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Old February 14, 2013, 02:02 AM   #1
Cavallino
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Follow-up ? on Lake City Brass

Guys answered me here regarding hash-marks 3/8th of an inch up from the base on the case of Lake City Match brass. Was told markings machined into the brass to make it easy for troops to ID match rounds against combat rounds. Question is, I understand older LC Match does not have the hash-marks machined on them. One guy said the newer stuff with the hash-marks is equal quality/consistency early on, but the hash-marks do cause a weak "ring" on the brass and that newer LC Match with the marks can;t be reloaded as many times as older stuff without the hashing. Yes?? NO?? Anyone know what year LC started marking the match brass with the hash-marks around the case??
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Old February 14, 2013, 06:28 AM   #2
Mike40-11
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M852 match, with the knurled marks, first came out in 1980. As noted in the previous thread, it was to ID the not for combat 168 gr HPBT bullet. Incidentally, it is the Hague Convention, not the Geneva, that prohibits hollow point ammo.

As to weakening it, like most things in the gun world, that's a point of debate. Depends on what you're loading it for. If you fireform for your bolt gun and neck size only it's not going to have much if any effect. If you're full length sizing and setting the shoulder way back on a brass eating M1A, that knurling is right where case separation is likely to happen anyway so it isn't helping. Personally, I use it in a bolt action like any other brass but I'd stop after three loads in a semi.

Here's a good article on the history of National Match ammo: http://riflemansjournal.blogspot.com...1_archive.html
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Old February 14, 2013, 09:21 AM   #3
Hummer70
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Well yes, no and maybe. Yes, as indicated the "hash marks" were placed on the cases by LC AAP and it was their decision and not by direction of ARRADCOM(Army Armament Research and Devopment Command)
I was involved in that program and the "load" was developed at Picatinny Arsenal and they could not load the ammo as they did not have any 308 dies. I had to bring my personal dies in and they were used to develop the load for the M852. The test tech that directed the loading was Lou Behling who by the way is one of the foremost ammunition experts in the world. The lady tech that did the actual loading was Betty Babbitt as I watched her doing the loading.

No while I have seen hundreds of exspurt opinions on shortened case life, "ruptured" brass etc I am not aware of any case failures directly attributable to the "hash marks" but then again Murphy's Law is in effect.

Now I can see maybe "hash marked" cases failing from firing in big oversize chambers and then reduced back with smallbase dies numerous times but the condition is also found in non "hash marked" cases. I have seen multiple commercial 308 cases develop insipient separation as (1) they are lighter in weight, (2) they are thinner in the "web area" which corresponds to the "hash mark" area. (3) they are smaller in diameter.

Here is why:

1.Commercial cases I have measured in unfired condition .200" up from case rim measure .465" diameter.

2. LC MATCH 7.62 cases I have measured in unfired condition measure .468" diameter.

3. Most all commercial chambers run between .471 and .473 by the drawings but I have seen numerous fired cases measure as much as .475" which means they are fired in oversize chambers which are caused by misaligned reamer in chambering.


Thusly a LC case should only expand a max of .004" on firing but a commercial case can expand .007" and still be "IN SPEC".

My 308 FL dies size from .468" to .469". If you guys would measure the base of your 308 dies and see what the diameter is or mic FL sized cases and see if you come up with something smaller. Please let us know.

I order my reamers with a base dimension of .4685-.469 tolerance thusly when I load 308 be it commercial cases they come out .004" and LC cases come out only .001" larger.

It is well known excessive case sizing "thins" the cases at the web area which corresponds to the "hash mark" area. Thusly we have a definite "maybe" of whether the "hash marks" cause anything.

Now the original M852 had "NOT FOR COMBAT USE" on the boxes because everyone was a lawyer and no one wanted to be blamed for war crimes against humanity and hung at Nuremburg or sent home with a note to his mother.

Next came the 175 Sierra MK which is load designated as M118LR (Long Range) which is the standard sniper issued round for the M24 rifle now which is much more accurate than the M118 match and does better at long range1000-1200 yards than the M852 with the 168 Matchking which was designed as a 300 meter competition bullet and tends to develop yaw after 900 yards.

The "convention" basically says a bullet will not be designed for increased lethality. The 168 nor the 175, 180, 190, 200 gr. Matchkings were designed for lethality. Only for efficient production cost and maximum accuracy. Now the 165 Sierra (we call it the poor man's Matchking) perform well in competition and are less expensive than the MKs) which is a hunting bullet with a larger hole in meplat and does expand and is listed in their catalog as a hunting bullet where they do not recommend the Matchkings for hunting. I would estimate that Sierra bullets are shot by 95% of highpower shooters.

I estimate 99% of my bullets are from Sierra as they have always been excellent performers for me.

Thusly if you have a big chamber or a much bigger chamber it may well shorten brass life for not only M852 but M118 and all commercial cases.

In my experience Federal Match brass is only reloaded two or three times depending on the "feel" of the primer pockets seating new primers. On the third firing I pick up brass and dump it in my reject barrel.

Winchester cases seem to hold up a tad better and good for about five or six loadings before the primer pockets get loose.

About the same for Remington cases.

Haven't shot enough of the Privi Partisan to determine case life yet.

Now if you want case life as indicated you need to have your own custom reamer made. As indicated my base dimension is .4685-.469 and the neck dimension is .339 to .3395. I have never found a M118 round that would not chamber in reamers of these dimensions.

RECOMMENDATION: If you get a custom min dimension reamer have your gunsmith take a 1" section of take off barrel and run your reamer up to about 1/8" below the shoulder. Then turn off other end till you can see exactly where the neck stops on sized cases. You can try every last round in this "gage" to see if there is a interference before loading rifle to give you complete piece of mind. I call it the Hummer GO GAGE, if it goes it shoots, if it doesn't go it doesn't get shot.

The absolute finest brass I have ever loaded is DWM. Followed by LC Match and FA Match though you won't find much of that if any.

Be advised the neck walls on M118 are much thicker than commercial cases and thusly when they are reloaded I set my Marquart turner about .015" and turn off the thickest part of the neck. Neck walls on M118 can vary .005" per the drawing.

For long range 308 I turn necks thinner as I have a reamer that cuts a .337" neck and that requires removing material 360° so loaded rounds are .336" diameter. A normal neck is in the .344" range.

Bottom line is check your chamber for fired case size and see what you have.

Case life of M118 is superb as I can easily get 100 loadings on LC MATCH cases. I also have min dimension reamers for 30.06 and I have one M72 MATCH case LC66 that I have loaded 157 times and it is still waiting for more.
One reason for such enhanced case life is the LC case heads are very hard and don't expand on firing like the softer commercial cases.

If you properly care for your brass and you run tight chambers brass will last for years. Case in point I have one lot of 500 LC63 and LC66 MATCH brass I have shot out two barrels with since 1981. New barrels were chambered with same reamer so previosly loaded rounds went right in and cycled just fine.

On the other hand if you run big chambers, oversize your brass etc you will get the separations identified.
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Old February 14, 2013, 11:43 AM   #4
Bart B.
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Good comments, Hummer70.

I've seen a few LC 7.62 match cases ruptured at the pressure ring and after some investigation, both were caused by the reloader's full length sizing die setting the fired case shoulder back too far. He got an RCBS Precision Mic and reset his die for shoulder setback of no more than 2 thousandths instead of the 5 to 6 thousandths his die setting produced.

It's my opinion that either M118 or M852 cases will have head separations when case headspace is way too short for the chamber and they're full length sized too often. Knurling on the M852 cases will probably cause shorter case life in a controlled test; same chamber, sizing die, same excessive shoulder setback and same cases used.
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Last edited by Bart B.; February 14, 2013 at 12:03 PM.
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Old February 14, 2013, 04:50 PM   #5
Hummer70
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absolutely when the shoulders have to take a lunch break before it arrives at shoulder of chamber the brass has to come from somewhere.

I don't like my case shoulders moving over .002".
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Old February 17, 2013, 09:34 AM   #6
Chick
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I have had 2 case head separations in the M1A. Both times the case head was flung backwards and tattooed me right in the center of my forehead. Ouch! The rest of the case left in the chamber, came out by simply shaking the rifle. One was with a Winchester case and one was a standard LC case. Both were on their 6th load. I never had any problem with loose primer pockets. I did get some of the LC brass from a man who shot on the Marine Rifle Team at Cherry Point, with Hathcock and Gonzales, but have never seen any with the hash marks you speak of. I have never gone to the extent of measuring and adjusting the sizing die, as Bart and Hummer have done. I did try the X-Die and did not care for it.
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Old February 17, 2013, 12:16 PM   #7
Bart B.
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Chick, I've seen a couple of caseheads from ammo used in Garands that's been full length size "just like the manual said to have the die hard against the shell holder with the ram at the top of its stroke" instructions, or the equavalent there of.

Here's what happens with rimless bottleneck cases when they're used in M1 and M14 rifles:

1. Round's chambered and the bolt closes, ejector's very strong spring pushes the round full forward in the chamber with its shoulder firmly centered in the chamber shoulder.

2. Firing pin's driven hard into the primer with enough force to push the round a bit further into the chamber setting the shoulder back a thousandth or so, then the round fires.

3. Chamber pressure builds up pressing the thinner case walls right behind the shoulder hard against the chamber as the bullet gets pushed out and into the rifling and the primer gets pushed out of its pocket a few thousandths.

4. More pressure builds and presses the case head back against the bolt face stretching the case's back half as more of the case body presses against the back part of the chamber wall. The primer's now pressed back into its pocket flush with the case head and the case shoulder's hard against the chamber shoulder; the bullet's now about 40% down the barrel.

5. Bullet goes past the gas port then exits, gas pressure in the cylinder pushes the op rod back opening the bolt and extracting the case from the chamber.

That fired case now has a greater distance between its head and its shoulder than when it was loaded.

Full length sizing that case and setting its shoulder back too far, reloading it then shooting it again in that chamber repeats the above. But the case gets stretched again and again each and every time it's reloaded. That stretches the brass about 1/4 inch up from the case head too much; it finally separates on the case's last firing when that "web" is the thinnest and weakest.

Sometimes, you can feel the inside of the case have a "groove" at that point with a long wire with a hook on its end moved back and forth inside the case at that point. If you can feel it, that's called incipient head separation; it's gonna happen in the next 1, 2, or 3 reloadings that set the fired case shoulder back too far each time.
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