So i'm new to Ar's and have a stock st15 m4, if i wanted to change the stock m4 handguards without removing the a2 front sight i can only go with a 7" right? now if removing the front sight is not a problem i can go all the way out as long as i change the gas block so it could fit into the rail correct? which size i'll pick is not important right now i'm just trying to understand better how this works.

Now let's say i'm correct about the the rails, by adding a rail system beyond 7" then my front sight will have to be mounted on the rail which brings the next question, fixed or flip ups? red dot will be coming in at last, but for some time i'll be only using iron sights.

I'm a big believer of knowing how to run your weapons before upgrading anything on it so i guess rail and sights first and red dot at last.

I personally recommend to always get intimate with the irons first before adding optics. Many shooters even prefer to stay on irons. I think fixed irons are best for their rigidity. But if you want the most convenient storage for your rifle, then flip up sights have a benefit.

As for the rails, your understanding is correct. Only clarification I would add is that you would need to remove and then reinstall the FSB in order to install a 7" rail. Or you could swap to a drop-in 2 piece railed handguard that will use the existing cap and delta ring.

I like having the fixed sites because it helps counter any paralax that I get when using a red dot. You should shoot just as accurate with the irons as the red dot. Using the red dot just allows you to acquire and enagage your target quicker than irons.

thanks Jax, like i said i'm a firm believer of knowing how to operat/troubleshoot/clean/fix your weapons before any modification is made. I like to have options if possible and for that reason i think about the SAR rail system it gives me the option to utilize/add gear that can make me a better shooterand more efficient. do you have a link to the drop-in 2 piece railed handguards? i think i know what you're talking about but i'm not quiet sure. On the other hand i see a preference in rear flip-up and fixed front assuming we're talking red dot, is there any advantage/disadvantage?. I was looking at the magpul rear flip-up and maybe the front as well or leave the a2 on front, either way it will be some time before i jump to red dots.

Thanks.

Agree with you 100%

Just wanted to follow up on this thread. I just ordered a complete upper and lower. The upper i order comes with the standard fixed front iron sight but nothing in the rear sight area. I will be buying some type of red dot in the future but for not will I be okay just buying a magpul flip up rear sight? Can I use the rear flip up magpul in conjunction with the standard front iron sight? Or would you guys suggest removing the front iron sight and getting a front and rear magpul??

How easy or hard is it to remove the front fixed sight??

Im new to the AR world.

I can already tell this is gonna be an expensive hoppy.

Just get the magpul rear. It will work. And its just a screw, to change the sight, you have to get a new gas block because your sight is the gas block now. I would get the Troy and keep it on when I put the aimpoint on. I went with magpul front and rear on my rifle and I'll move to troy or Samson sights in the future. Nothing really wrong with the magpul, I'd just like to have little more robust sights.

Cool. Thanks for the info.