Mod's to make my 30-40 Krag Sporter hit where aimed

[MUSTANG]

I bought a Krag 30-40 Sporter at the Kalispell Gun Show last November for $150.00. Added some comments on post #30 & #35 of another members posting ( http://castboolits.gunloads.com/showthread.php?229633-Springfield-Krag-30-40/page2 ).

After correcting the rear sight installation (turning it around and resetting the base), I took the rifle out to the rifle range yesterday to see if I couldn't get some indication of where it was shooting. (Load was a RCBS 200 Gr. Sil boolit sized to .311, with a 52 Grain charge of WC-860 surplus powder). Well I placed a target at 50 Yards and fired 4 rounds, no hits on a standard 25 Yard Pistol Target, so I pulled the Target and placed it at 25 Yards and fired 4 more rounds. I finally had a group on target telling me if I was high, low, right or left.

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Looks like the windage adjustment is OK for now, but it is shooting 8 inches too low at 25 Yards! That means I was hitting under the target, and probably below the ranges target Backer Board at 100 yards. The previous outing had produced lots of Snow and Mud flying in the berm, but no ability to identify where I was hitting. The group is pretty large for a 25 Yard distance, but we can work on that after we start getting the rifle on paper at 100 Yards.

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Above is a picture of my Original Configuration military Krag Rifle underneath the Sporter.

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As you can see from the picture, the Sporter (Top) retains the same original Krag sights as the original Military version rifle I have. Originally, the rear sights on the sporter (Top) were reversed 180 degrees, but I have since returned the rear sight base to it's correct position, and loc-tighted the threads of the base screws.

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As you can see from this picture, the Sporter (Top) has had the butt cut off a couple of inches, and the Butt Plate reseated when compared to the original military configuration on the bottom.

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A comparison of the Front Sights for the Sporter (Top) and the Military Configuration (Bottom) looking down on the sights.

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The Krag Sporter has a different set of front sights (Top) when compared to the Original Krag military front rifle sights (Bottom).

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Comparing the Front Sights for the Krag Sporter (Top) with the sights found on a Springfield 03A3 (Below) we can see that the original Krag Front Sights have been replace with a set of Springfield rifle Sights. A closer look at the front sight blade of the Krag (Top) will indicate that a Brass Sight Blade has been substituted for the Steel Sight Blade found on the 03/A3 Rifle (Bottom).

[madsenshooter]

Getting closer, what range did you have to set the sight to get your 25yd group?

[MUSTANG]

Correction of the point of aim will require adjustments to either the Front or Rear Sights. One solution may be to raise the ladder and use the 700 to 1800 yard settings to establish a 100, 200, 300 yard equivalent with the rifle, but that makes the standard "Battle Sight" useless; unless one takes the risk of shooting into the ground or below the Target Point of Aim. Given the distance the elevation is off, "Kentucky Elevation" could be quite a challenge.

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A rough estimate of center line of barrel to top of the Sight Blade on the Krag Military configuration rifle gets me a reading of 0.794 Inches.

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A rough estimate of center line of barrel to top of the Sight Blade on the Krag Military configuration rifle gets me a reading of 0.930 Inches. This means the Sporter front sight is sitting approximately 0.14 inches higher than the Original Military Configuration rifle (In relationship to the center of the Rifle Bore). I recognize that the measurements I made are not the most accurate given the center of Bore was a SWAG as you can see in the Pictures, but the relationships measured do indicate the Sights of the Sporter are considerably higher than the Military Rifle configuration. A shortening of the Front Sight should raise the impact of the Sporter Rifle.


Options:

(1) Use the Ladder Sight and build a Table of Short range (100 to 500 Yard) equivalents from the Ladders 700 to 1800 Yard Markings.

(2) Grind down the Krag Sporters Brass front Sight Blade (incrementally) until a 100 or 200 yard Zero is achieved.

(3) Make adjustments to the rear Sight? (Not sure this is the Direction I would pursue).

(4) Other options? I am not considering a peep sight for this Rifle at this time.

[MUSTANG]

Getting closer, what range did you have to set the sight to get your 25yd group?


Groups were shot with the Ladder in the Down Position ("Battle Sights").

[jrmartin1964]

As you already guessed, your front sight is WAY too tall.

Measure the distance from your rear sight to your front sight (in inches, as closely and accurately as you can).
Measure from your point of aim on your target (at 25 yards) to the center of your group (again, in inches, and as accurately as you can).
Multiply these two numbers together.
Divide that number by 900 (the number of inches in 25 yards).
The result will be the amount (and again, in inches) your front sight height will need to be reduced in order to move your group up to your point of aim.

You can either do some creative metalwork and alter your existing front sight; or remove that sight from its dovetail and obtain and install a front sight that is shorter than the existing one by the amount indicated (or as close to that as possible) in the preceding mathematical exercise. And remember, front sights are measured from the bottom of the dovetail.

[madsenshooter]

I see, I'd just work the front blade down until I got the zero I wanted. I just put a homemade .070 thick front blade on my 92/96. I left it tall just so I could carve it down to the right height for a 100yd zero. I'm hoping to get a good load developed using the NOE 316365 spitzer sized down to .311 for use at Camp Perry this year.

[Scharfschuetze]

Mustang,

At 8" below the point of aim at 25 yards, you're elevation error is about 32 MOA.

I'm guessing your carbine has a 22" barrel and about a 19" sight radius.

Given that, you'll need to reduce your front sight height about .176" or raise your rear sight an equal amount to zero at 25 yards. It doesn't look like you have a whole lot of front sight to file down.

The battle sight zero for the various Krag rifle sights was 375 yards. I'm not sure what the carbine battle sight zero was. If you have a carbine sight on your sporter, it should have a "C" marked on the base and on the bottom right of the leaf. A rifle sight will not be marked other than its range settings.

Krag sights can be confusing due to there being three or four different types in issue (for both the rifle and the carbine) and a couple of in-service recalibrations for the them due to experience as well as two different military loadings for the 30/40 Krag cartridge.

Some Krag carbine rear sights had a lowered base to compensate for reduced ballistics and for the shorter sight radius. If you have one of these sight bases, then you could substitute a rifle base which would help make up for some of that elevation adjustment. You might also consider some shims under the sight to raise your rear sight some.

[jrmartin1964]

I appears that the rear sight on the OP's sporterized Krag is a rifle sight, with the leaf graduated from 700 to 1800 yards. If this is so, then it is possible that it was originally a 30-inch barrelled rifle and that the barrel has been shortened. This would explain the band-type front sight base (most likely 'borrowed' from a '03 Springfield, as already noted) into which the front sight itself is dovetailed. It is a simple and inexpensive matter to remove the front sight blade from the dovetail and install a shorter one, once the proper height has been determined.

An alternative to the mathematics would be to simply remove the current front sight from the dovetail, then wrap a piece of stiff wire tightly around the barrel to use as a temporary (and easily modified) front sight. Simply leave a bit more that is necessary sticking up and fire a group at a target, trimming the end of the wire as necessary to bring the center of the group to the point of aim. Once that has been accomplished, simply measure from the bottom of the dovetail slot in the base to the tip of the wire sight - this will be the height of the new front sight needed. Sights can be had in a variety of heights for between $12 to $20.

[Mark Daiute]

Ok, adding my two cents here very quickly. Looks like both of the rifles have the model 1896 rear sight. This site takes the LOWEST sight blade.

did you try this load in your service rifle? I use a similar load in my service rifle and the load is nearly matched to the sight graduations.

Keep us posted!

[MtGun44]

Shorter front sight or taller back sight.

I normally adjust up a military ladder to 300 or 400 to get the
group right with low vel cast loads. Why is that so difficult?

Bill

[DaveInFloweryBranchGA]

Mustang,

After examining the pictures you've posted, it's plain and obvious the sporter has a 1903 front sight base - the earlier model with the dovetail, not the 1903A3 model. If that barrel has been modified to accept the 1903 front sight key, I would keep a 1903 sight on there, but would modify it.

The problem with that sight is the base is too tall and shortening the blade may very well make the sight blade too short or there may not be enough blade left to shorten enough. The top half of the sight itself (not the blade, but upper half of the sight holding the blade) may not have enough room for you to cut the sight blade notch lower (using a hacksaw blade or dremel blade) into the sight blade holder and file the height of the blade holder down some allowing you to lower the blade. You would also have to re-drill the pin hole for the blade.

If measurements indicate the 1903 blade holder doesn't have enough room to lower the blade notch, I suggest acquiring a 1903A3 sight base, which is a single solid piece and would have the room to lower the notch, file some off the top of the sight base and then drill a new blade pin hole. The 1903A3 base will mount on your barrel the same way a 1903 sight base does and look the same or better, but does not offer any left/right sight drift.

I hope this idea helps you. I may have a spare 1903A3 sight base, but would have to look to make sure.