AR Sponsor
Posted: 2/6/2013 5:24:21 PM EDT
|
I have seen this problem on this forum a bunch of times but I wanted to get an opinion on my rifle. Rounds are getting caught at the end of the ramps at the lugs. They seem really sharp. This happens when firing, racking the CH, or hitting the release. I am not riding the CH (although I did ride it for the pics to get the issue to dupe) There are no signs of under gassing/short stroking that I can tell. Bolt holds open with one round, and there is no sign of gas leaking. It is a shrouded carrier so that isn't the issue. This is a Stag rifle. I bought it as a complete upper (3H) and a Stag lower that I put a Stag LPK in. Had feeding problems when I bought it, another good scrubbing and generous lube seemed to clear it up. Around 1000 rounds later (yes it has been cleaned numerous times during that 1000) Im having FTF with good ammo. Hornady Varmint Express and Nosler Varmageddon (Some Win BST also). Scenario - go out hunting, see nothing, unload. I know the scratches from extracting a live round are normal. However there are some massive gouges and the round is pushed into the case. One instance at the range, trying to figure out the issue, the bullet was all the way into the case. Locking lugs at the end of the ramps seem really sharp. I have seen people say use files and sandpaper. What kind of file and paper? Here are the pics for you to take a look at. Any help is appreciated!
* The feed ramps in the photo may look off center (photo angle) but as far as I can tell it is centered on the lug. http://i1323.photobucket.com/albums/u596/Michael_J_Fritz/2_zps0dbb938d.jpeg" http://i1323.photobucket.com/albums/u596/Michael_J_Fritz/1_zps1bb4c1ab.jpeg" http://i1323.photobucket.com/albums/u596/Michael_J_Fritz/3_zps7d10cc8b.jpeg" http://i1323.photobucket.com/albums/u596/Michael_J_Fritz/4_zps395e4262.jpeg" http://i1323.photobucket.com/albums/u596/Michael_J_Fritz/5_zpsaa13f49c.jpeg" http://i1323.photobucket.com/albums/u596/Michael_J_Fritz/6_zpsc3f65f89.jpeg" |
|
Does the feed issue happen on one particular feed ramp or both? Take a dry erase marker and color the round and feed ramps, then manually cycle a single round from the magazine into the chamber, then extract it, and see if you can pinpoint where it is rubbing. Then if you can post some pics of the marks on the ammo and feed ramps where it is being rubbed off, this may help with the diagnosis. On the round of ammo that is in the pic, it may just be the pic or angle but it appears to not have a decent crimp, is this a pic of one of the problem rounds and if so what ammo is it (factory, home load, etc)? Have you tried several different magazines, with different types of followers, as sometimes feeding issues are magazine related.
CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 |
|
400 wet/dry sand paper rolled on a slit chopstick so you can polish the burs away at the end of the barrel feed ramps will solve this problem.
Just don't forget to clean the barrel when done to remove any remnits of the polishing work. P.S, pack the chamber with something solid so you don't over extend the chop stick into the chamber and start sanding away at it |
|
Hey dano Take a look at the last picture, the close up of the feed ramps, and look at the left side feed ramp, particularly the point where the left feed ramp on the barrel extension meets the left feed ramp on the upper. It looks like the case mouth rim is getting caught on the lip at that transition, look at the damage/peening at that point. I only see the damage/peening on the left and not on the right. I'm wondering if all his malfunctions are occurring when feed from the left side of the mag/left feed ramp. O.P can you pin point what side of the mag your getting this malfunction on. Left/right or both. |
|
Quoted:
Does the feed issue happen on one particular feed ramp or both? Take a dry erase marker and color the round and feed ramps, then manually cycle a single round from the magazine into the chamber, then extract it, and see if you can pinpoint where it is rubbing. Then if you can post some pics of the marks on the ammo and feed ramps where it is being rubbed off, this may help with the diagnosis. On the round of ammo that is in the pic, it may just be the pic or angle but it appears to not have a decent crimp, is this a pic of one of the problem rounds and if so what ammo is it (factory, home load, etc)? Have you tried several different magazines, with different types of followers, as sometimes feeding issues are magazine related. CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 I have tried every single mag I own. That took some time, and destroyed $40 worth of hunting ammo. I would like to think the taper crimp on Nosler and Hornady and even these BST Are sufficient. But obviously im wrong :-). That bullet is pushed back into the case about avg for all the rounds it's happened to. I have noticed its about 95/5 percent left to right. In the pic, that's a q tip "fuz" in between ramp and extension so I know that's sharp(the brightest spot, but there is definetly some damage) Will sanding that stop the bullet from getting caught in the lugs also? Use the paper wet or dry? Should I sand the posterior edges of the lugs too? Rounds are all factory. Pic is 55gr winchester ballistic silver tips. Also happening with 53gr varmint express from Hornady and nosler varmageddon. One nosler got pushed all te way back into the case while Hornady and Win look like the one in the pic. About halfway pushed back. |
|
Quoted:
Hey dano Take a look at the last picture, the close up of the feed ramps, and look at the left side feed ramp, particularly the point where the left feed ramp on the barrel extension meets the left feed ramp on the upper. It looks like the case mouth rim is getting caught on the lip at that transition, look at the damage/peening at that point. I only see the damage/peening on the left and not on the right. I'm wondering if all his malfunctions are occurring when feed from the left side of the mag/left feed ramp. O.P can you pin point what side of the mag your getting this malfunction on. Left/right or both. Although a slight problems, being that this is not a M-4 extended ramps barrel, so the upper receiver should not have any kind of ramping either, 99% of the time, the tip of the round is going to strike the feed ramps about center of the ram as it being feed out of the mag, Unless you have other problems. So having said that, take a good look at the chamber of the rifle, and tell me if anyone see's a cleaning and lubing problem, Hence why the rifle is semi short stroking to be with on the extraction stroke (read cleaning and lubing problem from the start), compounded with a feed ramp edge problems, and If I had to add a wild guess, would dare to say that the hammer is binding up on the firing pin collar on B/C closer as well? 
To sum it up, I this was a factory assembled upper, it needs to go back for a warranty replacement. The upper and barrel do not match. As for the possible FP collar/hammer catch, just pull the B/C, pull the bolt forward in the carrier, and compare the FP collar to the carrier ramp. Is a self build upper, then pull the barrel and taper the edges of the barrel feed ramps so they are not proud of the end of the short upper receiver ramps. The edge of the collar should be flush or slightly below the carrier ramp edge, and if it proud, then another problem that has to be correct as well. As for cleaning and lube, Sweets copper solvent to clean the bore of the barrel, then CLP to clean everything else, including the chamber with a chamber brush by hand. Lube, CLP again, and its the bearing areas of the upper receiver that you need to concentrate on here. Simply, the bore needs a good copper solvent to remove the copper, the chamber has to be brush cleaned by hand, then the rest of the rifle get just a oil changer (out with the fouled solvent, and in with the new clean solvent). |
|
Quoted:
Quoted:
Hey dano Take a look at the last picture, the close up of the feed ramps, and look at the left side feed ramp, particularly the point where the left feed ramp on the barrel extension meets the left feed ramp on the upper. It looks like the case mouth rim is getting caught on the lip at that transition, look at the damage/peening at that point. I only see the damage/peening on the left and not on the right. I'm wondering if all his malfunctions are occurring when feed from the left side of the mag/left feed ramp. O.P can you pin point what side of the mag your getting this malfunction on. Left/right or both. Although a slight problems, being that this is not a M-4 extended ramps barrel, so the upper receiver should not have any kind of ramping either, 99% of the time, the tip of the round is going to strike the feed ramps about center of the ram as it being feed out of the mag, Unless you have other problems. So having said that, take a good look at the chamber of the rifle, and tell me if anyone see's a cleaning and lubing problem, Hence why the rifle is semi short stroking to be with on the extraction stroke (read cleaning and lubing problem from the start), compounded with a feed ramp edge problems, and If I had to add a wild guess, would dare to say that the hammer is binding up on the firing pin collar on B/C closer as well? http://i1323.photobucket.com/albums/u596/Michael_J_Fritz/5_zpsaa13f49c.jpeg To sum it up, I this was a factory assembled upper, it needs to go back for a warranty replacement. The upper and barrel do not match. As for the possible FP collar/hammer catch, just pull the B/C, pull the bolt forward in the carrier, and compare the FP collar to the carrier ramp. Is a self build upper, then pull the barrel and taper the edges of the barrel feed ramps so they are not proud of the end of the short upper receiver ramps. The edge of the collar should be flush or slightly below the carrier ramp edge, and if it proud, then another problem that has to be correct as well. As for cleaning and lube, Sweets copper solvent to clean the bore of the barrel, then CLP to clean everything else, including the chamber with a chamber brush by hand. Lube, CLP again, and its the bearing areas of the upper receiver that you need to concentrate on here. Simply, the bore needs a good copper solvent to remove the copper, the chamber has to be brush cleaned by hand, then the rest of the rifle get just a oil changer (out with the fouled solvent, and in with the new clean solvent). I will admit it is dirty on the photo, but I literally took these after coming back from the range. Yes this was a factory built Stag upper. Purchased it as a complete upper. The upper came with a shrouded BC so That rules out catching on the FPSC correct? |
|
Yes, if the FP is not exposed to the hammer, then its back to end of ramp burs, beginning of barrel ramp step to the upper receiver, and lack of CLP to lube the upper receiver bearing surfaces.
Note:CLP has a cleaning agent in it, and when the upper bearing areas are correctly lubed, a trace amount of the CLP will transfer to the chamber to keep it clean as well. If you need a source for CLP for cleaning and lubing, BreakfreeCLP in the large 16oz spray can is under $10 at walmart. And ditch Hoppes cleaning solvent if you have been using it to clean the rifle. It leaves behind a protective residue that collets fouling like a magnet,and worse yet, when it mixes with CLP, even a worse mess. |
| I use gun slick foaming bore cleaner and their liquid stuff. I have both m pro 7 for lube as well as BF CLP. I'm partial to CLP bc it reminds me of Parris Island lol. That smell takes me back a little bit more than a decade. I appreciate you taking a look and replying. |
|
Have you tried this upper on a different lower? I am wondering if the issues is being caused by how the upper receiver is mating with the lower receiver. It is hard to tell without having it in my hands and doing some measuring, but in this pic the front upper receiver lug seem to be slightly off center (to the left) when looking at it compared to the center of the magazine well.
CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 |
Thanks to everyone who posted. I took a needle file and some 1000 grit and worked on both ramps. Smooth as a baby's butt. Cleaned her top to bottom (didn't want any filings in there) and she is flawless. Even when I ride the CH (just to test it), those marks on the rounds are non existent and the bullet doesn't move. Thanks Again!
|
AR Sponsor