112 replies to this topic

[boltsniper]

The rotating bolt system locks the bolt to the barrel and prevents movement when the bolt is closed. An issue I had with the FAR was the bolt bouncing back slightly when the punger hit home. When the botl would bounce it would relieve the pressure behind the dart. If the dart had not left the barrel yet then it only had it's own inertia to carry it out of the barrel instead of a propulsive force. The friction in the barrel would hinder range quite a bit on tighter darts. The tighter darts did not leave the barrel as quickly and were more affected by the bouncing bolt. This was something I had neve anticipated. I experimented with the FAR by holding the charging handle forward and firing the rifle. You could definietly feel the bounce and by holding it forward range would increase for a specific dart. I somewhat corrected the problem by jacking up the tension in the action spring, but the problem is still present. The rifle still shoots into the 70' but it was something that I was aware of and wanted to correct on my next version. By using the the lockup of the rotating bolt all the pressure from the plunger is used to propel the dart. Minimal losses.

[SKIZ]

Hey bolt just curious to know when you think you might get a write up for this? (dont mean to sound pushy just curious)

STRAYING ABIT HERE

You seem to stay to plunger alot in your recent homemades and was woundering what the obsession is? Personally prefer compressed air seems to have more power and easier to turn into semi-auto.

Also with things like the fAR i turned that into a compressed air gun and was woundering (in your opion) how big the air chamber would need to be (approx) i was thinking of just turning the stock into it. Do you think this will be enough?

[J cobbers]

BS has done air pressure and combustion guns before. I think he does the bolt actions because they are more challenging to design and if I recall he is some sort of engineering student. When do you graduate anyway BS or have you already? At anyrate an air pressure gun requires seperate power supply (which must be recharged between firings, rather than the quick and simple mechanical power imputed by a cocking the spring powered plunger.

[fobpawwor]

Ok, thanks bolt for answering my question. So mainly, that rotary bolt is to hold the thing down so the plunger can fire all the compressed air. Okay, that may come in handy. Thanks!

[m15399]

SKIZ, it depends on what kind of range you want, and what type of valve you will be using. Turning the whole stock into a PC would result in very high ranges, but would require a MASSIVE air tank to supply (unless you plan to pump it manually each shot).

[Ronster]

How good is the seal between the chamber, the shell, and the bolt with the brass?
Is it good enough you no longer need the use of o-rings?

[Maverick Master]

I will try to answer yo question Ronster the cover on the brass will channel the air to the shell.

[boltsniper]

Yes, the seal of 17/32" brass in 9/16" brass is good enough that you do not need O-rings.

[boltsniper]

I finally got some more shells made. I started a batch of ten but have only had the time to get 3 more done and headspaced. Here are some more videos of chambering and firing hte rifle.

Loading the magazine
A video of the magazine being loading. Nothing spectaculat.

Chambering 4 rounds
Closeup of 4 rounds being cycled quickly. I am not firing the rifle between rounds but just cycling them through.

Firing 3 rounds
Here is a video of the rifle actually shooting. I am firing three rounds at a paper target about 35 feet away. As far as I get get in my apartment. You can kind of see the darts in the video but you can definitely see the paper move. the second round just nicked the top of the paper so the paper doesn`t really move on that one. You can also see my cat going crazy with the darts. I only loaded three rounds into the mag and you can see me trying to cycle for a fourth. The bolt is haning up on the dummy round in the magazine, that's why it will not close. Kind of like a bolt hold open, but that is pointless on a pump-action. It does let you know that you are out though.

[m15399]

Kitty!
Is the SCAR able to shoot through a paper?

[boltsniper]

It will shoot through paper at about 30 feet if the paper is fastened at both ends. for the video I just hung the paper off a dish rack. the darts left some pretty big dents int he paper but did not piuncture. The paper just moved.

[Ronster]

Okay Bolt, here are a few questions:

1) Is the slide made from 1/2" PVC or 1/4" couplers?
2) How long is the plunger? Any smaller then the one in the FAR?
3) How long is the bolt carrier and the bolt?
4) Could you possibly get a diagram up of how long everything is in inches?

[boltsniper]

To answer a questions from Carbon a while back.

I weighed the plungers of my homemades. They are as follows:

SCAR-N: 51 grams
FAR: 110 grams
GNS: 28 grams

The SCAR plunger is less than half the weight of teh FAR. Quite substantial. I threw the GNS plunger amss in there just for comparison. Being a pistol it does not need the catch portion in the rear which is where a lot of the weight comes from.

I`m getting about 40 pounds of force behind the plunger when cocked. Plugging that into F=ma with the above masses for the SCAR and teh FAR. The SCAR plunger accelerates at a rate of about 11500 ft/s^2 while the FAR plunger only accelerates at about 5500 ft/s^2.

Ronster,
The plunger stroke is 4.5 inches. 2.5 inches less than the FAR. The entire plunger length is 9 inches. The bolt carrier is 6.3 inches long and the bolt is 2.3" alone. When the bolt is in the carrier the assembled group is 8.1" open and 7.3" closedI`m not sure what part you are referring to as the "slide". If you mean the pump slide that you grab on to to cycle the rifle. That is a 1/1/4" T-fitting cut to the desired shape. I will get some schematics of most of the part up on my website. Give a little time as I`m a bit busy lately.

Edited by boltsniper, 26 March 2006 - 08:21 PM.

[pat 1st Lt]

Boltsniper,


Nolan and I are proud to announce that we have an almost-entirley functioning SCAR-N after, collectivley, 50 hours! It's been a process, mostly consisting of Nolan and I yelling at each other in a dark basement while holding various pieces of PVC and sheet metal in our hands. It really has been a trial, but we have an almost-complete rifle now.

The only thing we have to work out is the ejector, and we just need to tirm off the burrs on the slide-handle so it doesn't impede the pumping action.

You seem to be a very busy man, and if you can't currently answer, fine, but we would greatly appreciate it if you could explain the action of the ejector, and possibly take several pictures of the ejector functioning.

We finally got the magazine well to work for us. IT looks nowhere near as good as yours, but it works: it's a plaster mold of our AR-15's mag well, with some spare parts we picked up at the local gun shop. It's pretty sloppy on the outside, but it works well.


I cannot judge how well the gun as a whole works, but it shoots very well one shell at a time (We have to unload the shells ourselves: they won't just fall out if you tilt the gun).

It is very accurate out to ~50 feet, and we're getting ranges in the high 80's.

Once we get the ejector working, we'll start mass-producing the other four so as to outfit our clan with a ready supply of, in our oppinion, the greatest Nerf plunger weapon ever.


Sincerley,
Pat

[Ronster]

Pics?

[Grenado]

Sorry, I know, old thread. But I have a burning question? Are there any stores that will sell the magazines? Can you use 16-20 gauge shotgun shells as shells? If those are too big how about a .410 caliber shotgun? Or what about high caliber rifles? Would those work as shells? I have a burning desire to know, so I can decide whether to make the SCAR or the NTS. Or both! They use the same ammo.

[Commonly Hunted]

How you gonna make the NTS? You don't have the magwells necessary. Unless you're gonna carve the magwell out of something, I suggest you make the SCAR-N because you can buy that magwell from david_scothern. I bought one from him and got it in a week just as he promised.

[Meaker VI]

Or what about high caliber rifles? Would those work as shells?

I'm nearly certain that high-caliber rifles would not work as shells. Their barrels might though. But who wants to mangle a 50-cal. rifle simply to fire nerf darts from a home-made nerf gun?

But seriously, you should get ahold of the various things you're bringing up and measure them, compaired to your foam and BS's specs for his shells, to see if they will work. And yes, there are stores that sell mags, you might need to be over 18 to get in though (I know Bear Arms, which has an M-60 on the front desk, has an 18+ unless-accompanied-by-an-adult rule).

[Grenado]

I can get the mags, won't be a problem. I was just hoping to find an alternative to buying all that brass...

[boltsniper]

As long as your state allows high capacity magazines you should be able to find them at any gun shop.

1/2" FBR fits great in .50 cal shells. I actually got the idea from 50 Beowulf shells. My original idea was to use Beowulf shells but they aren`t cheap to buy so I just made the shells from scratch. Plus you would have to drill out the Beowulf shells to be able to use them. And making an extractor to work with the shells would be tough. 50 cal rifle shells would work but they are huge and you would have a lot of wasted space where the shell necks up. The Beowulf shell is the only productino cartridge I an see working. I guess you could go with the S&W 50 for a rimmed shell.

410 shells are too small at 0.41". 20 gauge is a litle too big probably. Around 0.6". 28 gauge would probably work but I have never actually seen these sold anywhere common.

[david scothern]

Am I right in thinking that the .50 Beowulf is one of the largest that will fit in a (modified) M16 magazine?

[edit] no, it looks like there is sufficient width for larger calibre rounds without too much difficulty.

Edited by david_scothern, 20 January 2007 - 04:41 AM.

[boltsniper]

There is room for a larger cartridge but they don`t make anything larger than the 50 Beowulf that would fit

[Grenado]

Well, I'm canadian so I'll have to order the mag off of the internet. I have a lot of 28 gauge shells because I do a lot of hunting.

[nube]

I wanted to ask before the thread was too old to even talk in. I've been wanting to make this ever since I've seen this. I've been dying to know the progress on the plans, because it has almost been a year since this came out and if I could get this to my dad in March on my birthday, what's better than shooting your parent with foam from a beauty like this. I can see it now. Foamy death.

Edited by nube, 25 February 2007 - 12:22 PM.

[Grenado]

If you're planning to ambush your dad, forget it. I tried the same thing with a stock Maverick and even with that piece of crap he got mad. It might be better if you let him shoot you. And then you try to get him back with your other guns.

Edited by Grenado, 25 February 2007 - 01:47 PM.