AR Sponsor
Posted: 2/22/2013 1:34:21 PM EDT
|
I bought a complete upper from JSE back in November. It had an 18" Hbar barrel on it, and I got sick of the weight. I decided to go with a lightweight 20", shaved 11 oz off the front end. I was happy until I went to the range with it.
Every round was jamming on the feed ramps, right where the barrel extension connected with the upper's ramps. People say, not a big deal, just lightly file the barrel extensions ramps and be ok. Well, still couldn't get it to feed after getting it even. Well, decided to try a 16" barrel. Also found the feed ramps on this hanged over the upper's ramps. The ramps in the upper actually are silver(raw aluminum), which tells me that JSE put the ramps in too deep when they built it with the original barrel. I also remember that the 18" barrel fit very tightly into the upper, but both my 16 and 20 are very loose(obviously not when the barrel nut is torqued down. Any remedy for this other than the replacement upper? |
|
Quoted:
It worked fine with their barrel, but the two replacements have both been overhanging feed ramps. Tried at least 10 of my mags, switched uppers on my other rifle, no luck. I'm guessing jse won't do anything since I've changed the barrel out. I'd bet you are right, since it worked (albeit heavy) as built when bought. Your best bet would probably be to re-build it back as it was when bought, test it and prove it still works or not- then make your decision. At that point, sell that upper (if it works properly) and buy parts to finish the build as you want. Sounds like the parts are doing you no good as they are now... Just my .02 
|
|
Bring the barrel extension feedramps lower than the upper, not "even."
What feels and looks even to you is still creating a small lip for the bullet tip to hang up on. A gap to jump is fine. "even" or a lip is not. Also, if the barrel is "loose", find out why. If the notch in the receiver is too large, than your barrel is canting in one direction or another (likely to the right when you tighten the barrel nut), which won't help feeding. Shim it with aluminum (think scraps of soda can) to tighten the fit at the index pin. |
|
Quoted:
Well, decided to try a 16" barrel. Also found the feed ramps on this hanged over the upper's ramps. The ramps in the upper actually are silver(raw aluminum), which tells me that JSE put the ramps in too deep when they built it with the original barrel. If JSE went "Bubba" on those feed ramps with the barrel installed, then that original barrel and the receiver are now a unique set. As stated above, put it back to original, working condition and sell it off. |
Pic of old upper. Note the feed ramps aren't even. They are also a little rough, and were obviously not milled before anodizing. New upper went together withouta hitch, barrel seems to index without issue, no lip/edge. I wont recommend jse for anything, I understand grinding down a barrels ramps, but to basically destroy an upper and prevent a new barrel ever is unacceptable |
AR Sponsor