7mm Build Questions

[Ohio06]

Well this may be a long one, but I wanted to bounce this off people who are much smarter than me when it comes to this kind of stuff.



I've been researching for months on caliber and component selection for my next rifle build, for years I've been leaning towards one of the 7mm's. At first the 284 Win seemed like a go to, however I already have a .308 that's throated out for 210g bullets, so I'm not sure if I will really see as much gain in the .284 as what I'd like. So I looked further into the 7mm family and am leaning on either the 7 WSM or the .280 AI. Right now the short mag seems to be what I'm leaning towards.



The build components will be as follows:



Manners MCS-EH1

Badger M5 Mag Kit

Defiance Deviant Long Action

Bartlein Barrel

APA Micro Bastard Brake

Nightforce NXS 5-22 x 50

Timney Calvin Elite 2 stage



My main questions revolving around this are:



1. What twist rate should I go with for stabilizing 180g bullets? Will 8 be enough, 7.5? I've read numerous places where guys are running anywhere from 7 to 8, but never really got any good feedback on what the results were, but I'm thinking there would be a lot of grumbling if 8's weren't stabilizing these though.



2. The target velocity I want to hit is around 2900-3000 fps which I think will only be attainable with a 26-28" barrel. 28" is no concern to me as my .308 is at 26 right now and I find no issues at all with carrying it. What's your experience with barrel lengths on a short mag? Obviously if these velocities are easily attainable with a 26" I'll go with it, however if I'd be flirting with excess pressures at 26 to get it then I'll just bump up to a longer barrel.



3. What barrel contour? I've been leaning towards a light varmint contour or heavy target, but I am just all over the place. The target finished weight of the rifle is going to be around 12.5 lbs, so barrel contour will come into play as far as this weight target goes. I certainly don't want a pencil thin barrel, but I also don't want an M40 profile.





Appreciate feedback.

 

[lancetkenyon]

I run a 7 Rem Mag with a 1:8.5" Bartlein, and it stabilizes a 180 Hybrid @ 3000 and 183 SMK @ 2975 just fine. I have shots out to 1371 so far with great results.

Mine is a mountain rifle @ 9.6#, with a #3 fluted @ 26", R700 LA BDL, HS Precision, APA Micro Bastard brake, Seekins 20 MOA rail and medium rings, and a Vortex Razor Gen I 5-20. I am saving my pennies for a March 3-24x56 to save another 9 oz.

 

[sable tireur]

Ohio06,

This is all pretty straight forward.

I agree with most of your component choices except:

Timney Calvin Elite 2-stage

Nightforce NXS

Personally, I'd get anything but a Timney trigger for your rifle. Overpriced, under delivered. Get a Jewell and keep it clean.

I prefer the Schmidt and Bender scopes over almost any other. There is nothing wrong with the Nightforce, the S&B is just plain better and bullet proof. If you stick with the Nightforce, I'd get the MOAR reticle.

For the cartridge, I suggest using the 7mm-300 WSM for the longer neck.

Twist rate will depend upon if you might decide to run the 195 gr. Hybrid Hunter. Then you might want to consider the faster twist rate with the slightly slower velocity. Otherwise if you stay with the 180 gr. Hybrid, the 8.5 should cover any bobbles you might make with colder temps or lower, close to sea level shots. Even Berger states 1:9".

The barrel contour I use the most for building is the Bartlein #6 at 26" for the WSM cartridges. Easy to transport and carry yet stiff enough. To save a few ounces you could step down to their #5 or even a #4 for a hunter rifle. The #6 gives a good carry over between target and hunter.

Defiance actually makes an action suited to the cases which want to have the bullets seated out longer than the standard 2.800-2.95" magazines. It is the intermediate length titled the MX and it is a terrific fit for hunting rifles without having to use the longer actions. The maximum mag length is 3.200" which covered so many cartridges with long seated bullets.

Regards.

 

[Ohio06]

Thanks so much for the feedback.

I almost forgot about the 195's being out, I'll have to run those numbers and see what they look like.

With regards to the trigger, I actually had a Jewell on my current build and having grown up shooting mostly timney 2 stage I just couldn't get used to it. As a result I replaced it with a timney. Blasphemous right.


The reason behind my Nightforce pick was due to already having them, being used to their reticle (MOAR) and just the overall ruggedness. That being said I'm not stuck on them but rather just going with what has worked for me.

I don't have much experience with the 7mm-300WSM so I'll need to research that more.

One other question. If I end up with the 7WSM, is it better to neck up .270 or neck down 300? I'm guessing I'll have to neck turn the 300's, but it looks like I'd only be moving 7 thou of material on the .270 as opposed to .024 thou. Seems like that'd be the way to go??

 

[sable tireur]

Ohio06,

As a result I replaced it with a timney. Blasphemous right.

As with all things in shooting that we interact with physically, the choice of comfort, compatibility and confidence in a trigger is paramount. What works best and feels best to you is the component to choose. No argument there.

I like the MOAR in the Nightforce and I think it will serve you and your needs for this project.

The 7mm-300 WSM is pretty much that description. You can neck up the .270 or neck down the .300 with similar results. I neck up the .270 since I have more of that which I don't use as much of as opposed to having rifles chambered for the .300 WSM where I would use that case more. The cartridge could just as easily be named the 7mm- 270 WSM.

The reason behind this case is the longer neck which can curtail some of the damage to the throat . Be sure to check the necks for straightness.

Regards.

 

[Slick8]

Of those two, I'd pick the 280AI because I simply like that round and the wsm requiring a special action and brass sourcing.

I fear both will be a bit of a challenge to reach 3k with the 180's and would start with a 7rm especially if the 195 is on your mind.

I'm gearing up for a new build now with the specific intention of the 195 Berger. I'm torn between the 28 nosler and 7-300 Practical (wm). My smith has worked up an idea of an AI version of the 7mm practical where they removed the taper from the case and a 40 degree shoulder.

I located some RWS brass and am ready to commit any day now.

 

[N2TRKYS]

I, too, like a Timney trigger. I don't think you'll have to go as long of a barrel to get your velocity as you may think. I shoot a Remington Model Seven 7mm SAUM with a 22" barrel getting 2950fps with 160 grain Accubonds seated at 2.80".

Good luck and post pics.

 

[Ohio06]

Guys. Thanks so much for all your feedback. I have my stock on order as it's the longest lead time of anything (~25 weeks). The rifle builder has other manners stocks in house, but they aren't exactly what I want. So the wait to me will be worth it. My action is also there in house at his shop so that's taken care of.

I've spoken to one member on here at length on the phone and he really gave me some good insight to the 7mm family of cartridges. One thing that has me shying from 7 WSM is brass, it's non existent, so it's either a 7mm-300 WSM (I really don't want to fire form brass to the 7 WSM) although I'm not keen on buying custom dies and waiting. The .280 AI, well I still have comp dies and ~ 150 pieces of Nosler brass.... Sooo that's not out of the question either. Researching a lot in the evenings before I go to sleep, so then I dream about it all night .

Thanks again for all the help. I'll post pics when it's done... Next year

 

[slickyboyboo]

Guys. Thanks so much for all your feedback. I have my stock on order as it's the longest lead time of anything (~25 weeks). The rifle builder has other manners stocks in house, but they aren't exactly what I want. So the wait to me will be worth it. My action is also there in house at his shop so that's taken care of.

I've spoken to one member on here at length on the phone and he really gave me some good insight to the 7mm family of cartridges. One thing that has me shying from 7 WSM is brass, it's non existent, so it's either a 7mm-300 WSM (I really don't want to fire form brass to the 7 WSM) although I'm not keen on buying custom dies and waiting. The .280 AI, well I still have comp dies and ~ 150 pieces of Nosler brass.... Sooo that's not out of the question either. Researching a lot in the evenings before I go to sleep, so then I dream about it all night .

Thanks again for all the help. I'll post pics when it's done... Next year

I have a 280 AI at the builder right now, and although I plan on shooting 160-168 gr bullets, I went with an 8 twist, and will have it throated a bit longer, in case I want to shoot the heavier 175-195 gr bullets. It should finish between 25-26", and I figured that I should be able to get probably 2850 out of the 175 ELD-Xs, and maybe a touch more.

 

[BriKW]

I'm in the middle of a build as well around the 7mm family. I have yo admit that I love the 7mm's. I own my share of 30's too but I love the ballistics off the 7's better.

I struggled with the same choices you find yourself in. What made it easier for me was that I had a secret crush on the 280 Ackley Imp for quite a long time. Having a spare Remington 700 action laying around the gun safe made the choice easy for me. I went with the .280 Ackley.

 

[Lrt307]

I would just go with a 7 rem mag. Timney trigger works for me. Brux 26 inch 1:9 barrel. I run 71 grains retumbo 180 berger or JLK . Berger is 3080 fps. JLK is 3060 fps. A bit more bearing surface on JLK. 3000 fps is easy. I also used to run 69.5 h1000 with great results. This was right @ 3000 fps.

 

[SansSouci]

Good Morning, Ohio06,

The obvious question is the purpose of your rifle.

I'm a hunter. I'm not a target shooter; hence, my perspective is hunting.

As a hunter, I love your choice of cartridge. The 7MM Rem Mag was designed to be a long range elk cartridge. It has lived up to its billing. I would appreciate your explaining your bullet choice. Are you locked in to 180 grain bullets? Is there a reason for shunning 160 grain bullets? BTW, I'm beginning to think that a 150 grain bullet might be the best all around bullet for all North American big game except for the largest bears. For the largest bears, I'd go with a 175 grain Partition.

The 7MM Rem Mag has been neutered. I have decades old 150 grain Remington Corelokt ammo that I've chrono'd at better than 3200 FPS. My advice is to hand load. My elk load was taken from published data circa 1975. It uses 160 grain Partitions, what might be consider a lot of H-4831, and Fed 215 primers. Depending on the source, it's either a grain under max, 3 grains under max, or a grain over max. Regardless, it shoots perfectly in my rifle with nary an indicator of pressure. Newer loading data indicate that my H-4831 powder charge is way over max.

If you hand load, you should be able to get 3200 FPS with 150 grain bullets, 3100 FPS with 160 grain bullets, and 3000 FPS with 175 grain bullets, all safely and out of a 24" barreled rifle.

I have a stock Sako AV 7MM Rem Mag. It has a rate of twist of 9.5:1. It's the most accurate rifle I've ever fired. My friend who's now in Heaven owned a lot of custom rifles. He told me that not a one would shoot as accurately as my Sako AV.

A couple years ago I was fortunate to be drawn for what many elk hunters call the best trophy elk unit in the nation. It was a public land, fair chase hunt. I had loaded 175 grain Partitions for what might've been the hunt of my lifetime. My chronograph revealed that I was getting 3000+ FPS with 175 grain Partitions out of my Sako's 24" barrel. However, I one-shot killed a monster bull with one 160 grain Partition that I had loaded 20 years ago. My 160 grain Partition has chrono'd better than 3100 FPS.

I hunt the Rockies exclusively. From experience, 400 yards is a long way to shoot at high altitude. Environmental conditions would have to be absolutely perfect for such a shot. A solid rest would be a must.

Most hunters try to figure out how to make a 400 yard shot. I try to figure out how I can close distance. I'd rather kill big game at a 100 yards than farther.

Rifle weight is subjective. However, it might be objective when hunting at high altitude and long treks to game are the norm. I killed my bull of a lifetime after an approximately two-and-a-half hour chase over I have no clue how many high ridges. I had to catch my breath for about a minute before I put a 160 grain Partition through its heart. It was a through-and-through wound. He was 130 yards from me when I killed him. He was 10 years old. After he was down, I was darn near down from exhaustion. It was one of the most physically demanding experiences of my life. The rub is I could have killed that monster bull just as dead with a much lighter .270 Win.

With that out of the way, I'd approach your desire for a new rifle from the angle of a hunter. Do you need to incur the expense of a custom rifle? Is it possible to fulfill your needs with a factory rifle? I'm partial to Sako; however, many factory rifles are capable of incredible out-of-the-box accuracy. Computer aided manufacturing has removed human error from rifle manufacturing. While I do not own a Savage, I've yet to read a review of a Savage that wasn't 100% positive. BTW, Sako guarantees 5-shot MOA with its Model 85.

Rifle and cartridges are nowhere near as important as ability to put bullets where they need to go. At the risk of being branded a heretic, a .338 LAPUA will not kill the largest elk that has ever lived any deader than a .308 Win provided bullets from either destroy necessary blood oxygenating and pumping equipment. Any elk with its heart destroyed has maybe a minute of upside life remaining before it falls for good. When it falls, it will not get up. Hence, accuracy is the dominant criterion of all big game hunting. Keep in mind that every living being will remain in that condition for maybe a minute at most without topside oxygenated blood flow. For humans, it's 8 seconds.

Were it me, I'd look at rifles I already have. I'd rather spend money on hunting than buying a new gun that I don't need. And were I to buy a new gun, I'd have to know that it'll do something absolutely necessary that a rifle I already own won't. Not all that long ago I darn near bought a rifle I wanted, not a rifle I needed. After lucidity returned, I decided that it'd sit in my gun safe unused. But then again, I'm a hunter, not a gun collector.

The second most accurate rifle I have ever fired was another friend's absolutely 100% stock Remington Model 700 ADL of 1960's vintage. That darn rifle would shoot tiny groups all day long. The point is a hunter could spend considerable $$$ on a custom rifle that won't do what a good-quality factory rifle will do.

A few more points: barrels longer than 24" can become unwieldy in thick forests. I actually prefer a .270 Win with a 22" barrel. Again, this is from a perspective of actual experience. A lightweight, fast handling rifle is darn near nirvana in such conditions.There is magic in .284 caliber bullets. To get equal or better sectional density, one has to move higher on the caliber continuum. The 175 grain bullet has legendary penetration. An African elephant hunter felled close to a thousand of them using a 7x57 and 175 FMJ bullets. For elk and moose, 160 Partitions are excellent. However, I think Accubonds might be better. Not all that many years ago Partitions used to be the gold standard elk bullet. For all I know, they might still be.

I own a gorgeous FN .338 Win Mag. Rifle weight and recoil make it a poor choice for North American big game hunting. I've never hunted with it. It will not kill any deader than a 7MM Rem Mag. I've seen studly dudes having difficulty shooting .300 magnums. Anecdotally, from what I've seen, the 7MM Rem Mag is the most powerful cartridge that most hunters can bench shoot without flinching. Bench shooting builds confidence. Confidence kills big game.

I'm sure you've heard stories of elk soaking up a lot of lead and were lost. I don't doubt many of those stories. However, I chalk them up to poor shooting. The old hunter's bromide of a .243 Win in the boiler room is a whole lot better than an '06 to the guts is more truth than legend. No elk is going to go very far with its heart and/or lungs out of commission. Put bullets where they need to go, and get ready to do a whole lot of hard work.

Finally, rifle weight in a gun store is a whole lot lighter than rifle weight at Rocky Mountain altitude. twelve-and-a-half pounds will be heavy where oxygen is scarce. I can tell you from experience that this is true. Where oxygen is scarce, an additional slice of roast beef on a sandwich is heavy. Also, big cartridges in sporter weight rifles will produce noticeable and substantial recoil when bench shooting.

Ohio06, I wish you absolute and sincere best of luck on your quest for your perfect rifle. I hope it turns out to be everything you've anticipated.

 

[Lrt307]

^^^^^ I couldn't disagree with you more on several items in above thread. This is the longrange hunting forum of todays standards. There are many on here that can easily make much longer kill shots than you described ethically. I am one of them. Also 180 berger or Jlk bullets carry much higher bc than any 160 bullet I know of. 3080 fps with berger .659 or Jlk .735 is gonna outrun anything you described in the 150 or 160 going faster. I dont me to come of as a jerk I am just disagreeing with most of what said. Its a public forum and we are all entitled to our opinions and beliefs. My .02 though.

 

[SansSouci]

^^^^^ I couldn't disagree with you more on several items in above thread. This is the longrange hunting forum of todays standards. There are many on here that can easily make much longer kill shots than you described ethically. I am one of them. Also 180 berger or Jlk bullets carry much higher bc than any 160 bullet I know of. 3080 fps with berger .659 or Jlk .735 is gonna outrun anything you described in the 150 or 160 going faster. I dont me to come of as a jerk I am just disagreeing with most of what said. Its a public forum and we are all entitled to our opinions and beliefs. My .02 though.

I'm good. If you have written that you can kill big game at distances greater than 400 yards at altitudes where oxygen is scarce, I'm good.

I'm good with your disagreeing with me. After all, knowledge is derived via Socratic debate.

I'm operating from a perspective of experience. I've made two shots longer than 400 yards. Conditions were perfect, and I was unable to close distance. But those two exceptions do not negate my rule of 400 yards as maximum, for exceptions never invalidate rules. If I can close distance, I will. It's a quick, humane kill that controls my shooting behavior.

My foremost objective when hunting is to humanely kill an animal with minimal or no suffering. I want to walk up on a dead animal. I do not want to walk up on an animal that's fighting for its life. That screws with my conscience. Even worse, I do not want to wound an animal and have it lost to die in agony. Hence, I'd rather shoot at big game at a hundred yards than farther. Even at a hundred yards, I'll use shooting sticks. That which controls my behavior is hunting ethics.

I've known many a bench shooter who could ring steel targets at three hundred yards. Get them at timberlines, and the game drastically changed.

On my last elk hunt, my guide asked me how far I felt comfortable shooting. I told him 400 yards. He said his hunters never shoot beyond 250 yards. It was all about spotting game and hunting it. I killed a massive bull that year. My guide and I hunted him hard, about two & a half hours hard. Over I have no clue of how many high ridges hard. I shot him at 130 yards. My elk was dead standing upright waiting for his brain to stop functioning.

I do believe, as does Boone & Crockett and Safari Club Int, that there's a huge difference between big game hunting and big game shooting.

Also, keep in mind that in Rocky Mountain states it's a felony to shoot big game and not make effort to retrieve it. That means that if a hunter shoots a head of big game at a 1000 yards and it falls down a steep canyon, he has to get it out.

Finally, from my experience, I'm beginning to believe that a 150 grain bullet is the best all around .284 caliber big game bullet. But if a 160 grain bullet shoots better, I'd go with it.

I am curious: if you were to see a big game animal at a 1000 yards distant at 10000' elevation, how would you kill it? Would you use an absolutely steady rest? Would you assure there were no hint of even a slight breeze? What process would you use to kill beyond 400 yards?

How many misses would you suppose a long range hunter experiences before he makes a kill? If at a shot a big game animal runs away, would a hunter assume a miss as opposed to a wounded animal?

Lrt307, I wish you absolute success afield.