New Build

[556guy]

New build may be too strong, more like let’s throw some parts together and see what happens. So into the parts bin I dive. Old DPMS lower, Aero parts kit, rifle buffer tube,A1 stock, A1 pistol grip,and attach my new T91 upper. Hey that looks pretty cool. Magpul rear sight and it’s off to the range. A variety of ammo including the dreaded steel case. Ahhh! Zeroed with Federal M193. FYI, crank up the front sight post. Tried Fiocchi, South African surplus,PMC,an old box of Hansen,and the Federal. Now to the Wolf and Red Army Standard,will it or won’t it. It will! Feed and function were 100% with both.I am Happy Happy. Yesterday the Simple Sight arrived. The front sight post that comes with it is really skinny. Too skinny for my old eyes. Hmm,an A2 front post might be the ticket. If it’s still too tall,well I have a file. Today is Thanksgiving and I go back to work tommorrow ,so it will be next week before I can shoot it again and also post a picture. More steel case will be fired,Ahhh! I’ll post how it goes. Anyway that’s my story and I’m sticking to it.

[556guy]

Good range day today. A little cold here in SC,but not too awful. There’s good news and bad news. First tho,I am really liking the upper.The bad news, the simple sight doesn’t work. I tried the original front post ,the replacement post that came with the sight, and an A2 post. Could not get the rifle to zero.There was not enough elevation in the sight. At 100yds was still hitting about 4 to 5 inches low. Any ideas? The good news,with an MBUS rear sight and the original front post,zeroing was not a problem. I was very pleased that the upper shot everything I put through it. M193,M855,Fiocchi,Federal, SA surplus,etc. It also shot the Wolf steel case and Red Army Standard steel case without any problems. About 400rds. went down range,200 of them were steel case. All told ,a good day. Again, any ideas about the sights would be appreciated,Ireally like the look of the simple sight and would really like to use it. Dan

[apex]

I'm assuming you are using the stock two-piece gas block that came with your upper and have not swapped to mil-spec- this is the T91K1 gas block. Your front sight post will not work with T91 sights, and is designed for use with standard-height rear AR sights.
See picture:

T91 front sights.JPG

The sight block on the left is the Wolf "tall" front sight sighted for a Magpul MBUS, the block on the right is a standard AR-15 post sighted for a T91 simple rear sight. Neither are flush with the sight block shoulder. The left's post sits higher in the block and the right's post sits lower in the block.
If you want to use T91 rear sights with the K1 gas block, you will need to use either a standard AR-15 front sight post or a T91 post. The "tall" Wolf front sight post will not go low enough to sight in correctly with T91 sights.

[556guy]

apex,that’s what puzzles me. I used the new post that came with the simple sight and even though I had it all the way down, I’m pretty sure I did, it still shot 4 to5 inches low at 100yds. The front sight looked just like the one on right in your picture. I’ll try again on the next range outing and see if I didn’t have it screwed all the way down.

[apex]

Strange, the post should not be screwed all the way down to the bottom to the point where it will not turn anymore, but about 1/16th inch below the block shoulder. Did you do any sighting prior to the range trip? If not, I would highly recommend manually boresighting the upper to get the sights close.
Here's a pic of my front sight block from the top. This is sighted for the simple T91 rear sight at 25m and 300m. Note, I use a standard A2 front sight post, but the mil-spec T91 post and A2 posts are roughly the same height (I run the T91 post, mil-spec gas block and carry handle on another build and have measured both posts).

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And here is a view of the sight picture of both the 0-3 and 0-1 peep sights, respectively.

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