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Kilibreaux
Junior Member


USA
51 Posts

Posted - 08/17/2016 :  03:55:00 AM  Show Profile Send Kilibreaux a Private Message  Reply with Quote
I've read about all the magazine problems...it seems the M1 Carbine world is awash in poor non-feeding, unreliable magazines. But there is ONE "truth" and that is at some point there were plenty of reliable feeding magazines! This means there IS a baseline standard that works, so the key is apply root cause analysis to find the problem(s), sort out the core issue, and work upward from there.

To this end I started with my own modest supply of magazines...a single 10 round that came with my Inland new manufacture, two KCI 10/15 "blocked" with welded floor plates I got from Jestice Arms, and three 10/30 "blocked" I sourced from Fulton Armory to being RCA'ing the problem.

The original 10 round mag was about a 30% feeder...totally useless.

the 10/30's from Fulton Armory started out as a mixed bag....
Mag number one would feed 100% from the left side, and not at all from the right. It would consistently kick the round out to the extreme left to impact hard against the barrel and jam solidly. Also, the second to last right (right side) would bind against the oversize bolt hold open and balk on feeding further compounding the problem of kicking extreme left.

Mag number two fed about as close to 100% as possible! Left side, right side...

Mag number three fed almost as good as number two, but consistently the LEFT feed would slide right to hit the barrel and jam....yet the RIGHT side feed smoothly!

The 10/15's from Jestice are known KCI brand and BOTH feed pretty consistently! So these became my baseline standard.

I disassembled the carbine, pulled the recoil spring and guide so as to operate the bolt manually...this is purely about feeding, and in this condition I can control feeding force and speed. Generally any gun that will feed slowly at a moderate cycling pace will feed superbly during normal cycling speeds. My mission was to control the movement of the cartridge so as to WATCH just what happens.

Now, I started out with a dial caliper and checked every relevant dimension between mags only to realize that data to be of little use.

But along the way here is what I found to be of 100% importance! I noticed that in the near perfect feeders, the feed lips lie in perfect contact with the case along their entire length. I also noticed that ALL of the mags with feeding problems had a feed lip that did NOT lie in perfect contact with the case along its entire length!

The spacing of the forward quasi-lips...inconsequential due to the hard parts of the carbines feed ramp.
Total width between feed lips....generally very close, but of no consequence.
Magazine seating depth...again, I found no REAL relationship here. The factor mag is slightly below 1.50" yet did not feed well. The KCI's were slight...over 1.50" and DID feed well. The Fulton Armory mags are very cleanly 1.520"+ and one fed very well, one nearly as well, and one not at all from the right side!

So it all came down to those rear feed lips being in near perfect contact with the case body so as to either prevent the case from striking the feed ramp and shifting hard to the lateral, or in holding the case "down" too long causing a hard bump on the feed ramp.

Sure enough the feed lip on which ever side was allowing the case to either slide out laterally too early, or be held down too long was out of conformance! So this is IT? This is the big bad bugaboo that has people throwing magazines in the trash, or replacing EVERY component without success?
Well, it seems so...

I grabbed a pair of needle nose pliers - smooth jaw, and began to carefully "tweak" the lips either up or down depending until the case lay in perfect alignment with the feed lip's interior plane.

"Voila" the feed problems went away! Well, except for that oversize bolt stop that will need to be addressed, the mags suddenly "trued" right up and manually cycling saw the rounds..."cheap Russian Tulammo" feeding nicely into the chamber without any yawing at all!

Basically, if you have a cartridge lying in the mag that you can freely swing laterally...that feed lip needs to be "tweaked" down/in so the case stays in contact fully along its feed length. If you have a cartridge that hits low, you're looking at a feed lip that is warped down too far...slight upward tweaking will bring the feed up to where it needs to be.

I hope others will consider this approach...it simplified down to the feed side lip being in full contact with the cartridge...too loose the rounds kick out laterally and jam, too tight, the rounds jam low.




































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swampmolly
Senior Member



USA
764 Posts

Posted - 08/17/2016 :  07:49:47 AM  Show Profile Send swampmolly a Private Message  Reply with Quote
I guess a trip to the range is in order.
I sure hope that is the answer.
SM
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shadycon
Veteran Member



USA
1356 Posts

Posted - 08/17/2016 :  12:42:50 PM  Show Profile Send shadycon a Private Message  Reply with Quote
Good information and this should be the same on any double stack mag.My only problem is: I don't have a problem! My 30 round mags are Seymore, 15 round old GI, 5 round are 25-30+ yrs old and they all function as they should. Man do I love 'old manufacturing' GK

M1's-R-FUN!!!!!!!!!!!!
TSMG's-R-MORE-FUN!!!!!
ENJOY LIFE & HAVE FUN!!
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swampmolly
Senior Member



USA
764 Posts

Posted - 08/17/2016 :  1:34:55 PM  Show Profile Send swampmolly a Private Message  Reply with Quote
One question.
If the forward lips are inconsequential,why are they there?
Just asking. :)
SM
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Tuna
Moderator



3155 Posts

Posted - 08/17/2016 :  9:15:12 PM  Show Profile Send Tuna a Private Message  Reply with Quote
Very good. You have answered one of the several problems with commercial magazines made here. Another problem that is found on the 30 round magazines is that loading them they suddenly stop taking rounds in and the follower is binding against the body. This of course is right at the bend in the magazine where it is hard to try and expand the body a little bit. It can be done but it is time consuming and sometimes frustrating. Yup another magazine hit the circular file and I hate to say it but made in the USA. The KCI and the U or the UU marked Korean magazines are really good ones and the price is hard to beat plus they work.
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Kilibreaux
Junior Member



USA
51 Posts

Posted - 02/28/2017 :  03:28:43 AM  Show Profile Send Kilibreaux a Private Message  Reply with Quote
So far I've cycled several hundred rounds through these various, yet different brand and original capacity magazines and they are all feeding fine.

Original M1 Carbines were known as reliable feeders, and it's a shame that current issue mags taint the carbine's reputation. Having started with a "modern issue" Inland, I figured it was as closely built to tolerance as the originals, so any feed problems had to be the mags and so far that has been the case.
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Tuna
Moderator



3155 Posts

Posted - 05/30/2017 :  10:29:12 AM  Show Profile Send Tuna a Private Message  Reply with Quote
The new Inlands have feeding problems not caused by magazines. They are using cast parts from A.O. as well as their own and they are substandard in size. One being the magazine release. Replace it with a USGI release and feeding improves a lot if your having feeding problems with good USGI magazines.
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