FAMAE 540 FAQ: Why its cool, and you should own one

beltfed said:
Do the 5.56 / 222 receivers offer more 'rigidity' that translates to more inherent accuracy downrange? The bolt carrier and bolt essentially 'float' in the upper receiver and glide along the rails. Ultimately the bolt locks into the barrel and there should be really little the receiver is doing to support firing - not so different than the AR at that point, and AR receivers are just cases that support the firing bits, be it the 10 or 15. It's for that reason I don't buy into the receiver flex theory.
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Fortunately, the Receiver Flex theory does not require your buy-in to be valid and relevant to the discussion of the SG 542's worse than average accuracy. Just because primary lock-up occurs between the Bolt and Barrel Extension does not mean that the Receiver does not receive and transmit the recoil forces generated by the firing of the cartridge. Indeed, the full force of recoil is transmitted along the length of the Receiver walls, through the Buttstock, to the firer's shoulder. This force increases with the size of the cartridge fired, and it does not take a leap of scientific logic to understand that recoil forces can twist and flex a sheet metal Receiver, particularly one where the gauge of steel used is quite thin compared to the SG 542's contemporaries such as the G3 and its successor the SIG 751 SAPR.

Watch the linked video of an AK-74 firing and tell me that there is no Receiver flex going on there. Watch the upwards and downwards motion of the buttstock and ask yourself where that is coming from....

https://www.youtube.com/watch?v=HGivoWD9OvQ
 
Bartok5 said:
Just because primary lock-up occurs between the Bolt and Barrel Extension does not mean that the Receiver does not receive and transmit the recoil forces generated by the firing of the cartridge. Indeed, the full force of recoil is transmitted along the length of the Receiver walls, through the Buttstock, to the firer's shoulder. This force increases with the size of the cartridge fired, and it does not take a leap of scientific logic to understand that recoil forces can twist and flex a sheet metal Receiver, particularly one where the gauge of steel used is quite thin compared to the SG 542's contemporaries such as the G3 and its successor the SIG 751 SAPR.

Watch the linked video of an AK-74 firing and tell me that there is no Receiver flex going on there. Watch the upwards and downwards motion of the buttstock and ask yourself where that is coming from....

https://www.youtube.com/watch?v=HGivoWD9OvQ
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I'm not suggesting receiver flex doesn't happen, I'm simply not convinced that the flex imparts negative effect on down range accuracy, as the bullet has left the barn as it were by the time the flex happens.


Bartok5 said:
Fortunately, the Receiver Flex theory does not require your buy-in to be valid and relevant to the discussion of the SG 542's worse than average accuracy.
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Are you as condescending in real life as you are behind the keyboard? Ex Patricia officer...I'm guessing yes.

It may not require my buy-in, but it should follow logic and physics to some degree.
Science - it's like magic, but real....
 
beltfed said:
I'm not suggesting receiver flex doesn't happen, I'm simply not convinced that the flex imparts negative effect on down range accuracy, as the bullet has left the barn as it were by the time the flex happens.

Are you as condescending in real life as you are behind the keyboard? Ex Patricia officer...I'm guessing yes.

It may not require my buy-in, but it should follow logic and physics to some degree.
Science - it's like magic, but real....
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Well, we'll simply have to agree to disagree as to whether or not the "bullet has left the barn" before the recoil impulse is imparted to the sheet metal receiver of the SG 542.

Good guess as to my background though! You are right - I was unnecessarily condescending in my response. I apologize for my dismissive tone, which in hindsight was uncalled for. Although we clearly differ in our understanding of logic and physics as they apply to firearms, there is no need for a lack of civility in our discourse. My bad.
 
No apology needed, but appreciated none the less;) Likewise you have mine for being a smart a$$.

If we consider a typical barrel measuring 20" (1.67ft), and a muzzle velocity of 2400 ft./Second, account for 'some sort of delay' (fractions of a microsecond) from ignition to muzzle, the bullet travels approximately 1400 equivalent barrel lengths in that second which is .07 milliseconds.
From the below article "...In steel, the speed of sound is very close to 0.227 inches per microsecond, or about 18916 FPS. A wave will travel from the receiver to the muzzle in the barrel in about 0.12 mS. It can make around 4 or 5 round trips before the bullet leaves [the barrel]..."

There would be a delay from point of detonation to the brass expanding in the chamber and imparting force on the chamber walls that would then impart some (same?) force on the receiver (again, measured in microseconds); the 'annular wave' I think talked about in the below articles. I suspect that most of the force being generated onto the receiver that we see is the result of the gas and recoil system operating as it should, but this pressure pulse surely impacts (significantly?) on the receiver and could be cause for inconsistencies as you suggest.

There is little to be done about this pressure pulse; most certainly at the receiver, as modifications would be practically futile, but at the barrel, you would be left with modifications to ammunition to account for it.

https_://www.shootingsoftware.com/barrel.htm

http_://www.the-long-family.com/OBT_paper.htm
 
WQ9FK2k.jpg
 
Have anyone tried ERE Systems AR magazine adapters? Looking to get either one.

Also, any problem ordering a magazine adapter from the ERE Systems website?
 
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Goo98 said:
calgary shooting center has bipods in stock

hint hint
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Fixed-height bipods pretty much suck. They're either too high or too low, uneven or whatever. The lack of adjustability severely limits the applicability of such bipods. In the case of the FAMAE rifles, the utility of the bipod is further compromised by the poor integration of the Legs into the Handguards when folded. The wobble and rattle around between the mounting point on the Bayonet Boss and where they sort of mate with the Handguards at the "Foot" end of the bipod legs.

All aspects considered, the Bipod on the FAMAE rifles is a poorly-conceived afterthought that is best left in the parts bin as $250 of excess weight...
 
Anyone thought of trimming the stock locking lug below the charging handle? My goodness it comes outta no where and messes up your hand right quick
 
Moser40s&w said:
Anyone thought of trimming the stock locking lug below the charging handle? My goodness it comes outta no where and messes up your hand right quick
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If I keep mine I'm tempted to cut it right off, I dont really need my stock to lock folded and underhand charging is near impossible with it sticking out like that
 
I agree. Thinking about trying to design a rear stock adapter with a 1913 rail to accept all the stocks out there that mount to a rail. Most of those stock have the folding lock in the swivel point
 
Just screwing around with a zhukov stock.
It's actually very crooked when unfolded(in this position), but if lined up at the rear properly, it looks like when folded it'll sit right blow the ejection port & charging handle.
Width wise, very similar to the receiver.

Could be a very clean alternative stock for famae users.

H87J8VX.jpg
 
lone-wolf said:
Just screwing around with a zhukov stock.
It's actually very crooked when unfolded(in this position), but if lined up at the rear properly, it looks like when folded it'll sit right blow the ejection port & charging handle.
Width wise, very similar to the receiver.

Could be a very clean alternative stock for famae users.

H87J8VX.jpg
Click to expand...

Could you please post a pic of the stock not folded (as in straight) or possibly a top down view to see how straight it is in-line with the receiver and barrel? That would be super helpful as the original stock is terrible and I would like a replacement also. Probably most of would.
 
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