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View Full Version : Ident: Metric or Inch receiver differences


W.E.G.
November 16, 2000, 15:18
Harlan at Federal Arms wrote:

"The receiver marked "L1A1" is an IMBEL manufactured, Century imported unit. It is an inch pattern receiver. Look for the cut out at the front wall of the mag well, the cut out accepts the lug of the mag. If the cut out is a large horizontal rectangle, the receiver is cut for inch mags. If the cut out is a half moon, the receiver is cut for metric mags. Metric mags will fit into an inch pattern receiver, but with some slop. Also, look at the slot for the charging handle. If the front portion of the slot is milled away, in other words, if the slot does not extend all the way to the front of the receiver, the receiver is machined to an inch pattern. Both metric and inch pattern charging handles will install onto an inch pattern receiver. The other small feature to look for is the small cut out on the back of the slots for the top cover. Inch top covers have small tabs at the rear of the cover that will fit into the receiver cut outs. Both metric and inch top covers will fit onto an inch pattern receiver.
Timing washers on the barrel are only used on inch pattern barrels. If a metric pattern barrel is installed into an inch pattern receiver, no washers are used. The timing for the metric barrel is achieved through shoulder work on the barrel. Just remember that the thread pitch for an inch pattern or metric pattern barrel is the same."

gunplumber
November 16, 2000, 19:01
great synopsis. One minor elaboration. While inch and metric charging handles will fit an inch cut receiver, an inch cocing handle is a few thousandths thicker than a metric and may need to be thinned slightly - just lay the back against a belt sander ( with a bucket of water as it ill heat up fast) Takes about ten minutes of trial and error. Also, the peg that engages the bolt on an inch handle doesn't fit well in a metric receiver The rectangular portion on the end needs to usually be thinned by a few file strokes on each side. Otherwise it wedges in the front portion of the groove it moves in (using imbel as reference)


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T. Mark "Gunplumber" Graham
gunplumber@arizonaresponsesystems.com
Arizona Response Systems
5501 North 7th Avenue, Phoenix, AZ 85013
623-873-1410 http://www.arizonaresponsesystems.com

AR-45ACP
February 08, 2001, 01:52
Building inch gun on metric reciever any diferences besides mag cut and cocking handle mods?

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The first ones expensive,but after that,they're all free.

iizzie
February 08, 2001, 03:49
My century must be a real galemofery, it has a washer between the barrel and receiver and a half moon cut for the mag. metric mags wiggle around a bit but work just fine. I only have one inch mag and it doesn't lock into the gun real well. The mag that came with it has a different floor plate than the austrian ones that I get from DSArms, and from the local gun shop that has a few fal mags, it also has a metric type hook on the front lip of the mag.Inch hand gaurds fit real well but it took a metric butt stock to fit up right. The receiver states that it is an Embel import by CAI. It is a real good shooter and has made a good truck gun for some time now I hope to get a DSArms parts gun to replace it but for what I paid for it I'm not holding my breath. I don't want to hear how sorry you are for me. I have a DSArms Carbine for serious social work. iizzie

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EMDII
February 08, 2001, 06:51
iizzie:

MANY Century-built 'Inch' guns used Inch forwards assembled to IMBEL or Hesse Type 3 receivers. MANY also work just fine! The Type 3 REQUIRES the metric buttstock, so you're on the right path. The washer between barrel and receiver is called a breaching washer, and is part of the L1A1 headspace process.

IF your metric magazine (small 'nose') has a flanged floorplate, then it sounds like it came from the Republic of South Africa. If it looks like this: (go here)

http://albums.photopoint.com/j/ViewPhoto?u=101373&a=759572&p=22529949

then it's definitely RSA. If not, tell us the difference.

IF an Inch-pattern magazine fits at all, that's wild! The Inch cutout is a large slot for the lug on the magazine front. Slamming it into a metric cutout must be real interesting!

Don't be sorry, or have any regret. You have a shooter!
http://www.fnfal.com/forums/wink.gif
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1*.....Train Like You Fight: Second Place is NOT an Option.

E.M. (Ted) Dannemiller II

[This message has been edited by EMDII (edited February 08, 2001).]

iizzie
February 09, 2001, 21:48
EMDII
The mag that was sold to mea as an inch mag isn't after looking at as many pictures as I could on the files it must be metric. however it isn't like the others the hole in the floorplate is about 3/32nd of an inch in dia. and the metal around the hole sticks out from the back of the mag. nearly an 1/8" all the rest of the mags came from DSArms some hace a little side to side play but most fit tight. All fit snug in the DSarms receiver. Sorry about sounding off on Maximus but he is either and Anti or just needs to go Bear hunting with me. Thanks for all that you are doing for our sport. iizzie

EMDII
February 16, 2001, 19:28
Originally posted by iizzie:
EMDII
however it isn't like the others the hole in the floorplate is about 3/32nd of an inch in dia. and the metal around the hole sticks out from the back of the mag nearly an 1/8

Sorry about sounding off on Maximus but he is either and Anti or just needs to go Bear hunting with me. Thanks for all that you are doing for our sport. iizzie


Several magazines have a rearward protusion, and some even include a small hole in the corner. You can insert a SAK (swiss Army Knife- greatest plumber's helper I know) can-opener into the tiny hole and pull off the baseplate.

You certanly have a metric magazine. An RKI may have a reference showing which countries used this particular variant magazine, but all metrics are interchangeable.

As to Maxximus, al is forgotten. Join, share, enjoy. 'ALL I do' is be a part of it.

THANKS
http://www.fnfal.com/forums/wink.gif


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1*.....Train Like You Fight: Second Place is NOT an Option.

E.M. (Ted) Dannemiller II

prosecond
March 06, 2001, 21:28
So an Imbel receiver marked R1A1 sporter would be a metric receiver? I was concerned when a inch barrel would thread in and the lower fit. If I understand these recievers are good just no logo? I was planning on using this on my group buy kit. Is it what I want?

Sorry for so many questions. I have not put one together yet. I had a smith barrel and headspace an STG several years ago and want to do it on my own now. Bought an inch from Harlan and plan on receiver from Enterprise.
Thanks

EMDII
March 07, 2001, 08:30
Originally posted by prosecond:
So an Imbel receiver marked R1A1 sporter would be a metric receiver? I was concerned when a inch barrel would thread in and the lower fit. If I understand these recievers are good just no logo? ...Is it what I want?

Sorry for so many questions..... Bought an inch from Harlan and plan on receiver from Enterprise.
Thanks

The IMBEL R1A1 kit is a fine gun. Any IMBEL is still the only license-built copy of the original FN spec'd receivers.

As to whether it is inch or metric: it might be a real Franken-FAL, having the IMBEL metric receiver, mated to a metric TMH (no problem), but the magazine well has been cut for an Inch magazine. The Inch mag will have the large cutout in the receiver- a slot across the interior front of the magazine well for the larger lug on the magazine. Metric magazines may even fit. I would NOT, however, bet my @$$ on a metric-in-Inch combination. Things have a habit of going wrong at the wrong moment!
http://www.fnfal.com/forums/wink.gif

Inch and metric barrels share the same thread pitch going into the receiver. The 'Commonwealth' (Inch) pattern differed from the Belgian (Metric) pattern in only a few details- fastening of the PG, tang of the TMH to buttstock, selector shape, yadayada. See GunPlumber's Handbook (get it: you'll love it) for a more thorough list.

Lawrence makes a fine receiver: my second FAL has an Entreprise Type 1. My Inch kit will sport the Entreprise Inch-pattern, mated to my incoming UE62xxxxxx L1A1 kit!

There are no dumb questions, except the ones we never asked before making contact. In the kill-zone is a bad place to learn your mission! http://www.fnfal.com/forums/tongue.gif

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1*.....Train Like You Fight: Second Place is NOT an Option.

E.M. (Ted) Dannemiller II

[This message has been edited by EMDII (edited March 07, 2001).]