Modern Sporter builds Q&A

greg olmstead said:
Discovered another problem using the magpul ubr or a5 length buffer tube without the modification being done to the tube or lower on the first batch. If you don't use the metal spacer included with the jp Enterprise scs we were offered as a solution to the lower being thicker in the buffer thread area is the gas key kits the lower and dents it. Got a pretty good dent right were the gas key sits
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That sounds to me (without having seen your rifle) like it might be running a little big on the gas port, or could use a heavier spring on the JP. No changes were made to the inside of edge of the lower, just the thickness on the back end.
 
ATRS Shaun said:
That sounds to me (without having seen your rifle) like it might be running a little big on the gas port, or could use a heavier spring on the JP. No changes were made to the inside of edge of the lower, just the thickness on the back end.
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It's the thickness on the back end. The tube doesn't screw in far enough for the scs to bottom out on the bump stop on it. I put the metal spacer in and the gas key can't hit the lower anymore. I didn't notice the mark until I switched from a carbine tube to the ubr. It doesn't bother me. The rest of the rifle is scratched and dinged. It got used lots and has traveled many miles and seen many rounds.

Also I'm running a suparms adj gb tuned to just lock back on an empty mag
 
greg olmstead said:
It's the thickness on the back end. The tube doesn't screw in far enough for the scs to bottom out on the bump stop on it. I put the metal spacer in and the gas key can't hit the lower anymore. I didn't notice the mark until I switched from a carbine tube to the ubr. It doesn't bother me. The rest of the rifle is scratched and dinged. It got used lots and has traveled many miles and seen many rounds.

Also I'm running a suparms adj gb tuned to just lock back on an empty mag
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OH, I get what you're saying now. A small shim sounds like the best solution, in behind the tube. They make big ones for use in the rifle length buffer tubes. A slice off one of those would do it.
 
ATRS Shaun said:
OH, I get what you're saying now. A small shim sounds like the best solution, in behind the tube. They make big ones for use in the rifle length buffer tubes. A slice off one of those would do it.
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Or simply drop a quarter in the rear of the buffer tube before sliding in the SCS. It's just the thickness needed. I know it's a little bit of a bubba method but that's what I did, simple and it worked.

Only problem is that it's getting pretty hard to find a spare quarter lying around these days with trudope at the helm of this sinking ship....
 
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