Ruger 10/22 BX magazine problem....

Gday team, recently decided i should buy a new magazine for my 10/22 as i have been making do with a old broken butler creek 10 shot one thats held together with tape. The butler creek one feeds both supersonic and subsonic fine, but the new BX magazines (i bought two, a 10 shot box mag and a 15 shot extended mag) both jam on damn near every round when using subsonic ammo. Sometimes it doesnt pick up a round at all, and sometimes it picks one up but it doesnt "point" it directly at the chamber and results in a jam.
I have read that these magazines sometimes need "tuning" to feed subsonics, but I cant find any info on exactly what the tuning involves, and am worried if they are modified in any way they may stop feeding supersonic instead?
Anyone run into this problem?

It is not the magazine that needs tuning. The recoil spring in the 10/22 needs to be shortened by about 12mm to function reliably on the softer recoiling subsonic ammo. If you are reasonable handy it is a simple job. Strip the rifle and remove the recoil spring assembly, slide the cocking handle back on the shaft and clamp it in place with vise grips, peen the crimps out of the end of the shaft against an anvil, carefully remove the vise grips and pull the cocking handle, spring collar, and spring off the shaft, clip 12mm off the spring and reshape the cut end, reassemble with the cut end at the back of the shaft, support the end of the shaft on a block of aluminium or brass and peen the end of the shaft to a small mushroom head to retain all the parts, reassemble the rifle and shoot subsonics reliably. It is always a good idea to put a synthetic buffer pin in as a replacement for the steel pin. This cushions the bolt better with high speed ammo and also prevent scope damage.

I have two springs for the rifle and it currently has the subsonic spring installed, it also has a "tuffer buffer", it feeds fine and has no problems whatsoever with the butler creek magazine no matter what i feed it, thats why im pointing to the issue being the BX magazines.

The 10 round ruger mags (original) have a hex screw that you can adjust for tightness. You can loosen it off a bit and that may help. Google it on youtube first as if you loosen it too much it can unwind too much and wont feed anything lol.
I would think the Ruger BX mags would have the same hex screw on them but have not got a BX mag so not sure.

Sometimes the wide hollow point on Winchester Subsonic can cause feeding problems. To solve this the magazine needs to be fully stripped and the metal feed ramp needs to be scraped and polished to allow the nose to climb up. Compare the box mag ramp to the Butler Creek ramp to see where the angle needs to be altered. If you don't want to do it yourself then PM me.

Yes I found that my match 1022 would sometimes struggle to feed certain brands of ammo. I measured them and the collar part on some 22lr is wider than others. I switched to cci and havent had an issue since.
On my basic 1022 carbine it eats all ammo but has a different chamber.

hmm,you could be onto something here, im just looking at the mags and the feed ramps are slightly different, also the butler creek has a full length follower, the BX mags follower is shorter...

Butler Creek
http://i1374.photobucket.com/albums/...svxx6gcar.jpeg

BX
http://i1374.photobucket.com/albums/...smvbfu5ms.jpeg

Ruger recommend not to use subsonics or waxed bullets in their mags. I've found on the BX25 and BX50 that if you trim a .22 case (or use a .22 short case) and fit it over the pivot on the plastic follower it acts as a shim and will make the mag feed subsonics much more reliably.

I wonder how many waxed subsonic rounds it will take to cause an issue in a early 1990's vintage 10 round rotary mag. I have over 20,000 rounds through mine and it still works just fine.
Needless to say the feed ramp is nicely polished.
On a new BX15, I had to disassemble it, and polish the life out of the feed ramp with a dremel to get it to feed like the old 10 round magazine.

Its also possible the front lug on the mag is too small, on the extended mags at least this can make the front tip down jamming rounds into the chamber lip. Test this with the mag in rocking it back and forward.