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IMHO, yes - the bullet exits the barrel before the op-rod is in play, but the bullet does start some barrel harmonics as it exits and those harmonics need to settle down before the next round is fired. Rapid-fire doesn't allow this, but kkina's Accustrut helps reduce the harmonics, as does a flash hider as an attenuation.

If I was into extreme accuracy, I'd just get a bolt gun (which I did), but I got my Mini(s) as a carbine - not a sniper rifle.

Let's not discount the condition of the crown for accuracy, and equal spacing and torquing the screws of the upper and lower gas block.

Nonetheless, this is an interesting thread and gets the intellectual juices flowing. There were similar discussions regarding the 1911 IIRC (the bullet left the barrel before the slide engaged).
Stumbled across this on Youtube with a pre-580 series Mini. The bullet seems to be long gone before the op rod starts moving looking at the muzzle flash. Also, the barrel flex is clearly visible. It makes me wonder if Ruger knew about this while designing and testing the rifle, but I don't know how this compares to other rifles when fired and don't know if this kind of flex is "normal"? I can see where a barrel strut could help with this flex. It would nice to see the same thing done for a 580 series rifle/barrel or another rifle for comparison.

 

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Formerly "raf"
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Not being an engineer, I'm forced to go with what works for my 186 Pencil-barrel Mini.

Bedding the barreled action into a tight-fittting synthetic stock, installing a dual-clamp Accu-Strut, and installing a Choate muzzle device at the end of the barrel seems to have worked out well for me.

Every Mini is different. Suggest you take good notes on the ammo your Mini likes, and buy more of it.
 

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They all flex some more then others..
Thanks for the videos. Looking all three vids, it looks like the Mini flex isn't really that bad, particularly when compared with the AR. I suppose as long as the barrel returns to its original alignment after firing and flex, accuracy would be consistent from shot to shot. You learn something every day, and maybe this is one reason why heavy barrels with less flex can be more accurate?
 

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...I suppose as long as the barrel returns to its original alignment after firing and flex, accuracy would be consistent from shot to shot. You learn something every day, and maybe this is one reason why heavy barrels with less flex can be more accurate?
Yes, consistency is a great portion of a rifle's accuracy. Major factors are receiver bedding, stock rigidity, and barrel harmonics. Many bolt action LE sniper rifles that I've seen have short, heavy barrels and stiff, dimensionally stable stocks. A short barrel's harmonics generally have less variation. A heavy barrel heats up more slowly than a thinner barrel, and a hot barrel is generally more prone to bending, which will change the POI.
 

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To take the op rod out of play simply install a gas bushing without a hole. It is in effect a bolt action rifle after that. I have wanted to try that but it's on the "to do" list.
kwg
I changed the gas bushing today and the rifle would not function properly. This forced me to reload every shot and essentially have a bolt action. I sighted in my scope like this. Then replaced the bushing with the original. Rechecking my zero, I had to adjust just slightly to regain accuracy but nothing much had changed.
I have an accustrut, credit card mod, trigger job on my 581 mini14. Just for specifics.
 

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I decided to revisit this topic, as the weather is allowing me to tinker with my Mini more, lol. On my ASI gas block, I noticed a pattern, uneven contact of the Op-rod hitting the block. As per many discussions, uneven slamming is the likely cause of flyers. After reading Ed Harris' article again, I decided to take some measurements. I marked the Op-rod location relative to the receiver while it was full forward against the gas-block. I then removed the gas-block, and measured how far forward the op-rod would go based on the stop-point on the receiver/bolt alone. The difference seems to be in the ~.025" range.

I can certainly put the op-rod on my mill, and incrementally face it down, the question is, should I?

From the Ed Harris article
The fit-up can sometimes be improved by grinding 0.005-.010″ off the face of the slide, so that with the slide fully forward, a .001″ shim can be inserted between the slide block and gas block and be clear all the way around. This way the forward motion of the slide is stopped by the right locking lug in the cam pocket of the slide handle, rather than by the slide block slamming against the gas block...
The article goes back a ways for sure, prior to 2012. Has Ruger made any changes to the 584 series that necessitates the gas block being the stop.

Now .025 is certainly more that .010. I am wondering, was it Rugers intent to contact the gas-block, making it the stop. AND, is it safe to have the op-rod stopped by the receiver/bolt end alone.

Thoughts, comments, et all, appreciated :)


EDIT: In the pic below, I have found the lip face isnt entirely square. Its has a high spot on one side about .004 to .006 higher, which is exactly where the wear pattern is on the block.
Rectangle Auto part Wood Composite material Fashion accessory
 

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I have read the same article, and it makes some sense, to me at least.

No Expert but suggest "taking down" the "high spot" in lower photo, since that's likely the cause of the uneven striking of the gas block which is the fundamental concern here.

Installing a Wilson 1911 Shock buffer over the gas piston (tube) extending from the gas block should, in conjunction with above suggestion, even out op rod contact with the gas block.

Such buffers do wear out, so buying in bulk at some point will make sense if the idea works out.
 

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Thanks Bob. I really dont want to add another wear-item if I dont have too, but for me, this is more my engineering curiosity getting the best of me, lol. I've read some of the other threads here after pinning down the right search terms, and apparently theres more than a few guys that have removed it entirely. Several SEEM to run buffers, but only a few indicate as much. Given that the older Mini's dont have this lip, by design the op-rod is stopped by the bolt/receiver when fully forward. I can not find any reported instance of a 'related' bolt failure on older Mini's. I did find 2 mentions of a cracked RECEIVER on the internet, though its not clear what the cause was.

Given the casting and machine process Ruger uses, I could theorize that they had some concern of the 'op-rod, to bolt, to receiver' impacts upsetting a receiver that potentially had a minor casting defect some where. While a casting defect may have been uncommon, they probably made some calculation that removing the hammering effect would mitigate a potential defect (i.e. it turns into a crack) that could materialize otherwise.

The other thing that occurs to me, is that the Op-rod would serve has a highly effective damper, given its weight and position. If contact was true, and all things square/parallel, it may settle the barrel down a bit faster after a shot was fired. Since Ruger was trying to address accuracy (eventually), its a possibility in my book.

I took the gas block and the op-rod, and put'em together to get a feel for how they were making contact. A bit more wiggly than I expected. Pushing the block, you could tell it really wasnt so flush.

I threw the Op-rod on my mill, and I can tell you that on the face of that lip, squareness and parallelism was not on Rugers priority list that day. You can really tell how (not) flat something is/was when the end-mill starts making initial contact. Took off .002 at a time to see what shape manifested, besides a notable high spot, it was all over the place. Nearly impossible to tell by eye, but for a mechanical process, it could be a night & day difference when in use. In the end, I took off about .010 before it was perfectly flat and squared. When paired with the block, no more rocking/wiggle, completely flush.

The block and op-rod should be a nice machine fit when finally assembled, and I will check, measure that as well.

G
 

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Thanks Bob. I really dont want to add another wear-item if I dont have too, but for me, this is more my engineering curiosity getting the best of me, lol. I've read some of the other threads here after pinning down the right search terms, and apparently theres more than a few guys that have removed it entirely. Several SEEM to run buffers, but only a few indicate as much. Given that the older Mini's dont have this lip, by design the op-rod is stopped by the bolt/receiver when fully forward. I can not find any reported instance of a 'related' bolt failure on older Mini's. I did find 2 mentions of a cracked RECEIVER on the internet, though its not clear what the cause was.

Given the casting and machine process Ruger uses, I could theorize that they had some concern of the 'op-rod, to bolt, to receiver' impacts upsetting a receiver that potentially had a minor casting defect some where. While a casting defect may have been uncommon, they probably made some calculation that removing the hammering effect would mitigate a potential defect (i.e. it turns into a crack) that could materialize otherwise.

The other thing that occurs to me, is that the Op-rod would serve has a highly effective damper, given its weight and position. If contact was true, and all things square/parallel, it may settle the barrel down a bit faster after a shot was fired. Since Ruger was trying to address accuracy (eventually), its a possibility in my book.

I took the gas block and the op-rod, and put'em together to get a feel for how they were making contact. A bit more wiggly than I expected. Pushing the block, you could tell it really wasnt so flush.

I threw the Op-rod on my mill, and I can tell you that on the face of that lip, squareness and parallelism was not on Rugers priority list that day. You can really tell how (not) flat something is/was when the end-mill starts making initial contact. Took off .002 at a time to see what shape manifested, besides a notable high spot, it was all over the place. Nearly impossible to tell by eye, but for a mechanical process, it could be a night & day difference when in use. In the end, I took off about .010 before it was perfectly flat and squared. When paired with the block, no more rocking/wiggle, completely flush.

The block and op-rod should be a nice machine fit when finally assembled, and I will check, measure that as well.

G
What did you use as a datum point before making the cuts?
 

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Just curious and no special reason. NO expert, but I would think that the "cylinder" in the forward end of the op-rod into which the "piston" (gas pipe from gas block) fits is the only critical fitment area in that area, aside from obtaining a flush impact surface on the gas block's rear surface and the forward edge of the op-rod.

When "fitting" a gas block to a barrel, I generally snug the screws just enough to allow the gas block to be wiggled so that the gas Piston (gas tube) slides into the "cylinder" in Op-Rod without binding or rubbing. A little wiggling of the gas block will reveal the limits of its travel imposed by the gas piston/gas port, and the point within this range of movement that disallows contact between gas piston and gas "cylinder" on op-rod is where the gas block "wants" to be. Once done, witness mark bottom of gas block and barrel with sharp pencil to detect and prevent unwanted movement of gas block during final tightening/torquing of screws. The gas Piston usually has some "wiggle" to it, making this "fitting" a finicky business. The goal is to minimize interference between gas Piston and the "Cylinder" in the Op Rod.

I don't know if you have done this already, but member sandog has done some experiments on the optimal amount of torque applied to the gas block screws. He has observed some benefits to accuracy by using a torque value of about 25 IN/LBS as opposed to Ruger spec of 40 IN/LBS. I don't know how highly stressed these screws are, but being a "belt and suspenders" guy, replacing the old (torqued) screws might not be a bad idea, especially if the old gas block screws were staked in place at the factory.

I was fortunate in that the OEM gas block and Op-rod on my Mini seemed to be hitting squarely as determined by the marks on the front of the op-rod made by the "bar" on the gas block. I >>believe<< the compressible "Shock Buffs" may render the precise squareness of the face of the op-rod a moot point, but I understand and sympathize with your wanting the components to fit properly in the first place.

As to "Shock Buffs" I also understand your reluctance to install a "Wear-component", but the Mini can be hard on some optics and perhaps other electronic components, and the buffers help with the metal-to-metal contact/shock when properly installed at both front and rear of the op-rod. Your call, of course.

At any rate, all best wishes in your project!
 

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I got everything back together, the machined face of the op-rod really has a nice flush fit with the ASI gas block. The gas pipe is fully perpendicular off the block and has no wiggle in it. The block does have a slight range in which it can be rotated along the axis of the barrel. Only a few degrees left or right, but I figured this could cause some undue contact in the op-rod cylinder. Did a little experimenting to see if I could find the best alignment to make sure the gas pipe went into the cylinder as smoothly as possible. What I did find is that it is possible to rotate the block just a little too much in one direction and have it slide on 1 side of the cylinder more than the other. Didnt cause any binding or anything, but it is uneven contact... and harmonics being what they are. Thanks to the judicious application of play-doh on the gas pipe, I was able to find the most appropriate center-point, and align the gas-block/pipe accordingly. Just wanted the best all-round clearance possible.

Will it make any difference... hell if I know. Shooting at the range will say either way, lol.

I really never intended to use my Mini as anything other than a defensive carbine, but why pass up the chance to play with the setup. Since I decided to drill down on this (I aint lying, its fun), I took my Ultra Shot M-Spec off, and installed a proper scope. I have an Athlon Argos 6-24x50 that wasnt doing anything, so now its on the Mini. Complete overkill, but it'll be a good test instrument.

And yes, I use 25in-lb on the gas-block per Sandog's awesome research :)

G
 
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