Q for those of you who build a mil-spec FSB T91 with .750 journal 14.5/16 barrel

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niqstr
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Tue Jul 14, 2020 9:04 pm

hi thx 4 confirming that 9-10inch is smaller[side view looked smaller vs 11-14mark which is prob 750]

i am hoping that the pinning will secure it to the smaller diameter around the 9-10inch mark?

otherwise i might have to get 416r ba wylde barrel w midlenght.

how much did it cost you and what is the official process called for getting rid of the shoulder?

thx u for your time in replying back..


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Prelude
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Thu Jul 16, 2020 11:11 pm

My suggestion is to add a set screw under the T91 gas block if you want to go the M4 barrel route. (Carbine gas system)
I did this to my 9mm T91, same issue there, the barrel OD is too small.
That way you can semi secure the gas block before pinning it.
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Otherwise it will not stay put.
I think it costs me almost $100 including shipping to get that barrel turn down. Labor is around $60.
It is costly, so later I tried to turn down the barrel myself, using router and wooden jig. They turn out well.
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niqstr
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Wed Jul 22, 2020 7:55 pm

wow yours look nice.

just bought the m4 barrel today.

so i will see how it goes. mail has been really slow. checking via tracking 4 t91 is almost annoying when u see "in transit" message 4 past week.

take care
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niqstr
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Wed Jul 22, 2020 7:59 pm

sorry but the t91 piston rod work[able to go through upper hole] in regular ie aero precision ar15 upper?
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Prelude
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Thu Jul 23, 2020 2:44 pm

niqstr wrote:
Wed Jul 22, 2020 7:59 pm
sorry but the t91 piston rod work[able to go through upper hole] in regular ie aero precision ar15 upper?
the T91 piston rod is slightly larger than gas tube
need to enlarge that hole a bit
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By the way, that upper was used to install the T91 Tactical 14.5" barrel.
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niqstr
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Fri Jul 24, 2020 6:55 pm

damn that sux. man didnt know it would be this much work...lol

that t91 looks sweet.

thx for your replies. hope i didnt bug you too much.
just great to be able to bounce ideas of someone who went
through the process.

also thx 4 the pix. they help visualize the process.

thx & have a great summer
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