Zastava M70 scope bases

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Workin Man

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I recently bought a Zastava M70 and I am trying to mount a scope on it. I am specifically looking for 2 piece steel Weaver style mounts. I was able to find a set of Warne Maxima's (in stainless finish, but oh well). The screw holes line up and the threads are right, but putting a straight edge across the top of them shows that the rear base is around 1/16" taller than the front base (about 1mm for the younger people). I checked Warnes website and this is they set the specify for the Zastava. I also checked Weaver and Leupold but neither list the Zastava specifically, just Mauser 98 in general. Is there a different front or rear base that would correct this? Do I need to shim the front base? Any help or advise appreciated.

Thanks, Jim
 
Brownells publishes a Weaver base chart that shows the actual dimensions of their bases - height, radius, screw centres etc. I've used it in the past to resolve height mismatches on mausers.
 
murph83 said:
i think Marstar sell scope mounts for Zasdtva rifles.
Click to expand...

Thanks, I checked them out. The ones they have are Sun Optics, which are aluminum, not what I am looking for. This rifle is a 458 WM, I want steel rings and bases on it. Thanks for the heads up though.

I had the day off due to weather, so I decided to try shimming the front base. I cut up two Norinco 7.62x39 steel cases to make shim material. Two thicknesses (deburred) seems to have put me right at the correct height. I am not sure if this is suitable shim material or not. I was just trying it out because I had nothing better to do. Assuming this is OK, or I use a different material as a shim, should I find some longer screws for the front bases? The front base screws are very short.

I'm still not sure if this is the right solution, but it looks like it could work.

Thanks, Jim

Jim
 
Using shims is "time honoured" tradition - so many of the home-done mauser sporters, even many earlier factory rifles, do not have precise contours on the receiver rings and bridges. You are on correct track, I think - want those tops of bases to be on the same plane - square left to right and in line with each other, and more or less parallel with the bore centre line or the bolt body. "Cheap" trick, I read somewhere, is to buy an inexpensive feeler gauge set - select the thickness of shim that you need and cut with tin snips - cut in shape of "V" at each end - sets under centre of base and the "v" straddles the base screws front and back. Fussy people will epoxy or sweat solder the shim to base - not sure that is really needed, except as confidence builder?
 
I just put on Warne Maxima steel bases (M902/830M) on my Zastiva M70. They seemed OK when I sighted in the rifle today. They were 36.95 at AmmoSource.
 
Potashminer said:
Using shims is "time honoured" tradition - so many of the home-done mauser sporters, even many earlier factory rifles, do not have precise contours on the receiver rings and bridges. You are on correct track, I think - want those tops of bases to be on the same plane - square left to right and in line with each other, and more or less parallel with the bore centre line or the bolt body. "Cheap" trick, I read somewhere, is to buy an inexpensive feeler gauge set - select the thickness of shim that you need and cut with tin snips - cut in shape of "V" at each end - sets under centre of base and the "v" straddles the base screws front and back. Fussy people will epoxy or sweat solder the shim to base - not sure that is really needed, except as confidence builder?
Click to expand...

Thanks. I can epoxy bed the base around the shims to make sure have full contact with the receiver. Any thoughts on if I should get longer screws or not?

Jim
 
Longer screws is about how much shim you are installing? So, typically 6-48 are used for bases? Not sure that you gain any more "holding power" once past about 5 or 6 threads? Could consider re-drilling / re-tapping to 8-40 screws if worried about shearing off - would likely require redrill to the base holes as well? I use a drop of the blue thread locker - loctite or other brand - on scope base screws - seems to work and hold okay. I actually used Weaver #46 front and Weaver #45 rear on my Zastava M70 in 458 Win Mag - the aluminum ones - but have not seen any issues - but not one of my "higher" round count rifles with full power rounds, though...

Load on bases and base screws related to the scope used - lighter weight scope is less load on recoil pulse - I happen to have a Leupold "Ultralight" - probably an M8-2.5 power scope. Took the idea straight from Phil Shoemaker's bear guide rifle. I will never, ever get to use a 458 Win Mag like the guys like him have done, so I tend to follow what they used...
 
I just checked and I am about 5 full turns (threads?) of the screws when they tighten up. This is not going to be a high volume shooter for me either. The scope I am mounting ( for now any way ) is a Burris Fullfield II in 3-9x40, probably a bit heavier than yours. I do use blue loc-tite on the screws.

Thanks, Jim
 
I can not do the math or explain the physics, but a scope in recoil seems to act as if it wants to stay still - inertia. Rifle barrel wants to rise under recoil - the shooter's shoulder is normally below that barrel centre line giving a pivot point with the line of recoil above that point - hence rifle usually wants to rise. Since scope wants to stay still, the heavier front end (like of 40 mm scopes or larger) will want to "bow down" towards the rifle barrel - hence a preference for a "solid pillar" - straight up and down from front receiver ring to scope tube - Slo-Mo on internet shows the objective bell bending down significantly under rifle recoil - want to resist that with an up and down solid pillar. However, looking specifically at the Parker Hale RAHS system on the Lee Enfield No. 4, the only "recoil" resistance is in the rear scope base - so my "farmer thinking" is that the front base/ring assembly needs to resist up and down forces, and the rear base/ring assembly needs to resist front-to-back forces. Hence, nothing lost by shims, especially under the front base.
 
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