SA M-7
Arsenal Inc is the home of the only standard production milled AK variant ever made in the US under license and specifications of a true former Com Bloc AK manufacturer (Arsenal Co. of Bulgaria). What I speak of are the Arsenal Inc of Nevada SAM series rifles. That being the case, even though I had posted this information on another well known AK website, I also felt it would be appropriate to post it here. In addition, I've also included the advantages of using forged and milled AK fire control groups over other methods of manufacturing the sets:
There has been much discussion on the issue of AK receiver manufacturing methods. When it comes right down to it, as long as a stamped, forged and milled, or milled from barstock receiver is made using the correct quality standards, then any of these methods of manufacture will produce a very good AK receiver.
With that being said, there are advantages attached to a quality forged and milled AK receiver (which is the method Arsenal Inc uses to produce their SAM, SAS, and RPK series milled receivers). The Arsenal Inc milled receiver is made using the same material and specifications as used by the world famous Bulgarian firm, and is even licensed to do so by them.
The forged and milled advantages were expressed to me by a Representative of a "VERY" well respected AK firm. A firm that has made, does make, and will continue to make money by offering "quality" AK's using both the milled and stamped receiver methods. He did not want to have his name exposed (and it won't be). The most probable reason for him not making his statement public, is that it would shed a more favorable light on one method of AK receiver manufacture over another, which would be a bad idea for a company that has, does, or will make both method receiver AK's for the buying public. Making one method sound better than the other may not be good business (since they want to be able to sell both types). Even so, he was honest enough to give me the most important reasons why a milled receiver has some advantages over a stamped one. In blue, here is "EXACTLY" how he put it:
MILLED
General statement: A properly manufactured MILLED receiver is superior in all aspects to a stamped receiver, for the following reasons:
1. Rigidity. It doesn’t get any more rigid than this.
2. Strength. Considerably more tensile, shear, cross stress strength. Milled, forged steel is just plain stronger and more durable than any stamped assembly (regardless of how “thick” the stamping is).
3. Part/action alignment. The part and action alignment is consistent throughout the life cycle of the rifle. Being milled from one piece, there is nothing in the frame to loosen or shift out of alignment.
4. Much more stable platform. Fixed mating surfaces ensure alignment and function.
5. Longer service life. Stronger, more rigid, consistently aligned frame retards part wear and extends service life of action parts.
Disadvantage: Milled receiver AK is heavier than stamped receiver type. This is offset by slightly more controllability and less recoil from heavier weapon.
STAMPED
General statement: STAMPED receiver rifles are less costly to manufacture and thus can be offered for a lower price. Other advantages over MILLED receiver rifles are:
1. Lower weight.
2. Higher production due to reduced manufacturing time.
As one reads the above list, one can pretty much gather that they probably equally apply when comparing the stamped steel receiver to the milled from barstock type. My guess would be that with everything else being equal, the milled from barstock and milled from forgings receivers are more closely comparable to each other. Any differences are probably very miniscule between these two types of receivers.
I would say that a milled from barstock receiver (like those made by the Firing Line) would have the same advantages over the stamped method receiver that the milled from forgings has over them.
We know that most stamped steel AK receivers are manufactured using a 1mm thick stamped steel shell. When foreign countries use the stamped steel method for their machine gun designated AK's (the RPK), they use a heavier guage stamped steel receiver. This is done to add receiver strength to a firearm that will most likely see harder use from more constant firing. For the same reason that the RPK uses a heavier guage receiver (for it's added strength), the Arsenal USA company of Houston Texas (which is not affiliated with the Arsenal Inc of Nevada or Arsenal Co of Bulgaria firms) also decided to go with a heavier guage (1.6mm thick) stamped steel receiver for their new AK series offerings. This decision not only gave them the number one position in the US as having the strongest American made stamped steel receiver, but also puts them in the position to use this heavier and stronger receiver shell in AK's chambered in more powerful calibers without too much worry of whether or not the receiver shell will be able to handle it. Of course if they use these heavier receiver shells for more powerful chamberings than are usually associated with AK's, they will most likely require stronger front and rear trunnions to meet their new caliber needs.
***From the Arsenal USA of Texas website, (their reason on why they decided to go with the thicker 1.6mm stamped steel receiver shell):
"These receivers we feel are superior to any US stamped receiver and have no comparison with any of its type ever offered before in this country.
Our receiver shells are 1.6mm thick. Standard shells offered in the US are only 1.0mm thick. The reason for this is as follows: They are the strongest shells (meaning strongest stamped steel receiver shell), rivaling the strength of the milled type."
In that statement, Arsenal USA is clearly pointing to their 1.6mm thick receiver as being stronger than any of the other thinner stamped steel receivers being offered in the US. While they are very clear and confident about the strength advantages that their new receiver has over other stamped steel competitors, their wording is very careful when they make any comparisons with Milled receivers. Again, they confidently state how they feel that their new receivers are superior to any of the other American made stamped steel receivers, but only go as far as stating that their new receivers rival the milled type.
*Definition of the word(s) rival/rivaling: One who "attempts" to equal or surpass another, or who pursues the same object as another.
***From the Small Arms Review website, (the following is quoted from one of Jeff W. Zimba's articles):
"once you are set up to build stamped receivers it is not unreasonable to have the ability to manufacture hundreds
of units per day. On the opposite end of this spectrum it may take several hours to CNC mill only one receiver"
Of course it's not a new revelation that lower cost and shorter production time are some of the most common reasons known for manufacturers prefering the stamped over milled method. While Mr. Zimba's comparison of stamped vs. milled production time "may" be somewhat exagerated, there is no doubt that the basis of his statement is completely true. The forged and milled receiver method takes longer to produce finished product than using the stamped receiver method.
The information below is more appropriate when comparing the forged and milled receiver to a milled from barstock receiver.
***From the "forgefair dot com" website:
Forging refines the grain structure and develops the optimum grain flow, which imparts desirable directional properties such as tensile strength, ductility, impact toughness, fracture toughness and fatigue strength.
***From the "How Stuff Works" website:
The advantage of forging is that it improves the strength of the metal by aligning and stretching the grain structure. A forged part will normally be stronger than a casting or a machined piece.
***Also from the "How Stuff Works" website:
Q.Why choose a forged instead of a machined component?
A.Forging improves the grain flow of metal and therefore a forged component will always be stronger than a machined one. Machining is inherently destructive to the integrity of the metal.
***From the "Queen City Forging" website:
Machined bar and plate may be more susceptible to fatigue and stress corrosion because machining cuts material grain pattern. In most cases, forging yields a grain structure oriented to the part shape, resulting in optimum strength, ductility and resistance to impact and fatigue.
***From the "SniperCountry dot com" website:
Concerning forged vs. billet machined vs. cast;
if all else is equal (steel alloy choice, alloy purity,
reciever dimensions, heat treatment, etc) then forging,
if done right, has a strength and possibly a stiffness
advantage.
"Most" folks that end up building their own semi auto AK (or that have one built up by a custom gunsmith), will end up having a stamped receiver gun. "Most" folks that go out and buy an off the rack standard production post ban AK, will also likely end up with a more commonly found stamped receiver AK specimen.
The more common ownership of stamped steel AK's is probably one of the main reasons for us seeing so many folks coming in to express what they feel to be the ultimate merits of a stamped steel receiver, while literally trying to make the forged and milled variant's look totally obsolete and inferior. For similar reasons one can probably understand why some AK manufacturing countries promote their stamped method versions as being the best available in all regards, since most countries no longer produce the heavier and more expensive milled AK's. It sounds like the reasonable thing to do, to promote the only method AK one currently produces, which happens to be the lighter less expensive to manufacture stamped steel variants.
When the full truth is exposed, one can see that the biggest advantage of a stamped steel AK receiver still remains it's lower weight and time/cost savings during manufacture.
Photo showing a raw AK receiver forging (bottom), and a completely milled out AK receiver forging (top):
http://img13.exs.cx/img13/2730/Image92.gif
Here is a photo of an Arsenal Co of Bulgaria forged and milled AK receiver. The material & specifications used in Bulgaria to manufacture these receivers, are the same material & specifications used by Arsenal Inc of Nevada to manufacture their's:
http://img47.exs.cx/img47/8912/Image10.gif
Notice the receiver's light gray color?..... That is a phosphate finish that is not only found under the black paint of an Arsenal Co of Bulgaria rifle, but also found under the black painted finish of the Arsenal Inc of Nevada guns.
This photo shows a Bulgarian forged and milled receiver with it's lower buttstock tang & two rivets before installation:
http://img48.exs.cx/img48/1056/Image11.gif
So if someone tries to ridicule you for choosing a milled receiver AK variant, hold your head up high, you have nothing to be ashamed of ;)
On a related note, forged and milled semi auto fire control groups are usually found in such guns as the Bulgarian milled receiver SLR-95, SLR-95MB, SA-93, some SLR-101's, etc, and in the American made Arsenal Inc milled receiver SAM, SAS, and RPK series.
Just as forged and milled method AK receivers are considered to be the best, so too are forged and milled AK fire control components (when compared to other popular methods of making FCG's). Here in blue lettering is the way an Arsenal Inc Representative (Arsenal-DPC) put it:
"There are several methods to fabricating steel parts for high impact applications. They are (in descending order of quality):
1-Milled Forgings (the method used by Arsenal Inc): A heated billet is forced under pressure into the general shape of the end product, resulting in maximum density with multidirectional “grain” or elongation of the crystalline structure, conforming to the contours of the part. The part is then precision CNC machined into the finished product. Finally, the part is heat treated to exact specification, which further strengthens the part. The end result, although expensive to manufacture, results in the strongest and most precise part available with today’s technology.
2-Milled from a solid billet: Although considerably less costly, this process is inferior to milled forgings as the grain, is directional (flowing in one direction or plane); therefore the part has a weaker structural integrity.
3-Casting: Although, for reasons of economy, this method is widely used, it does not offer the strength of parts milled from forgings or the precision of CNC machining
4-MIM (metal injection molding): For reasons of economy this method is also widely used. Again, it does not offer the strength of parts milled from forgings or the precision of CNC machining"
A photo showing semi auto AK fire control components in their raw forged form, right next to forged components that have been milled to final specifications (A-Trigger B-Disconnector C-Hammer):
http://img6.exs.cx/img6/4071/Image63.gif
So there you have it, the forged and milled advantage. Just another reason why the Arsenal Inc SAM series is the best value AK on the market :)
There has been much discussion on the issue of AK receiver manufacturing methods. When it comes right down to it, as long as a stamped, forged and milled, or milled from barstock receiver is made using the correct quality standards, then any of these methods of manufacture will produce a very good AK receiver.
With that being said, there are advantages attached to a quality forged and milled AK receiver (which is the method Arsenal Inc uses to produce their SAM, SAS, and RPK series milled receivers). The Arsenal Inc milled receiver is made using the same material and specifications as used by the world famous Bulgarian firm, and is even licensed to do so by them.
The forged and milled advantages were expressed to me by a Representative of a "VERY" well respected AK firm. A firm that has made, does make, and will continue to make money by offering "quality" AK's using both the milled and stamped receiver methods. He did not want to have his name exposed (and it won't be). The most probable reason for him not making his statement public, is that it would shed a more favorable light on one method of AK receiver manufacture over another, which would be a bad idea for a company that has, does, or will make both method receiver AK's for the buying public. Making one method sound better than the other may not be good business (since they want to be able to sell both types). Even so, he was honest enough to give me the most important reasons why a milled receiver has some advantages over a stamped one. In blue, here is "EXACTLY" how he put it:
MILLED
General statement: A properly manufactured MILLED receiver is superior in all aspects to a stamped receiver, for the following reasons:
1. Rigidity. It doesn’t get any more rigid than this.
2. Strength. Considerably more tensile, shear, cross stress strength. Milled, forged steel is just plain stronger and more durable than any stamped assembly (regardless of how “thick” the stamping is).
3. Part/action alignment. The part and action alignment is consistent throughout the life cycle of the rifle. Being milled from one piece, there is nothing in the frame to loosen or shift out of alignment.
4. Much more stable platform. Fixed mating surfaces ensure alignment and function.
5. Longer service life. Stronger, more rigid, consistently aligned frame retards part wear and extends service life of action parts.
Disadvantage: Milled receiver AK is heavier than stamped receiver type. This is offset by slightly more controllability and less recoil from heavier weapon.
STAMPED
General statement: STAMPED receiver rifles are less costly to manufacture and thus can be offered for a lower price. Other advantages over MILLED receiver rifles are:
1. Lower weight.
2. Higher production due to reduced manufacturing time.
As one reads the above list, one can pretty much gather that they probably equally apply when comparing the stamped steel receiver to the milled from barstock type. My guess would be that with everything else being equal, the milled from barstock and milled from forgings receivers are more closely comparable to each other. Any differences are probably very miniscule between these two types of receivers.
I would say that a milled from barstock receiver (like those made by the Firing Line) would have the same advantages over the stamped method receiver that the milled from forgings has over them.
We know that most stamped steel AK receivers are manufactured using a 1mm thick stamped steel shell. When foreign countries use the stamped steel method for their machine gun designated AK's (the RPK), they use a heavier guage stamped steel receiver. This is done to add receiver strength to a firearm that will most likely see harder use from more constant firing. For the same reason that the RPK uses a heavier guage receiver (for it's added strength), the Arsenal USA company of Houston Texas (which is not affiliated with the Arsenal Inc of Nevada or Arsenal Co of Bulgaria firms) also decided to go with a heavier guage (1.6mm thick) stamped steel receiver for their new AK series offerings. This decision not only gave them the number one position in the US as having the strongest American made stamped steel receiver, but also puts them in the position to use this heavier and stronger receiver shell in AK's chambered in more powerful calibers without too much worry of whether or not the receiver shell will be able to handle it. Of course if they use these heavier receiver shells for more powerful chamberings than are usually associated with AK's, they will most likely require stronger front and rear trunnions to meet their new caliber needs.
***From the Arsenal USA of Texas website, (their reason on why they decided to go with the thicker 1.6mm stamped steel receiver shell):
"These receivers we feel are superior to any US stamped receiver and have no comparison with any of its type ever offered before in this country.
Our receiver shells are 1.6mm thick. Standard shells offered in the US are only 1.0mm thick. The reason for this is as follows: They are the strongest shells (meaning strongest stamped steel receiver shell), rivaling the strength of the milled type."
In that statement, Arsenal USA is clearly pointing to their 1.6mm thick receiver as being stronger than any of the other thinner stamped steel receivers being offered in the US. While they are very clear and confident about the strength advantages that their new receiver has over other stamped steel competitors, their wording is very careful when they make any comparisons with Milled receivers. Again, they confidently state how they feel that their new receivers are superior to any of the other American made stamped steel receivers, but only go as far as stating that their new receivers rival the milled type.
*Definition of the word(s) rival/rivaling: One who "attempts" to equal or surpass another, or who pursues the same object as another.
***From the Small Arms Review website, (the following is quoted from one of Jeff W. Zimba's articles):
"once you are set up to build stamped receivers it is not unreasonable to have the ability to manufacture hundreds
of units per day. On the opposite end of this spectrum it may take several hours to CNC mill only one receiver"
Of course it's not a new revelation that lower cost and shorter production time are some of the most common reasons known for manufacturers prefering the stamped over milled method. While Mr. Zimba's comparison of stamped vs. milled production time "may" be somewhat exagerated, there is no doubt that the basis of his statement is completely true. The forged and milled receiver method takes longer to produce finished product than using the stamped receiver method.
The information below is more appropriate when comparing the forged and milled receiver to a milled from barstock receiver.
***From the "forgefair dot com" website:
Forging refines the grain structure and develops the optimum grain flow, which imparts desirable directional properties such as tensile strength, ductility, impact toughness, fracture toughness and fatigue strength.
***From the "How Stuff Works" website:
The advantage of forging is that it improves the strength of the metal by aligning and stretching the grain structure. A forged part will normally be stronger than a casting or a machined piece.
***Also from the "How Stuff Works" website:
Q.Why choose a forged instead of a machined component?
A.Forging improves the grain flow of metal and therefore a forged component will always be stronger than a machined one. Machining is inherently destructive to the integrity of the metal.
***From the "Queen City Forging" website:
Machined bar and plate may be more susceptible to fatigue and stress corrosion because machining cuts material grain pattern. In most cases, forging yields a grain structure oriented to the part shape, resulting in optimum strength, ductility and resistance to impact and fatigue.
***From the "SniperCountry dot com" website:
Concerning forged vs. billet machined vs. cast;
if all else is equal (steel alloy choice, alloy purity,
reciever dimensions, heat treatment, etc) then forging,
if done right, has a strength and possibly a stiffness
advantage.
"Most" folks that end up building their own semi auto AK (or that have one built up by a custom gunsmith), will end up having a stamped receiver gun. "Most" folks that go out and buy an off the rack standard production post ban AK, will also likely end up with a more commonly found stamped receiver AK specimen.
The more common ownership of stamped steel AK's is probably one of the main reasons for us seeing so many folks coming in to express what they feel to be the ultimate merits of a stamped steel receiver, while literally trying to make the forged and milled variant's look totally obsolete and inferior. For similar reasons one can probably understand why some AK manufacturing countries promote their stamped method versions as being the best available in all regards, since most countries no longer produce the heavier and more expensive milled AK's. It sounds like the reasonable thing to do, to promote the only method AK one currently produces, which happens to be the lighter less expensive to manufacture stamped steel variants.
When the full truth is exposed, one can see that the biggest advantage of a stamped steel AK receiver still remains it's lower weight and time/cost savings during manufacture.
Photo showing a raw AK receiver forging (bottom), and a completely milled out AK receiver forging (top):
http://img13.exs.cx/img13/2730/Image92.gif
Here is a photo of an Arsenal Co of Bulgaria forged and milled AK receiver. The material & specifications used in Bulgaria to manufacture these receivers, are the same material & specifications used by Arsenal Inc of Nevada to manufacture their's:
http://img47.exs.cx/img47/8912/Image10.gif
Notice the receiver's light gray color?..... That is a phosphate finish that is not only found under the black paint of an Arsenal Co of Bulgaria rifle, but also found under the black painted finish of the Arsenal Inc of Nevada guns.
This photo shows a Bulgarian forged and milled receiver with it's lower buttstock tang & two rivets before installation:
http://img48.exs.cx/img48/1056/Image11.gif
So if someone tries to ridicule you for choosing a milled receiver AK variant, hold your head up high, you have nothing to be ashamed of ;)
On a related note, forged and milled semi auto fire control groups are usually found in such guns as the Bulgarian milled receiver SLR-95, SLR-95MB, SA-93, some SLR-101's, etc, and in the American made Arsenal Inc milled receiver SAM, SAS, and RPK series.
Just as forged and milled method AK receivers are considered to be the best, so too are forged and milled AK fire control components (when compared to other popular methods of making FCG's). Here in blue lettering is the way an Arsenal Inc Representative (Arsenal-DPC) put it:
"There are several methods to fabricating steel parts for high impact applications. They are (in descending order of quality):
1-Milled Forgings (the method used by Arsenal Inc): A heated billet is forced under pressure into the general shape of the end product, resulting in maximum density with multidirectional “grain” or elongation of the crystalline structure, conforming to the contours of the part. The part is then precision CNC machined into the finished product. Finally, the part is heat treated to exact specification, which further strengthens the part. The end result, although expensive to manufacture, results in the strongest and most precise part available with today’s technology.
2-Milled from a solid billet: Although considerably less costly, this process is inferior to milled forgings as the grain, is directional (flowing in one direction or plane); therefore the part has a weaker structural integrity.
3-Casting: Although, for reasons of economy, this method is widely used, it does not offer the strength of parts milled from forgings or the precision of CNC machining
4-MIM (metal injection molding): For reasons of economy this method is also widely used. Again, it does not offer the strength of parts milled from forgings or the precision of CNC machining"
A photo showing semi auto AK fire control components in their raw forged form, right next to forged components that have been milled to final specifications (A-Trigger B-Disconnector C-Hammer):
http://img6.exs.cx/img6/4071/Image63.gif
So there you have it, the forged and milled advantage. Just another reason why the Arsenal Inc SAM series is the best value AK on the market :)