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Caliber for new build - 260 vs 7-08 vs 284

turbo54

turbo54

Mr. 7mm
Full Member
Minuteman
Dec 10, 2010
4,995
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Michigan
Sorry in advance for this kind of thread - I hope this doesn't turn into the typical ridiculousness that generally goes with a thread of this kind!

I have several 308s and I am quite invested in the caliber. I love 308, and it does so many things well, but I believe *I* am ready to add an additional, higher-performance cartridge to my inventory, and to become my high-performance match/competition rifle.

What I want to achieve:

1. A cartridge that will take me from 100-1500 yards (or darn close). I feel that in typical field conditions, I have about a 75% chance of hitting a 1 MOA target at 1000 with my 308. At 1165 yards, I have about 25% chance. I want a cartridge that will get to 1000 NO PROBLEM, and even get to 1200 NO PROBLEM.

2. A "reasonable" cartridge that is inherently accurate and isn't going to be finicky. By "reasonable", I'm also talking at least fair barrel life. My opinion of fair barrel life is 2500+ rounds. Obviously, more is better, but I understand performance comes at a cost. I am not interested in the real hot-rods such as 7WSM or 7SAUM.

3. A short action cartrige - this coulda been up for debate, but I've already purchased an action and stock and bottom metal...I had *decided* on 260 and was moving forward, but now I'm reconsidering.

4. I am somewhat recoil sensitive. A warm 30-06 (unbraked) is about max for me. This rifle will wear an APA little bastard (removable), so I don't think any of these cartridges should be a concern...even unbraked.

5. I'm not concerned about being able to buy ammo at the store.

6. I see fellas with suppressors - which makes for a LONG rifle. Being that I live in state that won't allow them, I figure I'll choose a barrel at least 26" long, so I will be able to take nearly full advantage of any of these calibers.

Here are the pro/cons in my brain about each of the calibers I'm talking about... I might point out that I've ruled out 7-08AI because I don't want to develop a good "fireforming" load in addition to a good "fireformed" load, and have to keep the brass sorted.

260...
Proven ballistics
Easy to shoot
Fits a short action easily
"fair" barrel life
Excellent brass available "off the shelf" with no extra prep
Will have to buy into a bunch of new brass
Trendy, and desireable - good resale

7-08...
Seems like a "wash" ballistically with the 260
Good - quite good barrel life
Fits a short action easily
I can form brass from the heaps of 308 brass I already have
Will require brass prep to get good brass
Slightly "odd" caliber - niche resale

284...
Ballistically superior to either 260 or 7-08
Capable of launching seriously high BC bullets at NICE velocity
Hits harder down range
Good barrel life
Is "shoe-horned" into a short action (Alpha type 3 mags @ 2.985 will work, but its close)
Brass prep required (but not too much...just expand 6.5-284)
Will have to buy into a bunch of new brass
Oddball caliber - VERY niche resale

Overall, I think I'm leaning towards the 284. It seems to run just inside the line between reasonable and magnum, giving good barrel life and great ballistics.

Thoughts? Am I overlooking something?

Please provide rationale/explanation with your responses. "260 is the best" isn't very helpful!
 
Re: Caliber for new build - 260 vs 7-08 vs 284

turbo,

I think you covered each cartridge pretty well, but I think I can add some value, and some things you should consider.

1) I think the 260 Rem and the 284 should have near identical barrel life. I do not believe that the 284 is greatly better than the 260 in that department.

The 7mm 08 should exceed both by 1500-2000 rounds.

2) If your leaning to the 284, don't overlook the Seekins original DBM system designed for the WSM series. Although the mags are proprietary, they allow a COAL of 3.140". That's a large increase over alpha mags.

3) Have you checked the price of Lapua 260 and 284 brass lately? Although Lapua brass is excellent, field shooting and tactical comps looses you alot of brass. Better and more fun to tuck $1 bills into a strippers g-string than crawling around in the weeds to look for lost Lapua brass.

Win 7mm-08 brass is excellent and runs under $50. per 100. or less than half the price of Lapua.

In any event all three are excellent, and you will be well served with any you choose.

Bob
 
Re: Caliber for new build - 260 vs 7-08 vs 284

The choice of rounds you mentioned is the 284 but it is a long action round if you are going to get the most out of it.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

I would still go the 7RSAUM. Short action with a lot of available performance when wanted. There is also nothing stopping you down loading it to the level of both the 7-08 or 284. You will get increased barrel life.

Take advantage of the Seekins WSM DBM....

Then, if you do decide you want/need more velocity, its only more powder away!!

CHeers
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Thanks for the responses guys...

I should say I've got an FN SPR 308 action to work from, with CDI DBM. I just took a 308 case and pushed a bullet in for a COAL of 2.985 (MAX for Alpha mag). Looks like no feedramp clearance issues, but during extraction, the meplat JUST clears the ejection port... Probably no more than 20 thou clearance.

So... unless I relieve some material to enlarge the ejection port, the seekins DBM with bigger mags won't help me. I demand being able to extract a loaded round without removing the bolt.

Barrel life...

Vicarious data seems to show about 2500 rounds from a 260. Based on ballistics, I would think the 284 would use a barrel just as fast, but an G class guy I know runs a 284 with 180 Bergers @ 2950fps, and is still easily holding 1/2 moa at 600 yards after 3000 rounds. F class is pretty hard on barrels. He was getting 900-1100 back when he used 6.5-284.

Case capacity of 284 in a short action...

Definitely going to give up capacity by doing this. Hard to say just how much. The ass end of a 180 berger would be .290" below the shoulder neck junction. Seems like it would still have a significant capacity advantage over 7-08?
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ackley Improved</div><div class="ubbcode-body">I would still go the 7RSAUM. Short action with a lot of available performance when wanted. There is also nothing stopping you down loading it to the level of both the 7-08 or 284. You will get increased barrel life.

Take advantage of the Seekins WSM DBM....

Then, if you do decide you want/need more velocity, its only more powder away!!

CHeers
</div></div>

Not a bad point. Wouldn't I still be giving up a lot of available capacity, being that the max COAL I can extract is 3.000"?
 
Re: Caliber for new build - 260 vs 7-08 vs 284

So is there any advantage to the 260? Seems like EVERYONE is doing it! Also seems like the 7mm is a better choice - unless recoil is a serious issue...
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Turb054 -

BobinNC put together a nice cartridge capacity comparison in a previuos 7mm post:

Case Capacities for popular 7mm cartridges:

7mm-08 54 grains
7x57mm 59 grains
284 Winchester 66 grains
280 Rem 69 grains
7mm SAUM 73 grains
280 Ackley Imp 73 grains
7mm WSM 81 grains
7mm Rem Mag 84 grains

(link here http://www.snipershide.com/forum/ubbthre...rue#Post2706265)

I looked at the capacity from 7mm-08 (54gr) to 284 (64gr) to 7RSAUM (73gr). I chose 284 because I can load it down like a 7mm-08 or charge it up and send 180s with it. I would have gone 7RSAUM but I just did not need that much capacity but it might help getting to 1500.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Thanks for the link...

I crunched some numbers...

First I calculated the volume of the portion of a berger 180 that would be below the neck/shoulder junction of a 284 cartridge loaded to 2.975 COAL.

Then, based on the fact that IVI NATO brass holds 56gr water and 50gr varget to the brim, I got a ratio of grH20 to gr of Varget (representative of typical rifle powder in density-ish).

I figure 3.5gr of powder that could have been in the case can't be because the bullet is there instead.

Of course, this assumes someone would normally seat a bullet so that the base of the bullet was even with the shoulder - which is not necessarily the case.

With that in mind, would I really be "bastardizing" the 284 by running it in a short action?
 
Re: Caliber for new build - 260 vs 7-08 vs 284

I went through many of the same considerations about a year ago before I completed my build. The 260's low recoil, and extremely good ballistics really swayed me as I also really like the performance of the 6.5 Grendel.

I considered the 260 Rem Ackley Improved, but as the difference is only a couple of hundred yards, and the 260 will make it to 1500 yards anyhow, I didn't need to mess with making special brass.

The Lapua brass is a huge consideration for the 260, but till my necked down 7mm-08 brass dies, I'll stay with the 300 cases I'm working with for now.

I haven't regretted my 260 decision yet.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

I have come to the 260, first as a dedicated hunting rifle, and now working my way into a TRG in 260 as a dedicated LR precision rifle. I will say that I have had great performance from Nosler brass, and the new Lapua brass seems greart( just fired my first rounds load with it today). The 260 has been easy to work with, and performance always seems to be better than I expect.

BTW, its a great all around whitetail cartridge, especially loaded with 130 AccuBonds
cool.gif
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">.........With that in mind, would I really be "bastardizing" the 284 by running it in a short action? </div></div>

Turbo54 - here is a link that got me excited about a SA 284:

http://www.6mmbr.com/gunweek095.html

When I started my thinking about the build I was leaning SA but as primarily a hunting/sometimes LR rifle it made more sense to stay simple with a LA and BDL. However I did give a number of action and bottom metal manufacturers a call and talked it over with them. Suffice it to say there was always a small tweak one way or another that was required to get it done in SA. Then when talking it over with a gun msith and some others it just did not make sense for me to go SA.

Good luck and enjoy the process.

SG
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Want a new rifle, eh?
Have you thought about switchbarreling?

Winchester 70 push feed is an excellent action for building. Go Long Action and set your barrel throat so don't have to seat bullet below the neck. Might also look into cast bullets for their no barrel wear and excellent accuracy at moderate ranges, like under 300yds. If you are accuracy inclined and would prefer not to wear your barrel with each shot, cast bullets really offer a great deal of potential.

I would encourage looking at the .30/284 or the .338/284. The .338 gives you a very wide range of bullet selection with great ballistic coefficients. A LA receiver chambered in .30/284 with twist rate to take heavy match bullets and cast will give you much more versatility than either .308win or .30-06. The shorter case length gives you 06 performance and the enhanced accuracy of a short case body. The .284 case has 35deg shoulder so you have optimum case design.

Not really all that much to gain going down to 6.5mm or 7mm from the .308... 6mm or .224 with fast twist barrel gives you wider bullet selection and will shoot longrange with high BC bullets. A 6mm XC is a great choice, or maybe a .22-250AI with fast twist to shoot 90gr match bullets. 90gr Sierra or JLK in .22-250 or even a .223 has potential to group 10+rds in 2" spread at 1000yds as reported in Canada's Dominion Rifle Bulletin (http://www.dcra.ca/Marksman/Winter%20Spring%202008%20Edition.pdf) A 6mm with 107gr or 115gr will perform similarly w/o superfast twist...

Not really much that the .308win won't do; up to 800/850yds. 30/284 offers 1000yd potential plus heavier bullet weights.

Just some ideas...
 
Re: Caliber for new build - 260 vs 7-08 vs 284

At the end of the day, they are all very similar ballistically, capable chamberings.

Personally I would go with 260, heres why:

-although the bbl life may be a bit shorter, all of these chamberings have very long bbl life to start with. If it was your primary concern, you'd shoot a 22lr
-Lapua brass is easily available and suprisingly cheap
-projectiles widely available and cheap
-the least recoil of the bunch (you raised this earlier)
-Arguably the best ballistics of the bunch, but depends on pill and velocity etc.

I would not go with the 284 (personally) because the lapua brass usually forms donuts, so you need to ream the neck, and sometimes neck turn too (PITA, no more, no less)

I would not go with the 7mm08, because the BC advantage of the heavier pills is a moot point, because it is so much slower than the 260's with the same BC

My opinion, take it or leave it
smile.gif


Chris
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Why not run the 162 BTHP's in the 284 short-action and be launching a pill with the same BC as the top-end 264 VLD's several hundred feet a second faster, with none of the seating depth problems the VLDs have, and smack that steel with real authority? Sure, it's not "making the most of what a 284 can do" but the goal of your project wasn't "I want to maximize whatever chambering I select."

Just because someone else's 284 long action may have even better performance numbers than your 284 short action doesn't mean you've made the wrong choice. You've still got a rifle that will spank the ballistic lights out of your 308's while meeting all your original requirements.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Between the 260 and the 7mm options I have found the following.

The 260 runs right with my 7-08 right until 800 yards. At around the 800 yard mark the 7mm starts doing much better in the wind. And past 1200 its head and shoulders better in the wind than the 260. The 260 is still a capable cartridge and will easily make it to a mile as I've watched guys hit at a mile with it. It just takes much better wind calls to get you there.

My load out is still at 1000fps at a mile.

Good luck,
Merritt
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Let's see now - David Tubb - 2011 Long Range Champion again for the 7th freakin time still shooting 6XC with 115 DTACs at around 3000fps.

http://bulletin.accurateshooter.com/2011/08/david-tubb-wins-nra-long-range-championship/

Any questions ???

I know what I'm going to be shooting this year !!! :) :) :)

Read here - http://www.accurateshooter.com/cartridge-guides/6xc/

Compare ballistics for 6.5mm 142 SMK, Lapua 139, AMAX 140, Berger 140

to 6mm DTAC 115 HPBT Bn with a G1 BC of .590

Equivalent ballistics (drop, drift) at 3000fps

Still supersonic at 1400 yds

Less recoil then the 6.5mm or 7mm loaded hot

Better barrel life at 3000fps - see here - http://www.accurateshooter.com/technical-articles/overbore-cartridges-defined-by-formula/

What more could you ask for ??

 
Re: Caliber for new build - 260 vs 7-08 vs 284

Ratbert is dead on. I built a short action 284 and shoot the 162AMAXs in it.

I went with the 27 to 28" barrel because I didn't want to lug around a 30+" barrel. I had mine chambered for the 162s and whats not to like about a .625BC. I am not pushing mine hard and its a damn hammer!!!

It has been shooting 5 to 6" 1000yd 5 shot groups off the hood of my PU. The other nice thing is the vertical spread is around 2.5 to 3"s @ 1000yds.

I have the 260 and a 6.5x55 and neither one will shoot with the 284. I use 123 Lapuas in my 260 and 139s in the 6.5x55. My soninlaw and I were out shooting yesteday doing load testing at 400yds for his 260. He had nearly twice the wind dialed in for the 260 that I had dialed in for the 284.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Thanks for the replies so far everyone, I've seen some good points.

Ratbert:
You're right, my criteria doesn't include "using every bit of potential from a cartridge". Also, it really wasn't my intent to use the 180 bergers. I was calculating based on them as a worst case scenario because they are LONG...like golf pencils. While they have great BC, so do the 162 Amax's and 162 Hornady BTHPs (although not sure of the BC for the latter). Plus, the 162s are more reasonable in length.

Seems that even in a 284 short action, the 180s are still a viable option, whereas the 7-08 won't really drive them like they need to be. I know my 308 can't drive a 180SMK very well - about 2525fps, whereas I can get almost 2800fps from a 175SMK.

Zipollini:
David Tubb is a fantastic marksman and there is nothing wrong with that caliber for his purposes. For my purposes however, I am looking for more than simply paper-punching. I want to be able to ring steel, spot misses in the dirt, and like the idea of maintaining more downrange energy.

Raptor99:
Thanks for the info. That wind difference between the 260 and 284 is incredible! Was that the difference between a max load for the 284 and a starting load on the 260? I know the 284 is ballistically superior, but I didn't think it had 1/2 the wind drift! Do you know what velocity you're hitting with the 162? Do you know what kind of throat dimensions you've got? How about your COAL?

Thanks everyone - keep it coming!
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Go with the 284. I just got mine about 2 weeks ago and its a pretty impressive caliber. To stay .5MOA accurate at 700 yards while cruising at 3000 fps is pretty damn impressive no matter how you shape it. You are going to want to go long action if you ever plan on single feeding or really taking advantage of being able to load them out longer. I am 3.210 OAL and its almost using up that whole 300WM magazine.

260 is a good option but it wont hit like the 162gr amax moving at those speeds.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Crnkin</div><div class="ubbcode-body">I would not go with the 284 (personally) because the lapua brass usually forms donuts, so you need to ream the neck, and sometimes neck turn too (PITA, no more, no less)
</div></div>

Have you experienced the donut phenomenon from necked up 6.5-284 Lapua brass?

Has anyone else?

I'm not a big fan of meticulous brass prep, and I don't want to get into having to neck turn, ream etc etc etc. I don't mind doing it to a small batch to be used as "super match" brass, but overall - brass prep sucks and I hope to not have to deal with donuts forming.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

I haven't cronographed my load yet but I am no where near max load with it. The 260 would be right at 3000fps with the 120s he was shooting. He was also shooting 140 Bergers and the wind drift was the same on both the 120s and the 140s.

I "Have" cronographed my 260 load with the 123s and there running right at 3000fps and he was a grain hotter than my load.

I had .75 dialed into mine and was dead center he had at MOA and needed another half MOA on wind to be dead on.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Im a new reloader and even I can get the 284 loaded to shoot in the .3's at 100 yards with my hand loads. Its not that hard and I prefer the brass prep of Lapua to going with Winchester brass....

Buy quality and it lasts longer.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ackley Improved</div><div class="ubbcode-body">I would still go the 7RSAUM. Short action with a lot of available performance when wanted. There is also nothing stopping you down loading it to the level of both the 7-08 or 284. You will get increased barrel life.

Take advantage of the Seekins WSM DBM....

Then, if you do decide you want/need more velocity, its only more powder away!!

CHeers
</div></div>

I've been thinking of the same conundrum as the OP. And the above post is the answer. And is what I have planned. Basically...using a Surgeon WSM action, Mc A5, Bartlein 1:8.7 twist and the Seekins WSM DBM to make it all happen. Run it moderately on pressures and speeds and crank it up when needed. MORE FLEXABILITY. I never understand why folks want to get something then try to punish the hell out of it making I perform more than what it's built to do. Especially when there is a bigger better option with more FLEXABILITY to simplify things. Even cheaper do to brass options is the 7WSM.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Just some ramblings here. First, your post is very well thought out.
Second, I would have expected nothing less from my 7MM08 Brother Bob to recommend it. I have LR experience with the 260 and 7MM08. I side with Bob that the 7MM08 is best of those two. It is what I am currently shooting.
Now, for where I split off. I love the Berger 7mm 180 VLD for long range shooting but don't think it matches as well (case volume) with the 7MM08 case as with the 284 Win case. For what you are seeking I would go 284 Win in a <span style="text-decoration: underline">long action</span>. I would also recommend either Seeking DBM or using the Alpha mags. That way you will be able to get the most from that choice.
As for overall pick though, I am extremely happy with my 7 WSM, especially at longer ranges. It works in the short action fine and has the juice to go really long with the 180 Bergers. Also, if you brake it as you described, it is not offensive in recoil.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

I don't see how the Seekins DBM is going to help. I understand it will allow longer COAL than the alpha mags, but my action itself won't - I don't think.

As I mentioned before, I put together a 308 cartridge @ 2.985 COAL, and played with it in my action (FN SPR). I found that as the case head contacted the ejector and began to swing out of the ejection port, the bullet tip passed about .020" away from the front of the ejection port. This tells me that I couldn't extract a loaded cartridge longer than 2.985" + .020".

Am I thinking about this wrong?
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">4. I am somewhat recoil sensitive. A warm 30-06 (unbraked) is about max for me. This rifle will wear an APA little bastard (removable), so I don't think any of these cartridges should be a concern...even unbraked.</div></div>

Better be careful what you say here. Those 180's out of a 284 punch a little more than a warm 06, depending on rifle weight of course.
With the brake on, no worries.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

my vote, 7mm saum. if not 7mm saum 260 for sure. or even a 6.5 creedmoor. had one, it shot great. kept the 260 for the lapua brass option.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Perhaps the best answer is to pick another action. Surgeon WSM or a straight long action of another rollmark.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 65nut</div><div class="ubbcode-body">my vote, 7mm saum. if not 7mm saum 260 for sure. or even a 6.5 creedmoor. had one, it shot great. kept the 260 for the lapua brass option. </div></div>

Ok, what advantages do you feel 260 has over 284? Ballistically the 284 can launch a higher BC bullet at equal ir greater velocity. Both have quality Lapua brass available - although 260 can be loaded right out of the box, all fresh brass oughtta get sized.

Not flaming or really even disagreeing - just trying to get you to elaborate!
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"> but an G class guy I know runs a 284 with 180 Bergers @ 2950fps,</div></div>

Is this a straight 284, not a Shehane? And how long is that barrel?
2950 seems awful high to me unless you plan on only getting 2-3 firings out of your brass.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shiredude</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"> but an G class guy I know runs a 284 with 180 Bergers @ 2950fps,</div></div>

Is this a straight 284, not a Shehane? And how long is that barrel?
2950 seems awful high to me unless you plan on only getting 2-3 firings out of your brass. </div></div>

It's a straight 284. No idea what kind of brass life he's getting though.

In my case, with a 26" barrel, I'd be stoked to hit 2900 with a 162 Amax - but I think 2850 oughtta be doable...?
 
Re: Caliber for new build - 260 vs 7-08 vs 284

FWIW I am running a 7WSM in my FN SPR action. It has a 24" tube with an FTE on the end. Running 168 Berger’s was able to push them to 3200+. It just was not shooting like it should so ended up backing down to 3010(that is at 13ft asl). Recoil is lighter then a non brake 308. If you did a 300/7 you would have a little more room to play with in the mag and could use Norma brass. Just a thought.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shiredude</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"> but an G class guy I know runs a 284 with 180 Bergers @ 2950fps,</div></div>

Is this a straight 284, not a Shehane? And how long is that barrel?
2950 seems awful high to me unless you plan on only getting 2-3 firings out of your brass. </div></div>

It's a straight 284. No idea what kind of brass life he's getting though.

In my case, with a 26" barrel, I'd be stoked to hit 2900 with a 162 Amax - but I think 2850 oughtta be doable...?</div></div>

not to be bearer of bad news but that isn't worth much for the 284 if that is your velocity. my 708 pushes 168 berger vld at 2775fps and 2805 with 162amax with under book max on powders 46.5grains of H4350 26" 9tw 3 groove benchmark barrel and i have checked this velcity on paper to 1000yds to verify.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Here's my take on this whole thing.

You have a short action build lined up already. To me, that means you need a short action caliber, and although the 284 can and has been fitted into nice short action builds, it's just not ideal. Obviously it will work, but I don't personally like compramising to "make things fit."

It sort of reminds me of the whole 300 WM vs. 300 WSM in a long action. Both calibers have their purposes and both work very well. The 300 WSM can be used in a short action, while to get it's full potential, you typically need to utilize a long action. Yet, at that point why not just use a 300 WM right? Besides, it handles the heavy bullets better so it's just a more logical choice right? It's debatable at best, because both have great merits to them. Although I feel the whole "belted chamberings are flawed and/or problematic" argument is a complete load of utter bullshit, if you buy into it, you'll migrate towards the 300 WSM because it doesn't have a belt. What I like about the WSM is it has close to the performance of the larger 300 WM but uses less powder and this is due to being more efficient.

Okay, I realize this isn't about the 300 WSM vs. 300 WM debate so i'll get off of that and move back into your questions.

If you couldn't tell, i'm not for the 284 + Short Action build idea. If you had a long action though, I would say it sits at the top of the hill in this equation. This just isn't the case though, so on to the 260 vs. 7mm-08.

I like both calibers! And deciding between them to me is like asking if you want to drink from the blue cup, or the green cup. Obviously color preferences aside, both calibers do very well and will accomplish your goals. I truly feel that people read into the numbers WAY too much. So instead of looking at the ballistics sheets all day long I would highly suggest looking at other things to make your decision for you, as you clearly are doing by reading your OP.

I think you know I can't really add anything here that hasn't already been mentioned or discussed though, so I am nearing the end of my post.

If I were you, I would be looking at the 7mm-08 more than the 260. As I already said, both will work very well. I'm just more of a fan of 7mm for no reason other than hitting harder
wink.gif


Everything else is so similar between these two calibers that I feel it's totally a matter of personal preference. Some guys will choose the 260, others will go with the 7mm-08. I couldn't care less either way, I'll make either one work.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TeamSendIt!!!</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">

It's a straight 284. No idea what kind of brass life he's getting though.

In my case, with a 26" barrel, I'd be stoked to hit 2900 with a 162 Amax - but I think 2850 oughtta be doable...?</div></div>

not to be bearer of bad news but that isn't worth much for the 284 if that is your velocity. my 708 pushes 168 berger vld at 2775fps and 2805 with 162amax with under book max on powders 46.5grains of H4350 26" 9tw 3 groove benchmark barrel and i have checked this velcity on paper to 1000yds to verify. </div></div>

That is awesome! In my research, I have noticed 7-08 doesn't give up too much to a 284. I guess my aspirations oughtta be pretty easily attainable!? I'd reckon I oughtta be able to hit those velocities with less pressure with ~10gr more capacity (accounting for deep seated bullet)?
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Turbo,

There are a couple of points that you may have overlooked in trying to work high BC bullets from a SA 284 Win in Alpha mags:

1) Although the max COAL length of an Alpha Mag Type II is 2.985", OAL lengths of bullets do vary. I always subtract 0.010" ( or up to 0.020" if I'm using SMK's) to allow for that variation, meaning you are really limited to about 2.975".

2) With that in mind here are some numbers for you to consider:

Win 284 case is : 2.1701" long

Berger 180 Hybrid nose length: 0.850" Min Coal 3.0201"
Berger 180 VLD " " : 0.764" Min Coal 2.9341"
Berger 175 VLD " " : 0.820" Min Coal 2.9901"
Berger 168 VLD " " : 0.763 Min Coal 2.9331"
Hornady 162 A-Max " " : 0.750" Min Coal 2.9201"

I have defined the min COAL as the nose and ogive NOT being inside the case. It's tough to accurately seat your bullet off the ogive, when it's sitting inside your case neck. As such only the Berger 180 VLD, 168 VLD and the 162 grain A-max will work given your proscribed mag limitations.

That's why a Long Action or Seekins WSM DSM have been recommend to you so often. The 284 Win success as a SA cartridge if often seen with bullets of 160 grains or less.

But all this is not necessarily a bad thing, as those three are all very good bullets, but just something to keep in mind as you go forward.

As I said earlier, all three .260 Rem 7mm-08 and .284 Win are excellent, and it's hard to make a bad choice, even with a short action.

Bob


 
Re: Caliber for new build - 260 vs 7-08 vs 284

Bob: Excellent post/info as usual!

I completely agree that max COAL ougtta be ~.010" less than mag length to ensure no binding, and to account for meplat/ogive variations. 2.975" should be considered max for the alpha mags.

For my purposes, the 160gr and heavier bullets are what I had in mind. Looks to me like it would pretty much have to be the 162amax or the 162bthp. I would of course try the 180 bergers, but those take a bigger toll on capacity, and it's questionable whether the case would have the nuts to drive them hard enough.

I'm still curious what the Seekins DBM is going to do for me - being that my ejection port isn't long enough to extract/eject a cartridge longer than 3.000"?

Here's how I see this thing when it comes right down to it:

1. You're right, 260, 7-08 or 284 are all going to provide a serious performance boost over my 308.

2. All three of them give up performance to a magnum caliber

3. I wouldn't mind stepping up to magnum, but if I'm going to go all out, I would do a long action.

4. If I was going to go all out with a long action, I'd start with a surgeon action or similar. Doing this would add nearly $2000 to my build cost. I got a very nice deal on a complete SPR action, McM A4 w/ loggerhead, and CDI DBM. If I stick with the original short action plan, I can keep this build to a pretty nice price point.

5. For that reason, I'm going to stick with a short action.

6. While I could go "bigger" and get more performance, seems to me like the 284 is basically going to "maximize" short action performance....unless I went to a fat magnum....see #3 above!

7. While 7-08 is no slouch, and the 284 in short action doesn't do *much* more, it does at the end of the day have the capacity to load ~10gr more powder. So it is a clear step up from 708.

8. At some point, enough is "enough"! I have a 338LM to reach out really far, and this rifle build is intended to be a "reasonable" tactical rifle, which from what I've experienced, means I need the ballistics to reliably and consistently hit at 1150(ish) yards, at which range, I currently feel like I'm taking pot-shots with my 308.

I welcome comments! Especially in regard to the Seekins DBM!
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 65nut</div><div class="ubbcode-body">my vote, 7mm saum. if not 7mm saum 260 for sure. or even a 6.5 creedmoor. had one, it shot great. kept the 260 for the lapua brass option. </div></div>

Ok, what advantages do you feel 260 has over 284? Ballistically the 284 can launch a higher BC bullet at equal ir greater velocity. Both have quality Lapua brass available - although 260 can be loaded right out of the box, all fresh brass oughtta get sized.

Not flaming or really even disagreeing - just trying to get you to elaborate! </div></div>
I understand. the 260 is my fav. for the lighter recoil. it has better brass than the 6.5cm. I always had a problem with the 6.5cm brass lasting. maybe it was just the batch i had but primer pockets seemed to give out quickly. but one thing i liked about the cm, is the factory ammo was great if you didnt have time to load up a batch of rounds. the op said he was recoil sensitive. so that is why i chose to rec. 260. I dont have experience with the 284 but i do with the 7saum i went that route over the 284 because of some findings in my research people had trouble feeding the 284 from dbms. also, the rim of the 284 is just goofy to me. nothing wrong with the cartridge. just my .02.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

First, I don't know anything, I've just been playing with guns and ammo for 35 years. That's all.

Second, <span style="text-decoration: underline">bignada</span> makes points one might want to investigate further.

Third, ask <span style="text-decoration: underline">Terry Cross, WmRoscoe, or A10XRifle</span>, to name three among several others, what they think instead of <span style="text-decoration: underline">a bunch of clowns</span> who don't know a pile of mule shit from a pile of ashes. Those three have, and still, compete and build rifles. Everyone else? You could spend the rest of your life reading elementary ramblings about what they think know and who first picked up a Whamo air rifle last year.

Last, if I were to write more, I'd only write what <span style="text-decoration: underline">zipolinni</span> above wrote. 6xc, or 7rsaum, with a brake, even 243Winchester is THE "it". Get one of those guys I mentioned above to build your rifle, using his suggestions completely as to all components, take it, then just shoot and be very happy.

 
Re: Caliber for new build - 260 vs 7-08 vs 284

Turbo,

As to whether a SA 284 has enough nuts to drive a 180 gr Berger, run a JBM table with a "modest" muzzle velocity of "only" 2750 FPS (which should be very possible). Even at that "slow" speed were talking 8.1 Mils of drop and 1.6 Mils of drift and over 1k ft lbs of energy @ 1Kyds.

As to the Seekins DBM, I would give Glen a call and discuss with him. If anybody would know how to make his product work, it would the designer.

Also the old trick on pre-64 Model 70's used to be was shortening the bolt stop, not lengthening the ejection port. This will allow the bolt to come back further. I would speak with a good Mod 70 gun plumber, if you know one, about making those kinds of alterations.

Again I'm not trying to talk you out of a 284 Win, but the 284 Win, 7mm SAUM, and 7mm WSM, are three cartridges, that although designed for short actions, do require considerably more thought, planning, and yes, maybe even some action surgery, to get them to work properly in a SA with long High BC bullets.

Sure it can be done, but mag box geometry issues, and proper feeding are not a gentle walk in the park.

Of the three, 284 win, 7mm saum and 7mm WSM, the 7mm saum is the easiest to shoehorn, if for no other reason, the OAL of the brass, is damn near the same as the 7mm-08.

Just some things for you to think about.

Regards,

Bob
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">I don't see how the Seekins DBM is going to help. I understand it will allow longer COAL than the alpha mags, but my action itself won't - I don't think.

As I mentioned before, I put together a 308 cartridge @ 2.985 COAL, and played with it in my action (FN SPR). I found that as the case head contacted the ejector and began to swing out of the ejection port, the bullet tip passed about .020" away from the front of the ejection port. This tells me that I couldn't extract a loaded cartridge longer than 2.985" + .020".

Am I thinking about this wrong?</div></div>

You're correct in the analysis, but how often are you going to eject an unfired round? And if you have to; just hit the bolt release and no worries.

Also if you have room inside the receiver you can notch the port and add some room.


Keep your powder dry,
Goat
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Thanks everyone for your ideas and thoughts. After careful consideration I decided to go ahead with the 284.

I've secured a PTG reamer suitable and a fluted M40 Bartlein to finish at 26", and an APA little bastard bake. Bartlein is going to do the barreled action.

I was playing with a magazine, a case and some bullets this evening and learned I'll be able to use any bullet with a "nose" .800" long or shorter, without the case mouth hanging over the ogive. So, there is a nice selection of high BC bullets I can make use of. The Hornady 162s are an obvious choice, as is the 7mm 175smk, and several of the Berger 180s, although not the new hybrid or the XLD... Either way, I'm excited to get into a new caliber that will shoot flatter, carry farther and drift less than my old 308!
 
Re: Caliber for new build - 260 vs 7-08 vs 284

Goatphius, turbo54 cannot remove the bolt with a loaded round that is too long. He said he has a claw type extractor. The ejector is not built into the bolt but rather is a spring loaded pin that the bolt rides over. The more you pull on the bolt to remove it, the harder the pin pushes on the cartridge case.

Turbo54, I am also going with the 284 Win. I was leaning toward the 7mmRSAUM. But now I'm going with a Savage Target action and I won't have to do a thing with the bolt face to chamber the 284.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

I too am playing with the idea of .284Win in a short action. I'm thinking of a re-barrel of the GAP in my sig. It seems like quite a step up from .308 for sure, with some serious terminal balistics downrange.
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CamoWildcat</div><div class="ubbcode-body">Goatphius, turbo54 cannot remove the bolt with a loaded round that is too long. He said he has a claw type extractor. The ejector is not built into the bolt but rather is a spring loaded pin that the bolt rides over. The more you pull on the bolt to remove it, the harder the pin pushes on the cartridge case.

Turbo54, I am also going with the 284 Win. I was leaning toward the 7mmRSAUM. But now I'm going with a Savage Target action and I won't have to do a thing with the bolt face to chamber the 284. </div></div>

Reckon I could shave down both the stop and the ejector a little to get a smidge more clearance.

Ill also have to lay back the feedramp about 50 thou as well.

I'm fairly new to gunsmithing, but I have lots of experience in machining, as well as building racing engines. Anyone with experience building racing engines knows that NOTHING just "fits" out if the box. Everything gets tweaked and massaged. This experience is why I was willing to take on this project.

Good luck with your 284. Oughtta be a cake walk on that action - and perform a little better than mine too!
 
Re: Caliber for new build - 260 vs 7-08 vs 284

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gregch44</div><div class="ubbcode-body">I too am playing with the idea of .284Win in a short action. I'm thinking of a re-barrel of the GAP in my sig. It seems like quite a step up from .308 for sure, with some serious terminal balistics downrange. </div></div>

Yep! Thats why I was drawn to it. I feel its about as big as you can go on a short action and not be in magnum land. It's still a "reasonable" cartridge, but it just kicks the %&*$ out of a 308...even outperforms 260. Downside though is I can't form brass from my heaps of 308 brass like I could with a 7-08.
 
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