short action caliber barrel in long action receiver, blind mag, how to adjust feed lips?

The action was originally a savage 110 in 270 win center feed blind mag, and I now put a 243 win barrel on.

With this set up the 243 round pops out the lips before the bullet enters the chamber of the barrel, creating a situation where the rear of the case jumps out of the receiver, leading to misfeeds / jams.

I have read here that the feed lips of the magazine need to be adjusted (and maybe the magazine spring). The question is, ho do I go about this? Do I close or open the feed lips? and take some tension off the magazine spring or leave that spring alone?

Thanks for the input :)

Might you have the magazine spring in backwards?

Bill

Hi Bill, nope, i checked that, spring sits correctly.

I have had excellent results tweaking feed lips to reliably feed from mag boxes that were previously problematic. I have used wide jaw pliers as well as vise grip pliers to get the job done. I clamp the magazine box in my vise with the feed lips facing up. I wrap the pliers with Gorilla Tape to keep from scratching the mag body. I grip the feed lips down at the bend point and adjust them in a bit at a time until they feed reliably. If they have sharp edges, rounding the edges often helps to smooth up feeding and it reduces scratching on the case body. Some of the feed lips I have seen actually had sharp burrs on them that would impede feeding and chew up the cases pretty badly. None of my 223 sized mag boxes plus a couple of 22-250 setups fed well until I worked them over this way. They are all now 100% feeders.

Got it to work with the longer bullets. Pushed feedlips closer together and made the follower come up higher a bit in the front.

With 85 grain sierra hollow points the tip of the bullet isn't entering the chamber yet and so the headstamp side of the cartridge is jumping out of the port.

It's ok, i'll live with it, it's a bench gun and shooting the longer projectiles most of the times anyway.

As Vincent7 points out, it all has to do with OAL and whether the tip of the bullet is started into the chamber yet when the case head clears the end of the feed lips. Only real solution would be longer feed lips on the mag box that extended further forward and held the cartridge longer, but since such a beast doesn't exist you're kinda stuck.

At least you are getting some results. I must be lucky. I have two long actions with the old stagger feed boxes that both feed 22-250, 243 and 308 rounds perfectly.

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Originally Posted by geezerhood

At least you are getting some results. I must be lucky. I have two long actions with the old stagger feed boxes that both feed 22-250, 243 and 308 rounds perfectly.

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Here also have had far better luck changing the stagger feed long action magazines to short action cartridges, including 260s, 243s, and 6.5 creeds. The center feeds eventually work but with much more tweaking. I even converted a magnum centerfeed to 243 but it only worked with 3 rnds but not 4.
The 270/30-06 based center feeds will work just takes the work of removing the stock a bunch of times till you get it right.