Best caliber for Colorado Mule Deer.

[Buffalobwana]

223 is a bit small … literally everything bigger than that is fine.

 

[Maverick254]

Your RUM will be great. The biggest thing will be adjusting to western style hunting/hiking and shooting presentations/positions. If you haven't already, I'd seriously consider looking at what you want in a good backpack, quality binos for long glassing periods, and shooting sticks designed for a sitting position. I like the good old Primos Pole Cat Steady Sticks. Simple, light, compact, and effective. Best of luck on a big muley!

I agree. Good back pack, shooting sticks (I use Primos tall tripod b/c you can use them sitting, kneeling, or standing), and binos.
I live in Texas and had never used shooting sticks until I went on a Colorado hunt. Now I use them at home as well. I take a 300 RUM to Colorado and the 180 gr bullets have performed nicely.
Good luck on your trip!

 

[Tommy T]

All of my hunting buddy's use 6PRC with a 140 hunting bullet and it will drop elk deer out to I know 600 yds , it's all about placement good luck on your hunting

 

[Tommy T]

Oops that's a 6.5 Prc

 

[WYMIKE]

Start the new year off with a new gun. Get yourself a light weight 6.5 PRC with a 1:8 twist barrel. Enjoy your Colorado hunt

 

[epoletna]

WYMIKE has good advice. New year, new rifle.

 

[Chas1]

300 RUM kinda overkill IMO, I'd go with trust 30-06 even 308.

 

[4cMuledeer]

Just by judging what I saw in 3 days of scouting and 7 days of hunting it seems to me that the larger caliber and higher velocity rounds are the way to go. During scouting most higher quality deer where out a stretch between 400-600 yards and depending on glassing advantage very awkward angles for a Texas guy. Now that I have been and fully understand the needs and demands, I believe that the 300 RUM is the perfect gun for the challenge. Seems to me for these deer a round between 150-200gr is plenty as long as you have enough behind it to shot it flat and long if needed. I practiced for weeks preparing to shoot confidently out to 600 and killed my deer at 115 yards, beautiful part of the world and I will be back. Next task is Bull Elk.

Your post with the deer you said 426 yards. This post you say 115 yards

 

[BPollard]

Quite frankly it's never what you expect. When I go out west I bring two rifles. One for reaching out far and one for up close and personal.
Of course the day you packed a long gun is when you don't need it and the day you pack the short gun is when you need to long gun. Be prepared have fun, shoot straight. PS. I brought my 300 SAUM last time. The shot was about 400 yards 175 grain lrx.

 

[Stringstalker]

You have a pile of guns. For me I grab the one that I'm most comfortable shooting I've the most time behind. I feel a 300 rum is overkill for deer. But if that is what your good with. Take it. I have a 7mm rem mag that is my go to. Love it and take it on all my hunts. I have a pile of other guns too.

 

[82bluestang]

What can you shoot best?

what this guy said!! It's solid gold advice. No matter how big a cartridge is, you need to be able to shoot it well.

 

[Ronald W Schaefer]

Nate, fellow Texan here. Your .300 rum will be fine. In fact, any medium+ caliber will do. I shot a big Muley in Dove Creek a couple years back with a 7mm-08 at 475 yds, 145 gr Barnes LRX handload---DRT. The big tent pole IMO is optics. Get a good scope with selectable turrets and play with it until you are comfortable dialing for range, and you'll be good to go. Take a range finder and shooting sticks. Practice off the sticks. Right now, hot 6.5 are all the rage and pretty much any flavor of "PRC" or "Nosler" caliber 26 and up. I'm waiting on a 6.8 western from Fierce Firearms (still) to give it a go. I might have said the 6.5 Creedmoor is marginal for the task, except this year my rifle scope died on an Elk hunt in NM, so I had to borrow my pal's 6.5 Creed. Wound up putting down a nice 6X6 at 550 yds...so...there's a data point--it wouldn't have been my go-to gun but worked in a pinch. BTW, I'd love to get a shot closer than my last three. That said the old standbys work great, .257 WM (120 Nos Part), 6.5 "upper class" (6.5-284/6.5 PRC, 6.5 RPM etc.) 270 (140 gr bullet), 7MM RM, and you are never wrong with a dialed in .308 Win or 30-06, especially if you are simpatico with your rig. I don't usually reach for any of my big 30s+ in the gun safe anymore. I have developed a great fondness for lighter "mountain" style rifles in the last five years or so. My "go to" in 7mm-08 weights 7 lbs. with optics, or a 6.5 PRC I just acquired...beautiful rifle shoots like a laser, but a bit heavier--my wife shoots a Weatherby Camilla in 7mm-08 or a 7mm Rem Mag SAKO Finnbear I bought in Germany about 1988 using a 160 gr Federal trophy bonded bullet--it is Thor's hammer.
So yeah man--.300 RUM, dial turrets, practice off the sticks=good to go.

 

[LC Smith]

Nate you obviously prepared well and killed a great buck.... congratulations!

 

[Old Rooster]

When I first posted I said the 300 RUM will be fine but others caught your drift better than I did.
Your really looking for a new rifle!Now I get it.
The one rifle/cartridge combination that I traded many years ago that I wish I had back was a Winchester 70 in 300 WSM.
A great cartridge and very accurate and not tear your shoulder up like the RUM.
There get a 300 WSM.