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FAMAE 540 FAQ: Why it’s cool, and you should own one.
Background / History
The Sig 540 rifle has a long-stroke piston, gas-operated, rotating bolt operating mechanism and utilizes stamped steel for the receiver. It was developed in the 1970s as a potential replacement for the STGW 57 rifle in Swiss military service. Ultimately the Sig 550 series (a modified version of the 540 series) was chosen as the replacement service rifle for the Swiss military. Sig licensed production of the 540 series to Manurhin in France and FAMAE in Chile. ERE Systems imported semi-automatic only versions from FAMAE in Chile into Canada, and they are currently classified as non-restricted/restricted. The semi-auto FAMAE model designations are as follows:
SG 540-1 – 5.56mm 18.6” barreled rifle
SG 542-1 – 7.62mm 19.5” barreled rifle
SG 543-1 – 5.56mm 11.8” barreled rifle
Parts & Accessories
Magazines - for the FAMAE 540 and 543 are interchangeable with the Sig/SAN 550. They come in 5, 20, and 30rnd bodies (pinned to 5rnds in accordance with Canadian law). Manufactured by Sig/SAN in Switzerland, and by Dominion Defence.
Spare factory parts - are available, although there is not a wide variety of parts that are available. Spare barrel, bolts, bolt carriers, extractors, extractor springs, firing pins, and stocks have been made available for sale by Calgary Shooting Center and Tactical Imports.
Scope mounts - are available. These are quick attach/detach picatinny rails that mount to the rear sight block and front receiver lug.
Bipods - are also available. They attach to the bottom lug on the handguard cap and fold underneath the handguard.
Side folding stocks - are available and are easily replaced by removing the buttstock screw from the fixed stock and replacing the fixed stock with the folding stock assembly, then re-installing the buttstock screw.
Aftermarket magazine conversion block - for the 540/543 allows for the use of most STANAG magazines.
Aftermarket side-folding stock block - allows for the use of AR15 stocks on the 540/543. GS Designs also has an ACR stock block adapter.
Bayonet - attaches to the flash hider.
Maintenance / cleaning
Stripping for Maintenance
1. Make sure the rifle is unloaded and remove the magazine
2. Remove rear pivot pin
3. Push down on the lever on the bolt carrier, and remove the charging handle
4. Withdraw the bolt carrier and bolt. Rotate the bolt counter-clockwise and remove it from the carrier.
5. Remove Front pivot pin
6. Remove handguards by pushing the lower handguard to the rear, detaching it from the upper handguard.
7. With a screwdriver, rotate the bolt on the gasblock so that the “arrow” points towards the muzzle. Then slide the gasblock forward and rotate it 180 degrees.
8. Remove the gas piston and return spring.
9. Remove the gas tube.
Also, please see the video from ERE systems for how to field strip the rifle:
Field Stripping A FAMAE Rifle (eresystems.com)
Complete Strip
1. Using a pin punch, remove the roll pin from the left side of the selector switch, then withdraw the remainder of the selector from the right side of the lower receiver.
2. Remove the trigger pin, and withdraw the trigger assembly from the lower receiver.
3. Pull the hammer spring rearward and lift the assembly up and out of the lower receiver.
4. Remove the pin retaining clip
5. Remove the hammer pin, and withdraw the hammer from the lower receiver.
6. Unscrew the pistol grip screw and remove the pistol grip
7. Unscrew the adjustable trigger spring.
8. Unscrew the buttstock screw and remove the buttstock.
9. Unscrew the buttcap screw to remove the buttcap and sling loop assembly.
10. Remove pins from the flash hider and remove the flash hider from the barrel.
11. Remove the gas block assembly from the barrel
12. Using a pin punch, remove the roll pin from the gas selector.
13. Remove the gas selector assembly and gas plug from the gasblock.
14. Remove the spring clip from the locking bolt on the gasblock, then remove the locking bolt.
15. Unscrew the front sight from the gasblock, then lift upward to withdraw the front sight adjustment screw from the gasblock.
16. Remove the pins from the handguard cap and remove the handguard cap from the barrel.
17. Unscrew the rear sight from the rear sight block. Lift upwards on the rear sight adjustment screw and withdraw it from the rear sight block.
18. Remove the bolt hold open spring, then remove the bolt hold open from the upper receiver.
19. Remove the barrel from the upper receiver.
Adjusting the trigger
Using a 6mm and 4mm wrench, turn either the trigger pad (A) or the nut (B) clockwise to shorten the trigger pull distance, or turn counter-clockwise to lengthen the trigger pull distance. Displayed is what is assumed to be the “factory” setting.
Accuracy
Accuracy expectations should be the same as any other 18"-20" non-free floated barrel. See below of typical groupings at 100yards with the factory iron sights and xm193 ammo.
Reliability / Known Issues
Loose flash hider – Some rifles have a flash hider that is able to move slightly, and this has the potential to affect accuracy. This seems to mostly be a tolerancing issue, since the barrel has cuts made for the flash hider pins before the flash hider is installed. This can be slightly corrected by peening the cuts on the barrel in order to displace some steel, which will then tighten up the flash hider when the pins are re-installed.
Loose gas block - Some rifles also have a gas block that is able to move slightly, and this has the potential to affect accuracy, especially if using the iron sights. This seems to mostly be a tolerancing issue, since the barrel has a cut made for the gas block pin before the gas block is installed. This can be slightly corrected by peening the cuts on the barrel in order to displace some steel, which will then tighten up the gas block when the pin is rotated back into the locked position.
Paint chipping on part of the ejection port – fairly common. The problem is only cosmetic, since the area where the brass cases are hitting is spot heat treated and will not wear out over time.
Magazine issues – some have reported reliability issues with various magazines.
Bolt hold-open spring – some reports of the bolt hold-open spring breaking when removing it from the upper receiver.
Finish – The FAMAE rifles seem to be parkerized, then painted with a moly-resin paint. While this is a very durable finish, it can leave some parts very smooth feeling where they are not intended to be (ie, knurling on the rear sight and on the selector switch). Underneath the paint, the rifle has a very un-even parkerizing finish to it. I got Nick at Vulcan Gun Refinishing to re-park mine and he did an amazing job. I highly, highly recommend his services.
Differences between Manurhin and FAMAE 540s
While the Manurhin made 540s stuck to the original Sig design, FAMAE made some slight upgrades to the 540. The differences are as follows:
Handguards – upper handguard on the Manurhin is retained by the gas tube and handguard cap, and the lower handguard on the Manurhin is retained by the handguard cap and via spring-loaded detents that lock into the upper receiver. Whereas the FAMAE handguards are locked together and retained by the front receiver pin and handguard cap.
Bipod attachment – The Manurhin has a different type of bipod attachment point than on the FAMAE. Not sure if Manurhin made bipods will work on the FAMAE. Will update once I get confirmation.
Magazine – The Manurhin made 540s use a proprietary steel magazine. The FAMAE 540s use the same polymer magazines as the Sig 550 series of rifles. Still unsure if Manurhin 540 magazines will still function in the FAMAE 540, but I was told that they won’t. Will update this later once I get confirmation.
Selector – The FAMAE 540s use an ambidextrous selector switch that is very similar to the selector switch on the Sig 550 series, whereas the Manurhin made 540s use a different style of selector switch.
Take down pins – The takedown pins on the FAMAE 540s are of the same design as on the Sig 550 series, and the Manurhin takedown pins are a more simple design, and retained by a spring inside the lower receiver.
Bolt Carrier – The FAMAE 540s use a carrier similar to the Sig 550 series where you push down on a lever to remove the charging handle, whereas on the Manurhin you push rearward on a serrated button to remove the charging handle.
Rear sight – The FAMAE and Manurhin rear sight is nearly identical, except that the FAMAE sight has 100m, 200m, 300m and 500m settings, wheras the Manurhin 540s have 50m, 100m, 200m and 300m settings. These sights are interchangeable between the Manurhin and FAMAE made rifles.
Buttpad – FAMAE uses the longer buttpad on the 540 rifles (same as on the 542). Whereas the Manurhin made rifles have the shorter curved buttpad. These are interchangeable.
Finish – The Manurhin rifles are parkerized, and the FAMAE rifles are parkerized then painted with what seems to be some type of moly-resin coating.
Barrel Profile – Still awaiting confirmation of whether the barrel profile underneath the handguards on the FAMAE rifle matches that of the Manurhin, or if it is a heavier profile like the 550 series.
The 540 in conflict zones around the world
The 540 series of rifle has seen use in conflict zones all over the world. Here are some pics from use in the field.
France – FFL
Ivory Coast
Lebanon
Angola
Central African Republic
Chad
Guinea
Nigeria
I’ll try to keep this updated as much as I can, and please point out any errors that you see so that they can be corrected. Thanks!
Background / History
The Sig 540 rifle has a long-stroke piston, gas-operated, rotating bolt operating mechanism and utilizes stamped steel for the receiver. It was developed in the 1970s as a potential replacement for the STGW 57 rifle in Swiss military service. Ultimately the Sig 550 series (a modified version of the 540 series) was chosen as the replacement service rifle for the Swiss military. Sig licensed production of the 540 series to Manurhin in France and FAMAE in Chile. ERE Systems imported semi-automatic only versions from FAMAE in Chile into Canada, and they are currently classified as non-restricted/restricted. The semi-auto FAMAE model designations are as follows:
SG 540-1 – 5.56mm 18.6” barreled rifle
SG 542-1 – 7.62mm 19.5” barreled rifle
SG 543-1 – 5.56mm 11.8” barreled rifle
Parts & Accessories
Magazines - for the FAMAE 540 and 543 are interchangeable with the Sig/SAN 550. They come in 5, 20, and 30rnd bodies (pinned to 5rnds in accordance with Canadian law). Manufactured by Sig/SAN in Switzerland, and by Dominion Defence.
Spare factory parts - are available, although there is not a wide variety of parts that are available. Spare barrel, bolts, bolt carriers, extractors, extractor springs, firing pins, and stocks have been made available for sale by Calgary Shooting Center and Tactical Imports.
Scope mounts - are available. These are quick attach/detach picatinny rails that mount to the rear sight block and front receiver lug.
Bipods - are also available. They attach to the bottom lug on the handguard cap and fold underneath the handguard.
Side folding stocks - are available and are easily replaced by removing the buttstock screw from the fixed stock and replacing the fixed stock with the folding stock assembly, then re-installing the buttstock screw.
Aftermarket magazine conversion block - for the 540/543 allows for the use of most STANAG magazines.
Aftermarket side-folding stock block - allows for the use of AR15 stocks on the 540/543. GS Designs also has an ACR stock block adapter.
Bayonet - attaches to the flash hider.
Maintenance / cleaning
Stripping for Maintenance
1. Make sure the rifle is unloaded and remove the magazine
2. Remove rear pivot pin
3. Push down on the lever on the bolt carrier, and remove the charging handle
4. Withdraw the bolt carrier and bolt. Rotate the bolt counter-clockwise and remove it from the carrier.
5. Remove Front pivot pin
6. Remove handguards by pushing the lower handguard to the rear, detaching it from the upper handguard.
7. With a screwdriver, rotate the bolt on the gasblock so that the “arrow” points towards the muzzle. Then slide the gasblock forward and rotate it 180 degrees.
8. Remove the gas piston and return spring.
9. Remove the gas tube.
Also, please see the video from ERE systems for how to field strip the rifle:
Field Stripping A FAMAE Rifle (eresystems.com)
Complete Strip
1. Using a pin punch, remove the roll pin from the left side of the selector switch, then withdraw the remainder of the selector from the right side of the lower receiver.
2. Remove the trigger pin, and withdraw the trigger assembly from the lower receiver.
3. Pull the hammer spring rearward and lift the assembly up and out of the lower receiver.
4. Remove the pin retaining clip
5. Remove the hammer pin, and withdraw the hammer from the lower receiver.
6. Unscrew the pistol grip screw and remove the pistol grip
7. Unscrew the adjustable trigger spring.
8. Unscrew the buttstock screw and remove the buttstock.
9. Unscrew the buttcap screw to remove the buttcap and sling loop assembly.
10. Remove pins from the flash hider and remove the flash hider from the barrel.
11. Remove the gas block assembly from the barrel
12. Using a pin punch, remove the roll pin from the gas selector.
13. Remove the gas selector assembly and gas plug from the gasblock.
14. Remove the spring clip from the locking bolt on the gasblock, then remove the locking bolt.
15. Unscrew the front sight from the gasblock, then lift upward to withdraw the front sight adjustment screw from the gasblock.
16. Remove the pins from the handguard cap and remove the handguard cap from the barrel.
17. Unscrew the rear sight from the rear sight block. Lift upwards on the rear sight adjustment screw and withdraw it from the rear sight block.
18. Remove the bolt hold open spring, then remove the bolt hold open from the upper receiver.
19. Remove the barrel from the upper receiver.
Adjusting the trigger
Using a 6mm and 4mm wrench, turn either the trigger pad (A) or the nut (B) clockwise to shorten the trigger pull distance, or turn counter-clockwise to lengthen the trigger pull distance. Displayed is what is assumed to be the “factory” setting.
Accuracy
Accuracy expectations should be the same as any other 18"-20" non-free floated barrel. See below of typical groupings at 100yards with the factory iron sights and xm193 ammo.
Reliability / Known Issues
Loose flash hider – Some rifles have a flash hider that is able to move slightly, and this has the potential to affect accuracy. This seems to mostly be a tolerancing issue, since the barrel has cuts made for the flash hider pins before the flash hider is installed. This can be slightly corrected by peening the cuts on the barrel in order to displace some steel, which will then tighten up the flash hider when the pins are re-installed.
Loose gas block - Some rifles also have a gas block that is able to move slightly, and this has the potential to affect accuracy, especially if using the iron sights. This seems to mostly be a tolerancing issue, since the barrel has a cut made for the gas block pin before the gas block is installed. This can be slightly corrected by peening the cuts on the barrel in order to displace some steel, which will then tighten up the gas block when the pin is rotated back into the locked position.
Paint chipping on part of the ejection port – fairly common. The problem is only cosmetic, since the area where the brass cases are hitting is spot heat treated and will not wear out over time.
Magazine issues – some have reported reliability issues with various magazines.
Bolt hold-open spring – some reports of the bolt hold-open spring breaking when removing it from the upper receiver.
Finish – The FAMAE rifles seem to be parkerized, then painted with a moly-resin paint. While this is a very durable finish, it can leave some parts very smooth feeling where they are not intended to be (ie, knurling on the rear sight and on the selector switch). Underneath the paint, the rifle has a very un-even parkerizing finish to it. I got Nick at Vulcan Gun Refinishing to re-park mine and he did an amazing job. I highly, highly recommend his services.
Differences between Manurhin and FAMAE 540s
While the Manurhin made 540s stuck to the original Sig design, FAMAE made some slight upgrades to the 540. The differences are as follows:
Handguards – upper handguard on the Manurhin is retained by the gas tube and handguard cap, and the lower handguard on the Manurhin is retained by the handguard cap and via spring-loaded detents that lock into the upper receiver. Whereas the FAMAE handguards are locked together and retained by the front receiver pin and handguard cap.
Bipod attachment – The Manurhin has a different type of bipod attachment point than on the FAMAE. Not sure if Manurhin made bipods will work on the FAMAE. Will update once I get confirmation.
Magazine – The Manurhin made 540s use a proprietary steel magazine. The FAMAE 540s use the same polymer magazines as the Sig 550 series of rifles. Still unsure if Manurhin 540 magazines will still function in the FAMAE 540, but I was told that they won’t. Will update this later once I get confirmation.
Selector – The FAMAE 540s use an ambidextrous selector switch that is very similar to the selector switch on the Sig 550 series, whereas the Manurhin made 540s use a different style of selector switch.
Take down pins – The takedown pins on the FAMAE 540s are of the same design as on the Sig 550 series, and the Manurhin takedown pins are a more simple design, and retained by a spring inside the lower receiver.
Bolt Carrier – The FAMAE 540s use a carrier similar to the Sig 550 series where you push down on a lever to remove the charging handle, whereas on the Manurhin you push rearward on a serrated button to remove the charging handle.
Rear sight – The FAMAE and Manurhin rear sight is nearly identical, except that the FAMAE sight has 100m, 200m, 300m and 500m settings, wheras the Manurhin 540s have 50m, 100m, 200m and 300m settings. These sights are interchangeable between the Manurhin and FAMAE made rifles.
Buttpad – FAMAE uses the longer buttpad on the 540 rifles (same as on the 542). Whereas the Manurhin made rifles have the shorter curved buttpad. These are interchangeable.
Finish – The Manurhin rifles are parkerized, and the FAMAE rifles are parkerized then painted with what seems to be some type of moly-resin coating.
Barrel Profile – Still awaiting confirmation of whether the barrel profile underneath the handguards on the FAMAE rifle matches that of the Manurhin, or if it is a heavier profile like the 550 series.
The 540 in conflict zones around the world
The 540 series of rifle has seen use in conflict zones all over the world. Here are some pics from use in the field.
France – FFL
Ivory Coast
Lebanon
Angola
Central African Republic
Chad
Guinea
Nigeria
I’ll try to keep this updated as much as I can, and please point out any errors that you see so that they can be corrected. Thanks!
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