Extraction Issue - 223 Chamber

The force on the underside of the bolt is causing drag. Enough drag to impair proper loading. There are a few reasons it will do this. If your rounds are properly sized it is unlikely to be that.

I think (?) you mentioned running that MFS ammo in it - Is the chamber clean? A gummed up chamber could very well cause this. The MFS ammo is s**t in a match chamber.

Clean up your chamber really well and run some factory ammunition that it will feed through it for a couple of hundred rounds. Leave that MFS s**t for your Norinco.

Have you chrony'd any of your handloads? My go to 68gr. load is 25.5 gr. of Varget, so I kind of doubt you are over pressure...but who knows.

If you are running a hot load, the extraction could be trying to happen while the brass is still sealed with the walls of the chamber; the extractor can ride over the rim in this instance. I doubt this is it.


If you haven't done it yet, get a chronograph and chrony your loads.
 
The MFS is gone now anyway. I needed to run something through the rifle to see if it worked with anything. I also ran my CQB loads (24 Gn H335, 55GN FMJ) with out a hiccup.

I've chronied my 68Gn component combo with 25Gn and 25.5 Gn getting avg of 2890 and 2967 respectively. I believe that is not too high velocity from a 24 inch tube.

I'm leaning to tighting down my sizing die and doing a load work up again. If the drag from the mag is causing the bolt to not fully seat, then slightly smaller brass may be the answer. Again it extracts fine when single loading, just not when feeding from the mag.
 
If the case rims are getting ripped off, the bolt and carrier are trying to pull the case out before the pressure has subsided and slowing down the action will help. Try a heavier buffer and a heavier carrier.

I wouldn't be tailoring the ammunition to the AR15. If you want the gun to shoot hot loads reliably, you need to find the correct timing and tailor the AR15 to the ammunition.

I'd find some military ammo like C77, SS109, or M855 as a base and test platform for your gun. Once your gun is set to works reliably with these rounds, then work on your handloads. I think you're approaching the issues from the wrong end.

You're really not solving anything this way, you're compensating.

As for why your rounds have extraction/feeding issues from a magazine, have you tried different, quality magazines?
 
Easy

Same issue with LAR and Pmags. Commercial MFS works fine as does lower pressure (I assume) hand loads.

Used my Norc carrier too which I believe is heavier than the one in the DPMS. I could try my carbine buffer too.

Not sure where I can get military ammo.

If the bolt is unlocking too quick, why is it fine when single feeding? Am I on the right track with the idea that the bolt is not locking 100% when feeding from the mag, leading to premature opening and extraction?
 
Bolivar said:
I am having extraction issues with my DPMS 223 HB.

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.
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From the above quote, I don't quite understand the exact problem you're having.

Reading your above quote, you state it ejects fine. You also state the bolt goes back and skips over the rim. Is it ejecting the spent case, or not?

Do you mean it skips over the rim of the expended case still in the chamber, or do you mean it skips over the rim of the fresh round in the magazine? Does the bolt carrier skip over the rim of the round in the magazine on its rearward travel, or does it skip over the rim of the round in the magazine going forward?

Does the spent case eject, or does the extractor skip over the rim of the spent case in the chamber without ejecting it where the bolt and carrier travels back, picks up another fresh round from the magazine and feeds it on top of the spent case still in the chamber?

Forget the dies, forget anything to do with reloading and high pressure being the cause of cases stuck in the chamber and forget loading sized cases only into the chamber for testing. If a factory round chambers and the bolt lugs lock up, the chamber is fine unless it's very, very dirty with built up carbon and zinc particle deposit from the MFS rounds fired.

Also, I hope you're not reloading the MFS cases. The MFS cases are non-reloadable zinc coated steel cases.

It would be helpful to know what length barrel you are using as well? You need to make sure your gas tube and gas port is absolutely clean and free of that zinc coated stuff, carbon and oil cake.

Let's start there by answering these questions.

If I must, I will send you enough C77s for testing. An AR15 is a simple mechanical device, but you do need to know precisely what it's doing, or isn't doing.

When you have the gun running reliably with proven ammunition made to function in AR15s, then you can think of reloading to your desires.
 
Easy

Okay, to clarify because my initial post seems to be confusing.

I am having extraction problems with my handloads using RL15, when feeding rounds from the mag. If I single load the cartridge (laying it losely on top of the mag and releasing the bolt carrier) the rifle fires, extracts and ejects fine.

If I load the same rounds from the mag, the fired case becomes caught in the chamber, the bolt cycles back (the extractor either rips the rim or skips over it) and then jams after trying to feed the next round in the chamber, lodging the bullet tip in the feed ramp and getting caught by the round that is stuck.

I have only used MFS to see if the rifle will function at all. A handfull of rounds at most. It works fine. No, I have not tried reloading steel cases. I'm dumb but....:)

The rifle also handles hand loads using H355 and 55Gn FMJ. Same Winchester Brass.

The barrel is 24 inch.

I had not thought about the gas port. Given that it is ripping some rims and cycling back to feed new cartridges, it seems that there is lots of gas available for cycling.
 
I see now ... thank you for the clarification.

I now agree that you're simply having erratic operation due to overpressure loadings. Simple as that. Tone it down to 24.5g with the RL15 and see how that flies. Stay below 25 grains for sure.

I'd definitely consider a heavier buffer and carrier for full house loads and an extra power extractor spring to slow the action down a bit. And detent with a D-ring.

Don't know why it would function fine without a mag though. I can only imagine the issue being because of the erratic operation as well. Erratic bouncing bolts cause unpredictable consequences.

You mention your Hornady bible is the 5th edition. I have the 6th edition in my hands now and it does not state any RL15 loads for 68 g BTHP.

The only RL15 load they state is for the 75 grain A-MAX and BTHP bullets. Max for those with RL15 they state is 24.1 at 2700 fps.

For these same bullets, (75 grain A-MAX and BTHP) they list Varget with 23.5 grains max at 2600 fps if that helps.
 
I asked Hornady direct and they told me the max was 25.7, but they show the max Varget load to be 24.9 Gn. This ain't scientific but often Varget and RL15 have the same max charge weight.

Based on this and my problems I am thinking that my load it too hot for this chamber. I'm going to give a go again this weekend with work up from 23.5Gn and see if I can get things to work.
 
You started the thread saying you worked up the load and experienced feeding issues from the get go...
I'm confused-did you or didn't you?
 
Yes I did from the first session but I attributed it to the dirty condition of the bolt when I started (always clean a new to you semi-auto) interrupting the extractor. I changed out bolts that session and the extraction issue stopped but frankly I cannot recall if I was feeding from the mag then or if I switched to single feeding. As such, I can't be sure that I have an issue with any RL 15 charge weight until I repeat a work up this weekend.

I will set my die tighter but I am holding off on re re-sizing any brass until I get hold of my buddies headspace guage. My plan then is to check the shoulder bump back is in the order of 0.005 compared to the fired cases I have kept separated.

Once the die is set, I will load a range of charges and see if a) it works at all b) what the functional max is that I have to live with.
 
Bolivar said:
Any theory on why it extracts when single feeding but not mag feeding. I put together my guess in Post#12 but I may be off base.
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This is a mag fed repeating firearm. If it doesn't work as designed, fix it.

The rifle is overgassed and overpressured. Plain and simple.

Back off your loads and the problem will go away.

Try Benchmark or the H335 you know works with the other bullet. Use LESS of it for the heavier slug.

Trying to make an AR use bolt action loads is a good way to have problems.

'nuff said.

Jerry
 
The charge may be too high I agree, leading to over gas. Hence I plan to back off and start again.

But the charge is the charge and the gas is the gas regardless of how the round is fed.

Feed single - extracts and ejects
Feed from mag - no extraction no ejection

Why does it work single feed by not mag feed?

Hmmmm, a thought - Is my crimp too light, causing the bullet to be pushed back in the case, spiking pressures?

This wouldn't happen with single feed since I am just laying the case on top of the follower. The path to the chamber would be straighter eliminating resistance on the bullet tip. I can check this with an couple dummy rounds. I'll feed them and see if they are shorter after I extract them.

If that is the case, I can tighten the crimp but I will still do the work up on the weekend.
 
Nope, crimp seems fine. I loaded a pair of dummy rounds and cycled them from the mag to the chamber 3 times each. No change to OAL from start to finish (measured each one after each cycle).

Judging from how hard I had to work to pull the bullets later with an inertial hammer, they were in held in there quite well.

I just don't get what part of the process of feeding rounds from the mag is affecting the ability to extract the fired case.
 
If the pressure and/or time-pressure curve is just on the wrong side of allowing the case to contract before the bolt extracts it, as it appears to be the case here, any little added resistance to the rearward movement of the bolt may be just enough to cause a FTE. Even on an empty mag, the bolt rubs against the follower. In any case, there's no point in beating the issue to death, load down and give it a try. The fact that your gun works fine with factory ammo tells you that it's your load that is the cause.
 
Okay, moving forward, I took the rifle to Epps last evening and had the boys check the chamber with a bore scope. No issues showed up. The extractor seemed fine to them too. No worries.

So I gave it a good clean again this morning, even running a wire down the gas key and into the BCG body to make sure all was clear.

I loaded up a series of charges (3 rounds each) from 23.0, 23.5, 24.0, 24.5 and 25.0 Gn of RL 15 and headed to the range. I noted that 24.0 Gn and up, I could not hear any powder moving in a shaken case. So the loads were compressed.

The wind was howling so I didn't even bother with a target board. I just aimed at clumps of melting snow (actually after this winter, shooting snow was therapeutic)

Starting at 23.0 Gn, Good to go. All extracted and ejected fine. Bolt locked back on the empty mag and everything. Wow, I functioning AR.

23.5 Gn.....JAM! ..... F**K!!!!! Bolt cycled to the rear, fire case stuck in the chamber and the next round wedged between.

Once I got it clear, I fired the rest of that charge single loaded. No extraction at all. All rims damaged. At least it's consistent now and screws up the same regardless of how the rounds are fed to the chamber :)

I gave up and pulled the rest of the bullets for the higher charges.

So my functional max seems to be 23.0 Gn of RL 15. I wish I had bothered to set up the chronograph to see what kind of velocity I was getting. I am expecting it to be low however, maybe 2600 and change? (based on another similar length barrel) Not what I was hoping for but I've got to measure it to be sure.

I am going to do another work up tomorrow starting at 22.4 Gn moving to 23.0 Gn in 0.2 Gn increments to see what velocities are and if I can get bullets to land in some form of proximity to each other.

I am also thinking I should look at other powders to see if I get similar issues with published load data. The only other suitable powders I have on hand are IMR 3031 and IMR 4064.

Any reason to stay away from either of these in the 223 loaded in an AR?
 
For reloading with a powder measure, coarse IMR powders will produce some significant variation in charges thrown and for small cases like the .223, it may have an adverse effect in accuracy over 200 m+. If you weigh the charges, no problem with the powders mentioned. I would suggest you try W748 as well. It's a powder well suited for the .223 and being a ball powder it meters very well and it's very consistent from lot to lot and cheaper than R15 (Swedish) or Varget (Aussie). You have a tight chamber, apparently, so start low, as you did and work your way up. W748 may also give you more latitude in weight before you run into the same problem but it's time-pressure curve may be such that you avoid the problem altogether.
 
Are you using a rifle buttstock and rifle buffer, or a collapsible buttstock with a carbine buffer?
 
Miltiades

Yeah I have read the W748 is good for 223 and I will likely try some. For now though my cupboard only as the powders mentioned (well okay, I have pistol powders and RL19 and RL22 but I figured those were no goes :) )

Easy

Rifle stock, tube and buffer. I assume your thinking of slowing down the carrier cycle? I guess that is a possibility with a heavier buffer and carrier or going with Jerry's suggestion of cutting down on the gas.

The only way I can think of doing the latter is following what Jerry did with his norc and moving the gas block so it doesn't fully line up with the port, or going for a variable gas block (JP Enterprises?).

Moving the gas block is above my AR newbie skills.
 
Are you absolutely sure your chamber is completely clean? Particularly in the neck area of the chamber where your chamber brush won't reach. I'm thinking of those MFS cases you fired and their zinc coating and steel cased ammo is generally much dirtier. At least I know Wolf ammo is. Chamber may look shiny but ...

What about a rough chamber? Do any of your cases show rings around them? Can the chamber be a bit rough? It doesn't take much for cases to stick.

Also wondering ... can excess headspace cause cases to stick? Wouldn't excess headspace cause the case to stretch to a point too far to retract enough for a smooth extraction? Especially since you're redlining with your handloads.
 
The neck area would get cleaned well by the bore brush. I have her a complete clean this morning before going to the range.
I have really scubbed the chamber too. The chamber was scoped at Epps on Friday evening. They saw no concerns about roughness. Case show no sign either. I checked that when the issue started.

Cases are stretching about 0.004-0.005 measured at the shoulder (Stoney Point HS guage). I don't think this is excessive but I could be wrong.
I may take the upper back up to Epps and get them to check it with gauges in the next couple of weeks.

I don't know if 2.5 Gn under book max can be called red-lining :)
 
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