Factory DBM will not feed the last round

[JeepsAndGuns]

Model 12 center feed short action 223.
Rifle started out as a blind mag and a tupperware stock. Never had any feeding issues.
I got a accustock from another member here. The stock on the outside looked identical to the old one, except it had the aluminum bedding and had the factory flush DBM. The stock was from a 308 rifle.
I swap the recoil lug and reassemble the rifle with no issues. The mag, I take the 308 mag body, follower and spring off the floorplate and snap on the 223 mag body, follower, and spring from my old stock. It fit perfectly with no issues.
I go to sight in the rifle and everything is going well until the last round. It will not feed. The bolt just jumps over the rim. I remove the mag, look at it, everything looks fine, put it back in and still, it will not feed the last round. I push it about halfway out of the mag with my finger and it feeds with the bolt the rest of the way fine.
I reload the mag and the same thing. Rounds 1-4 feed fine, but the last round, will not feed.
I load the mag and look at how much of the rim is exposed, then unload all but the last and it "looks" to be at the same height as the rest.

Anyone have any suggestions?

[Dave Hoback]

Try preloading the mag a bit. Small spacer between mag & DBM or follower. Couldn’t tell you you how much....maybe 1/8” spacer.

[mnbogboy2]

The biggest culprit I have found with the bottom failure to feed was dirt/grit on the ammo or in the magazine. The cases do not like to slide up when things are dirty the follower spring doesn't have the snort to push them up. Reloading that spring with a spacer may just be plenty to finish the last push up.

[JeepsAndGuns]

Mag is clean, I keep my guns spotless, same with the ammo.
I will look around and see if I can find something thin to make a spacer out of and give that a try.

[Dave Hoback]

If you just want to test the idea, just cut a few pieces of cardboard to use. This will at least verify what I’m thinking. Then if it works, you can sort out something clean. Piece of hard polymer or aluminum sheet.

[Robinhood]

Can the spring be stretched slightly without loosing its temper?

[Dave Hoback]

That would work also. Unfortunately it’s only a temp fix, as the spring will collapse with some use.

[Robinhood]

That would work also. Unfortunately it’s only a temp fix, as the spring will collapse with some use.

Thank you Dave. :rolleyes:
Jeeps and g's, you need a new follower spring.

[JeepsAndGuns]

It is supposed to rain this weekend, and I have a handfull of dummy rounds I made for action testing, so I should be able to fool around with it this weekend.
I'll try some cardboard and see what that does. If it helps, I will look into a new spring.

[cm12setx]

Can I as a question here. Is the blind mag different depth vs. the detachable mag. And if so the 308 spring should work better. Thanks