Just spent the afternoon getting to know my M&P 15 better. I put a Vortex Viper 1-4x24 last week and took it to the range to sight it in. Love that setup!
Does removing the scope from the rail but leaving the scope in the rings have a large effect on the accuracy. I took it off to clean the rifle .
The same question applies to my I-bolt 30.06 for that matter.

not huge...but you will have to re sight it in every time you remove glass.

Follow up question, how far do you break it down after a day out, does the trigger assembly need to come out? Does it come out easily? I didn't see anything about that in the manual but it's not real easy to clean otherwise...advice on that.
I'm new to the AR world.

do not try to disassemble the trigger group - with q-tips you can clean the lower without any real difficulties

you only need to field strip to clean

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Steve

Good advice I'll take it for sure. I did that as well as rinse with solution. Freakin love that rifle! Did a full field clean when I got home.

This is not completely accurate. It's not wrong per-say, but not complete either. The whole answer will take a little to explain so...here goes:

Once a sighting device is adjusted to the particular gun it's on, any movement will affect future accuracy. The question then becomes, what kind of accuracy are you concerned about?

If you remove the optic, but don't move it in the rings, it should be close when re-installed. However, nothing is perfect and it will be a little different than before. How different will depend on a few variables; how good are the rings, and how consistent will your upper allow them to be?

For example, EOTech says their quick disconnect mounts are +/-1MOA upon remounting. This means that when you zero the optic so that it's perfect at 100 yards, when you remove and replace the optic, the point of impact (POI) will be the same as before it was removed, but could be as much as 1" away from where it was zeroed before. So, if it were dead on and you remove and replace the optic and now it's hitting 1" high, it's still within spec.

This leads to, what kind of precision do you expect from your gun? If you're happy with 2MOA, then removing and replacing your scope, as long as you don't futz with the rings, will not be an issue as long as you have a quality set of rings. (Hint: UTG does not make quality rings, but they work if you don't move them.) However, if you want the best accuracy you can milk out of your gun, don't ever move the optic once you've zeroed it.

Also, there are several factors affecting accuracy of your rifle. Quality of the sighting device, quality of the bore, quality of ammo, condition of the bore, quality of the chamber, trigger, skill of the shooter, type of rest...and the list goes on. All these things affect accuracy. If you want the best repeatability you can get, don't remove your optic once zeroed.

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Freedom isn't free.

I have to ask, why would you take the scope off to clean the rifle? And yes, as previously stated, you will have to re-zero. It will probably be close, but not perfect.

And some may disagree with me on this, but it is not necessary to do a full cleaning after each range session, especially if you only shoot 100 rounds or so. Adding a little bit of oil will keep it running for many rounds. After sighting in my rifles for hunting season, they don't get cleaned until the season is over. I sight mine in after the barrel has a little fouling in it. Nothing but a quick exterior wipe down and a little oil on the bolt. Shotguns the same... quick boresnake through the tube and a little oil in the action, or on the hinges of my over and under until the season is over.

For center fire ARs I never remove the trigger parts for cleaning as it is not required. If it gets gunked up I would try some aerosol cleaner or brake cleaner. Just be sure to re-lube.
Scope mounts. If you are using the ones that need tools to tighten be sure to tighten it the same amount each time. Place it in the same slots on your receiver and be sure to push the mount forward against the slots prior to tightening the mount. Some people use a torque wrench to ensure the mounts are put on the same way each time. There is no real reason to remove your scope for cleaning, I wouldn't. If you remove the scope from the rings you will most likely have to rezero all over again.
If you use a mount like the ADM or LaRue you can remove them from the receiver and many times the point of impact will stay pretty close, maybe 1/2 inch change at 100yds. The mounts are made to be taken on and off without rezeroing. These quick detach mounts are helpful when you want to go back and forth between two types of sights. The penalty of these is price, depending on the size of the mount it may run 150.00 to 250.00.

When I shot competitively back in the dark ages, the gun would get a couple of drops of CLP after each match or practice session. Full cleanings would be done every 500-600 rounds when accuracy started to deteriorate.

Remember that when you remove parts, you cause unneeded wear. I never remove triggers until they need maintenance or replacing.

Rastoff makes a good point about quality of the mounting system. Proper mounting technique is equally important.

I use Badger Ordnance rings and base on my Rem 700. I've removed and replaced twice (removing rings from base, rings stay on scope in place) with no noticeable shift in POI. it's a sub moa rifle, so any significant shift in POI would be quite noticeable.

I use a LaRue mount on my AR. LaRue advertises "no loss of zero, guaranteed." I don't use my AR for precision shooting, so I could not confirm that claim other than saying I have not noticed any.

Good rings/mounts properly mounted, loss of zero issues from removing and replacing is largely avoided.

If I have an extra few hours, I might be able to finish reading your response.....In the mean time, I stand behind what I said. From my experience, shooting my WOA 20" precision AR every weekend this year, from 500 yards and in....every time I have removed my Leupold VX-2 with Leupold rings/mount, I have had to re zero/re sight, and have never been able to maintain accuracy. So again, to answer the OP's question, in my own personal experience, removing your glass will have an effect.....whether it's large or not is debatable.

I wanted to get a good clean under the handgaurd and couldn't get the doughnut back comfortably with the scope on. I sure done plan on this every time . Thanks