AR Sponsor
Posted: 5/28/2012 11:39:02 AM EDT
|
Does a true military 20" A4 upper have M4 cuts in the receiver?
Thanks, JH |
|
Quoted:
Op, do you mean feed ramps? If that is what you mean, no they don't. However having a 20" barrel with M4 feed ramps does not hurt anything. He said M4 cuts in the receiver. The receiver M4 cut is the extension of the M4 feed ramp. Sounds like he is shopping receivers. |
|
Quoted:
Quoted:
Quoted:
No, it doesnt First post nailed it. Many flat top 20 inch uppers for the consumer market do though. My BCM A4 clone has them. Its really just value added when since the A2 stock and long rifle gas system result in a slow carrier velocity. Yea BCM has them. My guess it is either to keep less stock(run every upper with m4 feed ramps instead of having them with and without them), marketing(people think they need them), or just they feel they can help when you really run the stuff hard. Palmetto sells uppers with 20inch fn barrels. They have m4 feed ramps on the barrel and upper as well even though fn's m16's don't. Palmetto orders the barrels that way so FN puts a barrel extension on it with them. |
|
Quoted:
Quoted:
Quoted:
Quoted:
No, it doesnt First post nailed it. Many flat top 20 inch uppers for the consumer market do though. My BCM A4 clone has them. Its really just value added when since the A2 stock and long rifle gas system result in a slow carrier velocity. Yea BCM has them. My guess it is either to keep less stock(run every upper with m4 feed ramps instead of having them with and without them), marketing(people think they need them), or just they feel they can help when you really run the stuff hard. Palmetto sells uppers with 20inch fn barrels. They have m4 feed ramps on the barrel and upper as well even though fn's m16's don't. Palmetto orders the barrels that way so FN puts a barrel extension on it with them. while its not needed its just an added benefit. |
|
Quoted:
Quoted:
Quoted:
Quoted:
No, it doesnt First post nailed it. Many flat top 20 inch uppers for the consumer market do though. My BCM A4 clone has them. Its really just value added when since the A2 stock and long rifle gas system result in a slow carrier velocity. Yea BCM has them. My guess it is either to keep less stock(run every upper with m4 feed ramps instead of having them with and without them), marketing(people think they need them), or just they feel they can help when you really run the stuff hard. Palmetto sells uppers with 20inch fn barrels. They have m4 feed ramps on the barrel and upper as well even though fn's m16's don't. Palmetto orders the barrels that way so FN puts a barrel extension on it with them. If you're not contractually obligated to build to the TDP which is for rifle feedramps, it just makes a lot more sense to use extended feedramps universally. For companies like PSA or BCM, it hardly makes sense to have two different set of uppers that you can build on based on demand. FWIW, 20" rifles probably don't sell as well as carbines of any stripe - imagine how frustrating it would be to have 100+ rifle uppers sitting around that you couldn't use to fill backorders on carbine uppers. Neverminding the discussion as to whether or not there is a practical "need" for them on a semi-auto rifle not firing M855, they neither hurt nothing on either a rifle or carbine, and are more or less demanded by the market. When building a "clone," there's little reason to worry about having them when the "spec" says they shouldn't. If you were that concerned about spec, you would be getting a Colt or FNMI part anyways, meaning it would be "right." If you just want an A4 upper that will look the part from a quality company that looks the part as well as functions, the extended feedramps will either not affect function at all, or make it marginally better - I've yet to hear of a case / circumstance in which extended feedramps actually negatively effect performance. ~Augee |
|
Quoted:
Quoted:
Quoted:
Quoted:
Quoted:
No, it doesnt First post nailed it. Many flat top 20 inch uppers for the consumer market do though. My BCM A4 clone has them. Its really just value added when since the A2 stock and long rifle gas system result in a slow carrier velocity. Yea BCM has them. My guess it is either to keep less stock(run every upper with m4 feed ramps instead of having them with and without them), marketing(people think they need them), or just they feel they can help when you really run the stuff hard. Palmetto sells uppers with 20inch fn barrels. They have m4 feed ramps on the barrel and upper as well even though fn's m16's don't. Palmetto orders the barrels that way so FN puts a barrel extension on it with them. If you're not contractually obligated to build to the TDP which is for rifle feedramps, it just makes a lot more sense to use extended feedramps universally. For companies like PSA or BCM, it hardly makes sense to have two different set of uppers that you can build on based on demand. FWIW, 20" rifles probably don't sell as well as carbines of any stripe - imagine how frustrating it would be to have 100+ rifle uppers sitting around that you couldn't use to fill backorders on carbine uppers. Neverminding the discussion as to whether or not there is a practical "need" for them on a semi-auto rifle not firing M855, they neither hurt nothing on either a rifle or carbine, and are more or less demanded by the market. When building a "clone," there's little reason to worry about having them when the "spec" says they shouldn't. If you were that concerned about spec, you would be getting a Colt or FNMI part anyways, meaning it would be "right." If you just want an A4 upper that will look the part from a quality company that looks the part as well as functions, the extended feedramps will either not affect function at all, or make it marginally better - I've yet to hear of a case / circumstance in which extended feedramps actually negatively effect performance. ~Augee Augee, You hit the nail on the head. Easier for mass production, and helps the rifle length (at the very least does not hurt). |
AR Sponsor