I am new to the ar platform shooting. My rifle is a bushmaster predator 20"
I was shooting factory federal 55grn 193x military type rounds
I had several primers which came out and jammed the rifle, a couple fell into the lower receiver causing the trigger and or hammer to lock up up and in a few incidents the primers became lodged in the lock up area of the chamber causing failure to go into battery

Anybody experience this? any suggestions

Contact Federal directly. Perhaps the primer pockets are out of specification.

Have you fired that ammo in a bolt-action, or another semi-auto rifle (AR or other) to see if it happens there, as well?

George

The rifle is new, I have a 223 bolt rifle but I have not shot this ammo through it
I believe the federal 193X are factory military rejects that do not meet military standards however Federal states they are within factory specifications. If I remember correctly I fired a total of 80 to 100 rounds and had at least 8 to 10 casings that lost its primers inside the weapon.

I've never bought any of that. Does it have the miltary crimped primer? If it does something is really the matter if the primers are backing out. Even if they aren't crimped something is amiss.

head space or pressure problem of some sort..

disassemble one or two and see what the powder capacity is...

could be too much pressure or too low of pressure combined with a head space issue..or just general headspace.. and low pressure will cause the primer to back out also...

Based on what I know about semi's, there has to be an extraction problem, allowing pressure to blow out the primer before the casing is extracted. I examined all of the casings and not one of them had a rim that was fractured. I had a rem 742 that ripped the rim off and left the case in the chamber.
My research on these XM193F federal rounds are suppose to be cosmetics defects below military standards. Other people stated these new rounds had dents, discoloration and crimping on the primers that where less than perfect, I would have to agree on these descriptions. Federal staes they meet all specifications and are safe to shoot. I wrote a letter to Federal to see what they say

What I believe you were referring to (on an AR system) is bolt unlocking timing. If it unlocks a tad on the fast side the primer will show a false indication of high pressure. To give you an analogy of this David Tubbs markets a carrier weight that slows the timing down. He points out on his website how perfectly normal loads have very flat primers indicating high pressure. When the same load is shot with his carrier weight installed the primers look very normal with rounded corners. There can still be pressure in the bore if the bolt unlocks too soon. If you have the incorrect head space, which I doubt, compare one of your fired cases with the factory case and see if it's longer especially in the measurement from the case head to the center of the shoulder.

On the cases that blowed the primers out have tried to reseat a new primer to see if the pockets are loose? You'll have to remove that primer crimp first.

The 70 cases that kept its primer all display flattened primers indicative of a fair amount of pressure which is characteristic to military 5.56 loadings

That's characteristic of just about all loading in AR's that are any little bit off in bolt unlock timing. Also let me say that most AR's are over gassed to insure reliable operation under all conditions. What that boils down to is the gas port hole in the barrel is larger then necessary to operated the system. If you lived close to me I'd give you a carrier weight and let you shoot your rifle with the loads you say are getting flattened primers and I'd bet you they would look normal with the weight in use. I don't like a carrier weight because the carrier/bolt group is heavier then and it bangs the barrel extension more then suppose to...plus other things. You may ask then what do I use? The answer is an adjustable gas valve be it installed integral with the gas block or in the gas tube somewhere. That way the carrier/bolt groups doesn't beat the rifle up.

raamw;

What Chamber is your Bushy reamed for?

XM193 is 556 spec ammunition, and as such, is made for 556 chambers. The throat and leade are longer/shallower than a standard SAAMI 223 Rem, by a long shot.

Pressure tests indicate M193 ammo fired in 223 chambers will generate nearly 73k PSI vice the 60k PSI of the same in a NATO chamber.

223 Rem, of course, is made for 50k PSI loads if I recall (maybe 55k?)

My advice: STOP USING IT IMMEDIATELY. Check out your chamber, use ammo of the appropriate nomenclature for your chamber.

Some folks say it is fine to use 556 in 223 chambers, I disagree, for the specific reaso you are experienceing-pressure problems!.

Here are some pictures of the cases I used
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Here are some other 5.56 mil fired cases, weapon type unknown
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Federal responded to my info and requested to return a 20 round box for their evaluation

That last picture, those primers look pretty normal. The ones without primers look like blown would primers. The other cases the primers look, ah, so so, but there looks to be cratering around the firing pin dimple.

Yes as the other poster said make sure what your barrel is stamped. If it's stamped 223 don't shoot NATO ammo in it. If it's NATO you can shoot either in it. Lot of it has to do with the throat length, the NATO having the longer throat. Thus you can see if you shoot a NATO round in a SAAMI spec 223 chamber the bullet may be touching the throat increasing pressure in addition to the different pressure rating the NATO is loaded to. Tell us what your barrel is marked.

My upper is the Bushmaster predator 20", here is the specifications
20" Predator Upper Receiver/Barrel Assembly
Adapted from our very accurate and successful 24" Varminter, the Predator Upper Receiver/Barrel Assembly's 20" Fluted Extra Heavy Barrel is button rifled 1 x 8" to stabilize the heavier 69-77 grain bullets that a predator hunter/caller would choose for bigger varmints and predators. This superb barrel features fluting for increased cooling and weight reduction; an 11 degree competition crown; 1" diameter heavy profile under the handguard; custom match hybrid chamber with a tighter SAAMI Spec headspace from the shoulder of the chamber to the bolt face, and longer chamber throat or "Leade". This chamber accommodates 5.56mm ammunition without developing higher pressures encountered when firing 5.56mm ammo in a .223 chamber with shorter "Leade" (both calibers can be used safely). This Upper is sold complete with Bolt, Bolt Carrier and Charging Handle to ensure positive lockup between bolt and barrel extension. The Predator Upper also features a Vented Tubular Aluminum Free-Floater Forend with Bipod Stud (free-floats the barrel from the barrel nut forward) and B.M.A.S. 1/2" Mini-Risers to add scope height for correct sight picture and comfortable cheek weld.

Sounds like it has a Wylde chamber which is sort of an in between. It's a good chamber. It just may be your Federal NATO is not a good fit. Take one of your loaded round, black marker pen the entire cartridge, bullet included and carefully insert it in the chamber with your fingers and adhering to all safety precautions let the bolt slam home. Then carefully extract it and look for marks on the cartridge.

I have a RCBS precision Mic ordered so I can see what the chamber is should get it tomorrow

Raamw, I've had very poor results with Federal brass in my 16" Bushie Vmatch upper as well. The brass was once fired by our boys out at the DOC, but even on the first loading, trying multiple brands of primers, it wouldn't always hold them. I've never had this problem with any other brand of .223 brass.

My grandson has a Bushmaster DCM Competition model which is chambered for both 5.56 & 223 and when firing NATO spec 5.56 ammo a couple of years ago (Radway IIRC) we found several blown primers when policing the brass after firing a hundred or so rounds. I was not loading for the 223 at the time so don't know wheter the cases would have held a primer or not and he has not used any 5.56 ammo since.

The Predator is supposed to handle both 5.56 and .223 ammo according to Bushmaster. Here's what they say about proper ammo. Have never shot the 5.56 in mine, however.



Regards,
hm