Nightforce Benchrest 12-42 x 56 running out of elevation

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Omark44boy
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Joined: Sun Feb 25, 2018 2:03 pm

Nightforce Benchrest 12-42 x 56 running out of elevation

#1 Postby Omark44boy » Tue Mar 26, 2019 11:24 pm

Hi All

I have an Omark 44 in .308W with a 20 moa rail and a Nightforce Benchrest 12-42 x 56mm scope with the NP2 - DD reticle.

At my 300m zero I am 26.75 moa up from the bottom on the elevation turret, which only leaves me with 13.25 moa adjustment upwards.

At present, I need to use the bottom dot for a centre aiming point at 700m & at 800m I use the bottom dot with the top of the 3 ring (magpie) as my aiming point to try and hit the X ring.

I therefore need to source a well made steel 35 moa rail (hopefully local) according to my calculations.

Any recommendations?

trxdick
Posts: 21
Joined: Sun Apr 08, 2007 11:22 am
Location: Western Australia

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#2 Postby trxdick » Wed Mar 27, 2019 12:14 am

You could use Burris Signature Zee scope rings. The 30mm rings come with offset "pos-align insert rings" which should give the additional elevation needed.

Gyro
Posts: 418
Joined: Sat Jun 10, 2017 2:44 pm
Location: New Zealand

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#3 Postby Gyro » Wed Mar 27, 2019 6:14 am

U can also set some more angle ( i.e. tip the front down more ) into the scope setup by using an epoxy, like JB Weld for example, or any of the hard two pot epoxy bases.

The short version of this trick is as follows and is what I have been doing for years with winning F Class rifles : use a short piece of soldering wire ( which comes in varying thicknesses ) at the back end to act as a shim. You can compress the wire down a little with a piece of 30mm bar ( the bar diameter being the scope tube size ) by sitting it in the rings and tapping it down until it squashes the solder wire to the desired thickness.

Having got the right scope slope angle ( which is a guess, unless u work it out mathematically ) then thoroughly degrease the scope bases ready to form a good bond with the epoxy, then put a little epoxy in the rings bases, both the front and the rear ring bases. Obviously the solder wire is left in too as this sets the scope angle u have chosen.Then coat the 30mm bar with a release agent ( I just wipe on and off a HEAVY grease to leave a non-stick finish ) and sit it in the rings and leave it there, pressed down with some weight while the epoxy goes off.

You can speed the epoxys cure time significantly by running heat over it. If u like as the epoxy cures to a plastic state u can knife off any excess, or else just sand/file it off after it's fully hard.

And remember to deburr all the sharp corners on the scope bases afterwards, whether u have performed the above trick or not. Soooooooo many people ruin good scopes with ugly ring marks from the sharp edges left in the scope bases.

Barossa_222
Posts: 166
Joined: Sat Feb 08, 2014 6:58 pm
Location: Barossa Valley

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#4 Postby Barossa_222 » Wed Mar 27, 2019 7:14 am

+1 for Burris rings. Aside from them being quite thick and needing to peer around them to see the windage turret, they are not a bad thing. Got mine set up so it's 3 clicks until the scope bottoms out at 100 metres and I can shoot with them all the way out to 1500 yards with my 308.
I run Panda F's and the rail in integral, but with an Omark you could always just have a 40moa rail put on. Any competent gunsmith should be able to do that job for you.

Tim N
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Location: Branxton NSW

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#5 Postby Tim N » Wed Mar 27, 2019 8:24 am

This may be a silly question...
But that won't stop me asking, is there any chance the rail is mounted the wrong way?
We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC

UL1700
Posts: 208
Joined: Sat Sep 16, 2017 5:39 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#6 Postby UL1700 » Wed Mar 27, 2019 10:25 am

Tim N wrote:This may be a silly question...
But that won't stop me asking, is there any chance the rail is mounted the wrong way?


I was going to say exactly the same, with a 20moa rail, I am an inch high at 100 yards with the same scope and the elevation turret bottomed out. Running berger 155.5 at 3100+ fps.

James

Dicko
Posts: 12
Joined: Mon Apr 23, 2018 4:17 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#7 Postby Dicko » Wed Mar 27, 2019 1:09 pm

Post a good pic of your set up mate so that we can have a good look at the angle of your rail. I think the boys are onto it!

BillB
Posts: 41
Joined: Sun Dec 28, 2014 11:30 am

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#8 Postby BillB » Wed Mar 27, 2019 1:59 pm

My setup gives me 1min up from hard down is 300yds (set today ) and about 21 at 1000
Coke can shims atvrear of rail you can also use aluminium flashing used on windows see a local carpenter he should have some
Or go to bunnings and nip a bit off a roll (i didnt say that)

Barry Davies
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Joined: Tue Aug 24, 2010 12:11 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#9 Postby Barry Davies » Wed Mar 27, 2019 4:07 pm

Sometimes the recoil plate protrudes above the top of the receiver and the scope rail sits on this instead of on the receiver.
This in effect reduces the taper on your rail. Might be worth a check.

Omark44boy
Posts: 11
Joined: Sun Feb 25, 2018 2:03 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#10 Postby Omark44boy » Wed Mar 27, 2019 5:24 pm

UL1700 wrote:
Tim N wrote:This may be a silly question...
But that won't stop me asking, is there any chance the rail is mounted the wrong way?


I was going to say exactly the same, with a 20moa rail, I am an inch high at 100 yards with the same scope and the elevation turret bottomed out. Running berger 155.5 at 3100+ fps.

James



No, that was the first thing I checked. It is on the correct way.

There has to be something wrong somewhere in the set up to be 26.75moa up from the bottom at 300m with a 20moa rail.

I will remove the rings tonight and check things out more closely.

Thanks for the help so far guys, this is what makes the forum great.

UL1700
Posts: 208
Joined: Sat Sep 16, 2017 5:39 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#11 Postby UL1700 » Wed Mar 27, 2019 6:33 pm

So to be totally sure, the thick end of the rail is toward the stock, thin end toward the muzzle? It's just that you are almost exactly 20moa higher then you should be. This means you have 20 moa of taper between the rings or under the rail which should be obvious?

ben_g
Posts: 153
Joined: Sun Apr 24, 2016 7:37 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#12 Postby ben_g » Wed Mar 27, 2019 6:40 pm

Barry Davies wrote:Sometimes the recoil plate protrudes above the top of the receiver and the scope rail sits on this instead of on the receiver.
This in effect reduces the taper on your rail. Might be worth a check.


This happened on my old omark.

Just make sure you mill out the rail not the receiver !!!

Omark44boy
Posts: 11
Joined: Sun Feb 25, 2018 2:03 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#13 Postby Omark44boy » Thu Mar 28, 2019 9:58 am

20190328_084852.jpg
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20190328_084644.jpg
20190327_214955.jpg
20190327_214944.jpg


The rail is 184.5mm long.

The rear of the rail from the longitudal groove underneath the rail to the top of the rear ridge/dove tail is 11.10 mm & to the bottom of the groove/ dovetail is 8.22mm.

The front of the rail (muzzle end) , from the longitudal groove underneath the rail to the top of the front ridge/dove tail is 9.58mm & to the bottom of the groove/dovetail is 6.97mm.

The difference in height between the front & rear dove tails is therefore 1.25mm, or just over 20moa.

My scope rings are not attached at the rear & front dovetails, but I am assuming (I know) that the rail slope is constant.

I am wondering if the sqaure cross bar in the base of the Leupold PRW2 rings is riding up in the rail dovetail when tightened (well, the front ring anyway)?
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Omark44boy
Posts: 11
Joined: Sun Feb 25, 2018 2:03 pm

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#14 Postby Omark44boy » Thu Mar 28, 2019 10:14 am

My apologies, by my calculations the cant is approximately 23.4moa, not'-just over 20 moa' as stated above.

Cutanything
Posts: 149
Joined: Thu Feb 25, 2016 11:07 am
Location: Qld

Re: Nightforce Benchrest 12-42 x 56 running out of elevation

#15 Postby Cutanything » Sat Mar 30, 2019 10:43 pm

You need to move rail forward so back is flush with action you currently only have around 10 to 12 moa


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