new to model guns, questions on legal issues and modifications

I have an extensive collection of semi auto rifles, An m1 Garand, m1 carbine, AK47, M14, AR15A2, an M4 mws, A4, semi auto xm177e2 replica, and a real Mk14 mod zero EBR. I want to use cap firing guns to fill the gaps in my collection where semi auto rifles would be redundant or illegal with short barrels.

Here are my legal questions,
1. can a cap firing m16 be modified to fire m200 blanks? Legally and from a safety perspective. I don't know how much pressure caps exert.

2. does any one know the legal distinction between a cap or blank gun and a real firearm? I want to make a blank firing mk18 cqb rifle. I want to know how much i need to modify the barrel to so that i don't have an unregistered short barreled rifle on hand. a full auto one would be nice too, but I'm not sure if a cap gun with a real upper receiver and modified barrel would be legal.

I also have technical questions

Does any one know what level of parts comparability exists between the Marushin m16's and real ar15s? I want to buy one and replace the pins and hand guards with real ones, as well as magazines, and possibly upper receiver.

what is the threading of the muzzle of marushin m16?

napalm113 wrote:

Here are my legal questions,

Please note that we are not lawyers :-)

The only modelguns that were capable of conversion to firing blanks were (I think) CMC Sten, MGC MP40 and MGC Sten. They were made of (thin) steel, and with additional safeguards they could withstand pressure of blank ammo.

Other models CANNOT work with blanks unless practically everything is replaced and rebuild with stronger parts, making the effort impractical. These models wear out and fall apart even with the very weak explosive (0.01g of red phosphorus) that caps use. No clue about pressure difference, but it's there and it's pretty large :-)

I took the teeth off of the bolt so that the recoil of the shell can push the bolt carrier back with out a gas tube.

here is the deal, if i make a blank firing car15, semi auto or other wise, and it is capable of cambering and firing live rounds with slight modification then it is considered a real gun. And if the distance from from the muzzle to the closed bolt face is under 16.1 inches (409mm) then it is an illegal unregistered short barred rifle.

I'm trying to modify a real ar15 gas system to make a recoil operated setup, so that i don't loose most of the BANG just to make the bolt go back.

here is my conundrum, A gun with a plugged barrel plugged to fire blanks is still a gun. But a gun that was designed from the ground up to fire blanks is not a gun.

Granted replacing the barrel is easy, while machining a new barrel that will fit a blank gun is difficult.