P-300 BLK Scope Issue

[KingTiger]

I just picked up a RARR in 300 BLK that included a Nikon P-300 300 BLK scope & rings mounted. I tightened the base & cleaned, degreased & remounted the scope & rings.

I was using my laser bore sighter like many times in the past to somewhat zero it. Windage dialed right in, however, I ran out of elevation adjustment before I'm on zero ( it doesn't need to go much further).

Do I need to shim the scope under the front mount & reset my elevation to the middle of its range?

[smustian]

You can either shim it or buy a new base rail. They come in 10 and 20 degree. It is not good to run any scope near the end of it's adjustment range.

[Boolit_Head]

At what range were you trying to dial in? Anything under 50 foot with a bore slighter would not be close. Remember you have about 2.5 inches above bore to account for. I'd take that to the range and get it on paper before I tried swapping parts or shimming. My Nikon scope and mount only took a few clicks to get right in there.

[golfindia]

I wouldn't trust any laser bore sighter. Just another thing to be off.

You can get a 3-9 scope within 12" of zero at 100yds just by bore sighting on a bench.

[Rich Coyle]

I wouldn't trust any laser bore sighter. Just another thing to be off.

You can get a 3-9 scope within 12" of zero at 100yds just by bore sighting on a bench.

If the barrel is straight. Don't ask.

[KingTiger]

It came with a 20 degree rail factory installed, it's properly torqued.

Like I said, I've probably mounted 40 scopes using the laser bore sighter, it gets me on paper at 50 yards.

The rings it came with are split vertically vs. horizontally, so it may be difficult to shim. I think I'm just going to order some new rings of known quality & be done with it.

[Boolit_Head]

The 20 degree rail may be the culprit.

[Netpackrat]

The 20 degree rail may be the culprit.

Yeah, I would switch to a non canted rail... Not sure why anybody would use a 20 degree rail on a rifle chambered in an intermediate cartridge.

[KingTiger]

I think the rail is the culprit.

I can't determine if it really is a 20 moa from searching, but the muzzle end does look thinner than the rear. I don't have any experience with long range set-ups.

As mentioned, I'm not sure why Ruger would use it vs. a 0 moa rail. I thought they quit doing stupid stuff after 'ol Bill croaked.

Thanks for all the input, I think I'm going to put an EGW rail on it with Burris signature Zee rings.

[triehl27]

1. Go to the range and properly bore sight it, and try and sight it in from there.

2. Get a set of cheap Weaver 2 piece bases and see if that cures the problem

3. After #2 go back the range and resight it in.

YOU WON'T GET ANYWHERE NEAR A PERFECT SIGHT IT WITH A LASER.


NOTE, Laser bore sighters may be a bit faster BUT, it took me 6 of them to get one that was within 9 inches of the bore sight. They work for general, but DO NOT TRUST then for a final bore sighting. Go to the range and sight in, then you know. I have had them be 5 ft off target. Because the arbor wasn't straight OR more common the laser isn't straight in the housing.