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sadmin
30 March 2009, 19:41
Forgive my ignorance...
I purchased a spikes dedicated upper for my LMT lower and the version I ordered was the basic flat top with no A2 sight. The flat top on the upper receiver isnt the same height as the rail on the gas block. Is there a riser i need to use? I may be not be describing my question correctly so feel free to ask me to clarify. Thanks for any information, great site by the way!

Uglyduck
30 March 2009, 19:52
Are you putting a front sight on the gas block? What do you want the riser for? Elaborate a little.

sadmin
30 March 2009, 20:04
i was going too, but i was afraid that if i just ordered, say a troy front and rear buis, then the front on the gas block would be too low.
http://www.spikestactical.com/z/images/large/22LRM4Upper2%20(Small)_LRG.png

Uglyduck
30 March 2009, 20:17
Ok, you'll need a gas block mounted FF sight then. Midwest ind, GG&G, Samson, and YHM (amongst others) all make sights designed to be at the proper height when mounted on a gas block without the need for a riser.

Stickman
31 March 2009, 10:46
Gas blocks take a different front sight than a rail mounted front sight. The gas block sits lower, so it needs a taller sight.

Troy sights are designed for mounting on a rail, and they would not work if used on a gas block.

TecRsq
28 May 2009, 21:27
This adapter will put the railed type BUIS on the same plane as the picatinny rail the rear will be mounted to, it will raise it just high enough off the front gas block to be perfect for the MBUS or any other normal railed BUIS.

Best part is it is only about 40 bucks, I am doing the same for my Spikes ST22 Upper as it has the gas block also and I will be going a normal BUIS on the front.

http://yankeehillmachine.com/store/product491.html

Edited to add Important info: Magpul advises against mounting the MBUS on "any" railed gas block due to a possible heat of conduction issue, carry on.

I just found out the following information directly from a Magpul Industry forum so looks like I will be going with Troy Frt. BUIS instead to get around the heat issue.

http://yankeehill.bizland.com/store/media/YHM-230.jpg
http://yankeehill.bizland.com/store/media/YHM-230_2.jpg

Stickman
28 May 2009, 22:19
Thanks for posting that, I had not seen those yet.

TecRsq
28 May 2009, 22:24
Edited to add Important info: Magpul advises against mounting the MBUS on "any" railed gas block due to a possible heat of conduction issue, carry on.

I just found out the following information directlu from the Magpul Industry forum so looks like I will be going with Troy Frt. BUIS instead to get around the heat issue.