Unertl Scope Battery Reset

[mike radford]

Carlos did but one on Ma Duce. He also used one in his famous thru the PU scope shot of the Cobra. Rifle was M70 Winchester. Unlike this US rifle, his had a sporter stock.

Information

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[JerryB08]

Mines on a S42/G K98 And it returns right back to battery. Rarely does it need manually moved with milsurp ammo.

[Cosine26]

Unertl Scope Usage
Having used the Unertl target scope extensively on both a Winchester M&) 300 H&H Bull gun and a M70 Heavy barreled 30-06 I shall venture the following information.
a. The eye relief on the scope is very short. If the scope were rigidly mounted, during recoil the rifle and scope would recoil enough to hit the shooter in the eye. Hence the scope is free to move so that the rifle will recoil under the scope and the scope will not hit the shooter in the eye.
b. The Unert l is not a rugged scope. Heavy recoil from the hotter than hell target loads (180 gr and 200 gr BTM bullets, max load of IMR4350 or 4831) would impart severe shock onto the scope. Hence the scope was allowed to slide in the mounts under recoil. The purpose of the spring was to serve as a method of applying successively increasing shock absorbing restraint to gradually buffer the scope motion. The problem is that the spring was too effective. At the end of recoil, the spring would be compressed, the rifle would have recoiled towards the shooter’s eye , and the spring would drive the scope back to battery and possibly hit the shooter in the eye. For small bore work this was no problem, but for big bore work it was.
Resetting to Battery without the spring.
This is the method that I used. Both M70’s had low mounted bolt handles so clearance was not a problem, I believe that on some M1903’s the bolt handle was ground to provide clearance. Upon firing, the rifle, with the spring disconnected or removed, would recoil and the scope would be restrained by the stop ring.
After each shot I pulled the scope back to battery with a right rotational pull and then depressed the scope against the mount plunger to insure that the plunger had not stuck. The technique tended to make each shot with the scope in a consistent position. Even though the mounts were very precise, there was always some “slack” in the adjustments. The adjustment knobs were on the top ad side and were to move the tube, ergo the LOS, in windage and elevation. At a 45 degree angle to the bottom and side of the adjustment knobs, the spring loaded plunger was designed to keep constant pressure on the tube to keep it against the adjustment spools. With only slight adjustments or motion the plunger might “stick” if not exercised.
For small adjustments, most shooters “holdover or under”. Most used scorebooks that had grids marked in MOA so if one held the edge of the X ring or the ten ring, the light of sight moved and the line of bore moved.
Just some thoughts from and old Unertl user.

[NMC_EXP]

Paul

I agree with and will expand upon Cosine26's comments:

The U.S. Army Marksmanship Unit (USAMU) formerly used bolt action rifles for long range competition. U.S. NRA rules allow the use of scopes in some events and the USAMU used barrel mounted scopes such as Unertl and Lyman Super Targetspot.

For use with a centerfire rifle, the USAMU manual states the recoil spring should be removed in order to: (1) prevent the scope from being driven by recoil into the shooter's eye due to the short eye relief and (2) prevent recoil induced damage to the scope.

The manual goes on to state the scope must be returned to battery after each shot by pulling it to the rear until it reaches the stop and giving it a slight twist (always in the same direction).

For long range USAMU used calibers such as the .30-.338 and .300 Winchester magnum. Bullets from 190 to 220 grains and maximum powder charges so recoil was significant.

I have seen a couple of references to rubber bands being used as a return to battery device. This would seem to counteract the positive effects of removing the spring.

Regards

Jim

[Cosine26]

That looks like a 2 inch Unertl, and the recoil spring is still in operation. I suppose that the Ma Duce would require that as it probably had a lot of recoil.
I believe the rifle that Hathcock used was a M70 Winchester in 30-06 using M72 ammo - probably NM grade. Must have been a chore keeping those Unertl mounts operational in the Nam climate.
I had a friend who served in Nam with a USMC radio operatioin and repair outfit. Said that a Marine came in with an M16 and asked if he could use the sonic cleaner. The cleaner removed all of the finish, and my friend said that you could watch the rust form.

[vintage hunter]

A sniper in Korea with a Win.70/Unertl with spring engaged, anybody recognize him? Another M2/Unertl in Korea. Notice the angle of the scope, target must be way out there.

[Jim Tarleton]

That looks like a 2 inch Unertl, and the recoil spring is still in operation. I suppose that the Ma Duce would require that as it probably had a lot of recoil.
I believe the rifle that Hathcock used was a M70 Winchester in 30-06 using M72 ammo - probably NM grade. Must have been a chore keeping those Unertl mounts operational in the Nam climate.
I had a friend who served in Nam with a USMC radio operatioin and repair outfit. Said that a Marine came in with an M16 and asked if he could use the sonic cleaner. The cleaner removed all of the finish, and my friend said that you could watch the rust form.

Hathcock put his scope in a hot box at night, but the Unertls were all repaired more than once. The biggest problem was broken reticules. They used spider web for replacements.

Jjt

[emmagee1917]

A Ma Duce on a tripod and sandbaged does not move that much , so the scope would remain in place far more than on a rifle .
Chris

[Michael Petrov]

The only thing I have to offer is that when your working with under 1/2 MOA always push the scope back into battery with your left index finger and don't pull it back.

A few years ago I started using the recoil spring on rifles from 32-40 up to 30-06 and that is working well for me.


Admittedly the majority of my shooting is with lead bullet rifles at 100-200 yards.

[mike radford]

I got the repro Unertl. It is not a faithful reproduction. It is several inches shorter. The objective tube is slightly smaller. The blue is pretty poor. The rings are more narrow and do not seem as substantial. Optics are pretty darn good. Range test pending.