I am having an issue with my AR 15, cases won't completely eject when using A 2520 powder,they extract from the chamber but don't fully eject. I first noticed this issue a few months back when developing a load, the load did not work out well accuracy wise so I gave up on that project. A few weeks ago I bought some of the new Nosler 70 gr RDF bullets, worked up loads using RL 15, CFE 223 and A2520, I worked up to 26.5 gr with 2520 but that load was to hot, averaging 2860 fps from an 18 1/2 inch barrel, I backed off to 25.5 gr, averaged 2801 fps and shot groups under half inch but about half the time the rounds would not fully eject, I took the BCG apart and cleaned everything, removed,examined and cleaned the extractor.
I thought that I may have solved the problem, for about two years now when I chronograph and work up loads and also when I shoot for groups I single load the magazine. A few years back I was having an issue with a certain powder, had some real bad extreme spreads, talked to a tech at one of the bullet makers and he suggested to single load the magazines, I usually wait a minuet before I shoot the next round and he said that during that minute there is a round sitting in a hot chamber and that can effect the powder. I went out this morning with a box of factory ammo and three hand loads, 69 gr Sierra tmk 25.5 gr 2520, 77 gr sierra tmk 24.5 gr 2520, 25.2 gr Exterminator 55 gr fmj. Single loaded the factory ammo, fired three rounds, all ejected fine, single loaded the 25.5 gr 69 gr sierra load, two of three ejected, put three rounds in the magazine, first one ejected, second round failed to eject, third round ejected.

Single loaded the 24.5 gr load with 77 gr sierra, two rounds ejected, one did not, put three rounds same load in magazine, fired all three, all ejected. fired the 25.2 gr 55 fmj load, all rounds ejected, put three in the magazine, fired three rounds as fast as I could pull the trigger, all ejected. I am trying to figure out why the 77 gr load with three rounds did not have a failure. Anyway sorry this took so long but I would like some help or advise, could it be that my AR just does not like A2520 or is there another issue.

Use a different powder and move on. 2520 is not the best choice for an AR

2520 cycled ARs for years for thousands of folks when it first came around.... FWIW.

Does your 18.5" barrel have rifle gas?

Pressure curves can be quite different with different powders & burn rates, so obviously the easiest thing might be to try another powder that is a bit slower..............you don't say how RL-15 or Varget worked, but that would be 2 powders that's I suggest you try with the 77's.

Also, if you have a rifle gas gun, I suggest that you use a carbine (3.0 oz) buffer for starters until you see that the gun will function reliably then go heavier if you are able to.

Lots of possibilities, lots of interactions; and a few 3 round tests don't really prove much.

MM

Might work just fine in a 16" mid or carbine gas gun; maybe not so good in a longer barrel with rifle gas................just sayin' since we really don't know the details of his setup.

I never used that powder............

MM

Never had a gun with a barrel other than 20 inches in the 2520 days. I won't use AA due to lot to lot variation was so damn horrible years ago. John says thats all over now... so I"m a bit more at ease since I need to try a couple of AA powders for specific things, but I still dont' like the idea... 10mm and 200/220 hard cast and something to cycle the short 16 inch 300/221 AR with 194s or 115s... So I guess I'll see eventually.

But 2520 and 20 inch rifle, rifle gas, various port sizes actually, standard and M16 carriers of the day, standard buffers, bullets from 60 to 80 grains never had a cycling issue.

To me, that means 3.0 oz.

MM

Would love to use a different powder but with 70 gr RDF bullets I am getting groups under half inch.

JMHO, but if you're getting good groups with the rifle with that powder, it's very likely you'll get good groups with other powders as well.

There's very little to no difference in several of my guns with 3-4 different powders.

Both XBR-8208 & AR-Comp are truly top notch accuracy wise.

As are MR-2000, Varget, RL-15 & sometimes H4895........some may not give maximum velocity, but all are generally very accurate in most guns.

Sometimes you need to find the sweet spot in the charge weight to get best accuracy, but it's really not much fun to have a gun so finicky as to "have to have" only one particular powder to shoot well...........I really don't much want to have those guns. Truly good guns are usually not that finicky, whether they be AR's or bolt guns.

MM

dumb question. did you build it? You sure the gas block is aligned 100%?

If it doesn't function, it doesn't work.

I wouldn't be so in love with a load that I would tolerate a malfunctioning gun. You might as well trade it in for a bolt action.

A big +1 to Montanaman's observation. The .223 is such a forgiving cartridge that you hear lots of people say that load development didn't do a whole lot for them - they got many loads that shoot the same and the development was a waste of time.

If that 70RDF doesn't shoot with 24.5gr of Varget, I'd conclude that it doesn't shoot.

Rumor has it there are other powders available. Unless one has a rail car full of the stuff, switch.

2520 is fine in an AR; if anything it's a little slow in burn rate and may over-gas the rifle. The problem is your loads or the gun, not the powder.

Are your loads too light to cycle the action reliably?

Is the gas block aligned correctly, and is it tight?

Is your extractor spring weak, or the extractor worn?

Lots of other questions to answer before assuming it's the powder's fault.

I bought the upper from a local AR builder, purchased an Anderson stripped lower and had the parts installed by a local builder.

I built up the loads using three powders, besides 2520 I tried RL 15 and CFE 223, I fired three groups with each powder,RL 15 and CFE 223 both averaged .963, 2520 averaged .816, CFE shot the tightest group at .378 but the two other groups showed signs of vertical stringing, all the 2520 groups were nice three leaf clovers. Going into Reno tomorrow to pick up some of the new 72 gr eld bullets, may pick up a pound of AR comp or Varget, I have never tried either powder.

Everything you mentioned is fine, 2520 is the only powder that has given me this issue, I may increase the charge slightly, like maybe .2 of a grain and see what happens.

When it does eject with that load, where does the brass land? (use a clock face reference, 3:00 being directly to your right)

apparently in the chamber

If the rifle is ejecting factory ammo at ~3:00, it's working correctly. Either change the powder or the load. Brass, primer, and mostly your chamber can all be factors in speed and pressure. Not every load you try is going to work in terms of accuracy and function.

Try some varget, XBR-8208, CFE, etc.

Normal ejection is 3 oclock? From an AR15 in 5.56/223 with factory ammo and nothing tweaked?

When did that change so much?

I increased the charge on one of the loads that was giving me problems by two tenths of a grain, fired five rounds as fast as I could pull the trigger, all rounds ejected however they only ejected about three feet at about 3:30. It has never ejected rounds very far since I had it, some rounds eject farther than others, six feet is about as far as any rounds have ejected. I am now debating whether to stop using 2520 even though it appears to be working better or trying another powder in it's place, maybe AR comp.

Lets go over the tuning of a home brew gun that ejects 3 feet to the right.

Gas: My guess is that you are on the edge of enough gas with the intermittent stoppages you get.

Solutions: Lighter buffer, lighter spring, check your gas key, lube, gas block or tube issues. I am sure a handful of others.

I may be wrong, I am sure I left a few things out.

maybe a worn or light ejector spring too.

From his explanation, sounded like his upper was new; he also never said what length gas system he has either.

Could well be something other tan just ammo...............pretty hard to tell w/o more info.

MM

Lots we don't know here. Could still just be light loads or a poorly tuned rifle.

I think I have a mid length gas system.

If the weather cooperates tomorrow I am going to try something to see if I can find a solution to my issue, I have a Rock River Lar 15, it ejects cases from just about everything I shoot at least ten feet or more, it will put 10 empty cases into a 24 inch circle. I am going to take the upper from my Build and slap it on to the Rock river lower, if the cases eject farther then I would assume the problem is with my lower, possibly the buffer spring, if nothing changes then I would tend to think it's the upper, I took the BCG apart and removed and cleaned the extractor, the extractor spring looks fine.

oil the carrier and inside receiver really well when they are new.... not grease, oil....

Ejector spring controls WHERE the empty cases land... FWIW.

I like several AA powders but 2520 has been inconsistent and never really worked in anything for me including the 5.56. There are too many choices for me to put much sweat into building a 2520 load.

I am going into town tomorrow and pick up a pound of Alliant power pro 2000 and see how it works

This is why we quit it in the 90s. It was 200 fps slower and not accurate all of a sudden, this after we'd shot it for years and probably close to 50 pounds or so of it....

While I really like the 2000-MR with heavy bullets, AR-Comp is more flexible across the board with top shelf accuracy.................

MM

I went out earlier today and shot a couple of different loads using the lower from my Rock River Lar 15, cases ejected much farther even with AA2520, went to a gun shop and explained the situation, buffer spring replaced with one that is two inches shorter, will go out and see what happens tomorrow.

This sounds like a rifle spring in an M-4 tube.

kwg

Went out earlier this morning, new spring did not help, called on a friend of mine who has built a few AR's, we took the Bolt carrier group from one of his AR's and tried it in mine, cases ejected with no problem. When we took my BCG apart he noticed that the gas rings were not aligned correctly, correct that and also installed an O ring under extractor spring, will go out Tomorrow and see if that fixes the problem.

OMG, gas rings are about the first thing one looks for. Its so easy. Guess we all failed to think back to bare basics...

Its one reason I never am without a proven totally spare BCG for backup...

Swap it in and all works, you at least know where the problem is.

After seeing one run just fine with only 1 gas ring, I have my doubts the issue will be solved.

Gas key solidly in place and staked?

It appears to be.

I went out this morning and brought a box of Fiocchi factory ammo and three handloads, fired 10 rounds, all ejected fine, first handload 24.4 gr H 335 55 gr fmj, fired 10 rounds, one failed to eject. next handload 25.5 gr A2520 69 gr Sierra tmk, fired 10 rounds, two failed to eject, fired 10 rounds of same bullet loaded with 25.5 gr Alliant power pro 2000, two rounds failed to eject. one thing I did notice is that the H 335 ejected the cases a little farther than the other loads, however I did notice that the ejection pattern with all loads was different. The cases ejected at different angles, example the Fiocchi ammo, first two rounds ejected at 2:30, third and fourth rounds ejected at 4:00, fifth round back at 2:30. I am going to take the BCG out of my other AR and use it to shoot the same loads that I shot today, if they all shoot fine and ejection pattern is the same then I am assuming the extractor or maybe the gas tube may be causing the problem, don't think it's the lower.

Gas tube would be the last place I'd look. of course that means with my luck, the gas tube is the issue.

I'd still question the placement of the gas block...

Went to Reno gun show talk to the guy that built the upper, he was not there but a friend of his was, told him the situation, had the bolt with me, he took it apart and replaced the extractor, it works much better, shoots every load that I tried but still has issues with loads with A2520 powder. That particular load shoots groups under 3 inches at 400 yards and is just under max, may carefully increase the powder charge but hate to mess with an accurate load.