Plastic vs Steel

MUGEN

MUGEN

CGN Regular
Rating - 100%
10   0   0
Location
Ontario
Can someone help me understand why more and more modern firearms frames made of "Plastic" instead of Steel and/ or aluminum? like the frames of ACR, Tavor, HK Sl8/ G36, AUG etc...
What is the advantage and disadvantage other than plastic is more rust proof, in teams of functions, cost of manufacturing?
 
Polymers are easier and cheaper to manufacture. Features are generally easier to put on polymer frames such as checkering where they would have to be machined on steel. It's also lighter than steel and more corrosion/environment resistant.
 
modern glass and carbon re-enforced plastic is much more resistant to stress fatigue also. Where Aluminum can develop stress fractures over time (hence why Aircraft parts are so tightly regulated) plastic will only weaken and break if its heat and/or strength limits are exceeded.


Most modern polymer made rifles have steel re-enforcements as well, to add rigidity and wear resistance.

ETA

I see you mentioned the ACR, keep in mind its only the grip frame/trigger group that is made of plastic, the receiver is made of 7 series Aluminum (same as AR15 and XCR). HK has been doing this for decades with the roller locked guns: AKA G3/HK33/MP5. All the modern grip frame/trigger groups are made of plastic with steel re-enforcements.

The FN Scar is the same way, with the trigger group/grip/lower made of plastic, and the upper made of extruded Aluminum.
 
They use plastics wherever they can since most modern guns use Gene Stoner\'s idea of locking the bolt directly to recesses in the barrel extension. This alleviates any stress on the receiver (ignoring the barrel trunnion) enabling engineers to make lightweight stamped steel or plastic receivers.
 
Properly done, plastic frames will outlast steel ones. Depending on the orginal steel design, they may do it by factors of 3 to 1 or better if the propper materials are chosen. With aluminum, the numbers just get better, as other then lightness, it's not really an ideal material. Plastic's only real problem is curb appeal, plastic = cheap.

That being said, i prefer steel guns :redface: but i'm gettin older i guess.
 
Most metals have a tendency to undergo plastic deformation without failing, particularly where the barrel is threaded to the receiver and depending on the model of gun, where the bolt engages the receiver. This is why headspace is critical in older rifles like the FAL.
 
Steel and plastic weren't the only choices.
Zinc (match box toys car) is always very good for pistol frame.

For some strange reason, US government don't want guns that have cheap zinc frame. We now have expensive engineered plastic guns.
 
As has been stated already the reasons are largely performance based. In some cases the overall cost can be higher depending on the part and application.

Modern high quality polymers generally don't corrode, are generally lighter then aluminum, are generally unaffected by temperature fluctuations and provide a better performance in relation to impact and torsion stress. One really nice thing about polymers is that they are poor conductors so if its cold/hot outside and you put your face on a polymer buttstock there is a higher level of comfort, traditionally this was accomplished with wood but wood has its own set of issues.

FYI polymer pistol frames are not only much more affordable to make they offer superior performance to steel in almost every way. Except certain competition applications where people want the weight. The glock is a very affordable gun if you are mil/LEO, especially considering where its made.
 
You must log in or register to reply here.
Back
Top Bottom