The IOR Heavy Duty Flat-base Picatinny Optic Rail

19 May 2002
By Scott Powers

Looking for a heavy duty tactical base for your rifle but do not need a tapered base? I recently purchased IOR's latest version of their Rem 700 flat base heavy duty tactical rail and I have to say it is as good as any I have tested. Measuring 6.25 inches long, the base has three cross-slots at the rear and five cross-slots at the front. These accept any tactical ring built for the Picatinny Optic Rail specification, Mil-STD-1913 and I would imagine, some Weaver type rings. Badger Ordnance, DD Ross, IOR, MWG, and Leupold's Mk4s tactical rings all fit. The base comes with hex head action screws (my only complaint) and is finished in a black Chromate Process coating. This is said to be harder than a black oxide type of finish. You will have to be the judge as I don't understand the finer points of metal finishing. I am only knowledgeable in the denting, scratching and painting department.

You will need a metric Allen wrench to install the base as it is not yet provided at this time. The screws provided are standard size, 6-48s, but the holes in the base are easily adapted to fit a larger 8-40 if you so desire.

The base feels very substantial but not overly heavy. The steel base is hardened to 42 on the Rockwell scale and the finish is very well executed. I could see some very minor machining marks in the ejection port slot but other than that, the base appears very well executed and completely smooth over all. The contact surface between the base and the rifle's action for instance, is completely free of blemishes. The finish itself is a matt black granular coating I can best describe as resembling Parkerizing but I am informed that it is not. Sorry all. I have no idea what a chromate process is! Seems fairly tuff though.

My only true complaint is not with this base. It is with the type of action screw included. I have come to really appreciate Torx head screws for their ease of removal. Allen head screws, in my experience, have given me a bit of a problem when trying to remove them (God forbid if you used Locktite on installation!) because if torqued in improperly, you will often strip the head of the Allen wrench before loosening up the screw. It's a small nit though and one that would not stop me from mounting them into an action. As very few manufacturers have hopped onto the Torx head bandwagon, I am probably alone in this complaint. I have become spoiled by the Torx head type screw where available. If this bothers you, consider replacing the screws with equivalent Torx heads just in case you plan on salvaging the base for another project down the road. Otherwise, forget about it and drive on as most custom gunsmiths still stand behind the good old Allen screw. It is seldom one pulls a base from an action anyway. I think the fact that I recently tried to remove a Redfield base from one of my old hunting rifles is what has me on this kick. Those friggin Allen heads won't budge!

Back to the IOR base: The mount installed easily and the mating surfaces matched up perfectly. Like the DD Ross or Badger systems, the scope can go on and off with little change in zero, if any. The flat base is an IOR proprietary design based on the now well-accepted M1913 Picatinny system and judging by its performance at the range (flawless) it is a good one. IOR has often relied on DD Ross for input and corresponded with them in the design of both the flat and tapered base. I could liken the IOR flat base to the Leupold Mk4 one piece base but the IOR design has a bit more to offer in terms of versatility and apparent strength. It appears a bit more substantial which may result in less flex, combining this with the total number of cross slots and you have a bit more versatility when mounting various optical systems. If four cross-slots are nice, eight are better in my view as one can easily set up for daylight or night vision devices with a multitude of mounting options. The IOR heavy duty tactical, flat base, provides that kind of flexibility.

If you are in the market for a flat base you now have an excellent option in this second version of the IOR one piece base. Their older system, long discontinued, was similar to the Leupold offerings of that period, but like most tactical mounting system manufacturers, going to the M1913 system makes the most sense. It is just too versatile to ignore. They did their homework with this design and it works.

The base can be ordered direct from IOR at

Valdada IOR Optics
P.O. Box 773122 RCR #35
Steamboat Springs, CO 80477

Or you may find it at any number of outlets both online and via catalog, including our own Sniper Country PX.

Related READING: Flat or Tapered, which base do you really need?

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