Ultralight Ultralight Rifles

[StupidLightweight]

For those running open gas ports, I'd be curious to know how much velocity is gained by sealing the hole. Is it negligible? Is it 10 fps, or is it 100 fps? Interesting stuff.

My first attempt at a bolt-action AR was a decade ago with a heavy barrel .17 Remington. I used a pipe clamp and a scrap of leather, thinking it might contain the gas. Not a chance. The leather had a clean hole through it after the first shot. Don't underestimate the pressure at 7 (carbine length gas), 9 (mid length gas), or even 12 (rifle length gas) inches.

 

[packgoatguy]

For those running open gas ports, I'd be curious to know how much velocity is gained by sealing the hole. Is it negligible? Is it 10 fps, or is it 100 fps? Interesting stuff.

My first attempt at a bolt-action AR was a decade ago with a heavy barrel .17 Remington. I used a pipe clamp and a scrap of leather, thinking it might contain the gas. Not a chance. The leather had a clean hole through it after the first shot. Don't underestimate the pressure at 7 (carbine length gas), 9 (mid length gas), or even 12 (rifle length gas) inches.

The velocities I recorded showed about a 50fps loss without the gas port blocked.

 

[Taudisio]

For those running open gas ports, I'd be curious to know how much velocity is gained by sealing the hole. Is it negligible? Is it 10 fps, or is it 100 fps? Interesting stuff.

My first attempt at a bolt-action AR was a decade ago with a heavy barrel .17 Remington. I used a pipe clamp and a scrap of leather, thinking it might contain the gas. Not a chance. The leather had a clean hole through it after the first shot. Don't underestimate the pressure at 7 (carbine length gas), 9 (mid length gas), or even 12 (rifle length gas) inches.

If the pressure dropped in half by the time it got to the port, you’re looking at what 20,000-30,000 PSI. Yea leather, duct tape, jb weld-it will hold.

I have a Samson gas block back ordered, when it arrives, I’ll let you know exact numbers from my rifle. I have about 100-150 rounds through mine open, but I haven’t bothered to chrono it. It doesn’t matter for my intended use of the rifle, but I have been curious about the numbers as well. Guys port their 4” Glock barrels with much larger holes so I assume it’s no big deal as long as there isn’t anything above it.

 

[Thegman]

For those running open gas ports, I'd be curious to know how much velocity is gained by sealing the hole. Is it negligible? Is it 10 fps, or is it 100 fps? Interesting stuff.

My first attempt at a bolt-action AR was a decade ago with a heavy barrel .17 Remington. I used a pipe clamp and a scrap of leather, thinking it might contain the gas. Not a chance. The leather had a clean hole through it after the first shot. Don't underestimate the pressure at 7 (carbine length gas), 9 (mid length gas), or even 12 (rifle length gas) inches.

That reminds me of so many of my "experiments"..."Woah, I didn't think that would happen!"

When I was a kid,, I actually used the line, "It was just a bomb, everything is fine, go back inside." on my family running out of the house after a huge explosion. I didn't want to alarm them that it was actually a 3/4 iron pipe cannon held in a vice, loaded with hundreds of grains of black powder under a 50 cal bullet and aimed at some stacked wood leaning against the patio stairs. No one ever seemed to notice the chunk out of the concrete stairs.

 

[JBradley500]

If the pressure dropped in half by the time it got to the port, you’re looking at what 20,000-30,000 PSI. Yea leather, duct tape, jb weld-it will hold.

I have a Samson gas block back ordered, when it arrives, I’ll let you know exact numbers from my rifle. I have about 100-150 rounds through mine open, but I haven’t bothered to chrono it. It doesn’t matter for my intended use of the rifle, but I have been curious about the numbers as well. Guys port their 4” Glock barrels with much larger holes so I assume it’s no big deal as long as there isn’t anything above it.

If you remember, I'd be interested to see a video of shooting it with the port open.

 

[Taudisio]

If you remember, I'd be interested to see a video of shooting it with the port open.

Sure, what perception? You want to see the port? The chronograph? What are you looking to see? So I can try to capture it.

 

[JBradley500]

Just wondering if there's any visible gas flow (debris, etc.). Maybe do one with a piece of paper or something over it? Just curious about the force.

 

[Taudisio]

Just wondering if there's any visible gas flow (debris, etc.). Maybe do one with a piece of paper or something over it? Just curious about the force.

Yea, if the weather is decent this weekend, I’ll send a few rounds with some paper or cardboard over it

 

[JBradley500]

Awesome thanks!

 

[ChrisAU]

Rattle can go psshhhhhhh

Will get a weight later, it’s darker than the pic shows.

 

[FullyTorqued]

Rattle can go psshhhhhhh

Will get a weight later, it’s darker than the pic shows.

View attachment 680831

I like the Kryptek Highlander. What did you use for a stencil?

 

[ChrisAU]

I like the Kryptek Highlander. What did you use for a stencil?

It was part of a pack on a Amazon for like $5.99.

3 lbs 13.7oz for the 10” 350 legend as shown with mag and optics. Will be around 4.5 lbs with full mag and a YHM R9.

 

[ebrownw2]

Wilson emailed back and said no, but that it was something they were being asked for often lately so they might offer it in the future.

Never heard back from Shaw.

Don't want to wait 25 weeks on a Mos-tek and don't want to pay custom barrel price and still have extra weight in a gas journal (x-caliber).

Seems like Green Mountain is the place to be....GM-B3s on order. Now to find someone to skinny them up and thread them. I appreciate the leads on smiths and advice.

Solo 300 actions arrived at my house 1 week from order date.

TN Arms contacted me 5 days after I ordered to ask for my FFL. That was a few days ago. Sent it to them and have not heard back.

So, everything is going exactly like this thread told me it would. Haha.

Thinking Jag Composites UL 7.5" handguard. Stupid expensive--pretty things generally are--but dang it that is one sexy (and lightweight) piece of kit.

What's the lightest weight AR appropriate 1" scope mount without vertical split rings? Never used one of the Aero mounts that seem popular but I prefer horizontals.

 

[Thegman]

Rattle can go psshhhhhhh

Will get a weight later, it’s darker than the pic shows.

View attachment 680831

Nice work! Just don't set that thing down in the woods!

 

[JBradley500]

You guys filing down the bolt hold open on the mag or just dealing with it?

 

[ChrisAU]

You guys filing down the bolt hold open on the mag or just dealing with it?

I removed the bolt catch from my lower. If building a new one just don't put it in. Not used.

 

[StupidLightweight]

You guys filing down the bolt hold open on the mag or just dealing with it?

Same for me. I leave my mags original but don't install the bolt-catch on the lower.

 

[180ls1]

How are you guys carrying these things? Sling? Pack?

 

[Thegman]

How are you guys carrying these things? Sling? Pack?

Super lightweight sling. They don't need much, can hardly feel them at times.

 

[180ls1]

Super lightweight sling. They don't need much, can hardly feel them at times.

Thanks. I wasn't sure if they would carry "normal" or if the ergonomics and weight would make them flip or do something odd compared to a regular hunting rifle.