1903A3 Shooting High

I bought a 1903A3 with a 2 groove barrel last winter. I tried PPU 150 grain bullets. I sighted it in at 25 yds but I couldn't get any kind of group on the target at 100 yds. I even had a keyhole at 25 yds, never had that happen before. I switched to Greek surplus M2 and it groups now but shoots about 13-14 inches high. The sight I have is approx. 3/16" tall. I don't see any letter on it. The rear sight is pushed down to the 2 mark. If I aim at the bottom edge of an SR1 target and put the top of the post at the very bottom of the peep (where I can just make it out) I can hit the black. Any idea how tall of a front sight I will need to find? Thanks

Sounds like your barrel is hooped. Key hole at 25 yds would be a real good indicator...

I don't know what that means. I read somewhere 2 groove barrels don't shot boat tail bullets that well. I think that is what PPU's uses. The Greek M2 shot just fine, just high. The headspace is right, barrel gauges about 1, crown is good and the spent cases look fine also.

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Originally Posted by browningautorifle

hooped

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Originally Posted by yoopercollector

I don't know what that means

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That's Jim's way of saying your barrel could be well and truly f....uh..screwed.

To my knowledge PRVI/PPU 150gr .30 cal. bullets are flat based, both SP and FMJ. Perhaps you just got hold of a bad batch. It happens.
I've had no accuracy problems with BT's and 2 groovers as long as they were in good condition, but, strange things can happen when shooting BT's in a barrel with a wore throat regardless of how many grooves it has.

Strange some would keyhole and others not. Unless the one type are smaller by a great deal, flat based and boat tail shouldn't make THAT much difference, diameter will...true though what VH says about the throat erosion. If they start cockeyed, they stay cockeyed. You say the barrel gauges "About 1"...muzzle, throat...?

The muzzle measures one. Maybe I got a bad box of ammo. If I can find a taller front sight I'll take it back to the range. Only one shot keyholed, just never had that happen before. The Greek M2 seemed to group OK but it is hard to aim when you have to make the front post almost disappear below the bottom of the peep. I read where they make A-E sights, does many one know what letter a 3/16" tall post would be?

I can't help with the height question but in the mean time if you want to continue with the accuracy evaluation you could just fold a piece of electrical or duct tape over the blade of the sight you have now to raise the height and trim until POI is where you want it. It's a Bubba fix but it works.

Why would you sight with the top of the blade on the bottom of the peep? The top should be in the middle of the peep not the bottom.

Did you read the post? The rifle shoots real high. I have to hold it at the bottom of the whole target to get near the bullseye. I have shot 1903's and Garands, I know how to shoot. I was asking about getting a taller front sight. I'll just order the tallest one I can find.

And that's just the way to ask for help around here.

Yes I read the post but I missed that part. My bad! Was only trying to help but I will leave you alone so you can get a taller sight.

Sorry about my last post, was just a little frustrated. Was asking about front sight post because I'm hitting so high, I shouldn't have put all the extra stuff in my OP. From reading other post a lot of questions get asked about what is happening with the rifle so I put as much info as I could. Sorry again for sounding like an a$$.

It's all about the sight height...some of these guys have them lying around like so many pennies. If we knew more about your blade...But the keyhole thing...?

My sight is 3/16" tall, I ordered one that is supposed to be .535 tall. I have no idea how that will compare to the sight I have now. I only had one keyhole with the PPU but some rounds didn't hit paper. When I got on paper the Greek ammo grouped fine just very high. It was hard to aim because of the sight picture I had to hold. I could of had a bad box of ammo. I liked the suggestion about the tape on the sight blade.

I might suggest shooting a target much closer and that will decrease the error for the time being until you can figure out the ammo problem. I'd be suspicious of the bullets that went wide of the target too.

If you have a vastly taller sight on order, it can always be shortened a bit...always use the correct sight picture and correct point of aim, just use bigger paper and MUCH closer (12yd) to see what's happening. You can't move to 100 until it's correct with ALL ammo at 25. As you've found out, there's things we can't decipher. You just get frustrated...

By the way, 3/16ths is about .220....535 will be over half and inch.

Well , at least we know why your rifle is shooting low :lol: .

The shortest front sight blade measures .477 tall . From there they jumped in .015 steps , or in 2 MOA increments . 0.492 , 0.507 , 0.522 , and 0.537 .
You said your sight was 3/16 ( .1875 ) .
If it measures .1875 and 16 inches low at 100 , then you would need to come up 8 2MOA steps ( 8 x 2moa = 16 moa ) or .240 for a total of .4275 .
The .477 would be appx .050 too high which would now put you 6-7 inches low .
It could be filed , if needed.
Chris

Well... I can understand why Detroit asked that. For us to help with the question we will need to know what the actual POI (point of impact) is from the POA (point of aim). Having the tip of the f/s at the bottom of the rear app does not give us anything to work with. If you can give us the measurement with a normal sight picture (may need an extra large sheet of paper) and I would recommend placing it at 200 yds if your sight is on "2" and we can get accurate and applicable data.
Then apply this information, I consolidated this from bits and pieces I've ran across over the years. Might be a good sticky..

Data for sight blades 1903A3

The following data is from Ordnance Supply Catalog “ORD 9 SNL B-3” dated 20 May 1944. The drawing number would indicate that the “A” sight blade is the maximum height for the Model M1903A3 USGI sight.
A153078E - Sight, front (height 0.477) (M1903A3)
A153078D - Sight, front (height 0.492) (M1903A3)
A153078C - Sight, front (height 0.507) (M1903A3)
A153078B - Sight, front (height 0.522) (M1903A3)
A153078A - Sight, front (height 0.537) (M1903A3)

Note that the difference in height between each successive height is .015" This is equivalent to about 2" change in elevation at 100 yards.

Formula:
Measure sight radius, (27.75 03A3) divide sight radius by distance to target in inches (100 yds x 36 = 3600)
27.75/3600= .0077, so to lower a POI one (1) inch, you need to raise your front blade .0077
The above information corresponds with the 2 inch POI difference between the sight blades available.

---------- Post added at 12:10 PM ---------- Previous post was at 12:05 PM ----------

Also keep in mind, at that range the Army used a 10 inch black center and taught soldiers to use a 6 o' clock hold meaning the sights were calibrated to have an impact 5 inches high to hit center. So hitting 5 inches high at 1 or 200 yards is how they were intended.

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Originally Posted by Randy A

and I would recommend placing it at 200 yds if your sight is on "2" and we can get accurate and applicable data.

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If he's a bit out of whack, like he is, he'll have NO idea where he's hitting... You need to work close and do the math.

or bottom the rear sight and do it at 100, probably need about 4 feet of paper above the black, 3/16 is an extremely short front sight, an A blade will be a huge difference

Guys , he gives that info in the OP . Normal peep picture @ 100 yds with the sight set on 2 gives 14 inchs too high hits . 14 inches + 2 inches for the 200 yd setting = 16 inches high .
Wait .... would that be 14 - 2 = 12 inches ?
May be . Anyway , the shortest blade is going to be too high , but that is what I'd get . That would get him close . I would also check to see if the forend is appling the right amount of upward force on the barrel because these guns tend to be right on.
Chris