Ammo Problems (.223)

[pwoolford]

Anyone ever have bad boxes of ammo? I've had a Colt HBAR for 5+ years and left it stock and shot maybe 1000 rounds through it over that time. No issues with FTF/FTE. Over the past 6 months I've shifted hobbies from fast cars to shooting so I started to customize the AR a little. I put BCM upper on it and MagPul buttstock. I started having FTF/FTE issues with it so I thought it might be the gun not liking the new upper. I put it back to stock and still had ammo problems. What happens is I load a box of 20 rounds (PMC) and every round will fire and eject but not load the next round. I load the next box and every single round fires and feeds perfect. If I take 10 boxes to the range half might do this.
This gets old so I buy a Spikes complete lower and put the BCM upper on it and the exact same thing happens. Then I figured I'll just get a complete new AR to eliminate all of the problems so I bought an Adcor 16" AR. Last night was the first night shooting it and the exact same thing happens!
The it hit me that I bought two 1k boxes of PMC ammo from different places and put all of it into a storage box. Maybe one was bad? I tried 3 boxes of Federal XM193 from the range and they fired perfectly. I brought home 1k of the Federal and will try it in the other AR's to see how they do.
Sorry for the long winded post but I'm curious if anyone else has ever had anything like this happen?

(I searched by couldn't find anything like this so hopefully this hasn't been covered 100k times already)

 

[Deep Creek Rock]

Have you tried another magazine ? Does the issue occur if you use another mag?

 

[F-Stop]

Are you using the same buffer/spring/ tube/ stock as you were with the hbar on the new rifle?

Search short stroking. The 5.56 probably has a little more behind it and why it's feeding.

 

[pwoolford]

I've tried at least a dozen 20 and 30 round MagPul mags as well as steel mags.

 

[Boom Boom]

If you have calipers, start measuring the length of random PMC rounds from different boxes. See how close they are to 2.260" (hopefully not longer). Beyond 2.260", they are likely to hang up in the magazine. If you have non-PMC ammo on hand, measure those in comparison. It's possible the PMC brass is too long or the bullets are not seated deeply enough.

If that's not it, since you're seeing the same behavior across multiple rifles, are you lubing the action before you go to the range? ARs generally do not like to run dry (very lightly lubed).

 

[midcountyg]

When you load rounds that are acting up in the mag, will it lock the bolt back on the last round? If not, sounds like it could be short cycling. It could be under powered ammo, a lube issue, ect.

 

[pwoolford]

Are you using the same buffer/spring/ tube/ stock as you were with the hbar on the new rifle?

Search short stroking. The 5.56 probably has a little more behind it and why it's feeding.

I tried several stock/spring/tube combos on the HBAR and it didn't seem to help. I was trying to get the Slide Fire to work so I went through a couple tubes.

If you have calipers, start measuring the length of random PMC rounds from different boxes. See how close they are to 2.260" (hopefully not longer). Beyond 2.260", they are likely to hang up in the magazine. If you have non-PMC ammo on hand, measure those in comparison. It's possible the PMC brass is too long or the bullets are not seated deeply enough.

If that's not it, since you're seeing the same behavior across multiple rifles, are you lubing the action before you go to the range? ARs generally do not like to run dry (very lightly lubed).

I gave up and unloaded a mag last night so I have some of the problem rounds separated. I'll measure them tonight. I've tried a couple different lubes but lately I'm using CLP and I have been lubing it before I shoot it.

When you load rounds that are acting up in the mag, will it lock the bolt back on the last round? If not, sounds like it could be short cycling. It could be under powered ammo, a lube issue, ect.

When I have the ammo trouble it doesn't lock the bolt back. Also, I forgot to mention that sometimes it will start to pull the round in but jam with the round halfway in....stuck at an angle to the barrel against the bolt.

Thanks for all the advice!!

 

[ALBY]

Are you using the same buffer/spring/ tube/ stock as you were with the hbar on the new rifle?

Search short stroking. The 5.56 probably has a little more behind it and why it's feeding.

this


When you changed stock's, did you change buffers ?

In my experience, PMC chrono's about 250 FPS slower than xm 193.

I'd be really suprised if it was the ammo. I was shocked to see how consistent PMC velocity is out of my gun.

 

[Boom Boom]

I'd be really suprised if it was the ammo. I was shocked to see how consistent PMC velocity is out of my gun.

He purchased a lot of it at the same time, same place. He could have a bunch from an out-of-spec batch. It happens.

 

[crfakm4]

If you want to get rid of that PMC let me know, my rifles eat it like candy. I am also in White Marsh/Perry Hall.

 

[midcountyg]

Is they adcor a complete unaltered rifle? Is it doing the same thing? So you have a 20" Hbar and are using a carbine tube, spring, and buffer? Sounds like either bad lot of ammo, or wrong spring/buffer combination.

 

[pwoolford]

If you want to get rid of that PMC let me know, my rifles eat it like candy. I am also in White Marsh/Perry Hall.

If you go to Freestate I'd love to try this PMC in another AR!

 

[pwoolford]

Is they adcor a complete unaltered rifle? Is it doing the same thing? So you have a 20" Hbar and are using a carbine tube, spring, and buffer? Sounds like either bad lot of ammo, or wrong spring/buffer combination.

Yes the Adcor is unaltered and the HBAR is now back to stock. Last night was the first time I shot the Adcor and when it started doing the same thing I figured it must be the ammo. I've just never heard of that happening. What threw me off was buying two 1k boxes of PMC two months apart then mixing it up. Some range trips are great and some fail to feed constantly. Made me think I was going nuts!

 

[midcountyg]

Yup, if the adcor isn't running on it I definitely say week batch of ammo. Does your adcor have a gas setting for when it gets real dirty? That would increase the gas and allow you to run that ammo most likely.

 

[pwoolford]

If you have calipers, start measuring the length of random PMC rounds from different boxes. See how close they are to 2.260" (hopefully not longer). Beyond 2.260", they are likely to hang up in the magazine. If you have non-PMC ammo on hand, measure those in comparison. It's possible the PMC brass is too long or the bullets are not seated deeply enough.

If that's not it, since you're seeing the same behavior across multiple rifles, are you lubing the action before you go to the range? ARs generally do not like to run dry (very lightly lubed).

I spot checked 30+ boxes of PMC last night and they all measure about the same.... 2.220-2.245 or so. One good thing I found was I have two lot numbers so I'm going to go tomorrow and see if one is acting up. I'll bring a couple AR's and some Federal along to compare too. I had just about equal quantities of each lot number left so that could explain why some trips to the range are fine and others jam constantly.
Thanks again for all the advice.

 

[EL1227]

TIP ...

I've marked my mags and I always note which mftr I load in which mag and the batch # before heading to the range.

At least by doing that you can sort out a mag problem from a mftr, from a batch ... especially when you have multiples of each. Then you can go about determining whether it's the mag, the ammo, ... or gawd forbid, your AR or your mods.

 

[NathanJ]

Wait here...

"I gave up and unloaded a mag last night so I have some of the problem rounds separated. I'll measure them tonight. I've tried a couple different lubes but lately I'm using CLP and I have been lubing it before I shoot it."

Chad has said that CLP will burn off fairly quickly, try his full syn motor oil/syn wheel bearing grease lube job and see how it runs?

 

[zoostation]

Make certain you are keeping the bolt rings lubed. The AR system produces plenty of gas to cycle the action but you need to keep the bolt moving freely and lubed or it will start giving you problems. Of all the parts in an AR rifle that is the one most critical lube point for function, IMHO. You can have a filthy dirty *mil-spec* rifle and it should still cycle well with oil in and on the BCG. I'm talking about mil-spec rifles here, the off-brands or rifles with mismatched buffers, I can't say how they'll do, I don't think anyone really can.

I think what you are probably seeing though is a combination of the PMC ammo and an aftermarket upper that aren't getting along, maybe creating a type of "stacking tolerances" situation. I hear a lot of complaints about PMC ammo. I wouldn't buy it, and this is coming from a guy who shoots Wolf all day long and doesn't mind. I would make sure you have the correct buffer in and are keeping the BCG lubed, especially the bolt rings. (Most oils, even the good ones, don't seem to last too long under heavy use inside the BCG. I'm a fan of Rem Oil or Break Free just from experience but that's just me, but even those don't tend to go too long.) Those are probably the best things you can do to rectify the issues, IMHO.

 

[JWBanshee]

I had similar problems, I changed out my extractor springs and the little rubber bushiung , added the oring. All of my FTF problem as well as fte, went away. For a buck, try it.
JW

 

[pwoolford]

I went today and shot through 7 boxes of each lot #...#497 and #500. #497 failed over 80% of the time in my Spikes setup and up to 50% of the time in my Adcor...depending on the box. The #500 batch never misfired a single round and neither did the Federal!
I'll know in the future to double check my ammo. This time around it cost me a lot of parts and headaches. I changed BCG twice and rings a couple times along with the buttstock/tube/spring. I learned a lot so its all good.
Thanks for all of the tips!