US Enbloc clips, again


#1

For you clip and charger collectors out there ( you know who you are) I have a question regarding enbloc clips for the U.S. M1 Rifle.

I have seen stories about enbloc clips used for the 7.62mm NATO M1 Rifles, more specifically the USN Mk2. They imply that the clips were different although how, exactly, they were different they do not say. But, the word on the street among rifle shooters and collectors is that the clips are not different in any way.

What say you?

Ray


#2

My old shooting buddy has an M-1 that was re-barreled in 7.62x51mm for use in CMP and NRA service rifle matches. He uses normal/regular M-1 enbloc clips with no issue. As particular as he is, if a different clip were needed, he would have them…

AKMS


#3

As far as I know, the only 7.62mm NATO ammunition packaged in enbloc clips was the standard service grade Ball M80 from Lake City, as shown in the photo of the bandoleers. Any other cartridges found in clips, including Match M118, would have used whatever clips were available to whoever was doing the loading.

I’m still not positive if Lake City used specially made or modified clips for the Ball M80 or if they simply used existing clips.

Ray


#4

Ray, a 1964 report comparing the converted M1 (later Mk 2 Mod. 0) and the rebarreled M1E14 (later Mk 2 Mod. 1) indicates that the minimum clearance in the receiver of a 8 rd. clip loaded with Cal. .30 and 7.62 mm may be minimal but no problems ocurred because of this are mentioned. The graphic shown below indicates a minimum clearance of 0.010" when using Cal. .30 vs. 0.0035" when using 7.62 mm.

The LC cartridges found inside the pictured 7.62 mm metal box were packed using standard clips made by Borg-Warner (BR-W 4), and it seems that this applies for most or may be all of the rounds packed in 1965-66. There is an earlier style of metal box by LC marked “Grade R” (Rifle) but I don’t how the clips are marked (the lot indicates a 1964 date).

Regards,

Fede


#5

Fede

Thanks for that explanation and drawing.

The larger diameter of the 7.62mm case compared to the Cal .30 could have been a problem. That may be the basis for some to think that the clips were modified in some way to accomodate the difference, although I’m at a loss to see how when the difference is so small. Regardless, experience has shown that the original clips work fine with either cartridge.

The clips in the bandoleer are indeed marked BR-W 4

Ray


#6

Ray,

I am a little confused by your statement of “larger diameter of the 7.62mm case compared to the Cal .30”. As far as the U.S ordnance drawing information I have, they are the same at the rim and base or are you referring to where the side of the casing meets the front tensioning lips of the clip? If so, then yes, there is five thousandths difference in the taper.

Joe


#7

Joe

Yes. It’s the body diameter that is critical. The difference was as much as .008" on some of the cases that I measured.

Ray


#8

Looking at it from the POV of the rifle, there is sufficient Clearance between Mag.Well walls and the sides of the clip, definitely for .30/06, and also for the 0,005-0,010 difference in Shoulder diameter between 7,62 and .30 cal…the Clip Expansion is even less of a “problem” as the diff. in case diameters must be measured at the Point of the 7,62’s Shoulder, NOT the .30 cal. which is further forward.

The Bases, as mentioned, are more of less Identical, so the Clip Base (the “heaviest” Part) is the same.

In any case, all the countries which used “re-chambered” M1 Rifles (Set-back barrels or New Barrels --Italy etc.) did not change the clip dimensions at all, NOR changed the Internal Mag Well dimensions AT ALL.

Another Point is that the US Navy uses a different designation system to the US Army & Air Force…The Navy uses an “M plus Mark” system. Just to keep us all confused.

And the USN simply converted the M1 rifles by fitting a Chamber reducer ( Firmly pressed in place, and then, Reamed the remaining chamber to allow for the larger diameter Shoulder of the 7,62 case compared to the .30 case Diameter at the same Point. So if you lose the “Insert”, a subsequent .30/06 case will fire, but have a "double shoulder ( ever so slight). A 7,62 will still chamber and fire, but will come out a straight (slight shoulder) .45 cal. case!!! ( Just like mistakenly firing 7,62 in a unconvewrtyed .30 cal chamber (perfectly tapered case, with a slight mouth roll over where the 7,62 case reaches the beginning of the 30 cal shoulder and the shoulder and neck have blown out of the 7,62 case.

All very nice "Theoretical “Musings,” but of no Practical consequences for Clip supply.

Doc AV


#9

I took one of my M1 Garand rifles (May 1943 Springfield Armory) and took the clip Ray shows in his picture out of my collection. I loaded 8 rounds of LC 1968 M2 ball in it and measured with feeler gauges the gap in magazine well and side of clip lips most forward and I get 0.022" clearance on both sides. Then took same clip and rifle and put in 8 rounds of LC 1968 M80 ball. I then get the same clearance. Yes, I agree it should be different , but I get the same. I wonder if it is because the follower/lifter are putting equal pressure on the rounds and expanding the spring clip the same amount. I measured the outside of the loaded clip out of the rifle and I get ten thousands more loaded with the LC 68 M80 Ball. Yes it was a pain holding the op rod back and measuring, ha-ha, and I still have my thumbs.

I conclude the flower exerts the same pressure upward on the clip thereby causing it to spring open roughly the same amount.

I surmise if you had week spring material in a clip it might spring open to the point it might contact the sides of the magazine well causing problems.

Well thats my experiment for the day, back to sorting cartridges.

Joe


#10

The dimensions of the inside diameter of the top of the clip are 0.765+/-0.10 when unloaded and 0.870+0.05 when loaded with Cal. .30 cartridges, and the thickness of the walls measures 0.15+/-0.002 inches. In theory, this means that a clip loaded with 7.62x51 cartridges may have dimensions that are very similar to the maximum dimensions allowed for a clip loaded with Cal. .30 cartridges.

Edit: Drawing added.


#11

Joe - Thanks for taking the time to measure the differences. But don’t forget, there are manufacturing tolerances in the rifle, the cartridges, and the clips. A test with different components could give different results. But, we’re still talking thousandths of an inch and what’s a few thou between friends.

DocAV - The Army basic numbering system uses Model numbers (M) and modifications (A), whereas the Navy uses Mk and Mod.

My question, from the beginning, was, is there a difference between the enbloc clips for the Cal .30 cartridge in the M1 rifle and the clips loaded with 7.62mm NATO cartridges for the Mk2 Mod0 and Mk2 Mod1 Rifles? There was never a question of will either clip work in either rifle with either cartridge. We know that the answer to that is yes.

My military mind tells me that the USN would question the interchangibility, and if there was any doubt, they would design and manufacture a new clip. The information that Fede posted, plus the absence of a specimin, seems to support a conclusion that they did look at it but found no basis for a new clip. Even if you compare a minimum Cal .30 case with a maximum 7.62mm NATO case the difference is still negligible.

So, I’m satisfied. I thank everyone who replied.

Peter - If you are reading this and have a different looking enbloc, NOW is the time to show it. ;-)

Ray


#12

[quote=“RayMeketa”]

Peter - If you are reading this and have a different looking enbloc, NOW is the time to show it. ;-)

Ray[/quote]

Ray,

I’ve been over-doing things at work again and spent yesterday ‘recuperating’ so I’ve only just seen this.

I’ve never seen or heard of any sign of a specific (and different) clip used for 7,62x51 in Garand M1 rifles, I think the difference in dimensions are so small that they are within manufacturing tolerances of all the components involved, even at their extremes.

You’re not about to pull a rabbit out of the hat are you !!

Peter


#13

Thanks Peter. No rabbits here. I was kind of hoping that maybe you had one. ;-)

Ray