Extraction Issue - 223 Chamber

Bolivar

Bolivar

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I am having extraction issues with my DPMS 223 HB.

It feeds fine, but won't extract my hand loads when fed from the mag. Load is 25.3 Gn RL15, Horn 68 Gn HPBT, 2.25 OAL. Winchester brass. Fed 205 primer.

Strangely, it seems to eject fine if I single load them, but from the mag the bolt goes back, skips over the rim and then jams when trying to feed the next cartridge.The rifle has no issues with MFS ammo or my CQB load using 55GN bullets and H355 powder (lower performance load for sure).

With the RL 15 load, the base of the case expands about 0.002 to 0.376 after firing (0.374 when FL resized). Re-chambering a fired case results in a locked bolt that I need to open by pushing with a cleaning rod.

The rifle has been giving extraction issues from the start when I was working up from 23.5 to 25.5 Gn. At first I thought it was a dirty bolt. I cleaned it and still had problems. Then I figured it was my OAL which was too long to start with, causing hard feeding.

Now today, no go. I swapped out my DPMS bolt with my Norc, still not go. The same loads fed and ejected fine in the Norc.

I am guessing that I have a tight chamber. Would small base dies be worth a try? Again the rounds feed fine, but they won't extract.

Is the Winchester brass too soft? I have some IVI that I could do a work up with. I understand this heavier walled and better quality.

Anybody have similar problems with AR's? Any and all helpful advise is appreciated.

Thanks, Bolivar
 
My concern is the regardless of the size of the case when I size it, the expanded case will still want to stick. I even tried some of my once fired IVI brass (un-sized) and it jams the bolt too.

I don't see any signs of dings or scratches on the brass once I get it out. Maybe the chamber needs to be polished? What's a good way to do that?
 
Are your sized, loaded rounds dropping in and out of your chamber freely?

If not adjust your sizing die. I very much doubt you need to SB size your cases.

Winchester brass is very good and despite popular myth, the same thickness as IVI.
Polishing the chamber may help a bit (is it new?), but I'd hazard a guess this is a gas issue if the rounds are running fine in your Norinco.
 
Since you checked all else, I believe that your load-bullet combination is a bit too hot for that chamber. If factory loads feed and extract fine, as you indicated, the only alternative problem is too much pressure. The fact that the Norinco handles the same loads fine maybe be a combination of a looser chamber and perhaps a bit more freebore, all contributing to lower pressures in your chamber. Drop by 0.5 gr and see what happens and keep dropping until you establish a load that extracts fine.
 
Yeah, the charge/pressure is one of the things I am thinking. I may be over max. Does anybody have access to Hornday load data for 68 HPBT in 223 with RL15. I see their max of Varget is 24.9 and often weights for Varget and RL15 are the same in load manual. I have the 5th Edition so maybe later ones include RL15.

I'm also going to set my sizing die back tighter and run through a range of powder charges to see what works and doesn't, if it makes a difference at all.
 
Reduce gas port size or other way to reduce gas force on your BCG - you need to slow down that bolt cause the action is trying to unlock before the chamber pressure has reduced enough for the case to shrink.

A heavier buffer spring and buffer should help.

The stretched and enlarged base is a sure indication of overgassing/early unlocking.

If other ammo lower pressure loads are extracting properly, this is my best guess. I don't think going to a ubber strong extractor will help as you will likely start to tear off rims.

Re15 is a 'slow' powder for a gas gun and there is alot of port pressure and gas volume.

Jerry
 
Bolivar said:
Sized and un-fired cases pop out with no hesitation. I don't think it's gas since they work in the Norc, and commercial is fine.

Maybe I'm over pressure and need to try a new work up?
Click to expand...

You need to try the actual loaded rounds, not just the sized cases.
They should be dropping in and out with no prompting.

Regarding the gas, it very well could be a gas issue as you'd no idea how your chamber is cut compared to the 'rinco -unless you've taken a chamber casting?

RL-15 is listed in the 6th Hornady but only for 75gr. HPBT
If you look at the powder comparison from one load to the next (68s and 75s) you'll see that they list some of the same ones in different order. This is due to the fact that while some powders are very similar in burn rate overall, they can behave differently depending on the calliber, bullet, and other load characteristics.

If you haven't worked up the load I'd suggest you start there.

Based on the information you've provided and that information is correct, if the load cycles fine with no or an empty mag in it, then it is quite likely the drag of a loaded mag is hanging it up enough to not cycle properly.
That might indicate that the rounds are anemic and/or your chamber is tight enough causing short stroking.

In short, lots of variables at play that may or may not be influencing proper operation.
 
Replace your extractor spring with a heavier one and the blue spring buffer with a black one, and/or install a D ring under the extractor.

The D-fender ring alone will multiply extractor spring tension 4x and prevent almost all extraction problems with AR-15 firearms. The black extractor spring insert will prevent extractor bounce and losing contact with the case during ejection.

I don't have any D rings, but if you want I can sell you an M16 extra power extractor spring and black buffer for your extractor.

You can also use a round rubber seal, an O-ring, as a substitute for a D ring.
 
You need to try the actual loaded rounds, not just the sized cases.
They should be dropping in and out with no prompting.[/QUOTE]

Yup, the do, and eject easily.

beltfed said:
Regarding the gas, it very well could be a gas issue as you'd no idea how your chamber is cut compared to the 'rinco -unless you've taken a chamber casting?
Click to expand...

No casting. I am guessing based on empirical evidence.

RL-15 is listed in the 6th Hornady but only for 75gr. HPBT
If you look at the powder comparison from one load to the next (68s and 75s) you'll see that they list some of the same ones in different order. This is due to the fact that while some powders are very similar in burn rate overall, they can behave differently depending on the caliber, bullet, and other load characteristics.

If you haven't worked up the load I'd suggest you start there. [/QUOTE]

I have done a work up but I will be doing so again. Hornady got back to me today and said 25.7Gn is the max with RL 15 68 Gn HPBT in 223.

beltfed said:
Based on the information you've provided and that information is correct, if the load cycles fine with no or an empty mag in it, then it is quite likely the drag of a loaded mag is hanging it up enough to not cycle properly.
That might indicate that the rounds are anemic and/or your chamber is tight enough causing short stroking.

In short, lots of variables at play that may or may not be influencing proper operation.
Click to expand...

Yes, many variables. I am not sure how the round can be hanging on the mag on the way on, only on the way in.

Now, if my brass isn't being sized enough, the chambering force from mag feed would be reduced. The could even result in incomplete lockup of the lugs I guess.

When single loading the bolt would be closing with more force (less drag) seating the extractor better and/or closing the bolt 100%, thus the bolt would be un-locking later with lower pressure in the case and with the extractor having an even firmer grip on the rim? Maybe?

easy said:
Replace your extractor spring with a heavier one and the blue spring buffer with a black one, and/or install a D ring under the extractor.

The D-fender ring alone will multiply extractor spring tension 4x and prevent almost all extraction problems with AR-15 firearms. The black extractor spring insert will prevent extractor bounce and losing contact with the case during ejection.

I don't have any D rings, but if you want I can sell you an M16 extra power extractor spring and black buffer for your extractor.

You can also use a round rubber seal, an O-ring, as a substitute for a D ring.
Click to expand...

The rifle failed even with a different bolt, but worked fine with commercial ammo. Also, some but not all rims were damaged (ripped) by the extractor. I believe it is grabbing firmly enough.
 
Bolivar said:
Jerry

I hear what you are saying, I don't think that this would explain why I can't extract an empty fired case. The cases appear to be expanding to the size of the chamber and not shrinking.

Also, if I single load, the cases seem to extract and eject just fine.:confused:
Click to expand...

Of course it does. The pressure in the load is high enough and the unlocking of the action soon enough that the case has 'bulged' and gotten stuck.

If I am correct, dropping your load some will eliminate some of the issues. Easy enough to try. Drop your load 2gr and see what happens - don't worry about accuracy, you are checking function.

If this resolves your issue, I would cut the size of the gas port in 1/2 or more.

Anytime, I see dings on the extractor groove/rim of the case, I suspect that the BCG is being asked to cycle too fast (relative to the pressure in the chamber) and the extractor is tearing up the rims.

Jerry
 
Yeah, okay. I think that this weekend I will try re-setting the sizing die down first with my 25.3Gn load. If that does not work, I load a series of rounds starting a 90% of max and working up to see if can find a working "Max" for this chamber.

Hmmmm, I'm supposed to be painting the kitchen this weekend. :eek: I guess I will just have to sneak way. I really owe it to my wife and kids to get this figured out :D
 
No need to get fancy cause you want to change 1 variable. If the cases go in and out of the chamber now, there is nothing wrong with your sizing. The problem is when you pull the trigger.

Use the STARTING load and go up in 1/2 gr increments to your present load. 3rds at each amount and you will have your answers in 15 rds.

I bet the lighter loads will function just fine and eventually, you will start to see your extraction problem.

I will also guess that the cases that extract near when you have extraction problems will be extremely hot to the touch but the starting load cases will not.

Jerry
 
In most cases the D-ring fix on the extractor spring will do the trick. However, these D-rings are sometimes hard to find. A $0.10 O-ring (1/8" IIRC) available from your local Canadian Tire or hardware store will do the same. Good luck :)

AR15O-ringinstalled.jpg
 
RifleDude said:
In most cases the D-ring fix on the extractor spring will do the trick. However, these D-rings are sometimes hard to find. A $0.10 O-ring (1/8" IIRC) available from your local Canadian Tire or hardware store will do the same. Good luck :)

AR15O-ringinstalled.jpg
Click to expand...

There is no doubt the donut will help but if a part doesn't fit, using a bigger hammer just pushes the problem further down the line.

Eventually, tearing off the case head or extractor rim will be the next problem. Not to mention the potential for damage to the bolt head lugs.

Overgassing seems to be pretty prevalent and needs to be addressed.

Think of the battering the internals are taking now. a 10cent part can help to expand to be a multi hundred dollar problem

Jerry
 
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