Reloading with bolt locked back - first round doesn't feed completely

[andy t]

Rifle: Complete Geissele URG upper with Geissele BCG. Brand new, second range session.
Cold large pin lower with Geissele SSA-E, H buffer, standard recoil spring. The lower has at least a few thousand rounds on it.
Additions: Magpul BAD
Magazine: old (pre 94 ban) USGI mags.
This is the second time shooting this rifle. On the first time, rifle had about 300-400 rounds without any issues. Rifle was not cleaned nor lubed before this session.
Issue:
With the bolt locked back, insert a fully loaded (30 rounds) magazine. Press bolt release/BAD. The bold will go forward about about 1/4 into the magazine feed lips and start picking up the round. However, it will get stuck at that point. The round is positioned well and the bullet is NOT contacting the barrel extension.
Slapping the bottom of the magazine would allow the bolt to close and the rifle would function as normal.
This happened with 3 different magazines.
Would could be the cause ?
Photos:

[AndyLate]

#1: Clean and lube

#2: Steel cases have more friction than brass

#3: Use newer magazines or download by two round (to test)

[26 Inf]

Did you fire the steel-casede the first time you fired it? In other words, is it only doing it with steel-cased ammo?

Some folks report problems with primarily non-lacquered steel case.

You said pre-ban magazines, what color follower is in them?

I'd clean and lube the thing, try again with steel case, if that doesn't do it try brass cased.

Also might want to try a couple of new GI, or PMags.

ETS: What Andy said.

[andy t]

I used steel case the first time with no issues. However, for the first range session the rifle was cleaned/lubed. I forgot lube at home, so couldn't lube it today. The magazines have Magpul followers (I live in one of those states).

[Inkslinger]

I used steel case the first time with no issues. However, for the first range session the rifle was cleaned/lubed. I forgot lube at home, so couldn't lube it today. The magazines have Magpul followers (I live in one of those states).

Lube it up a try again. I apply lubrication every time I shoot. If you forget your lube, here’s a tip. Go pull the dipstick from your vehicle and use your finger to apply.

[MistWolf]

Replace your action spring.

[AKDoug]

I see you have a B.A.D.... I know folks had issues with those not locking the bolt back. I'm not sure I've heard of anyone having a feeding failure with one. Not too hard to remove and check.

[Clint]

There is obviously too much friction for the action spring to overcome.

Check the action spring length to verify it is good.

https://www.m4carbine.net/showthread...-spring-length


The top round may be binding as it feeds.

As the bullet tips up, the case pivots around the front edge of the feed lips and the rim pushes down into the stack.

If the stack won't push down easily enough, it could cause the binding.

The stack not depressing easily could be from lack of extra room in the magazine or friction from the steel cases.

Try loading from 28 or 29 rounds to isolate this.

[Iraqgunz]

Newsflash- AR's don't need to be lubed and cleaned every time you shoot. This is especially true with a low round count. There is something else happening and I would be looking at the action spring first (as someone else mentioned).

I would make every attempt to troubleshoot this by getting another upper receiver group and lower receiver to narrow it down. Then go component by component.

[andy t]

The action spring inside was 10.5" - while in spec, I replaced with a new one from Brownells. Will see how it behaves next time.