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View Full Version : AR short stroking and cracked cases!


thomasanelson
02-22-2008, 3:53 PM
OK, so I built an AR15 from a RRA lower, RRA lower parts kit, A2 stock, MM grip and Bushmaster 20" A3 Upper. My first trip to the range I had a lot of "short Stroking" (I think this is what's happening based on reading several similar postings on AR15.com), but I did not lube the BCG so thats what I get. I took the rifle home, cleaned it and lubed it. Took it back to the range and a few interesting things happened: I had two 50rd boxes of American Ammo (stamped AMERC 223) in two different boxes manufactured at different times. The first 50rds (from the older lot) functioned perfectly. During the second 50rds I started having "jams". Upon inspection, the BCG was resting on top of the next cartrige (ie. short stroking) and failed to hold the BCG on last round fired. This happened about 50% of the time and seemed to get worse with the more round fired. Additionally, 51/100 Cases were split, with some just cracked and others with visable opennings. I had no failure to extract incidences.

Is it normal to have that many split cases?
Is it likely there is something other than bad ammo that is causing the short stroking?
Can someone post or send a picture of what exactly should be lubed for proper operations....and what should not?
Do AR15's require a break in stage?

Thanks,

Tom
thomasanelson@yahoo.com

ocabj
02-22-2008, 4:02 PM
Well, the main issue here is your ammo.

Do any query on Amerc ammo on any forum and you'll see that it's utter garbage.

I suggest you get better quality ammunition and retest.

If you get some quality ammunition like Black Hills (Red Box preferrably) or some (X)M193 or (X)M855 and the problems still persist, then you know it's the gun.

thomasanelson
02-22-2008, 4:13 PM
Well, the main issue here is your ammo.

Do any query on Amerc ammo on any forum and you'll see that it's utter garbage.

I suggest you get better quality ammunition and retest.

If you get some quality ammunition like Black Hills (Red Box preferrably) or some (X)M193 or (X)M855 and the problems still persist, then you know it's the gun.

I figured that would be the obvious answer, but it also happened during my first session with S. African 55gr. Isn't that decent ammo?

pklin1297
02-22-2008, 4:21 PM
That was what was happening with my AR until I found out about oiling the BCG... Once I took it home and drenched both the BCG and the inside of the upper receiver, problem solved. I was shooting Hornady and Black Hills ammo first, then with my own hand loads with Sierra HPBT.

thomasanelson
02-22-2008, 4:24 PM
That was what was happening with my AR until I found out about oiling the BCG... Once I took it home and drenched both the BCG and the inside of the upper receiver, problem solved. I was shooting Hornady and Black Hills ammo first, then with my own hand loads with Sierra HPBT.

That's interesting. I am new to the AR platform and not too keen on how much lubing needs to be done. I lube my M1A1 and Mini 14 very little. Also, I have a Bushmaster Carbon 15CA that does not seem to need much lubing.

pgatour
02-22-2008, 4:31 PM
Hi Tom.. this might be an interesting article for you:

http://www.ar15.com/content/page.html?id=210

"I will make a blanket statement here by adding one ammo manufacturer which hasn't been rated: American Ammunition (AMERC headstamp). There have been many reports of this ammo, and the brass itself being substandard. Please avoid it at all costs. Scroll to the bottom of the page for more info."

CWM4A1
02-22-2008, 4:33 PM
BCG on AR needs quite a bit of lube to keep it function right. BTW, American Ammo (headstamp A-MERC) are known to output crap ammo that's completely worthless. Brass are made with sub standard material and are out of spec, even Wolf is better than that crap. Try get some American Eagle by Federal, or other name brand .223 brass cased ammo, lube your carrier and see what happend. S. African ammo is decent but if you didn't keep your AR well lubed, your gun is going to choke.

ETA: American Ammunition .45 caused Glock 21 Ka-Boomed, See linky:

http://www.thegunzone.com/glock/g21kb4.html

ETA: Another Glock 36 Ka-Boomed thanks to American Ammunition.

http://www.thegunzone.com/glock/g36kb.html

thomasanelson
02-22-2008, 4:40 PM
Hi Tom.. this might be an interesting article for you:

http://www.ar15.com/content/page.html?id=210

"I will make a blanket statement here by adding one ammo manufacturer which hasn't been rated: American Ammunition (AMERC headstamp). There have been many reports of this ammo, and the brass itself being substandard. Please avoid it at all costs. Scroll to the bottom of the page for more info."

Well, that's some good reading. I was one of the unfortunate ones who bought thousands of rounds of American Ammo from 32acp to 45acp and of course 223. :mad:

And, I guess that means I should throw out the Amerc brass!

aplinker
02-22-2008, 5:13 PM
Well, that's some good reading. I was one of the unfortunate ones who bought thousands of rounds of American Ammo from 32acp to 45acp and of course 223. :mad:

And, I guess that means I should throw out the Amerc brass!

What near everyone does with their BCG is to spay it down liberally with CLP, shake it off by waving in the air, reinsert.

The BCG should be wet.

thomasanelson
02-22-2008, 5:49 PM
What near everyone does with their BCG is to spay it down liberally with CLP, shake it off by waving in the air, reinsert.

The BCG should be wet.

More good info, mine was definately not "wet". No wonder the guys in Iraq are complaining about the sand in their AR's, if that is the required lubing. I have even heard they are trying to get M-14's to replace their AR's. Makes you wonder what they would do if stuck in the field for days without oil!

Knauga
02-22-2008, 6:21 PM
Mine was short stroking pretty badly wet or not. It wouldn't lock open on the last round, it would sometimes jam and crush a round it was trying to feed. Then all of a sudden in the middle of a shooting outing it started working perfectly and hasn't stopped. It was almost as if it had to wear down a rough spot or something.

thomasanelson
02-22-2008, 6:27 PM
Mine was short stroking pretty badly wet or not. It wouldn't lock open on the last round, it would sometimes jam and crush a round it was trying to feed. Then all of a sudden in the middle of a shooting outing it started working perfectly and hasn't stopped. It was almost as if it had to wear down a rough spot or something.

That is what I was hoping would happen for me, but..... Still waiting to hear from someone whether or not AR's need a breakin period.

bwiese
02-22-2008, 6:43 PM
That is what I was hoping would happen for me, but..... Still waiting to hear from someone whether or not AR's need a breakin period.

No, they don't.

Marginal ARs from bottom-feeder vendors might, or ones that don't have chrome-lined barrel/chambers.
Problematic magazines can increase issues too, along with poor/no lubrication and crap ammo.

None of my brand-new AR uppers have ever hiccoughed.


What brand of upper do you have?

I am assuming you have an OLL and not a registered AW: are you using a fixed 10rd magazine
or are you using a featureless build that allows you to use detachable magazines?

As first priority, sounds like you have two issues - crap ammo as well as poor lubrication.

Solve the first by using any of several standard brands. 55gr FMJ Federal Amer. Eagle,
Winchester white box or UMC yellow box will likely be the easiest obtainable. Black hills
55gr FMJ is very very good as well but harder to get at Wallyworld or Big5.

Lube your rifle with BreakFree CLP as per the USGI M16 manuals. Briefly, the bolt lugs, the mating lugs on the receiver extension at rear of chamber should both have a film of CLP on em. The bolt should be wet w/CLP in the carrier and the carrier should have a moist coat of CLP in the upper. Put a drop or two on the gas tube tip inside the upper, as well as inside the gas key on bolt carrier. A thumbtip's worth of CLP should be spread inside the upper receiver and the charging handle should have a daub of it too inside the underside lengthwise groove as well as on top. A few drops of CLP down in the trigger group is useful too. Cycle the action several times to spread things around.

rksimple
02-22-2008, 6:45 PM
More good info, mine was definately not "wet". No wonder the guys in Iraq are complaining about the sand in their AR's, if that is the required lubing. I have even heard they are trying to get M-14's to replace their AR's. Makes you wonder what they would do if stuck in the field for days without oil!

If the guys in Iraq lubed their BCGs that way, of course they will have issues. Sand and dust collect like mad on lubed surfaces. It makes a sludge that slows things down. You need light lube in the right places. All of my ARs will run pretty much dry, with one drop of CLP on the cam pin.

bwiese
02-22-2008, 6:46 PM
More good info, mine was definately not "wet". No wonder the guys in Iraq are complaining about the sand in their AR's, if that is the required lubing. I have even heard they are trying to get M-14's to replace their AR's. Makes you wonder what they would do if stuck in the field for days without oil!

Misinformation. All guns get dirty and can jam up.

The M14 had a poorer response to grit/sand than M16 as measured/evaluated in Desert Storm I: that is, the M16 went longer before failure/stoppage than the M14 did.

Once the BCG is wet and once a film of lube dries on bolt/inside upper it doesn't have to be as wet after that. (This is also why you don't 'overclean' an AR and why you don't use solvent to get the upper spotlessly clean, because you're removing a nice layer of CLP deposited on surface of upper.)

thomasanelson
02-22-2008, 8:22 PM
No, they don't.

Marginal ARs from bottom-feeder vendors might, or ones that don't have chrome-lined barrel/chambers.
Problematic magazines can increase issues too, along with poor/no lubrication and crap ammo.

None of my brand-new AR uppers have ever hiccoughed.


What brand of upper do you have?

I am assuming you have an OLL and not a registered AW: are you using a fixed 10rd magazine
or are you using a featureless build that allows you to use detachable magazines?

As first priority, sounds like you have two issues - crap ammo as well as poor lubrication.

Solve the first by using any of several standard brands. 55gr FMJ Federal Amer. Eagle,
Winchester white box or UMC yellow box will likely be the easiest obtainable. Black hills
55gr FMJ is very very good as well but harder to get at Wallyworld or Big5.

Lube your rifle with BreakFree CLP as per the USGI M16 manuals. Briefly, the bolt lugs, the mating lugs on the receiver extension at rear of chamber should both have a film of CLP on em. The bolt should be wet w/CLP in the carrier and the carrier should have a moist coat of CLP in the upper. Put a drop or two on the gas tube tip inside the upper, as well as inside the gas key on bolt carrier. A thumbtip's worth of CLP should be spread inside the upper receiver and the charging handle should have a daub of it too inside the underside lengthwise groove as well as on top. A few drops of CLP down in the trigger group is useful too. Cycle the action several times to spread things around.

Bill:

I have a RRA Lar-15 Lower with RRA lower parts kit.
A2 butt stock & MMG
Bushmaster A3 chrome lined 20'' upper.
Mags are both BM 10/20 & C products 10rd.

To be honest on the first session, I built and shot without even lubing the BCG. Upon the short stroking, I came home and "Over" cleaned the upper and BCG with Hoppe's #9. Then I lubed with an Outer's gun oil and took to the range. As stated in previous posts, there were no issues for the first 50rds, but after switching to the newer ammo I started to have FTF and failure to lock back on last round fired.

And thanks as always for your help & insight.

Tom

Knauga
02-22-2008, 9:49 PM
Bill:

I have a RRA Lar-15 Lower with RRA lower parts kit.
A2 butt stock & MMG
Bushmaster A3 chrome lined 20'' upper.
Mags are both BM 10/20 & C products 10rd.

To be honest on the first session, I built and shot without even lubing the BCG. Upon the short stroking, I came home and "Over" cleaned the upper and BCG with Hoppe's #9. Then I lubed with an Outer's gun oil and took to the range. As stated in previous posts, there were no issues for the first 50rds, but after switching to the newer ammo I started to have FTF and failure to lock back on last round fired.

And thanks as always for your help & insight.

Tom

Yup, sounds like crap ammo ;)

paulo57509
02-23-2008, 12:27 AM
The cracked cases.....where did the case fail? This may give some indication as to the failure mode.

BTW, I don't run my Colt very wet. I'd say it's more like damp; moisten patch with CLP and a quick wipe down. No drippy wet for me. No function issues encountered to date.

thomasanelson
02-23-2008, 1:28 AM
The cracked cases.....where did the case fail? This may give some indication as to the failure mode.

BTW, I don't run my Colt very wet. I'd say it's more like damp; moisten patch with CLP and a quick wipe down. No drippy wet for me. No function issues encountered to date.

The cases cracked from the top of the case down through the neck.

Army
02-23-2008, 8:55 AM
Which is so sad. I shot around 2000 A-MERC .45's in various local Action Pistol matches, with not one FTF, load, extract, or hold together. Very accurate, and plenty of oomph for the poppers and plates.

The next batch of 500 A-MERC....was complete crapola from the first shot to the 4th, which was all I was willing to take my chances with. They CAN make good ammo, I think they just don't want to.

BTW...no, we don't soak our BCG's, or any other part of our rifles for that matter, here in the desert. Lube it to -10 specs, and you won't have problems.

bwiese
02-23-2008, 2:12 PM
BTW...no, we don't soak our BCG's, or any other part of our rifles for that matter, here in the desert. Lube it to -10 specs, and you won't have problems.

Correct, but nobody seems to read the -10 anymore.

Thomasanelson:

Ok you have a good rifle & upper. I notice you said you used Hoppes #9. Be very careful and clean that crap out of your bbl/ upper as it's not good on chrome lining if left sitting there. Just use CLP all the time, and you don't need Outer's gun oil.

thomasanelson
02-23-2008, 3:34 PM
Thanks Bill and to you all for the info. Army...stay safe!