7mm choice in an SA - 7-08, 708AI, or 284 ???

[6.5BR]

Although a hardcore 6.5 fan, this project will be a dedicated 7mm SA build so no need debating using a long action for a 284.
Below has been decided:

Action - will be a Borden Alpine SA in .473 face
Barrel will be 20-21" Light Palma or Varmint/Sendero Contour, OR a 22-23" in a #3 Sporter. Will decide whether more use at range or carrying in field.
Using a BDL OEM or clone setup, almost certain will not build with a DBM.
Most use will be up to 162gr, informal paper and range work, mostly to 400 yds, stand hunting for deer/hogs typically under 400 but could stretch depending on things.

I assume a 284 will hold one less round in chamber. Doubtful I need more performance than a straight 7/08, but curious as to what I might gain with an AI or 284 re: brass life, though expecting bore life may drop some with a 284, unsure with an AI.

What quality brass choices are to be had in stamped 284 and is it comparable to 7/08?
I plan to run a 9.0 if I run 162 and under..but what twist is needed, IF I decide to run 180s?
Will a 7/08 shoot a 162 better in an 8.7 or something faster than a 9.0T ?

Pros/Cons of 7/08, AI, or 284 Win ??

I have shot the straight 7-08 a good bit, but anyone who has run any/all of the 3 rounds above, feel free to chime in. Thanks.

 

[DrewinTejas]

Going the 7mm route! If it were me in that barrel length I would go straight 708. I don't see any advantages of going 284, or 708ai with a barrel under 26". If you don't mind brass prep, lapua 308 brass necked down and turned is working awesome in my short barrel 708. I use win brass in my 26" comp rifle 708 because I lose so much. The only problem I have had with Windows brass is primer pockets getting lose after a few firings but my load is hot. The 284 you can get 6.5-284 lapua brass and neck it up. The ai your gonna have to fireform and cry when you lose it or at least I would. The 162 ,amax is awesome, 168 Berger shoots great in my Shorty, also the 140 Berger does great but the BC is not as high. Which would not matter if your just going to stay within its limits. You push it fast enough it will still out perform a 308 running the famous 175smk.

 

[turbo54]

284 is crammed into a short action, even at 2.950" COAL. Bullets must be seated DEEP, and brass prep/donut awareness becomes crucial. It works but I don't advise it. I've written quite a bit about short action 284s, search me.

Also, you're going to straight up neuter a 284 with a ~22" barrel.

Between the 708 and 708ai, its a wash. Sure the ai will give you a few fps. If its worth the FFing to you, then go for it.

I'd consider a 7mm Creedmoor from Mark Gordon @ SAC.

reason for this is because case capacity is more or less equal to 708, but the neck/shoulder junction is closer to the case head, which'll allow you to:

Fit a short action cleanly
NOT have to seat long, high BC bullets below the NSJ (not possible for a SA repeater in 708/708ai)
Match 708 speeds
Use a powder that's ideal for the cartridge (Varget). My experience is Vargets a shade fast for 708 and H4350s a shade slow, case capacity is the limit, not pressure.

I believe Mark gets ~2850fps from his 7CM with 162s, though he runs a 26" bbl.

 

[AKONA]

Hi,
I have a new development in 7mm that uses a 2.06 inches case based on the 6.5-284 shortened up a tad to make it more efficient.
Water capacity is 68gr of h2O and it is very easy to form and feeds flawlessly from the AI 308w magazines.
A 168gr VLD can be launched at 2780fps from a 24" barrel. 175gr VLD also good speeds.
This puts the 7mm rounds way out there in a nice package with flatter shooting and more momentum, speed and reach w/o the need for WSM barrel torches.
Since this is new I have not worked the loads yet because of the bad weather but soon I will be out.
Let me know if interested.

 

[6.5BR]

Drew, I have two projects in mind over the future, one in 6.5 as we discussed in the past, and at a later point, a 2nd that will be a 7mm. Unless compelled otherwise, it looks like given my choice of SA action, and bbl 23" max, the 7/08 will be used, and of course factory ammo an option if ever in a jam.

Thanks guys. No doubt if banging steel at LR distances, a longer bbl would have value, as would the 284. I have run wildcats in the past and formed brass, but not really interested unless a very compelling reason. Appreciate all input. Looks like my original idea of a bughole 7/08 will be the choice.

 

[AKONA]

The 7.08 can move some nice bullets at very decent speeds with some time and attention to reloads.
When I say forming is very simple trim on the powered trimmer(quick) and then run through the die and done. I am using a shortened 7mm rem dies so no need for anything special.
I like simple wildcats. No need to over-complicate things. The 7.08 is an awesome and practical cartridge.
I see you might also be a 6.5BR fan. I have a couple of systems on that one too.

 

[7mmRM]

7/08...

 

[Engine 22]

I run a 7-08 in a non-typical hunter pushing the 140VLD at 2900fps with Varget. The barrel is a #3 1-8.7 twist Bartlein @ 24". I'm very confident with this combo out past 500, if need be. I have yet to play with the heavies in this rifle as I have a 280AI in the stable as well.

 

[Jmilera]

Sorry to hijack, but will a boots obermeyer 1-8.4 twist stabilize a 162 amax or 168 berger bullet? Thanks Guys

 

[Runamuk]

Sorry to hijack, but will a boots obermeyer 1-8.4 twist stabilize a 162 amax or 168 berger bullet? Thanks Guys

Yes

 

[selfbowhunter]

The 7mm creedmoor seems like it would be REALLY good for what you want. I would open the receiver up for a wyatts mag box if your going to run BDL.

 

[6.5BR]

Does action work need to be done to use a wyatts?

 

[selfbowhunter]

Does action work need to be done to use a wyatts?

Yes. The wyatts mag boxes are longer and you have to mill out the rear of the receiver where the mag box sits in the bottom of the receiver.

 

[6.5BR]

Thanks for the reply, I had no plans to alter a good custom action, prob just opt for a reamer w/good throating.

 

[6.5 GUY]

7/08...

+1

The AI would mean more rounds down the barrel to first fireform, wasted barrel life for only a little gain so why bother. The 7mm-08 is widely available in loaded ammo and with brass you can either neck up or down any of them including Lapua brass. The .284 is a cool old cartridge but not meant for a Short Action, where as the 7mm-08 a 168 SMK can still be seated right at the neck/shoulder junction forgoing the deep seated issues a .284 would experience in a SA. Plus longer barrel life, and I'm pretty sure resale would be easy with the 7mm-08.

 

[selfbowhunter]

Thanks for the reply, I had no plans to alter a good custom action, prob just opt for a reamer w/good throating.

I believe the stiller predator is already cut for the wyatts oversized magazine box. I would think you want want to stay away from the neck/shoulder junction if possible. not going to happen with a reamer throated for the 162 at standard SA magazine length. you know how many people want to be different these days. I would think a 7mm creedmoor would be a very easy sale if the time ever came.

 

[6.5BR]

Sure the 7C would be sweet, but the factory ammo and stamped brass trump it for me using a 7/08. I will likely run alot of 120-140s in the rifle as my main ranges is 415 yds and under...a 150 SMK or 140 Berger should do well in wind, though will see what 162/168s will do. The latter will perhaps be used if I stretch it on another range that goes to 1K. No doubt a long action can make life simpler in the COL and a 280/AI or even RM would not be a bad choice, nor a 6.5x284 or similar if rocking a LA, though a Swede AI might be a pleasure to shoot.

No doubt, deeper than the SNJ is best avoided.

 

[XTREM HTR16]

I run a 7-08 in a non-typical hunter pushing the 140VLD at 2900fps with Varget. The barrel is a #3 1-8.7 twist Bartlein @ 24". I'm very confident with this combo out past 500, if need be. I have yet to play with the heavies in this rifle as I have a 280AI in the stable as well.

Sounds like a great hunting rifle! I debated a ton between the 260 and 7-08 for my non typical, ended up with the 260. Not much you can't do with your setup! Scope? Weight? Pics?
Thanks!


Sent from my iPad using Tapatalk

 

[Nortex]

I'm running a 7mm-08AI right now and love it. I am getting 2827 FPS with 162 Amax's. I do think my barrel is a touch fast though compared to the norm. I could safely get to 2900 but decided to drop down a touch. I'm running a 22" Krieger 1:10" twist 4 grove barrel with a 2.80" OAL. Forming for me was simple I used a few grains of pistol/shotgun powder without a bullet and then fired with the muzzle straight up and the case is 90% formed. After that just load and shoot as you would the standard formed round.

 

[cmh2007]

For me it would be either the .284 or the 7mm-08.

Sent from my SAMSUNG-SGH-I747 using Tapatalk

 

[6.5BR]

Good info, thanks guys.

 

[hawk_ce]

Unless you already have the short action to build with why not go 280 Remington?

Sent from my SGH-T769 using Tapatalk 2

 

[6.5BR]

I do have the action, no doubt if I wanted to run a LA, a 280 would be a great choice.

 

[2Shots]

I just got done building a 7-08 on a stiller AW, I have a long throated reamer that touches the lands on a 162 at 2.878. I'm getting 2770 from a 25" barrel with H4350 in winter weather. I'm sure it will speed up a little come summer. Some say the .284 is wasted on a short action because of the box length.

 

[Graham]

7mm choice in an SA - 7-08, 708AI, or 284 ???

I would not build any 7mm on a short action std bolt face. The advantage to 7mm over 6.5 is the highest BC 7mm bullets, which are also the longest and heaviest, and they won't go fast enough in a short action from any case that will fit in the action. You will end up with less performance than you already have.

 

[6.5BR]

Graham, barrel life for one

 

[gregsjt]

I would not build any 7mm on a short action std bolt face. The advantage to 7mm over 6.5 is the highest BC 7mm bullets, which are also the longest and heaviest, and they won't go fast enough in a short action from any case that will fit in the action. You will end up with less performance than you already have.

Are you describing the 7-08 or the .308? You can say the same thing about a lot of short action calibers, yet they still seem to be some what popular and most fill a nice niche.

Sent from my XT1080 using Tapatalk

 

[turbo54]

I would not build any 7mm on a short action std bolt face. The advantage to 7mm over 6.5 is the highest BC 7mm bullets, which are also the longest and heaviest, and they won't go fast enough in a short action from any case that will fit in the action. You will end up with less performance than you already have.

What is "fast enough"?

A 708 will usually achieve 2750-2800fps from a 162. That is fast enough for many folks. A friend has played with the 180 berger in his 708, and that runs over 2650. A .67 BC bullet @ 2650 is a damn fine performer!

My short action 284 acheives 2825 from a 175smk. That is plenty to hammer targets (steel and critters) at 1000 yards and beyond.

Not to say either of these is trajectory-competitive with a 243/105berger/3150+fps match rifle, but all around considerably more practical.

 

[Graham]

7mm choice in an SA - 7-08, 708AI, or 284 ???

Fair enough. I couldn't get 162s beyond 2725fps in my 7-08 without blowing primers, but I take your point.

I'm not arguing that a short action 7mm can't be done, just that if you already have a 6.5 it won't be a performance gain.

Of course, if you define 'performance gain' to include better barrel life, or increased bullet weight at at a lower velocity, or .30 caliber, then it will be a performance gain.

 

[turbo54]

I'm not arguing that a short action 7mm can't be done, just that if you already have a 6.5 it won't be a performance gain.

Agreed. Zip.shit difference in trajectory/drift between a 142smk @ 2825 from a 260/6.5creed and a 162amax @ 2775 from a 708.

Hardly makes a difference in game-taking either. There's no animal I'd try to take with a 708 that I wouldn't try for with a 260.

The OP mentioned a 22" barrel, though. I suspect a 708 loses less velocity per inch than a 260.

 

[wnroscoe]

Straight 7/08, 1-9 twist for 150/162's or 1/10 for 140's and under. Brass is easy to acquire/make. Skip the 284 in a SA due to the COAL needed to bring the 284 to life. The 7/08 AI would be fine but, the AI's do feed funny in a staggered feed internal box. If AI is the route you go look for a center feed internal box. I ran the 150 Sierra 150 GK in a 7mmRM for years at 3,050 and they hammer to 600 yards. The 140/150 SGK in a straight 7/08 would be deadly and accurate too. Good luck.

 

[6.5BR]

54 - agree, ran #'s, again, this build is not to try doing something a good 6.5 will not, but trajectory is darned close, and energy is hanging with the 6.5s out to 600 yds or so, and when hunting my furthest shots have typically been 2/3's that distance. If I were building for 1K I would put a long pipe on it, and zing heavies, but even a Berger 140 and SMK 150 look pretty good, if not a 140 AB for hunting, as you not a thing I would not punch with either round. Bore life, factory ammo (if ever needed) and brass are considered. I have run two 21" 700s one a blue BDL-V and other SS-BDL at 2900-2960 w/140s. No matter a few inches difference in one load/round to another, when shooting downrange, one will have to account for the dope of that set up, often by a turret twist. How many clicks I twist matters not to me.

WN- Did you ever run 150 NBTs and do you have any info on the new LRAB? I think the 150 at higher mv may give up little to a 160-162 but I have not run #'s. A 154 SST might be worth a look too, though probably not as stout, likely tough enough with sure expansion on long shots like the amax.

 

[Nortex]

There are some very good reports coming back on the lrab and the bc being pretty close to advertised. I'm very eager to get some of the 150s to try out.