The firearm thread

[jono035]

Looks good Jono.
Welcome to the very addictive world of reloading.
If you think mitre 10 is bad just wait till you walk into a shop looking for reloading gear or components.

Its like a kid in a sweet shop.

Chris

Did that yesterday in Reloader's Supplies... Between the Marlin 1894 Lever Action, Norinco M14 and the Dillon RL550 they had setup there I was definitely wishing I had a bit more money for spending on toys at the moment.

Had a couple of nice E cat safes there too...

[jono035]

Thanks, guys. That was everything I wanted to know. One more thing, though. I understand how blowback/gas systems work, but with the open bolt blowback and fixed firing pin as you described, obviously the firing pin sits on the primer pushing the round into the chamber for a small amount of time, and the round stops in the chamber while the firing pin keeps going, pushing into the primer igniting it. Do you just make sure the spring has a low enough speed/strength to make sure that it only manages to break into the primer as it has the still round to push against? Jono - With the weighted firing pin, how would you get a jam in between the round leaving the mag and entering the chamber?

You're quite right on the fixed firing pin and rounds failing to fully chamber are a common enough occurrence... If you have a round that has been dented or malformed in some way it won't fully chamber, leaving part of the case wall exposed which will then rupture when ignited. I think the more complicated weapons that fire from an open bolt release the firing pin when they go fully into battery (round completely chambered).

Edit: The 'open-bolt blowback' is just a plain blowback system that fires from an open bolt meaning that the bolt starts off locked back then when the trigger is pulled it gets pushed forward on a spring, stripping a cartridge from the mag, firing it then the bolt is blown backwards by the recoil to its starting position. Generally not as accurate as a weapon that fires from a closed bolt due to the moment of inertia created by the bolt moving forward causing the aim of the weapon to change, but much cheaper and simpler to make up for it.

[wbks]

So with an exposed firing pin how to you make sure that it pushes the round into the chamber rather than hitting the primer?

[Wolf]

So with an exposed firing pin how to you make sure that it pushes the round into the chamber rather than hitting the primer?

I surely do not know, so I'd play safe and use an inertial firing pin that is held to the rear of the bolt by a spring and then continues forward against the spring only when the bolt has come to rest with the round in the chamber.

[wbks]

Are you sure anything as small as a firing pin has enough weight to fly forward under its own weight and hit the primer hard enough? I just have a hard time imagining anything that small having enough "inertial" force. Were there many cases of exposed firing pin rifles or smgs like the sten (i think?) detonating the round before it fully chambers?

[jono035]

Are you sure anything as small as a firing pin has enough weight to fly forward under its own weight and hit the primer hard enough? I just have a hard time imagining anything that small having enough "inertial" force. Were there many cases of exposed firing pin rifles or smgs like the sten (i think?) detonating the round before it fully chambers?

You can always add weight to the firing pin or put a weight behind it to act as a hammer.

The bolt with a fixed firing pin could pick up and chamber the round without a problem, you have to put a fair amount of force on the primer to set it off, then once the round fully chambers and stops, the weight of the bolt would force the pin forward to dent the primer.

As for detonations I really don't know I'm afraid, probably time to start googling!

[Mr Merde]

I have never built a firearm from scratch so here I will have to agree with Jono, start googling. Google is you friend.

WOlf was right, you can build any firearm you hold a licence for. It needs to have a serial number stamped on it somewhere.,

One lad in the CAS game built a working copy of a Colt SAA with a Buntline barrel. He also added the fittings that allowed a shoulder stock to be attached.

Very impressive. Shot well.

[Mr Merde]

Did that yesterday in Reloader's Supplies... Between the Marlin 1894 Lever Action, Norinco M14 and the Dillon RL550 they had setup there I was definitely wishing I had a bit more money for spending on toys at the moment.

Had a couple of nice E cat safes there too...

A friend living down Thames way has 2 of the large Dillon Presses as well as a 550.

He also has a Magna engineereing automatic casting machine capable of casting 1000 projectiles an hour.

Needless to say he buys his lead by the tonne

[jono035]

A friend living down Thames way has 2 of the large Dillon Presses as well as a 550.

He also has a Magna engineereing automatic casting machine capable of casting 1000 projectiles an hour.

Needless to say he buys his lead by the tonne

Wow.

The big ones as in the 1050s? (7 turret completely automatic monsters)

Does he manufacture ammo for a living or something?

[The Pastor]

well looks like ive found my reloading setup.

$225 usd including the reloading gear,308me dies and shipping - which Im getting reamed on over half the price hahaha.

but they have it in stock!

[Mr Merde]

Wow.

The big ones as in the 1050s? (7 turret completely automatic monsters)

Does he manufacture ammo for a living or something?

No he likes to buy toys.

He will sit down and make a few thousand rounds of all that he shoots, at a time.

He also supplies projectiles to his friends. Quite cheaply.

[Wolf]

Are you sure anything as small as a firing pin has enough weight to fly forward under its own weight and hit the primer hard enough? I just have a hard time imagining anything that small having enough "inertial" force.

As Jono said, you have a weighted firing pin.

As you're making it yourself rather than using a stock firing pin, that is a minor matter - you machine the thing with a fair bit of mass at one end and a pointed skinny bit at the other. When you make your bolt block, you make a cavity inside to fit the weight and allow it sufficient forward/rearward travel. The bolt stops, the weighted pin keeps on going, boom!

Cheers, Chris, I'd forgotten the serial number requirement.

[Mr Merde]

I've been toying with the idea of getting some castings from

the States with which to build another single shot rifle.

Could be fun.

[The Pastor]

I've been toying with the idea of getting some castings from

the States with which to build another single shot rifle.

Could be fun.

what you should cast Mr Merde, is a cannon!

[jono035]

what you should cast Mr Merde, is a cannon!

Seconded. Nothing too crazy, 12 pound civil war style cannon or something?

Edit: It fits the category of single shot. There were also rifled cannons in use during the civil war according to ye olde wikipedia, so you could make yourself a single shot 'rifle'