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Posted: 10/2/2004 9:13:08 PM EDT
[Last Edit: 10/2/2004 9:17:59 PM EDT by ASO544]
Would like to build a replica XM-177E1 for my one of my R/R. I saw that CMMG had a very nice XM-177E1 (10.5" barrel and 3.5" fake mod) Upper but I really just need the 10" barrel assy (like original but a 10.5" will do) and the 3.5" fake mod. Who stocks these indiviual parts as CMMG does not seem to list them for individual sale according to their website.

Any other companies sell these type uppers or parts?

Anyone have any suggestions for this type project? I did a search, as I am sure this has come up before, but I can only go back 30 days.

Link Posted: 10/2/2004 10:14:25 PM EDT
[Last Edit: 10/2/2004 10:15:01 PM EDT by selfishselfless]
WA Tom manufactures replica moderators for the Colt XM607, XM177E1, and XM177E2 rifles. A suggestion for the barrel would be to use one manufactured by Bushmaster. Although it is of heavy profile, it would suit your moderator nicely. BTW. NFA rules do apply. Installing a 3.5" moderator on a 10.5" barrel would create an overall barrel length of 13".

Link Posted: 10/2/2004 10:58:24 PM EDT
Thanks for the info. This is going on a Registered M16 so the length will not be an issue.

I would like to stay with a 10" barrel like the original if possible. The BM is 11.5" but I did email CMMG and see if the sell their barrel assy and moderator as individual pieces. I also see that Model1sales has 10 1/4 barrels.

I also email Colt-653 since he seems to be the resident guru on this setup.


Link Posted: 10/4/2004 1:44:19 PM EDT
CMMG sells the 3.5-inch moderator for around $85. Mine is on order and is expected this week or next.

I had a post-ban chrome-lined Colt barrel and had it sent to ADCO to have the gas port opened to 0.093" and to have the barrel chopped of so that the locking ring for the 3.5-inch is 0.050" from the leading edge of the front sight base.

I also ordered one of the NIB vintage 1980s vinyl acetate covered Colt buttstocks. Should be in around the same time.

Highly recommend ADCO for barrel work the way you want it...


Link Posted: 10/4/2004 3:05:37 PM EDT
CMMG would be more than happy to break up the parts for ya. Heck, I got their very first XM177E1 and E2 uppers. I love them!
Link Posted: 10/4/2004 5:43:04 PM EDT
Did you need to adjust the gas port or were they reliable for full-auto use? I really like the E1 model (10" / 3.5 Mod). Did the original have a 3.5", 4" or 4.5 mod. I have read all different sizes regarding the original XM-177E1.

Link Posted: 10/4/2004 10:49:04 PM EDT
Link Posted: 10/5/2004 6:41:28 AM EDT
My XM in Central America (1983-84) had a 0.093" gas port and I never had any failure issues. All of my personal uppers that are 10-10.5" have been opened up to 0.093" because I know that diameter port works for me with that short of a barrel.

Still no failures for five 10-10.5" uppers...
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