[IrishCop]

I was able to get a couple hundred rounds of this on-line. When I opened one of the boxes to examine them, I could tell the cases had been annealed, the 55 grain bullets seemed properly set and crimped, etc. Then I checked the headstamp...okay there, Lake City and NATO markings. Last the primers...whoa. Something new to me...there were four marks around the primer, small straight bar-like indentations...the primers appeared to be staked in place.

I hadn't bought any 5.56 in several years...anybody else ever seen this? Anybody know why? I mean, are they afraid that the primers will back during firing or what? :?:

 

[CaptainGyro]

Here's a discussion which sheds a (very) little light on the subject:

XM193, staked in primers? - AR15.COM

The big question remains unanswered: Are they reloadable?

 

[Charlie Petty]

Most GI ammo has some form of primer crimp. The staked in type was probably first way back at the turn of the last century.

I don't think the type of crimp matters and there is always an argument over whether it is needed at all. The theory is that ammo used in machineguns needs it because of variable hadspace and high temperature.

I think the staked crimp probably has an advantage in the manufacturing process since it would not need as precise alignment as the ring crimp. That probably would allow the machine to run faster too.

 

[shep854]

I'm glad the makers know what they're doing; it seems to me that whacking primers hard enough to leave marks is a good way to Ka-BOOM a whole plant (or significant portion thereof).:shock:

 

[IrishCop]

Thanks, Capt! The photos in that link were exactly what I was trying to describe.

Charlie: I guess the pressure on the ammo companies to keep up with military contracts and civilian demand caused them to change their crimping/staking method. I didn't know that process was EVER used, much less being a century old!

That being said, what about reloading 5.56? I've never reloaded any rifle cartridges, just handgun. Is there some sort of die or tool that crimps in primers for reloaders? Or is it simply unnecessary except for, as you said, maybe full-auto weapons?

Shep: I hear ya, bro'. Even if such a tool or die was available for home reloading, don't think I'd wanna try it. I'm accident prone enough as it is. :ehsmile:

 

[William R. Moore]

A century ago, manufacturing tolerances were....ah, generous. It's why JMB felt that field adjustable headspace was a good idea in his heavy machine guns. The military also, for good reason, took a belt and suspenders view of new fangled things and this attitude begat staked in primers.

As for reloading brass with staked in primers, you remove primers the way you normally do. You then remove the crimp. Dillon and RCBS make swaging tools/dies that allow you to remove the crimp relatively painlessly. If you're cheap, you can remove crimps with a carpenters countersink toolbit and a drill, but the results will vary widely and can damage the brass if you get too enthusiastic.

Don't bother recrimping. If the brass gets worn enough that it won't retain primers by friction, leave it on the range to momentarily delight the finder or sell it as scrap.

But hey, if you have doubts, I'll offer your once fired brass a good home and long term employment. Shipping address provided upon request for postage paid packages.

 

[Skeptic49]

Has anyone else wondered why XM193 has been around for decades, but has never been type classified?

Geoff
Who has been hoping for a Romney win so he could pick up a lightly used AR for the wife...snerk.

 

[TommyGunn]

.....Who has been hoping for a Romney win so he could pick up a lightly used AR for the wife...snerk.

Not all that sure Romeny will be any better for gun owners than the Anointed One.

You may wish to invest in some EBRs irregardless of the vote in November...............

 

[Charlie Petty]

As usual Mr. Moore knows wherof he speaks...

If primer crimp was really a big deal why aren't ALL primers crimped?

Until very recently no commercial ammo had crimped primers but I've seen them on some of the new non-toxic (lead free) loads because of the higher impulse pressure of the lead free primer...

 

[Daniel Watters]

Has anyone else wondered why XM193 has been around for decades, but has never been type classified?

XM193 in this case is a commercial designation, most likely a play on words signifying "ex-M193" or "excess M193". Military M193 Ball was standardized nearly a half-century ago.

 

[shep854]

AIUI, onxe you get out of NATO, M193 or equivalent is pretty much the world standard

 

[IrishCop]

AIUI, onxe you get out of NATO, M193 or equivalent is pretty much the world standard

Could be, Pete. I know that I personally think it is the best anti-personnel round available for the 5.56 caliber. But then I'm an old fart.

No, I don't think it defeats barriers better than the M855's. But (dare I say it?) anecdotal evidence, such as Paul Howe's description of it's ineffectiveness on Somali combatants in Blackhawk Down, among others, keeps me in the camp of the 55 grain bullet.

Now whether the 1:9 twist still allows the original loading to perform as it did in the 1:12 twist barrels...:dunno:

 

[IrishCop]

A century ago, manufacturing tolerances were....ah, generous. It's why JMB felt that field adjustable headspace was a good idea in his heavy machine guns. The military also, for good reason, took a belt and suspenders view of new fangled things and this attitude begat staked in primers.

As for reloading brass with staked in primers, you remove primers the way you normally do. You then remove the crimp. Dillon and RCBS make swaging tools/dies that allow you to remove the crimp relatively painlessly. If you're cheap, you can remove crimps with a carpenters countersink toolbit and a drill, but the results will vary widely and can damage the brass if you get too enthusiastic.

Don't bother recrimping. If the brass gets worn enough that it won't retain primers by friction, leave it on the range to momentarily delight the finder or sell it as scrap.

But hey, if you have doubts, I'll offer your once fired brass a good home and long term employment. Shipping address provided upon request for postage paid packages.

No doubts, Mr. Moore...and since I STILL haven't gotten me a reloading setup, maybe I'll just send you some once fired .

 

[William R. Moore]

In general, the XM designation means the ammo either did not in some manner meet military specifications or was produced in excess of the contract amount. If PD follows the numerical disignation (XM193PD), it means the bullets were pulled, powder dumped and the cases reloaded, possibly with the same powder. This usually happens when the ammo didn't meet pressure or velocity specs. You won't see a type classification because since it didn't meet mil-spec or was produced outside the contract, it's not in the system......usually.

I've got some XM118LR and the large packages have very large printing on it forbidding use overhead of troops. Doing background on the lot indicated it was "XM"ed for exceeding the vertical dispersion spec at 1000 yards-meaning an excessive velocity spread (a 100 fps variation changes POI about 3 feet at that range). Works just fine at shorter ranges

I suspect that Federal runs their 5.56 x 45 mm production nonstop and just labels the excess as XM, plus anything that may not meet spec.

 

[Charlie Petty]

Interesting info... thanks

I suspect you're right about the non-stop production and since everybody and his brother has the stuff for sale I'd hate to think that LC makes that much out of spec ammo

 

[phantom4570]

If the brass gets worn enough that it won't retain primers by friction, leave it on the range to momentarily delight the finder or sell it as scrap.

Never leave junk brass at the range. Sell it as scrap yourself. I once dumped worn out brass with loose primer pockets in a trashcan and watched one of the club officers retrieve it. I told him it was worn out and he didn't care. He said someone would buy it. I told him he was a fraud to his face and did not get an argument.

 

[William R. Moore]

You have a definite point. However, I knew guys who would literally glue primers in to get one last use.

BTW, for clarification, I went down and looked at the large box of 7.62 and it's factory printed as XM118LR Match, For Training Use Only. Individual 20 round boxes are stamped XM118LR PD as a separate marking other than the factory printed M118LR. The notification not to use it overhead of troops was in the paperwork regarding use of ammunition other than regular issue (M193, M855 etc), which suggests limited special purpose use of such ammo .

I"d dearly love to get 8 lbs of whatever powder was used along with load data.

BTW, per the Federal website XM193 if first run, first quality ammo with sealed case mouth & primers and a velocity of 3165 fps +/- 40 fps @ 78 feet.