AR scope mount question

[Groundhog whacka]

I got a new scope for my Savage so I was thinking about giving my AR the hand-me-down. The picture is pretty old but it has a RRA one piece base on it now. I was just wondering if it would hurt anything to have the base partially on the receiver and partially on the tube. As long as the rail on the tube is aligned with the receiver I couldn't see a problem but I wanted to run it by the experts first ;)

http://i16.photobucket.com/albums/b50/Groundhogwhacka/orig.jpg

[OrneryCuss]

If they are EXACTLY the same height and parallel (very unlikely), the tube extremely rigid, is attached to the receiver and is free floating you shouldn't have any serious problems. The one piece base will probably be more forgiving than if you had individual rings. The closer to the receiver the better on the part that is on the fore end. Most free floating fore ends / tubes will flex when pressure is applied out front like with a bipod, sling or on sand bags. The farther out the mount, the more magnified the movement will be.

If they are different heights you could use Signature rings to overcome that issue.

I would personally never attach a long range optic to the float tube. Red Dot sights seem to be fine out there and hold an acceptable zero for their genre.

[Monkeyman]

If there is any way to slacken the forend tube it would be better. Slacken forend, attach scope mount tightly to recieiver first then forend, re-secure forend. That way youd be using the mount to align the forend and not the other way 'round.

[Markbo]

I think B-Square and Armalite both have mounts that position the rings more forward than the base... moves the scope about an inch further ahead. That ensures 100% rigidity and gets the scope where it needs to be.

Unless you are certain that aluminum or composite forend will never flex. ;)

[Groundhog whacka]

The mount I have is extended a bit and I think the new scope would be fine but I am not positive. It was just a question I always wondered. The tube is pretty stiff but if I grab the barrel and press against the tube with my thumb I can move it some. I am pretty sure the tube rail and receiver rail are the same height but I can lay a straight edge along it to be sure. The weather is supposed to be crappy this weekend so maybe I'll take the current scope and mount off and see how the new one will lay out.
Thanks for the help.
Brock

[44magfan]

Might try a 1" stock extention, this should put your eye an inch back farther from scope. I don't think I would want one ring on receiver and one on tube. Too much flex between the two.

Stock extention link (http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=5559&title=AR-15%20BUTTSTOCK%20EXTENDER)

[dtech]

+1 on the stock-extension and-or an ArmaLite mount. You will not be happy if you fix the front ring to your HG rail. It's simply not rigid enough.

[Redneckbmxer24]

what kind of a mount is it?

if it rings DO NOT put one on the receiver one on te forend, its not going to be perfect enough, and could screw up your scope.

nice choice in forend. why dont you go to them, and get a set of their super high rings?

[Groundhog whacka]

Thanks for the link 44mag. I will have to pick one of those up. For now I decided to try mounting part of it on the tube. The rail on the tube lines up perfectly with the rail on the receiver. I could probably deal with it being completely on the receiver but this is just a bit nicer. With a 1" spacer I could easily mount it all on the receiver. I will shoot it tomorrow and if accuracy goes to crap I'll move it back. As heavy duty as the mount and the tube are I really don't see any issues will flex, but we'll see.
http://i16.photobucket.com/albums/b50/Groundhogwhacka/DSCF0001-1.jpg
http://i16.photobucket.com/albums/b50/Groundhogwhacka/DSCF0002-1.jpg

[Groundhog whacka]

Scope mounted partially on the tube was a huge flop! I've had turkey loads group better than that. Tried apllying different pressures on the tube when shooting but there seemed to be no rhyme or reason to it. Moved the mount back onto the receiver and whammo back to 3/4" groups. Oh well, now I know for sure. Maybe next time when I ask the great masters a question I'll listen to the replies ;)

[Markbo]

So which mount did you end up trying next?

[mwatson]

I agree with what OC says.
Mike