I need to get my arms around the beast.

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I currently use two ammo types that are easily loaded through the breach; AA batteries and Nail darts.

AA batteries are good destruction-type ammo, but they are also inaccurate at long range (they start flipping over themselves and wildly deviate from their target in random directions) and they are also expensive to acquire in bulk, and generally one-shot-only. I currently only use them when I am out of darts or if I am firing at close range (5-10m).

My “nail darts” are a kinetic energy projectile and are what I designed the entire rifle around. They are great because they satisfy my ammo criteria:

1. High kinetic energy
2. Highly Penetrating
3. Accurate to medium-long range
4. Inexpensive
5. Easy to produce quickly

They are made from masonry nails, glue gun nozzles and a bit of hot glue. I can make around 60+ in an hour. (Don’t build these unless you have a quiet, safe and responsible place to fire them.) One of the great things about this ammo is that they are aerodynamic (the masonry nails have rifling through them and don’t require much pressure to fire at high speed). Even at long ranges these little guys are destructive and sure know how to bury themselves in a target.

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One of the great things about the darts is that even though only 3cm is exposed of the nail, on impact the momentum of the dart pushes the whole nail through the plastic stabiliser, shooting it off and imbedding itself to an almost irremovable state. Some pictures of what i mean will follow soon.

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When I bought the 3-9x56mm hunting scope I had no idea how bloody big it was, especially the objective lens (it is a huge 56mm!!) Mounting it was a day-long challenge but I figured it out and now its rock solid. Obviously because it’s a spud gun any scope has only a very limited amount of use, but it has improved my accuracy (compared to just looking down the length of the barrel) and it is just so damn cool to use.

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The bi pod is very basic and has been done before, I built it for when I use the rifle in the prone position and it is removable. It is one of the cheapest parts but is also one of the most useful. I recommend them for anyone who does target shooting.

In conclusion, the AMR-01 is my best rifle to date, I believe it pushes the boundary of realism and I hope you think so too. I’ll be more than happy to answer any questions you have about the rifle or any specific components including build details so don’t hesitate to ask!

Enjoy my Demo of the Rifle!

[youtube][/youtube]
(The target is kind of hard to see, it’s a wooden board. Shooter is a mate of mine. Nail darts are the projectile.)

Cheers,
Bboymatty and the AMR-01

Posted: Tue Apr 24, 2007 6:51 am
by souljahz_unite
That's one hell of a gun! It looks quite realistic and the scope plus the logn barrel make it even more fun to look at. You have any damage pics? The videos didnt load here or through the links because their said to be private videos :?

Posted: Tue Apr 24, 2007 6:55 am
by skinner
That looks really nice.

I like how the triple sleeved barrel looks like a shroud, if there were holes in the top layer of PVC, then that would look awesome.

Good work, and good luck in the comp.

--Skinner

Posted: Tue Apr 24, 2007 6:56 am
by bboymatty
All good now :)
Thanks for letting me know mate

Posted: Tue Apr 24, 2007 6:58 am
by jackssmirkingrevenge
Well done on aesthetics and performance, when you say "accurate" what sort of group sizes are you getting?

Also, how about sleeving the muzzle end with some say 40mm tubing as an integral suppressor?

Posted: Tue Apr 24, 2007 7:07 am
by leeeeshad
wow, looks really good, from the last video it quiet as well on criticism is it would look better with a longer stock

Posted: Tue Apr 24, 2007 7:09 am
by integral
VERY nice cannon mate, aussie pride all the way! just realised that i have the EXACT same foot pump...LoL

if i may extend jacks question... what is the maximum effective range?

good luck with the comp.

Posted: Tue Apr 24, 2007 7:11 am
by bboymatty
Grouping really depends on the conditions, and how well the darts were constructed. If they have any burrs or loose glue on them (which occasionally happens) they fly a little randomly, but normally spread is about 10" diam. at 30m with a dialed-in scope, on a windless day.

I thought about the suppressor, because obviously the M82A1 has one, but i felt like the time and effort required to make it look good and actually take hold to the metal might not be worth the final product. Then again, i might add it should i get bored with it's appearance any time soon. plus, i do like the metal tip!

I do wish i had of made the stock longer, but once it was all together i felt like it was adequate and it was a comfortable hold too. For it's comfyness i dont mind a little bit of shortness hehe

Maximum range ive tried is about 100-130m, at which the darts will still get in a fair way, like 1" or so, but obviously their velocity is much slower after such a distance. Bullet drop is something to deal with and the scope helps with that. Might try a little longer soon and let you all know.

Posted: Tue Apr 24, 2007 7:29 am
by integral
lol if u got a big enough die, and are going for the realism look... see if u can add an accessory thread on the muzzle and make the suppressor out of some larger OD SS and some motorbike muffler foam :lol:

Posted: Tue Apr 24, 2007 7:35 am
by chaos
very nice man i lurve the scope, and the stainless barrel although im not sure where you got the 15mm stuff from i couldn't find any at my scrapyard, must be coz the stuff we use is for different purpose we have to use bsp fittings ect.

can you please put some ammo pics up i'd like to see the darts.

aussie aussie aussie.

peace
chaos

Posted: Tue Apr 24, 2007 7:35 am
by paddo
best of luck in the comp mate. :D that is a very very nice gun.

i like the metal barrel end aswell. and the scope may well be overkill but damn thats nice. i like the barrett rifles aswell really nice. good work mate inspirational. :lol:

keep it up. good luck.

Posted: Tue Apr 24, 2007 7:36 am
by Pyro Ninja
Thats one beautiful gun..........very very good job...
The pics don't work :(

Posted: Tue Apr 24, 2007 7:42 am
by chaos
is the I-D of the barrel 15mm? or is the 15mm the O-D coz your first post diddnt say.

oh and ya should have a go at using fishing sinkers they give some kick and they are pretty accurate

Posted: Tue Apr 24, 2007 8:18 am
by SleekZ
nice gun mate, I reckon there's nothing better then a well performing sniper, which actually looks respectable (yours is way more then just respectable though!) :wink:
$250 bucks eh, so how much was the scope? I'm guessing that's where most of the cost was!
anyway great job!

Posted: Tue Apr 24, 2007 9:29 am
by jackssmirkingrevenge
10" at 30 metres not at all bad for a smoothbore barrel on a homemade rifle, but as you say inconsistent ammunition isn't going to give you any better. In our circumstances, the best ammo for accuracy would be very tight fitting spherical projectiles. Another solution would be to use commercial rounds designed for 12 gauge shotguns in a 3/4" barrel.