580 Series Mini 14

The current Ranch Rifle that is available from Ruger is the 581 series and not the 580, which was the version that was available after they changed the tolerances and tooling. The 580 series on has the new rear and front sights. The current 581 series rifles have hammer forged barrels which are tapered in front of the gas block. I understand that some 580 series had the same barrels, but some were not tapered, however I am not sure if the overall diameter of the barrel was the same for both the non taper and tapered barrels at the front sight. The tapered barrels were apparently meant to reduce stringing when the barrel heated up according to some posts I have seen.
 
You're correct about everything except the series numbers:

580 Series = Mini-14
581 Series = Mini Thirty

Both the new series started in 2005, and continue to use the 580 (Mini-14) or 581 (Mini Thirty) prefix in current production.
 
rhino62 said:
The current Ranch Rifle that is available from Ruger is the 581 series and not the 580, which was the version that was available after they changed the tolerances and tooling. The 580 series on has the new rear and front sights. The current 581 series rifles have hammer forged barrels which are tapered in front of the gas block. I understand that some 580 series had the same barrels, but some were not tapered, however I am not sure if the overall diameter of the barrel was the same for both the non taper and tapered barrels at the front sight. The tapered barrels were apparently meant to reduce stringing when the barrel heated up according to some posts I have seen.
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Wrong. I have a 580 series with the new tapered barrel. The 580 series is the tactical model i do believe.
 
Farmer Harv said:
Been playing around (read: spending money and tinkering) with my 580 Ranch the last couple of weeks, and it's both educational and a good reason to go shooting. As I have a mitt full of PMC 55gr I decided to use it exclusively, and have been working through some of the suggestions on the perfectunion forums.

To start I mounted a Nikon Prostaff 2-7x32 and sighted it in at 100yd. Groups were what I consider normal, with most under 4", a couple just under 3" and one at almost 6". Good fuel for the "can't hit the broad side of a barn from the inside" Mini hater crowd.

I then received a gas bushing kit from ASI, and after trying them all decided on the .045 bushing and stronger recoil spring. This left the brass in a nice pile about 5' to the right, but more importantly the groups shrunk down to ~3" average, with one nearing 2" and only one ~4". Whether this was due to the bushing and spring, evenly torquing the gas block or a combination of it all I'm not sure, but a 25% reduction in group size is always a good thing.

Yesterday a NcStar Muzzle brake arrived, and though it just kinda fits and hangs on (needs lots of loktite I guess) I took it for a spin and was rewarded with yet another improvement...groups were now around the 2" mark, with one at 2.5", and one just over 1.75".

So for a $30 investment and a bit of time my groups are roughly half the size of when I started. Cool. If only it was this easy with all my rifles. Never one to leave well enough alone I also ordered an AccuStrut, which I'm hoping will squeeze the groups down a bit more as 1.5" is all I really want.

And then testing will start with some different ammo. Even more reasons to shoot. :)
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Where did You order those accessories if I may ask?
I'm on the market for a Mini as well :)
 
The gas bushing kit ($14) came from Accuracy Systems. When you call in to order ask for 4 screws for the gas block also ($5) as the factory screws are staked and might not survive the unscrewing unscathed. http://www.ruger-mini-14-firearms.com/mini_14_30_accessories.php (about 2/3 down the page)

Also, when reassembling torque the gas block screws to 35 inch pounds (Not foot pounds) in an X pattern starting at 15 in/lb and going up in 5 in/lb increments while keeping the gap even on both sides. This ensures a nice mate with the barrel, and while it may not help much, it definitely can't hurt.

The muzzle brake came from Marstar (NcS-AMB14 - $13), and I'll try to get a pic of how poorly it fits. It does work though, just looks bad. http://www.marstar.ca/ac-NcSTAR/Muzzle-Breaks.shtm (bottom of page)

The Accu-strut is from http://www.accu-strut.com/index.htm. Hopefully it works as advertised, and I'm hoping to be able to remove the brake and get sub 2" groups with the strut alone.
 
581 series mini14

Farmer Harv said:
You're correct about everything except the series numbers:

580 Series = Mini-14
581 Series = Mini Thirty

Both the new series started in 2005, and continue to use the 580 (Mini-14) or 581 (Mini Thirty) prefix in current production.
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I got a new 581 series mini14 from Ellwood Epps at the beginning of the month, it serial number is 581-226xx
 
Series numbers and barrel stiffness

Farmer Harv said:
Well isn't that interesting. Are all Mini's (14 or Thirty) 581 series from late 09 now? If so it won't be the first time, as it looks like they also had the same prefix from 2001-04 before splitting again in 05...

http://www.ruger.com/service/productHistory/RI-NewMini14Ranch.html
http://www.ruger.com/service/productHistory/RI-NewMiniThirty.html

Games you can play with serial numbers... :redface:
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I did not know they had done this before. I looked in the book "Ruger and His Guns" which has serial numbers up to 1993 and saw they had not used the same series for different models of the Mini up until this time. This will make it difficult for Collectors in the future.

There are a lot posts about the mini 14 accuracy with the older models prior to the 580 series. One thing that got me thinking was on the barrel diameters which I have measured on a number of Mini’s also an M1A for comparative purposes. I measured the diameter in front of the gas block and also at the back of the front sight:

Mini14 - Series 182 - 0.564 at gas block 0.562 behind front sight

Mini 14 Ranch rifle - Series 188 - 0.564 at gas block 0.564 behind front sight I

Mini 30 Ranch rifle - Series 189 - 0.625 at gas block 0.625 behind front sight

Mini 14 Ranch rifle - Series 581 - 0.780 at gas block 0.625 behind front sight – This rifle has tapered barrel

Mini 14 Target rifle - Series 580 - 0.785 at gas block 0.785 behind front sight – This
Rifle has a harmonic adjustment weight


M1A – 1978 vintage - 0.600 at gas block 0..600 behind front sight

I would be curious to know if the barrel diameter on 581 series mini thirty is the same as on a 580/581 tapered barrel mini 14. I read an article on hammer forging at Ruger in which it stated that the mandrel used in the hammer forging is only for the rifling and that they drill and ream the chambers in the hammer forged barrels after completing the forging of the barrel.
 
Farmer Harv said:
The gas bushing kit ($14) came from Accuracy Systems. When you call in to order ask for 4 screws for the gas block also ($5) as the factory screws are staked and might not survive the unscrewing unscathed. http://www.ruger-mini-14-firearms.com/mini_14_30_accessories.php (about 2/3 down the page)

Also, when reassembling torque the gas block screws to 35 inch pounds (Not foot pounds) in an X pattern starting at 15 in/lb and going up in 5 in/lb increments while keeping the gap even on both sides. This ensures a nice mate with the barrel, and while it may not help much, it definitely can't hurt.

The muzzle brake came from Marstar (NcS-AMB14 - $13), and I'll try to get a pic of how poorly it fits. It does work though, just looks bad. http://www.marstar.ca/ac-NcSTAR/Muzzle-Breaks.shtm (bottom of page)

The Accu-strut is from http://www.accu-strut.com/index.htm. Hopefully it works as advertised, and I'm hoping to be able to remove the brake and get sub 2" groups with the strut alone.
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Thank You.
 
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