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Discussion Starter · #1 ·
I posted on this rifle a year ago I guess. I never did find which piece is out of spec. This rifle groups well. The issue is the bolt barley contacts the left side cartridge when cycling / being fired . Fact check. Several ruger 20 rnd mags used. All had stoppages. Several different brands of 5.56 used. Federal xm193 , Winchester, SA battle pack 5.56. It’s not the ammo. At least 2 stoppages a mag. The bolt is barely making contact with round trying to push it in chamber. I have a blued 580 series and the bolt contacts it twice as much vs the SS rifle. I have swapped various parts to try to figure out where the out of tolerance is at. I’m down to the mag latch height or receiver trigger guard shelf not in the right spot as far as height is concerned. I guess I need to send it back to ruger. How big of pain is it to send back. I don’t have a box. And will they ( ups ) come to the house and pick it up. Ty Wardawg
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UPS has been pulling a lotta shenanigans with gun & ammo shipments lately. Insure it for a sufficient value so as to buy another rifle if yours gets "lost or damaged" in transit.

Have you compared measurements between the two rifles in the mag well area? How deep the mag sets SS vs. blued rifle.
 

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Discussion Starter · #3 ·
I swapped trigger groups and gained basically nothing. I measured mag latch retaining pin hole and they was nearly identical. A taller mag latch would push the rear of mag up and probably solve the issue. If it didn’t create a new one.

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Hand Hood Revolver Finger Automotive lighting


This is my blued 580 tactical. Notice it has really good contact with round.

I’m going to look it over again this weekend before I mail it off. Maybe I’ll find the issue. Even if ruger has to work on it.
 

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What about the pin that catches the hole in the front of the mag - any comparison there?

Seems like it's a receiver geometry issue with the pin and latch.

Ruger will make it right.
 

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The centerline, i.e. the firing ping hole, and its relative position to the perimeter of the top cartridge is clearly different between the 2 rifles

On the rifle with the issue, the cartridge is farther to the left of the rifle while at the top, putting it farther out relative to the diameter of the bolt face.

Thank for that observation.
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Being a cast receiver with that pin integral to the front of the magwell, it may require them to replace the rifle.

Older rifles were different in having a notched pin inserted thru the receiver, held in with a cross pin and spring tensioned by the op rod spring guide rod end. Link to schematic below:


I think that cast in place pin was a cost saving measure to streamline production.

You're SOL if that tit ever breaks off or wears too much to catch the hole in the front of a magazine.
 
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In looking at the pics again you can see the SS seats the mag differently - low and to the left.

Has Ruger seen those pics?

When ya call and request an RMA to send the rifle back, tell them ya don't have a box & ask if they'll send ya one to ship it back to them in. Never hurts to ask.
 
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Since you have two Minis, is it possible for you to accurately measure the length of both latches?

If the "faulty" latch is appreciably shorter than the properly functioning one, than that might be your problem. It would be ideal to swap them out and see if the problem follows the suspect mag-latch, but changing mag latches can be a fuss. If you elect to do so, use proper-sized drill bit as a "pilot" to line things up prior to installation of the pivot pin.

Assuming the rest of the receiver/bolt is/are of correct dimensions, then worst-case scenario is to buy a spare mag latch, and have someone TIG weld a little metal to the tip of it, and grind/file/sand to correct height/profile.

It may well be that Ruger has somewhat "taller" height mag latches for this sort of problem, and Ruger can check all the relevant parts dimensions. It may also be that the mag latch is of "correct" height/dimension, but the pivot hole may be a little "off".

Stack-up of tolerances/dimensions happens.

It would be optimal if you did NOT need an unusually "tall" mag latch, as that would preclude changing-out the OEM mag latch for a different one. It's always nice to have options.
 

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If you have a set of calipers measure the following:

A - height of latch from the center of it’s pivot pin to the top that contacts the mag

B - center of bolt - firing pin hole - to top of latch

Front mag pin from:

C - bottom of receiver

D - center of bore ( measure with round in chamber)

E - Side to side


Comparison of both rifles should show something. It’s either the latch, front pin or a badly finished receiver that just seats the mag wrong.
 

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If you have a set of calipers measure the following:

A - height of latch from the center of it’s pivot pin to the top that contacts the mag

B - center of bolt - firing pin hole - to top of latch

Front mag pin from:

C - bottom of receiver

D - center of bore ( measure with round in chamber)

E - Side to side


Comparison of both rifles should show something. It’s either the latch, front pin or a badly finished receiver that just seats the mag wrong.
Above is a better, more comprehensive response than I provided. With any sort of luck, your mag latch is out-of-spec, and replacement with an "in-spec" unit will fix things. Swapping them out might be revealing; asking Ruger for an "in-spec' mag latch, if that seems to be the problem, might be less hassle than sending the Mini back to them. OTOH, Ruger will give your Mini a thorough exam, and maybe fix some problems that you don't know exist.

Your call.
 

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Discussion Starter · #17 ·
Ok I put the SS trigger group in the good rifle. It lowered the mag . TG or mag latch. I put blued mag latch in SS TG did not change height. Still low. So it’s the trigger group. There is nothing that stands out. I think it’s where the TG slides up into receiver. Maybe the height of the trigger group. I will measure things again tonight. I have access to a mill at work. I also have a spare TG to compact it to. I’m not against sending it back.Just trying to figure out it out. Cheers WarDawg
 
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