Member Login
Member Login
Member Login
CA, USA
|
Built a new ar15 flattop. My third.
getting frequent jams, dents, and heavy scratches. Not from ejection. METHOD bcg fully cocked and held back load one shell in the mag insert mag release bcg 6 jams out of 50 shells, failure to get completely into battery Dents are at the 8 o'clock position, a quarter of the way down the shell. The black line is at 12 o'clock in the mag. https://www.sugarsync.com/pf/D984499_7601439_472659 I can replicate the problem on the bench by slowly allowing the bcg forward. The tail of the shell gets forced down and left. Any thoughts on what could be causing this? thanks, doug How do I insert an image? |
|
|
|
Posted: 10/2/2011 5:40:29 PM EST
[Last Edit: 10/2/2011 5:41:14 PM EST by Dano523]
Mag/rifle is load feeding the tip of the bullet right into the upper receiver below the feed ramps causing the problem.
Start with confirming that the bolt catch threaded end is flush with the face of the mag catch release button. Next, Bring us up to speed on the mags being used (make/brand and number of rounds that they should hold), and if you have pulled them apart and CLP cleaned them before you tried to use them. |
|
|
|
CA, USA
|
Posted: 10/2/2011 7:58:12 PM EST
|
|
|
|
Posted: 10/2/2011 9:48:36 PM EST
What brand of barrel?
DI/Piston? |
|
|
|
|
Posted: 10/3/2011 1:19:12 AM EST
[Last Edit: 10/3/2011 1:20:35 AM EST by Banditman]
Looks like m4 cut receiver and non m4 barrel extension.
In fact that barrel extension looks plum nasty, |
|
|
|
|
Posted: 10/3/2011 3:25:03 AM EST
Upper receiver has some ramp'g done by free hand grinding (read did not start out as a M-4 receiver), while i cannot tell if the barrel has M-4 ramps.
A better photo of the barrel and front of receiver is really needed. As for the third photo, can plainly see that the tip of the bullet is striking the face of the upper receiver, and not being cleanly feed to the ramps, which is causing the bullet set back in the case neck, and the cause being bent as well. |
|
|
|
CA, USA
|
Posted: 10/3/2011 9:18:53 AM EST
The receiver was ground by hand.
This is a Schilen barrel and matched bolt. The barrel shoots very, very well. I have another Schilen just like this one, (this one's a gift). That barrelt looks exactly the same. The bullet tip is NOT hitting the receiver, it's an optical illusion in the photo. I can watch it being fed, and it hits the middle of the ramp. The binding doesn't occur until the shell is part way into the chamber. Maybe a half inch or so. I think the cartridge is being fed at too steep an angle. Then hitting inside the chamber at 2o'clock, the bolt continues forward and places the dent at 8 0'clock on back edge of the chamber. Or not sliding across the bolt face as easily as it should. I'm going to load a mag with more shells and see if the extra pressure from the mag will force the butt of the cartridge up more quickly. thanks for everyone's help. doug |
|
|
|
Posted: 10/3/2011 9:31:07 AM EST
What brand of lower?
How does the distance of the mag catch slot from the top of the lower to the slot compare to your other lowers? |
|
|
|
CA, USA
|
Posted: 10/3/2011 9:47:52 AM EST
Spoke with Schilen. The feed ramps need to be adjusted.
Sending the upper assembly to them. Should just take a week. |
|
|
|
Posted: 10/3/2011 2:35:57 PM EST
Op in the future if you are building it correctly there should be no need to
modify parts. |
|
|
|
AR15.COM is the world’s largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2019 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
