Best caliber for Colorado Mule Deer.

Best caliber for mule deer (out to 800 yds)?
6.5mm
.257"
7mm
.308"

I might get some hate for this, but here is my opinion:

6.5mm could be anything from a 6.5x47L to a 26 Nosler. From a good 130 to a 156. They will rock a muley, and recoil is not bad. So easy a kid can do it.... ;)

.257" could be a .250 Savage to a .257 Wby. But, I would go with a fast twist and heavy bullet like the 133 or 135 Berger to really capitalize on this caliber. Maybe a 115gr in a 1:10" twist, but 600 is getting about max for me with that combo. The heavies definitely hit above their weight class. Run those numbers.

7mm, I have never been a big fan of the smaller 7mms like 7-08 w. 140s even though tons of guys like them. So I would say 7SAUM, .280AI, 7RM, 28 Nosler etc. w. a 160gr-195gr bullet. Plenty for much longer shots, and can double as a good elk round as well.

.308 for me seems to start getting good in a .30-06, .300SAUM, .300WSM, .300WM, .300RUM. 180-230gr bullets. But definitely (for me), the big .30s are getting into that "overkill" range for deer, but dead is dead, right? Plus, recoil starts to really go up in a big 30 pushing heavies.

You could slip 6mm in there as well, but they tend to start to peter out at 700-800. The 105-115gr actually do quite well on deer-sized game. But out to 600, they work very well.
Well said.
 
One fine public land muley for sure! Congratulations!
Being a bit long-in-the-tooth I prefer the lightest rifle I have that shoots well at my estimated maximum distance. I've lived in Colorado 48 years and taken a few mule deer. Used everything from 243 to 300 WM. Put it in the boiler room and they work fine.
To me though the ideal muley cartridge would be the classic 270. Plenty of gun and shoots flat enough. JMO&E
Best of luck when you come here next for elk!
 
Like many others on this site, I've hunted with quite a few different rifles in various calibers. I've settled on the opinion after decades of trial and error that the .270 Winchester is really the best "all around" cartridge to use for big game on this continent. The caliber you have already will work just fine though if you're comfortable with it. If you want something lighter that shoots flat and doesn't recoil excessively you can't go wrong with a good quality rifle chambered in the grand old .270 cartridge. If you're building a custom rifle, I'd suggest going with a 1:8 twist so you can take advantage of the newer high-BC heavy-for-caliber .277 bullets which won't stabilize in standard 1:10 twist barrels. Whatever you decide, happy hunting Sir!
 
I would like to thank all for the great input to my hunt as you can see, I was blessed to harvest a great Mule Deer Buck. The 300 RUM shooting Nosler Accubond 180gr did the trick easily, distance was only 426 yrds so not that stretched for the territory. This is a public draw deer hunt, so I am proof that it can happen if you put in the time and effort to scout. There are great maps these days that make it easy to figure out scouting and hunting strategies. Good luck out there my friends. View attachment 411630View attachment 411631
Great buck! Congrats!
 
Sounds like 4 Corners/Durango area. I shot a nice bull elk there in 1993. Never saw a buck up where I was. Bucks don't like to be around noisey smelly elk. Found that out in a few states.
I agree, scouted and found elk first morning and no deer. Next morning scouted opposite direction 180 about 2 miles and there they were. Thanks for the tip, never really put it together.
 
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.
Bingo...
 
I agree with others here. I live at 8,700 ft in Colorado and your 300 RUM is more than adequate. Now if you're using this tag to justify buying or building a new rifle, I can get behind that idea all day long! I personally love .280 AI for almost anything. If you don't have one, that's my recommendation. I also use my .257 Roberts for many deer hunts here and think it's a cool catridge to shoot. Altitude won't really be a consideration for hunting. You'll notice it shooting long distances from the bench but I wouldn't take any long shots at deer here with all the crazy wind and thermals moving erratically at times across the topography - far less predictable than the TX flatlands and hill country. I'd tune up your 300 RUM and focus more on getting your legs and body ready to climb the hills at altitude - and if you don't have high quality optics, use your rifle money to get a great pair of binos as most of my best deer have been taken because I found them in the glass first and then put the stalk on them to get within range upwind. Make sure your boots are comfortable and broken in - it won't be unusual to put 8-10 miles on them in a day...especially if you need to get away from other hunters to where the real deer are at.
 
Yuup that 300 RUM will work, but you carry it more than shoot it, in these mtns. A lighter 7mm something may suit you better. Judging good mule deer at 600 plus yards takes again some heavy glass. If your guided not a problem he carries. Remember the phrase" carry up the mtn." , and your trip will be more fun.
 
Yuup that 300 RUM will work, but you carry it more than shoot it, in these mtns. A lighter 7mm something may suit you better. Judging good mule deer at 600 plus yards takes again some heavy glass. If your guided not a problem he carries. Remember the phrase" carry up the mtn." , and your trip will be more fun.
Why would weight have anything to do with it ? Because of caliber ? Not so. depends on rifle itself .🤔😉
 
I am a South Texas deer hunter and own many caliber of deer rifles, but I am going on a public draw deer hunt in Colorado and need to know what is a good all round caliber for Mule deer. I use a 300 RUM in Texas due to long Sendaro shooting out to about 600 yrds, but want some input for Mule deer in Colorado. I am under the understanding that altitude can effect preformance.
You should use what you can shoot the best!!
As for higher altitude your bullets trajectory will be slightly higher than in Texas. The thinner air results in less drag so your drop will be less at given ranges but probably not enough to get overly concerned about.
You could input you data into the Hornady ballistic calculator for your current elevation and again for the altitude you'll be hunting and see the difference at impact ranges.
I live in GA at 1200 ft and hunt at 8000-9000 in Colo all I do is aim 2-3 inches lower.
 

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