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5/8/2016 9:15:46 PM EDT
I recently took a .300 blackout rifle in trade with the intention of selling the barrel and making it a .556. It has a douglas heavy barrel with a BATS match barrel extension. Here's my issue, apparently the gunsmith that built this rifle milled out a larger channel for the BATS barrel extension index pin which is apparently larger than milspec. What can I do to fit a milspec .556 barrel in this upper or am I stuck with it as is? Sorry if this is a noob question but I'm no expert, thanks for any help.
5/8/2016 9:53:44 PM EDT
[#1]
Quoted:
I recently took a .300 blackout rifle in trade with the intention of selling the barrel and making it a .556. It has a douglas heavy barrel with a BATS match barrel extension. Here's my issue, apparently the gunsmith that built this rifle milled out a larger channel for the BATS barrel extension index pin which is apparently larger than milspec. What can I do to fit a milspec .556 barrel in this upper or am I stuck with it as is? Sorry if this is a noob question but I'm no expert, thanks for any help.
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For the amount of trouble and the price of uppers, I would probably leave it as is and sell/trade the upper.

Its certainly doable to create a 5.56 barrel with an oversize index pin to fit the upper, but hardly cost effective.
5/8/2016 10:00:04 PM EDT
[#2]
Stripped uppers can be had for about $40.  No point in keeping it.
5/8/2016 10:14:55 PM EDT
[#3]
it's a billet matched upper and lower from Sun Devil in Az., I really want to find a way to remedy this an save the upper
5/8/2016 10:25:45 PM EDT
[#4]
Quote History
Quoted:
it's a billet matched upper and lower from Sun Devil in Az., I really want to find a way to remedy this an save the upper
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Still not worth it.  You could use shims around the pin, but it's probably an oversized extension so it's unlikely that a standard extension will fit tightly in the upper.  You could have a 5.56 barrel made wth a BAT extension.  Or you could sell the upper with the barrel and get a better upper made from 7075 instead of 6061.
5/8/2016 10:49:02 PM EDT
[#5]
what would be good to use as a shim? Since you mentioned shim I thought about taking a very small stainless square nut and filing the front off to fit behind the pin
5/8/2016 10:52:38 PM EDT
[#6]
coke can works, or stainless shim stock.  Just cut to fit.
5/8/2016 10:54:15 PM EDT
[#7]
good idea I'm going to try it when I get time tomorrow evening, thanks man
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