Poll: Which 6mm?

Just me, but I'm (still) in the process of building a 6 Dasher. Based on the research and everything that I've done it's something I'd recommend. While the 243 Win and 6 Creedmoor do share similar case capacity you will have more work with the 243 than the 6CM with trimming and all due to the body taper. On that same note, a 6mm Creedmoor will give you more magazine length for the longer 6mm bullets than a 243 would, not that that would come into play but it might. For me it's a dasher and it's more of a competition rifle but I wouldn't hesitate taking something like that on an antelope hunt.

The accuracy node with my 6 XC, 28", 8T is with 41.5g of H4350, Rem 7 1/2, Palma brass, 105 VLD hunting at 3150 fps....no slouch load. I use Whidden dies. There is another node at 3250 with R#17, but I do not like how hot this powder burns with expected fire cracking in 400 rounds.

In a 6 Rem, I would be running the 115g Berger vld hunting with R#26 with cci 250s. I had a 6 Rem AI with a 10T, 26" douglas, ran the 95g Nosler Ballistic tips at 3550 with R#19, tiny groups, and my nephew has that rifle now.

I have two Dashers now, and a 6 BRX. I sold the Dasher reamer opting to go 6 XC till my last breath, it is so easy to work with using powders that are slower burning giving longer barrel life. The 6 XC gave me longer barrel life than the Dasher by a long ways, and I believe that this is due to the long neck. Any of the 4350s and AA2700 work amazing in the 6 XC with 105-108g bullets. Dashers love the 4895 and equivalents which have been MUCH harder to attain over the past couple of years, and they burn much hotter with a throat life of 1100-1400 rounds max.

There is not much difference between the 6 XC and the 6x47 Lapua, I have the reamer and dies for the '47 and will get around to it someday.

I formed 6 XC brass from 308 PMC, Winchester, Hertenberger, and Chinese military brass into 6XC and the cartridge still shot 1/4" groups. The primer pockets in the Chinese military brass only lasted two firings, while the other brass is still going strong. Forming the brass is a labor of love, a great Winter project when you are housebound.

The 6 Remington has equal ballistics to the 243 AI, but the 6 Rem AI is a monster. The 70g Nosler ballistic tip is a great deer bullet at 4100 fps with its solid base, and the 80g Nosler ballistic tip at 3800 also kills deer with authority(R#19 with CCI 250). A friend here is shooting his 6 Rem AI using 55g Nosler ballistic tips on deer with a MV of 4400 fps, deer and hogs flop.

The std 26" 6 Rem has an accuracy node at 3600 fps with the 80g Nosler with IMR 4064 and Federal 210s, using Winchester brass.

Op has some really great choices with a re barrel of his Ruger #1!

Personally I would not mess with dads rifle for sentimantal reasons. Also some gunsmith don't fool with single shot rugers. I would do a semi custom with a shouldered prefit on a custom action. It's quicker and when you shoot out the 6 creed you can rebarrel It or make a switch barrel rifle out of it. You can buy all the stuff right now from Northland shooters. They have a bunch of 6 creeds in stock plus bighorn actions and the action wrench. Call and talk with james.

Keep the Ruger as is.

Then either buy a Seekins Havak in 6 CM or build 6 CM. My 18" 6 Creed is one of my favorite rifles to shoot.

I love my older 243 for its versatility even though it's a 1:10 twist. I would get the factory tikka and some components for reloading and have some fun. Plenty of factory options for ammo out there too. For hunting and casual target fun you couldn't go wrong.

Build a 6-6.5 PRC, you won't regret it.

My vote for the 6ARC is purely because it's the only one I have experience with (although my Seekins PH2 in 7mm RM is my favorite rifle, so you can't go wrong with that choice). My daughter harvested her first ever deer last year using the 6ARC, so I have some emotional attachment to the thing as well. Handloaded with ELD-X's that little 6mm pill blew a 4" hole out the opposite shoulder of that big doe. I'm a fan.

Seekins for me, but there's probably not a wrong answer. Everybody has different wants.
And no way I'd ever sell your Dads rifle.

I have rifles my Dad left me when he passed in 21, 2 of them were Ruger No.1s in 300 win mag and 22-250, wouldn't touch them , will keep as is and shoot.

Just my 2cents but I'd keep rifle as is and build a super sexy fast twist 6mm-284, an oldie but a Goldie IMO.

I have a 6CM and a 6ARC. Depends how much you shoot. I chose to run my 6cm at a light load. I'm pushing a 115 at 2840 from a 22" barrel. I'm at around 1100 rounds and the velocity and accuracy are still good. I'm starting to keep more track of the velocity though. I'm around 1300 on my 6ARC AR. I won't even care until I get close to 4k.

The 6 CM has done exactly what I wanted an could do a lot more, and the barrel life limitation was well known. The 6 ARC on the other hand has not lived up to my expectations. I have a 20" Proof barrel and I have to run a 108 in the low 2500s. I wanted to be in the mid 2600s. However, when I've gotten close to 2600 with temp stable powders (Varget, 4895) the loads have shown too many pressure signs.

if you can swing full custom go that route. You get exactly what you want and the custom 60 deg actions in a CF chassis or stock with a nice trigger tech or bix and Andy with a good cut rifled barrel is really hard to beat.

I think that 6mm Remington is better than any of the newer 6mm cartridges, slightly faster than 243 and the heirloom factor would play a big part for me. I say rebarrel it and stick with 6mm Rem. Texas your daughter that one carefully place shot is all one really needs. I had a Remington 788 in 6mm, absolutely great rifle and shot 1/4 minute all day. Wish I'd kept it.

I voted 6ARC but actually have a Whitely 6mmAR…it's predecessor. Acquired the upper about 20 years ago, Used this rifle for 200/300 yard Egg Shoot Competition for several years with excellent success. At 3000+ rounds down its 8TW Hart barrel, it still holds <.25MOA with no evident barrel erosion. I run 107SMK's at 2800FPS. 20+ reloads on necked down Lapua 6.5 Grendel brass.

I voted "other".
IF I were to build a 6mm for the uses that the OP listed I would have a hard time passing up a 243 Win.

Really the only cartridges that I would pass it up for would be a 6mm Rem, or 6mm Rem AI.

But I like the obsolete cartridges.
They really get overlooked. Shame because any perceived advantages of the new wonder cartridges are not that great.

I think the Havak is a bargain. Mine shoots as well as my customs and is light enough to carry without issue...