by Tom Gaylord
Writing as B.B. Pelletier

Rail Lock compressor
The Air Venturil Rail Lock spring compressor is compact.

This report covers:

  • Attaches to the scope rail
  • Let’s look at the unit in detail
  • How shall I test it?
  • Developed for gas spring guns
  • Installation
  • The coolest feature
  • Quirks
  • The price

Today we start looking at a mainspring compressor that’s very different from any other. The Air Venturi Rail Lock spring compressor is a compact 1.5-pound unit that attaches to the scope rail of the gun being disassembled. The threaded rod is then pressed against the end cap of the rifle — whatever configuration that might take. From that point this compressor works the same as any other, but in the next few reports I will show you in detail, plus today we will look at its design very closely.

Attaches to the scope rail

Right off the bat you might be wondering if this unit will fit most spring-piston airguns. As long as they have a scope rail either cut into the spring tube or attached, it will work. There are a few vintage spring rifles and pistols that don’t have rails like the Haenel model 28 pistol and some Diana model 27 rifles, and this compressor won’t work without a rail. But the majority of spring rifles being sold today, plus a number of spring pistols, do have a scope rail. On them the compressor should work well.

11mm dovetails and Weaver/Picatinny dovetails
It fits both kinds of dovetails — 11 mm and Weaver/Picatinny. There’s no worry there.

Rail Lock compressor rails
The compressor rails are a short section of dovetail grooves on the unit. They clamp to both 11mm and Weaver/Picatinny dovetails.

Let’s look at the unit in detail


Rail Lock compressor details

Here are the parts of the Air Venturi Rail Lock mainspring compressor.

How shall I test it?

My thinking is I will start with an easy disassembly and proceed to more difficult ones after I get the hang of operating the compressor. The Beeman R1 is the easiest spring rifle I can think of that needs a compressor for disassembly. The TX200 Mark III is even easier, but that’s mainly because a compressor is not needed for disassembly.

Developed for gas spring guns

This compressor was initially created as a shop tool — not for resale. Tom Gore of Vortek needed a compressor that would work on gas piston and gas spring rifles as well as airguns with conventional coiled steel springs. Gas spring airguns may only need a fraction of an inch of compression to get them together, but because the gas pressure is so high they are very difficult to assemble. So Tom created this unit, which he says makes assembly of a gas spring easy. I guess I need to try it that way.


The unit clamps to the scope rails of the airgun with the rail shown above. A screw at the front and rear of the unit clamps it tight in place. I will report on how well that works when I test it. Two Allen wrenches are packaged with the compressor for all adjustments.

Rail Lock compressor installed
Here’s the compressor installed.

One thing several readers noticed in my 2017 SHOT Show report is the threaded screw doesn’t align with the center of the spring tube. That depends on the diameter of the tuibe. It isn’t necessary that the unit be centered for it to work and we will have a chance to look at that as this report progresses.

The coolest feature

I will cover installation in the next section of the report, but you can guess how it works. The dovetail of the compressor is clamped to the dovetail of a spring piston airgun and then the threaded rod is screwed down for tension. Bur the coolest feature is the quick release button that allows you to slide the threaded rod in and out. So installation goes fast. I will have more to tell you about that after I’ve used it.


Where this may get dicey is on strange airguns like vintage BSAs and oddballs like the Hakim. Not all spring guns have end caps. Some, like the BSAs. require you to use a tool that reaches inside the rear of the spring tube and also passes around a crosspin to engage an inner sliding sleeve. Additional adaptors may have to be made for these guns, but that’s true of any mainspring compressor. It’s too soon to know for sure how the Rail Lock compressor will do, but I plan to challenge it in this test!

The price

Well, it’s $100. That’s half of what the only other mainspring compressor is selling for. Whether it’s worth it will depend on how useful it is, but I know there is a demand for a good mainspring compressor, so let’s see how good this one is.

Air Venturi Rail Lock spring compressor: Part 2