View Full Version : types of receivers

June 28, 2007, 17:30
I am exploring which kind of FAL I want to build (inch vs. metric) and a couple of questions came up:

1. I have seen inch and metric pattern receivers classified as type 1, 2, G1 type 1 receiver etc. What do these classifications mean? and can any metric receiver interchange with any other metric parts kit? (and any inch receiver with any inch parts kit: R1A1 receiver with L1A1 kit)

2. I have run across many different receivers and parts kits, Century, DSA, Entreprise, Imbel etc. Are there any real lemons to look out for?

Please pardon if these questions have been covered before :-)

June 28, 2007, 17:47
Only about ten thousand times, and as recently as today, just a few threads down this forum. It would be appreciated if you would put a teeny bit of effort into looking up the answers before posting your question.

Grainy B&W photo, but what you see are:

Top: Type-II receiver
Middle: Type-III receiver
Bottom: Type-I receiver


All three of these receivers are on a Type-I lower, as you can see from the bottom rifle where the "receiver line" matches exactly. Biggest mismatch is Type-III on the Type-I lower in the middle, although most people wouldn't notice. VERY hard to tell a Type-I to Type-II mismatch, the differences are rather subtle, probably invisible to your eye as seen on the top rifle.Originally posted by AndyC

Differences other than cosmetic - ok, I'll try.

Type 1 was the original.
Type 2 has a bit more meat at the rear of the receiver, supposedly because some Type 1's cracked at the back under full-auto fire.
Type 3 is the cheapest to make because there are less machining operations required - and consequently has the most metal of all the types, making it presumably the strongest.

All of these are METRIC receivers. An INCH receiver will look closest to the Type-I/Type-II Metric, with a completely different "lightening cut" scallop on the right side of the magwell. [EDIT: See Andy's photo below.] The Inch receivers had only a couple of machining changes from the Metrics, and virtually all parts will interchange, although some with minor modifications when going either way between Inch and Metric.

All Metric parts interchange with other Metric parts. The photo above shows you can put any type of receiver on any type of lower. Furthermore, you can put a Metric lower on an Inch receiver, and vice versa, although the front and rear sights will be a different heights, so you will need to run an Inch rear sight on a Metric lower if using an Inch barrel, or a Metric rear sight on an Inch lower when using a Metric barrel.

Things that will NOT interchange between Inch and Metric:
* Many parts of the gas system
* Front sights
* Fire control parts
* Pistol grips

Things that will interchange with some modifications:
* Dust covers
* Buttstocks
* Charging handles
* Inch magazines in a Metric receiver (either to the mag itself, or the magwell on the receiver)
* (Metric mags fit okay in an Inch receiver, only a little bit loose)

Everything else will swap between "families" pretty easily.

What to avoid? The game has changed these days, about the only receivers you'll be able to get would be DSA, the best; IMBEL, great but no longer imported and spendy; Entreprise, spotty quality control but some are just fine; Century and Hesse, both are quite often problem children and better for the advanced builder. Hesse is no longer in production, I don't think Century is, either. DSA and Entreprise have a bit of a waiting list going.

Parts kits? Get anything with a good barrel, the rest doesn't matter that much unless the rifle was totally worn-out trashed. Really nice parts might need refinishing, no big worry there. Your parts kit is almost certainly going to be military de-milled surplus, Austrian StG, Belgian FN, German G1, South African R1, Brazilian IMBEL, a smattering of Israeli and Argentinian. DSA makes/outsources a few parts, particularly barrels, now that their formerly huge supply of StG parts are finally being exhausted.

That's all I can think of, and with one [EDIT: Two] major edit[s] to boot.

[EDIT] It so happens I was the person who coined "Alumi-Bomb" to describe the Williams Arms Company (WAC) receivers, released in 2001. I doubt you'll find one out there unless you look hard... they are NOT for anything but a blowback operation in my opinion. DPMS made a handful of receivers about six years ago, they're ugly but functional. Armscorp also made a few, again rather rare. The Dan Coonan, or DCI receivers were fantastic in their initial release around 2002, but the recent versions issued this year had some "problems" according to user reports. Very frustrating wait on these, some guys have been patient for over a year. At today's prices, it's hard to beat a DSA at $350, with almost guaranteed quality. [END EDIT]


June 28, 2007, 17:49
can any metric receiver interchange with any other metric parts kit?

2. I have run across many different receivers and parts kits, Century, DSA, Entreprise, Imbel etc. Are there any real lemons to look out for?
Yes - unless you know what you're doing, or have access to someone who does, stay away from Hesse/Vulcan - going up the scale is a matter of opinion, but for me it then goes Entreprise then Century - then onto the decent ones like Imbel, DSA and DCI (the latter seems to be completely unavailable).

Typical Inch-type receiver:

June 28, 2007, 17:54
Type I Receiver

Type II Receiver

Type III Receiver

L1A1 Receiver

G1 Receiver

Most inch and metric patern parts are interchangeable, though you will see differences in things like the bolt hold opens, magazine release, barrel, sights, pistol grip and a few other parts which won't easily fit the other variants receiver due to size or part differences.

You can't go wrong with Imbel, DS Arms and Coonan Receivers (when you can find them).

Stay away from the Williams Aluminum Receivers, otherwise known as the AlumaBomb. They've been tried and tested in sub caliber conversions but avoid if you're going to build a 308.

Century receivers are either Hesse / Vulcan Arms origin or Imbels. The imbels are great receivers and the Hesse's are workable, but not my personal preference and may require some work.

Entreprise receivers have been hit or miss in my own personal experience, and there is a thread in the General Manufacturers Forum detailing both Successful builds and those who have had issues.

Dammit Guys, I found this thread first and you beat me to the reply!!! ;)

June 28, 2007, 19:50
Too old, too slow :D