8.6 Blackout? Need help with feeding

[tammons]

4.27" stagger feed short action.
I bought a Shaw 8.6 BO barrel when they were on sale and finally got around to setting it up.
However, I am having problems getting it to feed. Before this barrel, it was a 6.5 creedmor or 7mm-08 and both of those fed fine.
At first the magazine feed lips were too straight and the bullet nose was jamming and not hitting the ramp.
So I bent the lips up slightly mostly towards the front and kept the lips as straight as possible.
That helped and it will feed the 1st cartridge of 4, but it wont feed the 2nd cartridge.

The 8.6 BO shoulder is so far back, that when I try to cycle the 2nd round, it tilts on corner of the shoulder pinned between the cartridge underneath and the feed lips and never fully seats on the lips. So the bolt rides over it. I can push the nose down so that the bolt will catch it, but then it nose dives. If I push the back down the bolt will miss the case head and ride over it.

Any suggestions?
All are welcome.

[Dave Hoback]

Well, the 6.5CR & 7mm-08 were meant to be fired through the standard mag box/follower/spring setup. The 8.6BLK was not. You’ve zeroed in on the cause of the condition. The issue now is simply getting the mag to work.

Let me ask, what are you using to adjust the feed lips? If you are prying the lips with a screwdriver or bending them with standard pliers, this is part of the problem. It’s not very good adjusting the feed lips evenly that way. I recommend you have one of these tools below first. Also, it may be possible that more spring is needed. Or the follower may need to be shaped a bit different. Magazine adjustment & modification is an art form. LOL!

This is the correct tool. Magazine Feed Lip Adjusting Tool. There are many different available but this is a simple inexpensive option.
https://masterpiecearms.com/shop/mpa...justment-tool/

These also work. They are Sheet Metal Pliers.
https://www.amazon.com/IRWIN-VISE-GR...l%2C109&sr=1-2

[tammons]

If Shaw had a faster than 10 twist 338 barrel I would have bought a 338 federal barrel instead.
All these years and I didnt know they made a tool for adjusting feed lips, LOL. Never had a problem before doing a minor tweak.
No screwdriver and no pliars.
I have it cycling 2-3 shells now, but I dont think simply bending the feed lips more will fix the problem. But maybe it will, who knows.
Anyway, the issue seems to be the way the shells stack in the magazine when more than two.
I think they need to stack perfectly square, but then the bullet will hit below the ramp.

Thanks for the help.

[Dave Hoback]

No, I didn’t say simply bending the feed lips would do it. I expounded on possibly needing more spring tension and/or modification to the shape of the follower. As I said, modifying magazines to feed different cartridges is an Art Form.

Don’t feel bad. Even the AR guys are having problems getting the 8.6BLK to feed properly from the magazines. Just look at some pictures of different Cartridges magazines. The differences in length & height of the feed lips as well as the shapes of the followers. There’s a reason they are different.

[tammons]

The 1st cartridge seats correctly.
The 2nd is close to seating correctly, but rocks only very slightly.
The 3rd cartridge rocks more.
The 4th even more.
If I remember correctly, I had similar feeding problems with a 338-284 I built and eventually was able to get that corrected but it was a real PIA.
Now I think the follower is just as much of a problem.
However, last time I tried to modify a follower, it was a huge fail.
Thanks for the help.

[sharpshooter]

You need a .223 magazine.