Carbine sight heigth ? [Archive] - Jouster2 Shooting Forums

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joem

11-09-2013, 12:41

kcw

11-09-2013, 03:14

Do carbine sights come in different blade heigths. I have a early Inland that has the adjustable rear sight but the carbine still shoots high. I would like to find a sight with a taller sight blade if they were made.

There was one height only as supplied by the maker. When U.S. carbines were originally made each front sight was custom filed down to hit a standard target designed for the purpose. Unfortunately when the original flip sight was replaced with the newer adjustable one there was usually no effort made to install and regulate a new front sight, thus the problem you have. You'll need to find an NOS GI sight or commercial replacement with an original height blade. The GI tech manual (found as reprints) for the carbine as the specs for the arsenal targets, 25 & 100 yd I believe. You file the new sight as needed.

jimb

11-09-2013, 03:18

Originally all carbines were equipped with a tall front sight. They were test fired at the factories and the front sights were cut down to zero the carbine. During rebuilds, the front sights were removed and thrown into bins. When they were reassembled, they just grabbed any old sight and stuck it on there. That is why some shoot high and some shoot low. Yes there are taller sights available. You may need to search around to find one.

kcw

11-09-2013, 03:27

If you know how much taller it needs to be (there's formula floating around for that) to hit @ 100yds on the lowest setting, you may be able to pick up a used one at a gun show. You'll need to carry something to measure whatever you might find (micrometer?). I'd try to find something a bit taller than your estimate. You might also need a new pin.

Richard H Brown Jr

11-09-2013, 08:27

Dear Joem:

http://tinypic.com/r/2v8s945/5 is a modified version of the standard elevation adjustment target for adjusting the bullet strike for 100yrds. Print out on standard 8.5x11 page. Set up at 25yrds. Set the rear sight to 100yrds.

From a good supported position put the front sight post at 6 O'clock hiding the added post. From a 7 rnd string, 5 should be in the dotted area. if not file the top of the front sight blade down a bit. Paste or use another copy of the target and repeat till the 5 are in the dotted area. NOTE: if the front sight wiggles, you need to use a punch to pin in the blade key. See TM 9-1276 para 44 on page 59. for how to stake a loose front sight. As you get closer to the minimum requirement take less and less, off the post top, until you're satisfied. Always remember to keep the fileing flat and straight.

Numrich sells USGI front sight parts: part nos 26, 27, 28 http://www.gunpartscorp.com/Manufacturers/USMilitary-33541/Rifles-42386/M1Carbine-40100/PartsList-37101.htm?page=5

RHB

dave

11-10-2013, 07:14

Does the rear sight adjust down to 100yds? seems mine have low settings for mor then that. I am not going to look now. No one asked what range he was shooting at.

7 ring

11-10-2013, 02:53

Do carbine sights come in different blade heigths. I have a early Inland that has the adjustable rear sight but the carbine still shoots high. I would like to find a sight with a taller sight blade if they were made.

How high does the carbine shoot and at what distance? What is the height of the front sight blade ? I believe that a front sight that has not been filed down should measure 0.315" in height.

joem

11-10-2013, 03:42

Thanks guys. I'll have to check the blade height and I'll most likely buy a couple of front sights.

jim c 351

11-11-2013, 05:53

kcw

11-11-2013, 03:43

I have 3 carbines that shoot about 8 inches above point of aim at 100 yds. Two are Inlands and one Winchester. This is with 3 unmodified front sites, the highest available.
The only solution would be to have the site raised by welding, something I haven't done.
I'll bet you have a carbine like mine.
Jim C

Remember that the carbine was not designed to shoot to point of aim. If the carbine was inspected for acceptance on the 100yd arsenal range with the appropriate arsenal target for that distance, it would be accepted if it could place 5 of 7 rounds somewhere in the space between POI and 12" above POI. That was the acceptance standard for the adjustable sight with the ap set @ the "100" mark. The armorer would file the front sight blade only if the weapon shot low of POI. I would assume that carbines which shot high of the 12" mark were rejected. Also it was considered acceptable for windage purposes of those same 5 of 7 rounds could be kept in the area encompassing 8" to either side of POI. My guessimate is that there was around 175 sq." of territory on those 100yd arsenal targets for those 5 of 7 shots to land anywhere on for the gun to be accepted. A target rifle it was not designed to be. That being ,said I've never had problems getting the several I've had to shoot 3" or less.
The little research I've done seems to indicate that a "new" front sight blade would measure .333", just shy of being even with the top of the sight ears.

Richard H Brown Jr

11-11-2013, 09:07

joem:

AFter replaceing a loose front sight with complete new parts from Numrich, by a gunsmith and after the first trip to the range didn't adjust right. Read the TM 9-1276 on how to tighten the front sight and staked the key, so the sight didn't move.

http://i39.tinypic.com/2nvgxg1.jpg final adjustemt test.

Being a modern range, the 25 yrds was more like 25 meters.

IIRC Started final adjustments looking like this: http://i42.tinypic.com/2wex4jb.jpg

Month previously with a mixed bag of us and russian carbine ammo and the loose front key: http://i44.tinypic.com/2i9pks9.jpg

All shooting done from a bench sitting position with a folded fieldjacket wrapped around a travel pillow. target frame at 25m and sliding sight set for 100yds per the TM.

and since I stacked the targets ontop of each other the first target with all 100rds of playtime looked like this: http://i44.tinypic.com/9k9gys.jpg

rhb

RHB