Carbine won't zero with new stock

[EdL]

I wasn't really sure how to title this.

I tried a different stock on my 1943 NPM and with it the gun shoots about 6" high at 50 yards even with the rear sight on the lowest setting.

Here is the background. I recently got a 1943 NPM from the CMP. The gun has a Buffalo Arms barrel. I took it shooting and found it a bit more accurate than my 1943 Underwood. Also, I found that the NPM would function reliably with soft points which the Underwood would not always do. The only problem was that the NPM had a potbellied stock, which I did not like compared to the Underwood's stock.

So I switched stocks.

The problem is that when I run the NPM in the Underwood stock the gun shoots about 6" high at 50 yards even with the rear sight at the lowest setting, while in the potbellied stock it had not problem shooting dead on at that distance.

Any thoughts as to why this occurs?

Should I just change back to the original stock that it sights in with?

thanks

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[rokwell]

My guess would be that the front sight was filed down to work w/ the potbelly stock, so now when in the Underwood stock, it's too short, which causes you to raise the sight blade high to get a good target picture (which causes the high shots). But I'm not a gunsmith.

[Tired Retired]

EdL,

I believe you are seeing the difference in the M-2 and M-1 stocks when it comes to mating with the carbine metal. You may want to check this, but I will make a wild guess.... When the carbine is in the M-1 stock, the barrel sits very close to the barrel channel in the bull nose? and when in the M-2, the barrel sits higher above the wood of the barrel channel? If the barrel is in contact with the wood in the bullnose of the M-1 stock, your carbine is not properly supported and is causing you to tilt the stock (and line-of-sight) higher. If that is the case, you are going to have to work with the recoil plate of the M-1 to get the barrel to "float" above the barrel channel about 1/4".

[EdL]

Tiredretired,

I think what you say makes sense. To be honest, I am new to the M1 carbine and even though I have read the various guides including the one on the CMP's website, I have no idea what I would have to do to "work with the recoil plate of the M-1 to get the barrel to "float" above the barrel channel about 1/4."

Also, the nonpotbellied stock which I want to use with the NPM carbine is not a spare one, but one that came with my Underwood. so I don't think that I want to be experimenting with it, since it might mess it up and both guns can be sighted in with their original stocks--the only problem is that I want to use the regular M1 carbine stock that came with the Underwood with the NPM, which itself came with the M2 potbelly stock set. I guess I could buy a new/used stockset for the NPM to experiment with.

Maybe if I bought a stock and handguard from someplace like below:
http://whatacountry.com/m1carbinestocks.aspx
but then it still might not be hitting point of impact and I would still have to do some voodoo on the stock--none of which I know how to do.

thanks,

Ed

[Tired Retired]

Ed, in discussing your situation, let me share a few NON-EXPERT stock observations and OPINIONS (not facts). First, M-1 stocks in gerenal were not known for their accuracy. They are thinner and lighter in their cut. Second, stock for stock, they have also more likely to have been used more, show more wear, been exposed to wartime elements and conditions and been out the weather more. A higher percentage of the M-1's have shown alot of wood shrinkage. The M-1's are also much older on the average (not made since 1945) where SA was making some M-2 stocks up through the 60's. Oh, and don't forget the cosmoline storage factors - longer to soak it in. The M-2's generally have not seen as much action. Ok, Korea happened, but like I said, SA was making stocks through the 60's.

There are exceptions to all these general observations, of course. I have one Trimble that is in almost museum condition and I have one SA M-2 stock that looks like it went through the Chosin fight. Personally, I have always considered the M-1 stocks as historical show pieces and the M-2 the shooter stocks. When it is a particular carbine's turn to go to the range, if it normally wears a M-1 stock, I swap it to a second M-2 stock so that I don't mess the good one up at the range. You don't let your daughter wear a ball gown out to play basebal, do you?

Whatacountry has some good stocks. Damon even helped me find a rare HQ handguard at a good price. He has the "highend" stocks listed and he also has some "regular" M-1 stocks which are not so expensive.

Oh, one last comment on my stock Sermon this Sunday morning. I noted in the picks at the Camp Parry carbine shoot, a large percentage of competators were using M-2 stocks to shoot.

Of course, if you are not able to get those worn-out, off-target, can't hit anything carbines to straighten up, you are more than welcome to send them to me for disposal!

[imarangemaster]

WHen I switched my CMP Inland racker from an RMC Type I to a SA potbelly, I "hung" the receiver in the stock per CMP instructions. My group size was cut in half. I am sure it has to do with the weapon having been zeroed in the potbelly. Front band tension on barrel (downward deflection when tightening) etc. can make a big difference. I would leave it in the potbelly if it is dead on. The mixmaster CMP has more utility as a shooter than cool factor of a Type I stock, IMHO.

[INLAND44]

You have stumbled on the right kind of stock for it, because 6" high at 50 yds is just about perfect. The rear sight low setting of '1' - '1.5'. Means it should hit maybe still a little high at 100 but still get a good hit at 150, maybe an inch low. This trajectory will be high at 50. Congratulations. Technically, the stock shouldn't matter since the Carbine does not need the stock to be completely functional, but incorrect assembly of the Carbine into one or the other stock can affect accuracy. I'd guess you simply got lucky when you put it in the other stock and got it hung right on the recoil plate.

[imarangemaster]

You know I-44, you are right, I hadn't thought of that. At 25 yards it is 1 1/2" above POA to be dead on at 150! Should be good for a 6 o'clock hold on 100 meter targets!

[Tired Retired]

That's fine for all you guys with big fancy houses... I am in Texas, and it still ain't 150 yards from the front porch to the street.... I need to get a bigger yard if I am going to be shootin' that far...

Ed,
Seriously, half the fun of carbines is the buying, switching and shooting till you get it the way you like it. Inland is ballistically correct. But let your carbine lead your way....

[EdL]

I guess I am spoiled because the first carbine that I bought a few months ago from a friend was dead on at 50 yards--which is the max distance at the indoor range where I shoot it. Its regular M1 carbine stock is far more comfortable to my hands than the potbelly of the NPM that I recently got from the DCM. The NPM is the gun that shoots 6" high at 50 yards.

---------- Post added at 10:20 PM ---------- Previous post was at 10:16 PM ----------

My guess would be that the front sight was filed down to work w/ the potbelly stock, so now when in the Underwood stock, it's too short, which causes you to raise the sight blade high to get a good target picture (which causes the high shots). But I'm not a gunsmith.

Thank you sir.

I compared the front sights of the two guns and it does appear that the NPM carbine that originally came with the potbellied stock does have a shorter front sight than the underwood which shoots to the point of aim at 50 yards. So I imagine any attempts to use a standard M1 carbine stock not be successful.

So I guess the answer is to switch stocks back and have 2 guns that shoot to point of aim.