Does removing barrel change zero?

[Birdyblaster]

Has anyone noticed a change in zero after removing a barrel to clean it and replacing it afterwards?  I know it wouldn't for sights mounted to barrel but what about scopes and red dots mounted to the receiver?  I've got my red dot zeroed really well and don't want to have to re-zero with $6 shells just because I removed my barrel for one last cleaning before season.  If you have noticed an impact shift, how much was it?

[Rem Man]

Unless the optic is mounted to the barrel yes! Make sure you mark your cap and barrel before removal, this will definitly help!  If it were me I wouldn't touch it.

[Birdyblaster]

How much would it be off?  I can understand if it was a rifle sighted in at 100 yards but I just can't see how a shotgun could be off by more than an inch at most at 30-40 yards unless the barrel to receiver tolerances are very poor.

[STP22]

What gun is it?
My Ithaca Model 37 Featherlight doesn't lose zero after reinstalling, but the barrel is semi-threaded to the receiver.
With my 870's...I have not noticed any difference after reinstalling a barrel. Granted, I don't use the 870's for turkey...just waterfowl, buckshot, and slugs (cantilever mount).
Steve

[Birdyblaster]

Rem 870 SPS

[STP22]

How bad was your shift? Your mounts (rings and base) secured good?

[MACHINIST]

in for the conversation

[STP22]

Ah! Sorry!
My guess is every gun would be different. I wouldn't think it would be much of a shift.
If it concerns you, leave it as is. You can always cleaning the barrel with a pull-through system like Otis.
Steve

[Birdyblaster]

How bad was your shift? Your mounts (rings and base) secured good?

I haven't tested it yet.  I like to take advantage of other people's mistakes instead of make my own 

[Snoodsniper]

I take my barrel off for cleaning and it's not been an issue. Lock the mag cap down the same each time.

[STP22]

There are many variables that can alter the POI such as temperature, chokes, shell inconsistencies, etc. Yes, in theory, since the 870's barrel/receiver is not as secured as one threaded into the receiver (rifle), the POI can change with every shot. How much? Not enough to notice shooting turkey loads at turkey distances. I think you would be fine either way you decide. This has been my experience with the 3 870's I have.
Like Snoodsniper said, just tighten your mag cap the same each time and make sure your mounts are secured and all will be good.
Good luck this season, Birdyblaster.
Steve

[allaboutshooting]

Rem 870 SPS

The only thing that holds the barrel in the receiver on your 870 is the magazine cap. As has been stated, the torque on that cap can change the point of impact. I recommend that a cap be tightened by hand as tight as possible and then, using some padded pliers, tighten it 2-3 more clicks. Then mark the cap and barrel band in some way, red nail polish works well, so that you can look at it and know that everything is in the same place.

Once a gun is sighted-in, if it must be cleaned, I recommend cleaning from the muzzle end and not removing the barrel. If you're concerned about "gunk" entering the action, just put a piece of paper over the open bolt and angled outward to deflect debris outward. If you'll use a Boresnake from the chamber, you won't have to worry about debris.

To answer the other part of your question about how much impact shift, it's possible to move the POI several inches, depending upon how tight the cap was when you sighted it in and how tight it is when you reinstall the barrel. It's important for that cap to be tight and even more important that it be the same all the time. A barrel that's loose can cause a scattered pattern and can be a real source of aggravation when trying to pattern an 870.

Thanks,
Clark

[Gobble!]

Always tighten the cap down the same and your good to go

[the Ward]

I usually do it like Clark does if I have a receiver mounted sight/scope. I clean thru the muzzle and put some paper towels or a rag in the receiver to catch any gunk. Sometimes I will swap the choke to a stock cylinder or i.c. to make it easier to get the patch down the barrel and then clean the turkey choke separately. Haven't noticed any change of impact doing it like this so far.

[chatterbox]

Once my gun is shooting where I like, I never remove the barrel to clean.
I also make sure the receiver has a rag in it to pick up any gunk.
Once it's sighted in, I leave nothing to chance. Even with the mark on the cap.