MK III Feed Ramp Jams? -> It's the Mags.

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Preston817
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MK III Feed Ramp Jams? -> It's the Mags.

Post by Preston817 » Mon Oct 12, 2009 11:37 pm

I finally purchased a MK III Hunter a couple of weeks ago and immediately (round #1) experienced a feed ramp jam with bullets I have fired flawlessly out of a MK II.
The MK II was never picky about needing the "right brand" of ammo.

I found that there is quite a bit of info posted at many sites about problems and fixes for feed / ejection problems. These are largely correct and may be related to the problem I found.

I have posted photos and a summary here:
http://www.prestonsdocsonline.com

To the point, the front mouths of the MK III magazines are cut deeper than the MK II mags (at least the 3 that I have) and now there is nothing to start many types of bullets properly on the feed ramp.

Preston

Preston817
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Post by Preston817 » Wed Oct 14, 2009 9:44 pm

I should note that the MK II magazine shown in my photos is about 20 years old.
I compared new Ruger MKII and MK III magazines at the gun store a couple days ago.
I found that the new MK II mags also have the mouth cut deep like the MK III mag that I show.
This suggests that the same stamping die pattern may be used for the body of the both MK II and MK III mags with a second stamp for the MK III to form the side release tabs, cutouts, etc.

In any case, the old style MK II mag will feed virtually any type of ammo, while the MK III mag is picky (as well as many of the newer MK II's by the number of people reporting problems in various forums).

Does anybody know when Ruger made this change or maybe even why?

Thanks,
Preston

SKnight
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Post by SKnight » Thu Oct 15, 2009 1:34 am

I've fed several brands of ammo through my MkIII with no issues feeding. Remington ammo won't fire, but that's a primer problem.

What brands are you having issues with?
If you find yourself in a fair fight your tactics need work.

raw6464
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Post by raw6464 » Fri Nov 06, 2009 8:32 am

I had feed ramp problems also and thought it was the mags. The "fix" that worked for me was:
1. Polish the feed ramp using 0000 steel wool wrapped around a cotton swap.
It takes a little dexterity but it can be done.
2. Stop using any viscous oil, use only Teflon oil.

I use Rem oil or equivalent oil with Teflon. Viscous oil creates a gummy residue on the ramp and migrates to the top of the mag when mixed with the burnt gun powder.

Clean the gun, polish the ramp, lube with Remoil, load up a mag and manually cycle the bolt and see if it helped.

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