Mid-80s Mini-14 ammo

[abnmacv]

What gr. weight would be best for accuracy? Anyone know the barrel twist for that era?

 

[wxl]

This was posted a while back in Perfectunion. Mid 80's was when the twist changed from 1:10 to 1:7. I have a 1:10 and it shoots 55g FMJ very good. I heard that the 1:7 prefers a heavier bullet. There's a lot of good info on bullet weights vs twist rates at Perfectunion.

180 Series Mini-14
Beginning
Serial Nbr
180-00001--1974--1 in 10
180-05101--1975--1 in 10
180-28282--1976--1 in 10
180-59251--1977--1 in 10

Mini-14
Thin barrel, ejector is in the bolt, no scope ring scallops cast into the receiver.
Beginning
Serial Nbr
181-07488--1978--1 in 10
181-48351--1979--1 in 10
181-84879--1980--1 in 10
182-45601--1981--1 in 10
183-03581--1982--1 in 10
183-40455--1983--1 in 10
184-17175--1984--1 in 10
184-26063--1985--1 in 10
184-95448--1986--1 in 10 and 1 in 7
185-14140--1987--1 in 7
185-50455--1988--1 in 7
185-56556--1989--1 in 7
185-81009--1990--1 in 7
186-05029--1991--1 in 7
186-18250--1992--1 in 7
186-20065--1993--1 in 7
186-31116--1994--1 in 7
186-42502--1995--1 in 7
186-58133--1996--1 in 7
186-66855--1997--1 in 7 and 1 in 9
186-81445--1998--1 in 9
186-87432--1999--1 in 9
*196-06325-2000--1 in 9
*196-44553-2001--1 in 9
*196-80982-2002--1 in 9
*196-99207-2003--1 in 9
*197-12180-2004--1 in 9
* Mini-14 serial numbers rollmarked with Mini-14 Ranch Rifles beginning in 2000


Ranch Rifle
Thin barrel, ejector in the bolt stop assembly, scope ring scallops cast into the receiver, buffer sytem using the recoil spring assembly.
Beginning
Serial Nbr
187-00001--1982--1 in 10
187-02611--1983--1 in 10
187-13218--1984--1 in 10
187-27226--1985--1 in 10
187-50919--1986--1 in 10 and 1 in 7
187-59308--1987--1 in 7
187-70033--1988--1 in 7
187-84127--1989--1 in 7
188-01157--1990--1 in 7
188-30499--1991--1 in 7
188-50902--1992--1 in 7
188-66901--1993--1 in 7
188-71086--1994--1 in 7
188-85981--1995--1 in 7
195-06037--1996--1 in 7
195-27761--1997--1 in 7 and 1 in 9
195-44221--1998--1 in 9
195-63542--1999--1 in 9
196-06325--2000--1 in 9
196-44553--2001--1 in 9
196-80982--2002--1 in 9
196-99207--2003--1 in 9
197-12180--2004--1 in 9


New Mini-14 Ranch Rifle
580 Ranch Rifle (early version): Thin barrel, ejector in the bolt stop assembly, scope ring scallops cast into the receiver, buffer sytem using the recoil spring assembly, new tooling resulting in a slightly different look to the receiver (more rounded edges, etc.)
580 Ranch Rifle (later version)-581: Thicker flanged barrel, ejector in the bolt stop assembly, scope ring scallops cast into the receiver, buffer sytem using the recoil spring assembly, new tooling resulting in a slightly different look to the receiver (more rounded edges, etc.)
Beginning
Serial Nbr
580-00001--2005--1 in 9
580-15286--2006--1 in 9
580-32382--2007--1 in 9
580-50951--2008--1 in 9
* 580-76276
and 581-00000--2009--1 in 9
* 581-48753--2010--1 in 9
* 581-71056--2011--1 in 9
* 581-95645--2012--1 in 9
* New Mini-14 Ranch Rifles rollmarked with Mini Thirty Rifles beginning in 2009.


Mini-30
Beginning
Serial Nbr
186-00501--1986--1 in 10
189-00001--1987--1 in 10
189-15143--1988--1 in 10
189-17652--1989--1 in 10
189-25005--1990--1 in 10
189-38805--1991--1 in 10
189-51041--1992--1 in 10
189-52528--1993--1 in 10
189-59348--1994--1 in 10
189-65480--1995--1 in 10
189-75697--1996--1 in 10
189-82126--1997--1 in 10
189-84971--1998--1 in 10
189-89313--1999--1 in 10
189-96162--2000--1 in 10
*196-06325-2001--1 in 10
*196-44553-2002--1 in 10
*196-99207-2003--1 in 10
*197-12180-2004--1 in 10
* Mini Thirty serial numbers rollmarked with Mini-14 Ranch Rifles beginning in 2001


New Mini-30
Beginning
Serial Nbr
581-01002--2006--1 in 10
581-05892--2007--1 in 10
581-06747--2008--1 in 10
581-11910--2009--1 in 10
581-48753--2010--1 in 10
581-71056--2011--1 in 10
581-95645--2012--1 in 10

 

[abnmacv]

Thanks for this detailed information.

 

[wxl]

I bought mine in the mid-80s as well during the transition period. I had heard that during this transition period, a mix of the two different twist were manufactured. To make sure of my twist rate, I ran a cleaning rod down the barrel. I placed a mark on the rod and ran it down until it made one complete turn. I then marked the rod where I stopped and measured the distance from the mark to the end. Mine measured 10 inches so it confirmed what the chart said it was. It would have been a lot simpler if Ruger had marked the gun or at least put something in the box that indicated the twist rate. I had also heard that shooting 55 gr and lighter contributed to the accuracy issues with the 1:7 twist models.