Which and why? .270WSM .300WSM .338 Federal/Lapua

[Tactical45]

I am researching a new upper for either of my AR builds. A few years ago I built a LR10 in .308. I have no issues with it, just looking for a harder hitting round at 500-700 yards. Five years prior to that build is my DPMS 5.56/.223, no issues here either.

While researching I have seen some issues with the .300WSM with ejecting, and such. I am well aware of the debated recoil with the .300 and .338 calibers. It is all subjective to the shooter, weight of the rifle, and all parts of the load used. I have a M44 Nagant that I call Thor because of the recoil of a wood stock, and a steel butt plate. So, needless to say, I am used to recoil when I have to be.

For those of you who have one, or more of these calibers in a AR platform, please chime in with what you max range is with a given load. Would you only hunt deer out to say 500 yards, or is Elk, and Bear still and option at that range? I would like to keep the upper at 16", but I do believe that may take away from the overall muzzle velocity... The more information the better...

 

[budlight]

You are not being realistic Semi- autos are inherently inaccurate compared to their bolt action counter parts. 16 inch barrel and 500 yards is not what I would call ethical hunting

AR's bleed off pressure depending on the distance to the gas ejection port. I have 308 ar-10's with rifle length and rifle +2 inch ports and 24 inch barrels. They are made to eject properly with the slowest for 308 rem powders and achieving the highest velocities. Like Ram shot big game with 168 gr hpbt chronoed at 2800 fps with good groupings. or 175's with H414 and Hybird 100V with 180's

But if you must 270 wsm is an great round with 26 inch barrels

 

[Tactical45]

But if you must 270 wsm is an great round with 26 inch barrels

With what load? How far down range? How big of game?

I do hand load. My 5.56 I stay with NATO loads that go with the grain I am loading. My .308 like my loads with 175 SMKHBT.

The three calibers in the title I will have to develop, but need something to start from. I don't expect to knock down elephants at 1,000yds, but do want a good clean kill at the ranges listed above. I am aware of the bolt vs semi auto comparison. I am not discounting a bolt action, but my first choice this time around is an AR platform.

Thank you for your post...

 

[budlight]

We have taken 4 bison with 270's. 140 and 150 grain. I did come across this:

The bolt face for the 270 WSM is considerably larger (@ .535) than the .308 version (@ .473). While the bullet may perform flawlessly, I think you may run into bolt stamina issues, especially with a short mag beating on it. I'm not saying a 270 WSM is a bad idea, I love it, I just wanted to point out where your more expensive replacement parts would be.

 

[Tactical45]

What was the distance that you till them at? Rifle specs?

 

[budlight]

First answer a few questions? What does ethical hunting mean? I was in the military and some days shot so many 308 rounds that I was sick of shooting and later competitively shot larger calibers. I studied the anatomy, practiced for months, and perfected one rifle with one type of round, I had all my ballistic tables with me. so I could make that one perfect shot. I stated that I don't think that semi autos are accurate at 500 yards with 16 inch barrels.

I don't hunt game animals with semi-autos. high volume shooting. Pigs and Varmints is what they are good for.

About 30 years ago I went deer hunting with a co-worker. I didn't know that he was a spray and pray man with a browning 7 mag. semi. It was so disgusting what he did to a deer with 5 hits out of 8 fired from under 200 yards. The deer was balling gut shot and missing a front leg at the knee and still trying to get away. You might as well have thrown it in a garbage can because nothing was left with blown up intestines. I went over and shot it in the head to stop the balling. I was so F-ing ****ed that he was lucky to make it home that day. I never talked to him again

 

[nmbarta]

Ar's are plenty capable of achieving 700 yard accuracy. Wouldn't be my go to, but that's not reason for you not to.
700 yards on elk with a 16" barrel might present some problems but I'm not well versed on the velocities you could expect and what bullets function reliably in those rifles.

I see questions like this quite a bit, will said gun with said bullet kill said animal at said yardage?

The question to ask here is,
Will a 180gr accubond leaving the muzzle at 2500 fps out of a 3/4 moa rifle reliably kill elk at 700 yards? ( hypothetical)
The bullet is unaware of the case, the rifle, the powder, and so on once it leaves the muzzle.

Though I don't have any experience with any of those in an ar platform, if you can get a good bullet moving at acceptable velocities with acceptable accuracy, there is no reason your rifle is any less effective because it is an ar.

I have an ar that shoots better than most bolt rifles, but I have bolt rifles that shoot better than it does!

I think it would be good to consider the advantages of adding a little length to the barrel in any of those cartridges, 16" is just going to give you a massive fireball and spit unburnt powder out of your barrel. Might not be exactly what you want, but will help achieve your goal

 

[Tactical45]

By ethical, I mean at a given distance, will the round do the job it's intended to do, or just wound the animal and it suffers instead of dying. Retired military here as well, been shooting for over 30 years. Just never used any of the three calibers I mentioned. I do know any of the three are capable of accurately doing what I want with a 24 plus inch rifle.

I guess it was more of a "has anyone done this, if so did it work" question. I was hoping to be able to use one of my existing lowers, and just build an upper and be done. Shooting precise holes in paper at 1,000 yds is one thing, making a kill shot, having enough energy to go through thick fur, and tough skin and fat is another. That is the information I'm after.

My last build was a AICS chassis, 26 inch single cut full stainless Kreiger, 700 SA .308 bolt. I want a different round this time. Was going for AR, will go bolt if needed. As I mentioned, 16" is too short, what length did someone go with that worked with an AR?

 

[budlight]

You can take on anything in the lower 48 states with 270's. All the buffalo were one shot kills. My first was a culling the herd 1500 pounder 4 year old bull. These were park hunts. I paid the fee and showed up with my 29 inch 270 win F1 class target rifle. The park rangers told me that they required 30 cal magnums at a minimum. I told them that I think that I can do it and told them that I had rounds that could go though 1/2 inch steel at 200 yards. They were all armed with big cals as backup. I was the first shooter and picked at one an it fell over dead with a torn up heart at @ 200 yards

. Some of the other hunters with big mags like 416 had to shoot them multiple times.

 

[Tactical45]

I would be interested in knowing what your load is for a 270 that put a hole in a 1/2" plate at 200 yds. Also what load you used to down the buffalo. I'm not saying it can't be done, I am just gathering data for loading. Are you shooting with a 270 WSM? If not, what?

And thank you for the info..

 

[cohunt]

Short mags require proprietary parts in AR's (especially bolts, but sometimes carriers and even special uppers- or at least modifying ejection ports)

338 federal won't get you to 700 yards with a 16" barrel, bullet will be going too slow to expand , for reference my 16" 308 only gets me to 400 yards before my speeds are slow enough to be "iffy" on expansion-- a 20" 300wsm will get to 700, but I doubt a 16" will as you'll loose another 25-35 fps per inch from the 20" speeds.

You said 338 federal/lapua
Are you considering a 338 lapua mag? Or am I reading that wrong -- whole other ballgame if you are

 

[Tactical45]

I think I have decided on the .270 WSM in 24". I'll probably start out with 130gr, and go up from there. If the illusive 180 gr can't be found, I think I see myself at the 160gr. There is just enough difference between the .270 Win, and the .270 WSM to make me go that route. The .338 (anything) will be too much for smaller game like deer and such. Yes, I could loaddown, but then there is the factor of "kick" as well. I was considering the .338 Lapua Mag, but I will not be shooting that far while hunting... The .300 WSM is not as good as the .270 WSM in trajectory, and if I want more energy, I can always upload...

Thank you for those who added info., it did help, and maybe the next shooter can use this info as well to help make their decision.

 

[budlight]

https://www.sierrabullets.com/product/270-caliber-140-gr-hpbt/ I have 29 inch down to 26 inch custom rifles long throated .277's in 270 win 270 AI and WSM. The 29 inch rounds are loaded so long that it is a single shot Those hard copper 140 destroy metal swinging targets where the majority of big magnums just make impact craters. Also chrono data shows them going 3200 fps. Accurate mag pro and reloader 25 are good for 140. 169.5 grain VLD.s I used to use retumbo until R-26 came out I never got the 190 gr .277 to shoot right with my 9 twist. 175 gr matrix is about the max weight

2 bison were 140 and two with 150 speer moly coated spbt

110 and 120 hpbt's are excellent long rang PD rounds up around 3500 fps


169.5 grain compared to 150 spbt moly

 

[Tactical45]

Thank you for the info.