Last weekend I bought a nice .30 cal M 1 carbine built on a Springfield receiver. The gun is a shooter, and though the parts are USGI, it has no collector value.

When I shot it for the first time, I found that the rear sight had not been staked! Fixed that, but the rifle is shooting 4 inches low at 20 yards!

My front blade is 5/16 inch high, and I would need to remove about 1/8 inch to get it where it should be. The question is, how high should the front site be? Could any body measure thiers for me?

Any comments or suggestions on this matter would be appreciated.

Crash

Crash, I would not file my front sight down based on anyone else's spec's. Every gun is different and if you file it down too much, you're screwed! Just take the baby to the rifle range with you and include a good course file along with your ammo. Shoot and grind on the sight, repeat until you get it right.

Here is another great idea for the M-1 Carbine. DRILL OUT the rear peep so the hole is about twice the diameter it is originally. What this will do for you is allow better shooting in dim light conditions and secondly, allow better aiming on moving targets do to larger field of view. You may think this will harm your accuracy...but it won't I've owned several of these carbines and this became one of my standard overhaul proceedures.

Oh, here is another good tip! Cut you a piece of 1/4" wooden dowel about 3/4" long. Now disassemble the carbine. In the receiver you will see a hole where the bolt return spring fits into when the gun is assembled. Drop the piece of dowel into that hole and then reassemble your carbine with the spring against the dowel.

Most of the bolt return springs are about on their last legs by now. This chuck of dowel in that hole will jack up the pressure on that spring and make the bolt snap back shut like a bear trap...thus ensuring better feeding and almost jam proof operation. No, I've never had this cause jamming with anything like a propper M-1 Carbine load.

If you reload for this rifle, the 100 gr "Plinkers" (which I assume Speer still makes?) are good carbine bullets..........as are 115gr gas checked cast bullets. With these bullet changes this gun is DEADLY and will practically cut a rabbit or fox in half.

Have fun with it. These are neat little rifles with a bit of TLC.

Crash I just reread your post about the sight dimensions on this rifle. Something sounds fishy. I wonder if you have the original sights or something someone cobbled together just to sell the gun?

If so, you should be able to order replacement mil surplus sights for the rifle and start over.
Something ain't right with the sights on the gun. It should never be THAT low!

I've often filed down front sights on my match M1A's to achieve a 200 yard zero near the bottom of the rear sight's travel. I like about 4 clicks from the bottom. We do this to avoid problems with stock weld when back at 600 & 1000 when the rear sight it WAY up in the air. Tough keeping your cheek firmly on the stock that way.

The Brownell's catalog has (or did) a chart to show how much change in bullet impact you get for a given change in sight height for a given sight radius. My M1A's have a 27" sight radius, so I whittled off about 60 thou, IIRC. Your shorter carbine would need less, for any amount of wanted impact change.

HTH,

Redial

Crash, in order to give you an accurate answer you need to come up with the following and precise info :

- error in " ;
- line of sight in yds. (= distance from rear to front sight) ;
- range in yds. ;

Crash--

The formula is: The amount of change in inches, times the sight radius in inches, divided by the range in inches.

4 x 21.6 = 86.4 divided by 720 equals .120

Since .125 is an eighth inch I'd bet that gun needs a 3/16 front sight blade.

Thanks for all the replies. Just to set the record straight, I intended to ask some carbine owners to measure their front sight blades for comparison. As I stated in my orignal post, the formula required about and 1/8" to be removed leaving a 3/16" or .1875" blade height.

I have filed sights on both rifles and pistols before and know how to do this. What I was trying to figure out was if I had a bent barrel or an unsquared receiver. By getting the actual length of blade on several examples, I could determine if the rifle had just not been finished (this was a "parts gun" and the rear sight had not been staked) or if I had a greater problem needing more work.

I called Springfield Armory, and they were kind enough to measure several carbines for me and give me the answer I was looking for. The rifle is fine, the builder just didn't finish the job!

Because the M1 carbine is basically a fixed sight gun, once assembled, you zero the elevation by filing the front site (the elevation adjustment on the rear sight is a BDC).

Thanks again,

Crash