Author Archives: David Bookstaber

Environmental Impact?

This Dyson vacuum comes in 3 pounds of packaging. This includes more than a dozen separate elaborately cut-and-folded pieces of corrugated cardboard. (The cutouts mean that the amount of cardboard that was consumed in producing the packaging was even greater.)

Dyson V8 packaging: 3 pounds of cardboard

The packaging also includes the following note (on that black paper in the middle):

To reduce our environmental impact, we’ve moved your full manual online.

I weighed the full printed manuals that came with two other vacuums, and each was just half an ounce. That’s 1% of the weight of the packaging here. From the picture here, does it look like Dyson has gotten the packing cardboard to within 1% of the minimum needed to protect the product during shipment?

I’m beginning to suspect that this “environmental impact” business is a pretext for something else….

How to restore water pressure by removing flow restrictors

Low water pressure used to be something I only experienced visiting third-world countries.  And the rare occasion when an extended power outage prevented water pumps from refilling water towers (e.g., New York City on August 14, 2003).

First world water infrastructure is supposed to deliver potable water at a pressure of 60psi.  Water conservation fanatics came along and thought our 1/2″ pipes and 3/8″ fixtures were delivering too much water to faucets and showers, so they pushed flow restrictors.

When I stay at hotels the showers are often so weak that I wish I had brought a five gallon bucket to shower from (like I did in some areas of Mexico).  Instead I now pack a small wrench to remove the shower head so I can pry out the flow restrictor.

Often the restrictor will be a small plastic disk like this, in which case all you have to do is pull out that black O-ring and regular flow will be restored.

Higher-end restrictors might have more pieces, but they can all be pried out to restore flow.

I was Emptormaven

When I first started this blog in 2006 I called it “Emptormaven” – from Latin emptor (buyer) and maven (specialist) – and I bought and hosted it under the domain name I had intended to write about lots of products, but the majority of my posts ended up being about firearms.

By 2020 I was dropping my pseudonym across my online content, so I moved the blog under my domain and set up a 301 redirect for the last year I owned the domain.

I recently discovered someone else bought the domain name and is hosting gun-related content on it! I guess I had created significant SEO value. So to whoever is using the name now: You’re welcome.

AR-15 buffers, springs, and cyclic rates

Animation of the AR cycle: Gas tapped from the barrel unlocks the bolt and pushes it rearward against a buffer and spring in the stock. During this travel it ejects the empty case and cocks the trigger. The recoil spring pushes the bolt assembly back into battery, and along the way the bolt strips a round from the magazine and pushes it ahead into the chamber.

Here is a good page describing the essential components and design considerations in an AR-15 action. In this post I summarize some research I did focusing on the tail end of the system: The recoil spring and buffer. In order to see exactly what goes on in there I cut a viewport into a buffer tube, clamped rifles into my test fixture, and recorded high-speed video of the action cycling.

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Classic Machine Guns

I had the good fortune to meet Kyle Paaren, proprietor of Paaren Firearms, who specializes in rebuilding classic machineguns – often by rewelding demilitarized receivers. Many of these are brilliant pieces of engineering whose reliability and durability were proven in the mass military conflicts of the twentieth century.

I think the MG42 is the most impressive: It shoots full-power .30-caliber ammunition at a rate exceeding 1100 rounds per minute. It uses a roller-locked bolt mechanism that is unlocked by muzzle pressure (captured in its distinctive muzzle device) pushing back on the barrel itself. Its barrel can be changed in under five seconds.

I was allowed to take photos of some of these recent rebuilds.

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Understanding Gun Precision

I’ve written a number of posts over the years in which I test the precision of various firearms. Some readers have asked about the particular methodology I use.

When testing guns for accuracy it is common practice to look at the Extreme Spread of a group of 3 or 5 test shots. I will explain why this is a statistically bad measure on a statistically weak sample. Then I will explain why serious shooters and statisticians look instead at some variation of circular error probable (CEP) when assessing precision.

It is easy to fool yourself with Extreme Spread, and it’s even easier to fool others.
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Maple Water

Maple syrup is typically made by reducing maple sap by a factor of 40. For some time I was wondering what raw maple sap tastes like. A recent stop in a local grocery store’s Expensive Water section turned up quarts of Vermont “maple water” selling for $4.50! To satisfy my curiosity I bought one of these:

It smells something like diluted coconut water and tastes relatively neutral, with only a hint of sweetness and a woodsy aftertaste.

Of course the economics of this are crazy: A quart of Vermont maple syrup runs under $15. Why not buy maple syrup and dilute it with water, 40:1, thereby reconstituting “maple water” for a tenth the cost?

I guess you wouldn’t get the fancy packaging advertising the not-from-concentrate version’s “electrolytes, antioxidants and prebiotics,” some of which might be lost in the process of reducing sap to syrup?

Range Day

Over the winter I accumulated a bunch of new factory ammo, and a few handloads, I was waiting for a nice day to test. That day finally came! Suffice it to say that with four rifles, two of which I switched in the field from .338LM to also test .308, this was an all-day affair. Now I need to find time to analyze all the targets and radar data….

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