Has anyone installed the T91 Front Sight Assembly?

[KalashniKEV]

Is it as simple as driving out the pin, popping the old gas block off (with a press, I've heard?) and sliding the new one on and reinstalling the pin?

Is there any requirement to drill on the new block?
Is there any requirement to modify the handguards?

Thanks!

[codyphillips48]

Is it as simple as driving out the pin, popping the old gas block off (with a press, I've heard?) and sliding the new one on and reinstalling the pin?

Is there any requirement to drill on the new block?
Is there any requirement to modify the handguards?

Thanks!

Yes many have installed the T91 gas block. Now with the new gas block there selling on here its easier to install but that also depends on your tooling. You'll need a press to get the old gas block off or if you dont care about it you can cut it off with a cut off wheel. With a little sanding of the journal on the barrel and in the gas block it almost slides right in. next you will need a 2.2mm drill bit and a 3mm drill bit. You can find those at ace hardware by the taps. Installing the new gas block will require you to drill a new pin hole in the barrel. then you will need a taper reamer for the pin. Me I did one myself and the 2nd one I sent to my gunsmith. It can be done The new gas block will need the gas port drilled and the pin hole drilled. Handguards will need a little sanding to make it easier to get them over the 1913 rail (at least mine did).

[changhsu08]

My gunsmith used a shop press to remove the wolf A1 gas block and installed the T91 one. That's the easy part he said.
He had some trouble drilling the gas port on the gas block and broke two drill bits; not as simple as he thought it would be. The upper now is completed and I have put around 200 rounds through, it runs good; the new gas port in the T91 gas block is smaller than the one on the wolf A1.

[akguy1985]

I'm taking mine to the gun smith in the morning.

[KalashniKEV]

I've lost access to my shop (old employer), and will have to use a gunsmith on this job.

What are the 3mm and 2.2mm bits for? 2.2 on the port and 3 on the retaining pin?

Has anyone done instructions for this?

[e292644]

Correct, 2.2mm on the port with 30 degree angle and 3mm on the retaining pin.

[codyphillips48]

I've lost access to my shop (old employer), and will have to use a gunsmith on this job.

What are the 3mm and 2.2mm bits for? 2.2 on the port and 3 on the retaining pin?

Has anyone done instructions for this?

I know on my gas block it was easy to figure it out. Both holes were started. The gas port was almost drilled threw it was like a 16th of a inch from being finished.

I don,t see installing this being any different then installing a A2 style or a AK gas block. Installing the sight is no different the then a A2, Drill smaller hole then ream out to fit the pin. Then drilling the gas block is like drilling a AK gas port. That's how my gunsmith explained it to me. That's also how I did mine on my own.

[e292644]

Exactly, make sure the drill bit is 90 degree vertical, only tilt the barrel/FSB to 30 degree and drill it through carefully. Mark your drill bit depth and lock it with either drill press, lock ring, or with masking tape so you won't drill into the bottom of your barrel.

I know on my gas block it was easy to figure it out. Both holes were started. The gas port was almost drilled threw it was like a 16th of a inch from being finished.

I don't see installing this being any different then installing a A2 style or a AK gas block. Installing the sight is no different the then a A2, Drill smaller hole then ream out to fit the pin. Then drilling the gas block is like drilling a AK gas port. That's how my gunsmith explained it to me. That's also how I did mine on my own.

[codyphillips48]

I found drilling the barrel pin to be the hardest part of the whole thing. Keeping the gas block straight was the hardest thing for me but thats just me

[KalashniKEV]

OK... so now that I have the new block in hand, I see exactly what you guys are talking about:

1) Complete drilling of the port by doing 30 deg, 2.2mm on the new gas block.
2) Remove the pin and press off the old gas block.
3) Press on the new gas block.
4) In proper alignment, drill new retaining pin (3mm) and install the wider pin.
MAYBE open up the gap on the bottom of the HGs.

Is that the job?

[e292644]

I would recommend following steps:

1) Remove the pin and press off the old gas block.
2) Clean and lightly smooth out gas port journal area, apply lubricant for press in the new block. If you experiencing tight fit, you may bore the gas block or use 500-1000 sandpaper polish the gas port journal area to get it fit. We use reamer to smooth out the front sight base.
3) Press in the new gas block, align with upper receiver. Fit your piston system and hand guard, mark retaining pin drilling point with masking tape or something similar.
4) In proper alignment, drill new retaining pin (3.0mm) use #2/0 Spiral Flute Taper Pin Reamer expand it and install the new pin.
5) Complete drilling of the gas port by doing 30 deg, 2.0mm 1st, then ream it with 2.2mm on the new gas block. Be very careful on this process. Go very very slow on rpm and feed or you will end up with broken drill bit inside the gas port. Use plenty of the lubrican.

OK... so now that I have the new block in hand, I see exactly what you guys are talking about:

1) Complete drilling of the port by doing 30 deg, 2.2mm on the new gas block.
2) Remove the pin and press off the old gas block.
3) Press on the new gas block.
4) In proper alignment, drill new retaining pin (3mm) and install the wider pin.
MAYBE open up the gap on the bottom of the HGs.

Is that the job?

[codyphillips48]

I would recommend following steps:

1) Remove the pin and press off the old gas block.
2) Clean and lightly smooth out gas port journal area, apply lubricant for press in the new block.
3) Press on the new gas block, align with upper receiver. Fit your piston system and hand guard, mark retaining pin drilling point with masking tape or something similar.
4) In proper alignment, drill new retaining pin (3.0mm) and install the new pin.
5) Complete drilling of the port by doing 30 deg, 2.0mm 1st, then ream with 2.2mm on the new gas block.

Only thing I see missing is taper reaming the barrel pin hole. The new pin is a taper pin. My gas block almost fell right on after cleaning up both the barrel journaling and gas block journal. Im gonna guess that's why it was hard for me to keep it straight.

[ZX672]

I would recommend following steps:

1) Remove the pin and press off the old gas block.
2) Clean and lightly smooth out gas port journal area, apply lubricant for press in the new block.
3) Press on the new gas block, align with upper receiver. Fit your piston system and hand guard, mark retaining pin drilling point with masking tape or something similar.
4) In proper alignment, drill new retaining pin (3.0mm) and install the new pin.
5) Complete drilling of the port by doing 30 deg, 2.0mm 1st, then ream with 2.2mm on the new gas block.

Question on number 5. When you drill the new gas block and press back on, your 2.2mm port will align with the gas port on the barrel correct? I assume the gas port hole on the barrel is chamfered to allow some wiggle room?

I have not pressed of the original gas block so I just want to get an idea on what I should expect.

[ZX672]

Finally had a chance to replace my wolf gas block with the military style T91. It was pretty simple. I decided to clear the gas port hole while the T91 gas block was off the barrel. When I pressed it back on, the gas port holes from the block and barrel aligned.