Home Forums Hunting & Shooting Ask The Gunwriters One-piece vs two-piece scope bases?

All my current rifles have two-piece scope bases. I've got a new 700 Alaskan on the way and I'm thinking about a one-piece base for it. What are the pro's and con's of a one-piece base?

HighRoad,

Your talking about the Sako one-piece Ring mounts correct ?

I'd be interested in an answer on that as well.

Personally I'm hoping Talley will make a modified base that will fit the sako actions, or maybe a better route would be to have a gun smith drill and tap the Sako receiver top to accept a talley integral ring (one piece).

Spot

i have a one piece base on my 243, and 2 piece bases on my other rifles. never had a problem with any of them, although i believe a one piece base is more stable (steady) than a 2 piece. others may differ which is why they make different types.

My perception is that a one piece mount can induce some stress on an action if the screw holes do not mesh exactly with those of the receiver. Might be rectified somewhat if the mount is used as a guide to drill the receiver. Stress may also be induced if the single piece mount and receiver are fabricated from different metals and expand/contract at different rates.

We may have the same issue though with 2 piece mounts as most scopes are of different metal than the receiver. The old target mounts where the scope was free to travel on recoil might have gotten around that. One needed to remember to reposition the scope after each shot and many a group was spoiled with that slip.

For hunting units this is likely not much of a significant issue. I go AC/DC though among my units, but mostly use 2 piece units on the heavy kickers.

Back in the last century the one-piece was mount regarded by some as stiffening the action, and the two-piece mounts were better for keeping weight down.

After using both I use the two-piece bases now.

jim

Typical one-piece bases only use three screws, 2-piece bases use four. This relates to the old adage that a chain is no stronger than its weakest link. A 1-piece base itself may be stronger--but its connection to the rifle s weaker. Of course, the base(s) can be epoxied to the action, something a few real rifle loonies do.

Personally, on hunting rifles I much prefer the lighter weight and four screws of 2-piece mounts. I especially like mounts that attach directly to dovetails on the action, or mounts where the base and ring are one piece, as in the Talley Lightweights, mostly because I've found both types stronger than the typical screw-on-base/ring combo (though obviously the typical mount has proven strong enough for about any use).

In reality, about the weakest mount on the market is one of the most popular--and heaviest. The typical Redfield-type mount, using a 1-piece base with dovetail on the front end and windage screws on the rear, is the worst at holding a scope in place. It only uses 3 base screws, and the windage screws at the rear are not enough to keep a scope from shifting forward slightly under about any significant recoil. Yet because the whole system weighs close to half a pound, many shooters regard it as stronger than Superman.

Mount some Seekins Precision alloy one piece base and rings on this rifle and don't look back.

Forget Leupold, redfield type of stuff and even Talley. Get the Seekins and be set for any conditions and nocks that you can give to your rifle.

They are aerospace quality and the price isn't as high as you might assume. Look them up on line and give Glen Seekins a call.

I would love to try some Seekins mounts, but apparently he is having a really hard time keeping up with demand, which is pretty specialized (limited) so far. Any word on that?

I have found the Talley lightweights will keep a hunting scope in place for at least 10 years of hunting, or at least harder hunting than the average guy does.

Mule Deer:

This is the second time I have read this about the Redfield type one piece base and the opposing windage screws. The first time, IIRC was in an article by Ross Seyfried.

I had a synthetic Weatherby Mark V in .300 WBY, with a Leopold 2 1/2 by 8 Scope.

After two or three shots, the screw in the ring would ride up out of the little dove tail in the base and the shots would start climbing. After four or five shots, the rifle would be shooting about a foot high at 100 yards.

Could this be the reason Leopold came out with the dual dovetail mount?

This problem should be given more emphasis in the shooting magazines. I like to have never figured out what was causing the groups to climb like they were, and I would guess that other shooters have had the same problem on lightweight and heavy recoiling rifles. A heavier scope, such as a variable only adds to the problem.

Actually, I didn't figure it out until I read Ross' article.

There is something else I have experienced, and you might have, also. If the front two screws are tightened down, sometimes, due to both the rifle manufacturers and mount manufacturers tolerances, there could be several thousands of clearence between the bottom of the base and the top or the rear receiver ring.

Tightening the rear base screw down will bend the base, introducing unwanted stress, and also the scope won't be perfectly concentric between the front and rear ring.

When I find this in my rifles, I shim the rear until it doesn't give when the rear screw is tightened. I have never experienced the front ring being too low.

This situation can also happen with two piece bases, except it would not be as obvious, but due to the above reason, manufacturing tolerances, one base could be slightly lower than the other, introducing stress to the scope tube.

My bad earlier...

I was thinking one piece / two piece ring base combo.

Spot

Superior products tend to be hard to keep in stock for a small manufactuer like Seekins Precision. Just supply and demand. Besides if they get too big then QC is out the window and you have to start a customer service program. Make it once and make it right.

1234567,

Yes, that is one reason Leupold developed the Dual Dovetail.

Also, if recoil is hard enough, the ascope heavyenough the rings high enough (which seems to be case more and more, as hunters go to larger and larger scopes) the front mount can actually bend during recoil--or at least tip, if the dovetail has any slop at all. The scope actually pulls forward, the rear ring shifting forward slightly between the windage screws. You can se this in many rifles that have been shot much, by looking closely at the rear ring.

In some actions, especially older (but good) actions like the 98 Mauser, a 1-piece can actually warp. the action slightly when the screws are tightened. This also does accuracy no good.

Of course, the best way to fit any mount/scope to any rifle is with as little stress as possible. This is why some custom makers make a mount specifically for that particular rifle--and why rings are lapped once mounted on a rifle.

All of which is why I tend to use two-piece mounts on most of my rifles. Sometimes these are as simple as Weavers (which in many ways are darn good mounts, with enough "give" to accomodate the difference between rifle actions and scopes, yet enough strength to hold scopes very well), and sometimes they are Talleys, either Lightweights or steel, or Dual Dovetails. In general, such mounts hold scopes better, with fewer problems, than all but the very best custom 1-piece base mounts.

Varmint Als website had an excellent article of stress analysis of one piece vs two piece. He also examined the expansion characteristic mentioned earlier by one minute. I dont recall all the detail but more stress was placed on the scope from dissimilar material between the scope and the action than one vs two piece. In short if you shot a rifle with a steel receiver you should have a steel tube to match the thermal expansion/contractions to prevent stress.

I've read about bases being epoxied or silver-soldered onto the receiver, but not a whole lot of detail about it. Either way, it occurs to me that it would be best to epoxy/solder first, then run the screws in later; otherwise if the epoxy or solder gets down into the threads, you'd just about have to ruin the receiver to remove them. Maybe one could coat the screws in release agent and carefully screw them in while the epoxy is runny...

Can you expand a bit on how its done, what to look out for (particularly for stainless actions), etc? And are there tools or jigs to check the "base axis" against the bore axis? I can imagine a steel rod like a ring lapping rod, with a laser innit.

It would seem that soldering or epoxying scope bases to a gun should be considered a permanent installation (not to be removed).

-

I was always told (50+ years ago) that one-piece bases stiffen the action and make it more accurate. Now I know that advice is not correct. Unless the base is welded to the action to make the whole thing a monolitinc structure, it is not any more rigid than a 2-piece base set-up. The screws holding the base to the receiver add nothing to rigidity.

There is one disadvantage to one-piece bases - access to the magazine to load cartridges is impeded. Yesterday, I was at the range and put about 300 rounds of 260 Remington and 308 Winchester downrange and found it annoying and painful (arthritis) to load the magazine.

Lighter weight , easier magazine access and, (arguably) a better appaeance means that I'll switch to 2-piece bases for future purchases.

Big Redhead,

Epoxied bases can be removed by heating them. This melts the epoxy long before the mount or action is affected.

Forum member Brad turned me on to using JB Weld to epoxy bases. It works very good and isnt very hard to remove.

I would not consider a one piece base on any rifle.

The whole concept of accuracy is based on stress removal from the 6 layers of a rifle.

Floorplate to stock
stock to action
bases onto action
lower rings to bases
scoper tube to lower ring
top ring to scope (maybe)

Any binding or sress will at some point releive or change in the tension created, so that accuracy will become affected, whether permanenet or temporarily.

If you are serious about determining the potential accuracy of your barrel, you need the entire lockup system of your rifle tight and as stress free as possible.

My .460 has worn several brands of scope bases, mostly for testing, and still wears Leupold bases today. They will outlast me and the rifle. I do not trust scope mounts and lapp them all. The bases I glue on the action.

Rings and bases are mass produced as are rifle actions. I consider it unreasonable to expect two independent metal objects from two independent manufacturing sectors to be a perfect stress free fit.

AGW

Mule Deer:

You wrote, "The scope actually pulls forward, the rear ring shifting forward slightly between the windage screws. You can se this in many rifles that have been shot much, by looking closely at the rear ring."

When I finally found out what was happening, my thoughts were that the scope was staying in one place and the rifle was trying to jump out from under it.

The base has a sort of what would be called a round dove tail, which the heads of the screws tighten into. As the ring moves, it is slightly jacked up because of the curvature of the dovetail. This raises the rear of the scope, causing the rifle to shoot high if the same aiming point is used, but I guess you already know this.

I imagine that if you kept shooting it, the shots would get higher and higher, maybe three or four feet high.