Before I buy or install a FN upper on one of my AR15's, I need to know if it is necessary to change the buffer and spring.
Anyone done this conversion?
If so, where did you order the buffer & spring?
Installing a 5.7-28 upper on one of my AR15's
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Re: Installing a 5.7-28 upper on one of my AR15's
The upper should come with a buffer and spring, a buffer at the very least. Someone correct me if I'm wrong.
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Re: Installing a 5.7-28 upper on one of my AR15's
Yep, the upper comes with a buffer. OP, I'm going to list my used AR57 16" upper in the next week.
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Re: Installing a 5.7-28 upper on one of my AR15's
I bought one last October. It comes with a carbine buffer, no spring. I ordered the rifle buffer seperately as I shoot with a rifle stock.
Re: Installing a 5.7-28 upper on one of my AR15's
Where are you getting these uppers?
Re: Installing a 5.7-28 upper on one of my AR15's
One of the sellers is Copes Distributing. I've got good experiences with these guys.
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Re: Installing a 5.7-28 upper on one of my AR15's
http://www.heavybuffers.com/ar15carbine.html
I put one of the 9mm-QT Buffer - 11.5 ounces - $125 (comes with stiff spring) in mine, but that was to compensate for the longer barrel I bought for it (28"). I will say that the heavier buffers causes the cases to come out of the gun shaped more uniformly with less deformation than with the "factory" buffer and spring.
I got my AR-57 upper through Blackheart International for $600 - the cheapest I could find it on the web and they are still at that price (I just checked).
I put one of the 9mm-QT Buffer - 11.5 ounces - $125 (comes with stiff spring) in mine, but that was to compensate for the longer barrel I bought for it (28"). I will say that the heavier buffers causes the cases to come out of the gun shaped more uniformly with less deformation than with the "factory" buffer and spring.
I got my AR-57 upper through Blackheart International for $600 - the cheapest I could find it on the web and they are still at that price (I just checked).
Re: Installing a 5.7-28 upper on one of my AR15's
Copes is selling them for $ 575.00
Interesting about the buffer. I've got the rifle buffer by Aero Precision in mine with a standard rifle spring. That one weighs 233.5 gram. Your's is about a 100 gram heavier. Might this also work for the 16" version? Don't you feel more movement in the rifle?
Interesting about the buffer. I've got the rifle buffer by Aero Precision in mine with a standard rifle spring. That one weighs 233.5 gram. Your's is about a 100 gram heavier. Might this also work for the 16" version? Don't you feel more movement in the rifle?
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Re: Installing a 5.7-28 upper on one of my AR15's
Even better price - everyone should have an AR-57 upper!
I think I'm right on the edge of blowback vs spring/buffer - I had one factory round that didn't cycle properly after I put in the buffer and spring. If I understand the mechanics of the 5.7 reading the material on this site, the pressure spikes quickly so the barrel length may not be a factor. I have read that you need a heavier buffer if you are using a silencer, but I don't recall the exact reason.
It's got a definite thunk-a when it cycles - I'll have to try the regular buffer/spring to see what the difference is.
I think I'm right on the edge of blowback vs spring/buffer - I had one factory round that didn't cycle properly after I put in the buffer and spring. If I understand the mechanics of the 5.7 reading the material on this site, the pressure spikes quickly so the barrel length may not be a factor. I have read that you need a heavier buffer if you are using a silencer, but I don't recall the exact reason.
It's got a definite thunk-a when it cycles - I'll have to try the regular buffer/spring to see what the difference is.
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