bought a 200rd value pack last summer.  55gr FMJ IIRC.  On roughly 3 out of 10 rds the bullet was pushed back into the case and the case neck caught on the feedramp.  The gun in questions was a RRA M4gery with old mags, new mags, new mags with magpul followers, and shitty orlites with cracked feed lips.  The rifle DID NOT have M4 ramps.  The rifle has around 10,000 rounds through it of various types and weighs but i mostly shoot wolf 55 or 62gr.  The ammo also functions noticable better (but not perfect) with the orlites with cracked feed lips.

Fired 50 rds 68 gr BTHP from RRA Elite Comp w/ no problems... Extremely accurate and clean. Purchased from Cabela's.

bought 300 rnds from cabelas 2 years ago. very dissapointed. not enough neck crimp/tension. bullets would dislodge upon feeding. went through the entire box and about 1 in 15 were NFG. i could push the bullet back into the case wit LIGHT finger pressure. 55gr hp. prof ord type 97 rifle. i would never buy this ammo again. just cant trust it.

Only Ultramax I'veused is the 68 gr. load. It has always worked well for me.

I've shot this through my Remington 700 SPS and my Olympic Arms AR-15.  I shot 150 rounds (one value pack) and it cycled fine, but was the worst ammo I've ever used.  The powder is extremely dirty and is really hard to clean compared to other factory ammo.  Multiple casings had split necks leading me to believe that this brass is not once fired, but fired multiple times before it makes it's way to ultramax to be reloaded.  I'll never use this ammo again due to its mediocre accuracy, dirty powder that fouls bad and looks like a black cloud coming out of your muzzle, and the multiple split case necks from a relatively low power load.  Pay a little more money and buy some accurate, clean, and safe ammo.

I have 800 rounds of BTHP 68gr, this stuff is extremely accurate. Comparable to Black Hills 68gr as far as accuracy

It's been a couple years since I used any. I used about 500 rounds of UM 55 gr SP for coyotes and varmints when I was too lazy to reload. No problems. Accurate and reliable.

Also used about 500 rounds of UM 55 gr FMJ. No problems as well. Both comparable to Black Hills like mentioned above.

I bought 2 150 round boxes of 55 grain FMJ the other night at dicks.  I am shooting it out of a bushmaster flattop with a 20 inch full floating hbar 1 in 9 twist, with a cheapa@@ vism scope.   Sighted the gun in with Hornady 55 grain sp ammo, and was getting .5 to .75 inch 3 shot groups at 75 yards, but when I went to 10 shot groups I would get 2 or 3 flyers that were outside the main group, which averaged 1 inch for about a 1.5 inch to 2 inch spread. Out of 8 groups, one group had 5 outside the main group all over the place up down and right or left. Thought that I must be jerking the gun or doing something wrong with my technique I changed over to the ultramax and fired a 3 shot group to see what adjustments needed to be made.  To my surprise the rounds hit exactly where the Hornadys were, and made a nice tight cloverleaf with each shot touching. Shot 6 more 10 shot groups with the ultramax and it actually shot better than the Hornady, with the best one being .71 inches, and the rest being between .9 and 1.15 inches with NO FLYERS.  I was shocked at how well this ammo shot and am almost hesitant to post this cause it sounds to good to believe.  Have not tried it at 100 yet, but will do so and report.  So to recap:

 Bushmaster 20 inch 1 in 9 twist with vism scope set at 8x, Harris bi pod no rear rest.  Second time shooting the gun.
 55 grain ultramax FMJ.
 Shot 63 rounds.

    Looking to try some good 62 to 65 grain ammo, and get a better scope to see how well this thing will really shoot, but for now I am very impressed esp with the type of ammo I am using.  First time out with the gun I was all over  the place and could not manage a 2 inch group at 50 yards (with federal 62 grain match grade) if my life depended on it.  Was not sure if it was the scope, the gun, or me, but it had the grittiest hardest trigger pull of any weapon I have ever shot, truly the worst trigger I have ever felt.  I used to shoot ARs at a job I had, and have shot prob. 30 colt and bushmasters, and this had by far the worst trigger.  Worked over the trigger by polishing it up and weakening the trigger and hammer springs a tad and it made an incredible improvement.

Shot 50 rounds of the 55gr value pack that was a year and a half since purchase no problems what so ever.

One question if someone can answer because I know nothing about reloads. It seems to he loaded in 5.56 brass when compared with 223 the neck is a little longer. Does this mean that its actually 5.56 ammo even though its marketed as 223?

Thanks!

Eta: 16" barrel with 1x7 twist, mid length gas. PSA lightweight profile.

Ultramax is definitely .223 .  Everything they load is within SAMMI spec (commercial) and always seem to be in the lower half of spec, but they do seem to shoot nice groups most of the time.  I've shot a lot of it.  I like BH better for sure,  but like Ultramax better then Remington UMC, the Walmart cheap Federal, or anything steel cased.

I ran 100 rounds of 230 grain HP through my Smith and Wesson M&P .45 I got it on sale at the local gun dealer for 21.99 for 50 rounds. It shoot smooth and produced nice groups at 10/15/20 yards over all I was very happy with it for plinking ammo for the price and I will buy some more. They had some .223 and I think I will buy a couple boxes of it and run it through the Ar and see how it functions next weekend!

Wish I had seen this thread back in August 2008. Same load but in an experimental build by LRB using a Armscorp cast receiver with H+R parts. Same case head failures and lost a mag from blowout. Have 500 rounds of .223 SP coming in, will review ASAP.

I ran almost 1,000 rounds of 55 gr FMJ .223 through a POF 16 in gun a few years ago with no problems.  Have some 55 gr soft point that I've used lately in a different gun, didn't group the best, but no other issues.

Another blown up gun from ultramax:

http://www.ar15.com/forums/t_3_118/612006_Yet_another_Kaboom_____Updates_in_OP.html

I've shot probably 1000 rounds or more over the years of the 223/ 150 round pack from Dicks (I buy when on sale).  Mostly shot through my M&P15A a few through my 6920 and not one malfunction ever. It's good clean practice ammo IMHO.

ultramax ammo blew up my Remington 700 .223 HB and almost cost my hunting buddy his eye sight. 10th round out of a box on prairie dog hunt. Took an attorney, medical records, the damaged rifle and remainder of the box of ammo to get some acknowledgment that the event  happened.

You could not give me this ammo.

I want even get into personal knowledge of young employees working there while high.

I no longer have the photos or lot #, but I had an instance after firing some 55 grain where the brass broke and separated completely in half about half inch up from the base. It was noticed upon ejection. No damage, and the person firing my rifle was fine.  Actually I probably still have that ammo somewhere and can find the lot #. Purchased 2007-2008.

I had this same problem when I got my first AR. I thought it was the gun. One shot and it would push the next bullet into the case luckily jamming as well.
I tried some of a buddies ammo and it worked flawlessly. Never again.

That's nuts that they are still having problems with neck tension. My incident above was from 10 years ago! Never will I buy this shit.