Howdy y'all,
I recently went halves with a friend on 1k of that Hornady remanufactured 75 gr. HPBT that Maj. Carl Leisinger is selling.  (should be here by the weekend, maybe Monday)

I have a Bushy DCM rifle (1:8 twist) and my friend has a mini-14.  I'm not sure what the twist rate is on a mini, but I'm thinking it's like 1:12 or so--isn't that too slow for a 75 gr. pill?  I tried to tell him I thought it was, but he insisted on getting some since the price is so good.  Now I'm wondering what kind of crap I'm gonna be hearing about "those POS reloads I talked him into buying that group 1' @ 100 yds"  I guess I could take 'em off his hands for like $10/ box of 50 h

Ruger Mini-14's have a 1:9 twist barrel.  It is unlikely that his rifle will be able to stabilize these bullets out past 50-90 yards, if at all.  However, some (very few) people with 1:9 twist barrels are able to stabilize the 75gr rounds.  He'll just have to give it a shot and see.

It depends on when his Mini-14 was made. When they were first introduced back in the 1970's, they had a 1:12 twist just like the SP1 AR's. I think they also made them for a short period in the mid-late 1980's that used a 1:7 twist. Then finally they went to the 1:9 twist. I am pretty sure most of the ones made in the 1990's have the 1:9. To get the exact dates, you might look around the Ruger website or email them. They should be able to tell you and your friend when the gun was made and what twist it uses based on the serial number.

If it is a 1:9 twist and his gun won't stabilize them, buy the remaining portion of his rounds and have him buy some of the Black Hills reloads. The 68/69 gr should both work well with the 1:9 twist rate. If he has one of the older 1:12 twist barrels, he's pretty much screwed and will have to stick to the light stuff, 60 gr and under for best performance. I wouldn't recommend it for defensive use, but for pure accuracy, the Black Hills 52 gr BTHP is often highly regarded as a very accurate load. Hopefully one these loads will cover his rifle. But being he has a Mini-14, he shouldn't expect it to throw lead in tight patterns like most AR's. Mini's aren't exactly known for their accuracy.

-Charging Handle

Not all minis are 1 in 9"- gave my son a 184 series, made around '87, and it is 1/10"...I do have a 1/9" A2 that stabilizes pretty well out to 600-but with the mini's inherent inaccuracy, I would think he might be disappointed, and take you up on your offer!

Just to repeat what Charging_Handle and mikr already wrote, call Ruger directly and find out exactly when the rifle was made (if you don't know) and then the exact dates for the different rifle twists.  That way there is no way to blame a non-optimal twist rate and you'll know that it's just the Mini-14's intrinsically poor accuracy.  Yes, I own a couple of Mini's and have seen this first-hand.  That's why I own an AR. LOL

Yes, the Mini-14's accuracy is poor.  It can also be cured with a $20 bedding kit and a little TLC.  You'll have 1"-2" groups in no time.