AR not cycling correctly

ezmoney · December 25, 2012, 06:00 PM

In a gas operated AR can Powder rate burn affect cycling of the bolt?

DnPRK · December 25, 2012, 06:28 PM

Yes, it can. Especially if your rifle has a 16" barrel.

One cause for a new rifle to fail to cycle is lack of lube. Make sure your rifle is well lubricated. The bolt carrier group should be dripping wet with lube. If you think you have too much lube, add some more. A properly lubed AR-15 will spit lube from the ejection port during the first 3 shots. Add more lube every 20-30 rounds.

After 100 rounds or so, you'll be able to cut back on the amount of lube.

Another cause for failure to cycle is using underpowered eastern European-manufactured steel cased ammo. New rifles are stiff and using American-made brass-cased ammo will help cure cycling issues.

Nathan · December 25, 2012, 06:51 PM

Need more details.

Yes to your question, but I've never heard of an AR which would not run due to powder only.

AR's usually run....period. When they don't, cleanliness and lube are first checks...

The only design things on a home build which must be considered are reciprocating mass vs gas port size/location vs spring weight. These are almost always close enough!

Jimro · December 25, 2012, 06:52 PM

Yes, there is a burn rate range needed to properly cycle the action. What problem are you experiencing? Are you using handloads (if so, what recipe?).

Details are helpful.

Jimro

ezmoney · December 25, 2012, 07:21 PM

Details are helpful.

Jimro

New firearm not mine, all I know about his reloads they were 55 grain. They would Cycle enough to eject but would not pick up another round.my reload were 65 grain using 8208 power traveling at 2850 fps. Mine would cycle his would not. I will probably Go to the range with him again in a couple weeks . I will make sure he Oils the firearm heavily. Sorry I have no more information than that. I did ask him what powder he was using but I have forgot.

mehavey · December 25, 2012, 07:37 PM

If yours cycle and his short-stroke, it's likely too light a powder load on his part.
If you can find out what his recipe is, we can probably help.

RLFD5415 · December 25, 2012, 08:06 PM

FYI, lube is used in quantity to band-aid other issues e.g. headspace, gas tube, brass sizing, buffer problems. I do not lube any of my AR's, either in the 308 or 5.56 configuration, with other than some light grease on the lugs and some light oil on the BCG. They run for hundreds of rounds w/o issue. If they do have an issue, it can be traced to some other problem as mentioned above.

JMHO, YMMV

rdmallory · December 25, 2012, 08:37 PM

New Rifle?

Check and make sure the gas tube is correct. I built one once and missed with he roll pin.

Doug

CTS · December 25, 2012, 10:15 PM

Quote:

FYI, lube is used in quantity to band-aid other issues e.g. headspace, gas tube, brass sizing, buffer problems. I do not lube any of my AR's, either in the 308 or 5.56 configuration, with other than some light grease on the lugs and some light oil on the BCG. They run for hundreds of rounds w/o issue. If they do have an issue, it can be traced to some other problem as mentioned above.

I agree. My ARs get a light coat of oil on all metal parts and that's it. If it's dripping with oil it needs a good wiping down IMO. More than likely a light powder charge.

globemaster3 · December 25, 2012, 10:24 PM

I agree with what has been said in the negative on excessive lube. I've never ran any that wet, even when I was in Afghanistan. However, I do not run them dry, either. Just a light coat is all I've ever needed.

As for the failure to feed, were you both using the same magazine?

Jimro · December 26, 2012, 12:56 AM

Well, given the information available, it sounds like your friend needs to redo his load workup.

Jimro

10-96 · December 26, 2012, 09:26 PM

Quote:

FYI, lube is used in quantity to band-aid other issues e.g. headspace, gas tube, brass sizing, buffer problems. I do not lube any of my AR's, either in the 308 or 5.56 configuration, with other than some light grease on the lugs and some light oil on the BCG. They run for hundreds of rounds w/o issue. If they do have an issue, it can be traced to some other problem as mentioned above.

BINGO! Give that man a cigar!
If a shooter has good luck with the dripping wet process- great. Please just stop making it sound like The Gospel According to Colt. I was first introduced to M-16's and AR's in '87 and I have NEVER had the need to resort to that method.

December 25, 2012, 06:00 PM	#1
ezmoney Junior Member Join Date: January 12, 2012 Location: Jacksonville, Arkansas Posts: 3	AR not cycling correctly In a gas operated AR can Powder rate burn affect cycling of the bolt?

December 25, 2012, 06:52 PM	#4
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	Yes, there is a burn rate range needed to properly cycle the action. What problem are you experiencing? Are you using handloads (if so, what recipe?). Details are helpful. Jimro __________________ Machine guns are awesome until you have to carry one.

December 25, 2012, 08:06 PM	#7
RLFD5415 Senior Member Join Date: July 3, 2004 Location: Upstate NY Posts: 129	FYI, lube is used in quantity to band-aid other issues e.g. headspace, gas tube, brass sizing, buffer problems. I do not lube any of my AR's, either in the 308 or 5.56 configuration, with other than some light grease on the lugs and some light oil on the BCG. They run for hundreds of rounds w/o issue. If they do have an issue, it can be traced to some other problem as mentioned above. JMHO, YMMV __________________ It took me 6.25 years to reach 100 posts...

December 25, 2012, 10:24 PM	#10
globemaster3 Senior Member Join Date: January 28, 2006 Posts: 1,482	I agree with what has been said in the negative on excessive lube. I've never ran any that wet, even when I was in Afghanistan. However, I do not run them dry, either. Just a light coat is all I've ever needed. As for the failure to feed, were you both using the same magazine? Last edited by globemaster3; December 26, 2012 at 08:00 AM.

December 26, 2012, 12:56 AM	#11
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	Well, given the information available, it sounds like your friend needs to redo his load workup. Jimro __________________ Machine guns are awesome until you have to carry one.

December 25, 2012, 06:28 PM	#2
DnPRK Senior Member Join Date: August 24, 2001 Location: LC, Ca Posts: 1,917	Yes, it can. Especially if your rifle has a 16" barrel. One cause for a new rifle to fail to cycle is lack of lube. Make sure your rifle is well lubricated. The bolt carrier group should be dripping wet with lube. If you think you have too much lube, add some more. A properly lubed AR-15 will spit lube from the ejection port during the first 3 shots. Add more lube every 20-30 rounds. After 100 rounds or so, you'll be able to cut back on the amount of lube. Another cause for failure to cycle is using underpowered eastern European-manufactured steel cased ammo. New rifles are stiff and using American-made brass-cased ammo will help cure cycling issues.

December 25, 2012, 06:51 PM	#3
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,331	Need more details. Yes to your question, but I've never heard of an AR which would not run due to powder only. AR's usually run....period. When they don't, cleanliness and lube are first checks... The only design things on a home build which must be considered are reciprocating mass vs gas port size/location vs spring weight. These are almost always close enough!

December 25, 2012, 07:21 PM	#5
ezmoney Junior Member Join Date: January 12, 2012 Location: Jacksonville, Arkansas Posts: 3	Details are helpful. Jimro New firearm not mine, all I know about his reloads they were 55 grain. They would Cycle enough to eject but would not pick up another round.my reload were 65 grain using 8208 power traveling at 2850 fps. Mine would cycle his would not. I will probably Go to the range with him again in a couple weeks . I will make sure he Oils the firearm heavily. Sorry I have no more information than that. I did ask him what powder he was using but I have forgot.

December 25, 2012, 07:37 PM	#6
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,896	If yours cycle and his short-stroke, it's likely too light a powder load on his part. If you can find out what his recipe is, we can probably help.

December 25, 2012, 08:37 PM	#8
rdmallory Senior Member Join Date: February 10, 2009 Location: Deltona FL Posts: 953	New Rifle? Check and make sure the gas tube is correct. I built one once and missed with he roll pin. Doug