Help, 7mm rebarrel conundrum.

[ezmobile]

Hello all. I'm currently thinking about rebarreling my target rifle (.308) with a 7mm tube due to its high b.c. bullet availability.

I am looking at a long, cut barrel (30+ ins) with a 1:8 twist. But, for the love of me, I can't make up my mind what cartridge to chamber it in.....I'm being pursuaded into .284 Win but it seems that hardly anyone makes cases for it, or if they do they're pretty expensive. Also, not many dies etc for it.

I have heard it's a bit of a barrel burner - not as bad as some though. Now, I dont have an endless supply of cash for new barrels every five minutes and don't want to suddenly find I can't find any brass for it !!!!

So, the question is, can anyone suggest another chambering for for a 7mm i.e. 7-08 for instance which can still exploit the potential of this bullet? I would just like a cartridge for which I can get an easy supply of consumables & fairly kind on barrels.

Before anyone says it, I know you can't use a 7mm for T/R, its meant to be an alternative / swith over barrel.

Over to you

Cheers.

[trucraft]

.284 is a great round and winning a lot of long range matches.

 

Probably your best choice. Gives good barrel life and components are no more expensive than the other competitive 7mm.

How many rounds are you hoping to get from a 7mm and how far are you shooting it?

 

http://www.1967spud.com/shop/redding/redding-type-s-bushing-neck-die-set-284-winchester/

http://shop.marchscopes.co.uk/products/norma-brass?variant=4717117377

 

You could also neck up 6.5- 284 brass.

[gbal]

ez,Im sure you will get more focussed advice if you say what your intended usage is-eg the 7-08 is a dandy deer cartridge,the 284 also,but it is far far more popular as an Fclass and 1000y number these days....30 inch /target does strongly suggest relatively long range (1000y).

Brass is an issue-but again,depending on your shooting,better to have one top quality supplier (eg Lapua) than several lower quality suppliers (if precision etc is your priority).Top brass often lasts longer-it may turn out no more expensive,though it's always a tad better.

Dies-you will only ever need one set-again,quality makes sense,and any cartridge your are tempted by will have at least one quality supplier.....Forster,Redding comp etc at the better end of choices...

 

Get the tool that suits your job,don't worrry about all the things you won't need (alternate cheap dies for example-you will still only need one set).

Barrel life-you will get shorter life the more powder the cartridge burns,but if you need the performance you have to live with it-but I cant see anyone not choosing say,280 rem as a stalking rifle and prefering 7-08 on the grounds of barrel life alone....no -one shoots enough deer for the differnce to matter! But a hot 7mmm short magnum will be quite hard on barrels shot in competition....but it is also at the cutting edge for performance.....no free lunches,but a decent menu available...how hungry are you?.....:-)

Switch barrel can make a lot of sense-use what is closest to the application on the day.

 

BUT let us know what you want to shoot-and distances etc...a seven WS mag at 600y is needlessly 'expensive',especially for 'club shoots' though works fine! It isn't a luxury for competitive 1000y competitions at national level,anything much less tends to handicap rather than advantage...

 

gbal

[Tom D]

I'm not a competition shooter, but I have a 7-08 deer rifle. I wonder wether a couple hundred fps difference is worth the extra hassle of the 284, after all if you know the range exactly in a competition then surely its more about accuracy rather than velocity?

 

How about a 7-08 AI? easy to obtain quality brass and maybe a little closer to the 284 velocity...

[gbal]

Tom,the 7-08 is an excellent UK deer cartridge (after all,it's essentially a modern 7x57-once my choice.)

And of course ,competition users know the range distance,so why the premium put on velocity...?

 

Wind-better velocity (and even more so BC) means less dispersion in wind,and especially changing wind-and there is no way of guaging just what is winding at 1000 yards away. On score competitions,the cartridge might save you a point if you are not spot on in wind reading,and for group (Bench Rest) it means a corrsponding smaller group-certainly enough to justify the 'hassle'-if indeed it is-for the competitive shooter.

An interesting recent realisation is that you can go for a hot wind bucker (relatively)-the hot 7s;but plan B is use an intrinsically shootable (accuracy) 6BR class,and hope to get shots off in the same wind condition (eg fast). One reason the Dasher does well-sometimes very well-in benign conditions,but is a riskier choice when the wind blows..-we seldom get very light steady wind.....and of course this really matters as distance increases (much less critical for 300 yards of course,where any trade offs are much less critical....)

Of course target shooters can ignore terminal performance (a hole in paper is a hole),but live quarry shootes can't...a different set of compromises apply.

Interesting the 284 was designed as a challenger for the 270w,but in a lever action (Win 88)-but it flopped. (don't need it in Pennsylvannia woods).

The 284 was revived by LR shooters-enough (capacity/velocity) but still 'shootable' (recoil etc).

 

What is really new,which is where we came in -with the 7-08 mauser......:-)

g

[trucraft]

Bolt face will also determine your cartridge and whether its a long or short action that your rebarreling. short mags are out due to bolt face.

280AI is a great round and should give you reasonable barrel life.

Nosler does 280AI brass though it's pricy.

Or form your own from cheep once fired 30 06 or 270 brass.

[ezmobile]

Morning Fellas.

Sorry, I should have explained a lot better what I was looking to get from the rifle.

I'm going to marry it up to a "paramount" short action, single loaded. It sits atop a "Gemini" stock, so its essentially a Target rifle / F classer and so I'm looking for best accuracy out to 1,000+ yds. Its a fairly old action now, but still very accurate.

In its current form, its a .308 win with a 1:12 twist 32" Border barrel and is very good for T/R. I understand that the bolt face will accept both 7-08 & .284 rebated rim cartridges. Just one other thing, I don't hunt.

 

Thanks a lot for all your input so far!

 

Ez

 

 

[gbal]

Ez,thanks-it was fairly clear on rereading (30 inch barrel!) that you were likely to be target shooting at longer range.

 

The 284W as you say is currently in favour,and rightly so (others would probably be as good,but 284w is now well tested,and works-and there are the derivative wildcats like Shehane,a tad bettter,maybe).

The 7-08 is outclassed (as is the parent 308w)-just capacity. Not to deny the 308 is OK,and mandatory in effect for some competitons,but it can't compete on equal erms (except with punishing heavy loads-which isn't equal...cf 300 mags).

 

As in my first reply,I'd not let the reduced choice of brass etc be an issue-especially as the best (Lapua) is available...having the best is seldom a negative in competition shooting!

 

I'm sure other 1000 yard shooters will comment-there is nearly always some choices,and it becmes a fine personal choice among the favoured options.....are Berger bullets worth an extra tenner a competition...if you did well,using them.....or didn't,not using them ? :-)

 

gbal

[ezmobile]

Cheers for that gbal. I kinda knew the .284 was the way to go, but I'm always open to other suggestions from wiser heads than mine & I do tend to procrastinate sometimes before diving in head first about stuff like this. I think I'm going off the boil slightly as regards to Target rifle shooting at Bisley, I just dont seem to be able to hold the bloody thing still so well anymore, but with a scope on top & simple bipod under it, I think I did o.k. at this years Imperial 300yd McQueens...50.9 v's first time out....I was happy with that, so the rifle & reload combo still shoots well I guess.

Anyway, I've set the ball rolling, just ordered the .284 dies (Forster) from the states & Mik @ Dolphin is sorting me out with a barrel...........off we go again!

Thanks for the feedback, I appreciate it.

[mikeroz]

Can't go wrong with Mik. You'll have a tack driver there.

ATB

Mike

[spclark]

Greetings from across the pond!!

 

Please consider a fairly new 7mm designed by R. Chombart a few years ago: 284INCH

 

Uses 308WIN brass w/ shoulder angle kept but shoulders blown forward 3.5mm. Not much neck though, just about 3mm.

 

I built one on a CG INCH action this year. After some extended load development targeting best propellant with Berger 180 Hybrids I settled on Hodgdon's H4350. Getting 2,750 fps & on its first match outing at 1,000 yards late last month I fired 200-15 (US NRA scoring, 20 shots @ 10 points each, X's are inside 10" circle) to tie a National Record for match sights.

 

Barrel life so far is pretty good: after 800+ rounds throat's moved all of 0.025" in the Brux 1:9 barrel I had on hand when I found out about this catridge late last year. I'm using previously fired Lapua Palma brass for fire-forming, case life is excellent. Some have been fired over eight times & still shoot good.

 

180's probably aren't what you'd be choosing for varmint control but with the excellent 7mm bullets out there you ought to have no trouble finding several that shoot great.

[Blue Haze]

Cheers for that gbal. I kinda knew the .284 was the way to go, but I'm always open to other suggestions from wiser heads than mine & I do tend to procrastinate sometimes before diving in head first about stuff like this. I think I'm going off the boil slightly as regards to Target rifle shooting at Bisley, I just dont seem to be able to hold the bloody thing still so well anymore, but with a scope on top & simple bipod under it, I think I did o.k. at this years Imperial 300yd McQueens...50.9 v's first time out....I was happy with that, so the rifle & reload combo still shoots well I guess.

Anyway, I've set the ball rolling, just ordered the .284 dies (Forster) from the states & Mik @ Dolphin is sorting me out with a barrel...........off we go again!

Thanks for the feedback, I appreciate it.

I was just about to ask what your intentions with the rifle are??? So it was TR (which I myself also tired of recently, and am planning on joining F class next season) but you now want to use a scope and bi-pod, and get better ballistics than a .308? Starting to sound a lot like F class to me!

 

In that respect if you don't use .308 then MR is out, it really only leaves F class. Since you have moved away from .308 then F-TR is out and F-Open is in. In F open the 7mm rules the roost as it has the very best ballistics with the 180 Bergers (unless you are super human and can take the constant beating from a 300 WSM). You already have the action and a bolt, so magnums are not on the table. The best of the rest is the .284" win.

 

It has the best performance of the std bolt face options, and also has the most reasonable barrel life of any option that is not a massive disadvantage. I would disagree on the availability of dies and brass etc. You have a superb availability of target brass. Lapua make 6.5-284 which you can neck up with very little effort to .284", and Norma now make .284" brass which is as good and is nearly ready to go (which I am sure Mik stocks). You also have a very plentiful supply of Berger bullets, and dies are available a plenty from Redding, Forster etc...

 

Are you planning on trying to have a play at F-Class, or just wanting to build a capable toy for club shoots? How much of the other stuff do you have, such as a scope, rail etc?

[Andrew]

Years ago I built a 7mm-06 single shot for a man who used it well out to 1200 yards. HE liked it due to the ease and cost of making brass. I shot 500mtr off hand metallic silhouette with a 7-08 for a while and loved it. (Still use one for deer hunting) The 284 is a good choice but brass is difficult to come by where I live.~Andrew

[gbal]

Years ago I built a 7mm-06 single shot for a man who used it well out to 1200 yards. HE liked it due to the ease and cost of making brass. I shot 500mtr off hand metallic silhouette with a 7-08 for a while and loved it. (Still use one for deer hunting) The 284 is a good choice but brass is difficult to come by where I live.~Andrew

As long as we can trade with EU advantageously,Lapua and Norma help over here (284,and so the Shehane for targets.)

7x64 is less popular/available,despite impeccable european provenance

 

280 Rem-please tell me that is available in Montana,Andrew ! :-)

 

g

[Andrew]

As long as we can trade with EU advantageously,Lapua and Norma help over here (284,and so the Shehane for targets.)

7x64 is less popular/available,despite impeccable european provenance

 

280 Rem-please tell me that is available in Montana,Andrew ! :-)

 

g

Virgin brass is scarcer than hen's teeth in 280 unless you want nickle plated Rem which is pretty much throw away. It refuses to be full length resized. I find Norma and moreso, Nosler brass. Remington and Winchester both have listings of "Temporarily unavailable from Manufacturer" on my favorite mail order site. Factory ammo is plentiful tho.~Andrew

[Swarovski1]

284 really needs to be in a long action unless you will be using lighter bullets which defeats the object of the 284.so far I've had 3 or 4 roebucks with it.it doesn't seem to be any better or worse than my 6.5 06 or my 6.5x47 is either.kills them just as dead.200 or so fps isn't going to see a noticeable difference.in my experience 30 cals bang them over better.

[Laurie]

Exotic (or not so exotic) wildcats aside, you have five or six options, in size / performance order:

 

7mm BR. A lovely little cartridge, but short of legs for long range.

 

7mm-08 (and its Ackley 'improved variant). If adopted, the gunsmith must provide the freebore to see 160-180gn bullets seated at COALs of 2.950-3.00". The standard SAAMI version with its 2.800" COAL is limited to 140-150gn BT bullets.

 

7X57mm Mauser (and its AI version). A very nice 'old soldier', great in historic arms and deerstalking, but not offering that much over the 7mm-08. Because of its marked case taper, the 'improved' version offers a very useful increase in case capacity / powder charge and would make an effective all-rounder in the match role. I know of one such in occasional use, but it is a rarity and you'd likely have trouble sourcing dies. No Lapua brass either (but Norma and RWS).

 

284 Win, the obvious choice. It must be throated out as per 7-08, in this case with COALs in the 3.050-3.150" for 180gn bullets. There is a very nice slightly improved variant, the 7mm Shehane whose capacity seems to suit the calibre to a 'T' and has racked up some impressive results on both sides of the Atlantic.

 

280 Rem, 7X64 Brennecke, 7mm-06, (and AI Versions). Three different but very similar cartridges with near identical ballistics. They have marginally greater case capacities than the 284, but not enough to make a real difference ballistically except for the 280AI and a similar 30-06 based 'improved' version. There has been a modest revival of interest in the 280/280AI in the USA. The 280AI has a marginally greater capacity than the 7mm Rem SAUM short magnum, but with its 0.473" dia' case-head / rim fits non-magnum bolts. The rationale for the 7mm-06 / AI wildcat is to use high quality and strong Lapua .30-06 brass rather than US made stuff.

 

Does it fit your Paramount action? Everything up to the 284 Win version does so, although with the 284 (and likely even with the 7-08 in long-throat 3-inch length form) you'd have to unload a live round by removing the bolt. (Not an uncommon situation - applies to some 308 Win loads these days too.)

 

The 280 is based on the longer .30-06 case and you're into COALs of 3.45-3.5" with a chamber throated to accommodate 175 / 180gn match bullets, longer than you want for the Paramount.

 

Brass?

 

Lapua makes 7mm-08 as does Winchester (but like hen's teeth these days), as does Remington (but pretty well forget it). The very strong and efficient Lapua 308 'Palma' small primer brass can be necked down to 7-08 by simple sizing in the latter's die but may need neck turning afterwards depending on the chamber neck diameter.

 

284 Win - Hannams has genuine Winchester brass (Americans would kill for it), but it needs a lot of sorting, batching, prepping and reckon on a 3-5% discard level. Norma now makes 284 brass - Brian Fox has it in stock. Not heard any reports on it here, ............. but that's most likely because 99.9% of UK 284 shooters buy Lapua 6.5-284 cases and use a mandrel or expander die to expand necks up to 7mm. Very good quality, and if you keep the loads sensible, lasts a long time especially if regularly annealed. The Winchester made brass isn't as strong and standard pressure loads will expand primer pockets in five or six firings.

 

7mm-08 dies aren't an issue and while 284 Win isn't as common, you shouldn't have any problems with ordering through a a specialist supplier such as Mark Ellis (1967 Spud) or direct from Whidden Gunworks in the USA. (Phone - like most US outfits they never answer emails IME.)

 

Performance?

 

A long-throated 7mm-08 will give the 160gn Sierra TMK / Hornady AMAX 2,750-2,800 fps with single-based powders such as Viht N160, likely more with 'high-energy' types such as N550/560 and RS60/70 from 30-31 inches barrel.

 

It'll give the excellent 175gn Sierra MK 2,625 fps or so with N160 and 2,700 fps plus with the hot high-performance powders.

 

These MVs may seem very low, but they outperform any 260 / 6.5X47 / Creedmoor load at long distances ballistically.

 

The 284 gives 175/180gn bullets 2,800-2,850 fps, lighter bullets like the 168gn Berger VLD, 160 TMK an easy 2,900 fps. A lot more if 'pushed' using the higher energy powders, to wit Reload Swiss RS60.

 

 

Barrel life?

 

7-08 should be pretty good depending on powder choice, pressures, and rate of fire. 3,000 should be 'on', likely more with 58,000 psi level loads and the cooler burning powders.

 

284 is reckoned at around 1,800-2,000 rounds in US use with H4831sc and their fast 'string shooting'. In our 'two on the mound' system, barrel temperatures stay much lower. Use Viht N165 for the 175/180s and life should exceed 2,000 by a margin, possibly a large one. Use RS60 and the maker's guarantee is withdrawn!

 

The 7-06AI with strong Lapua brass run at 60,000 psi + pressures gives short magnum performance, likewise the 280AI with Nosler brass. If run at full performance, they give short magnum barrel life, ie you start to worry at 1,000 rounds barrel round count mark.

[Andrew]

I know that you are talking competition use, but in the "for what it's worth" department, I have been making 7-08 brass for my Tikka from military surplus. The only preparation I do is to partially resize the diameter of the military 308 case in a 308 Lee Collet die. I size just enough to allow a 30 cal Forster neck reamer to take a skim cut inside the neck. I then FL resize in a small base 308 die, and then Fl resize in the 7mm-08 die. The next step is to swage and uniform the pockets and remove flash hole burrs. I sorted quite a bit of the finished brass by weight (they were remarkably uniform, actually) and when those cases are used, my accuracy was at .5 MOA and under from a stalking rifle.

 

This process is easy for me as I have all the equipment already, as well as several thousand once fired Lake City cases. When 7-08 was hard to get, this is what I used. 7-08 is now more plentiful but I'm still using it. This brass has been accurate and durable and if I lose one, not an issue.~Andrew

[Swarovski1]

Some of you put alot of time and effort into case prep.some to save money and others just like doing it.i am ok most the times but I do have the odd occasion I can't be arsed.i have to master the neck turning next.ive done some just taking some scrapings off.ive not done the tight neck turning.

[Swarovski1]

Some of you put alot of time and effort into case prep.some to save money and others just like doing it.i am ok most the times but I do have the odd occasion I can't be arsed.i have to master the neck turning next.ive done some just taking some scrapings off.ive not done the tight neck turning.ive got the gear but not all the idea

[Swarovski1]

Some of you put alot of time and effort into case prep.some to save money and others just like doing it.i am ok most the times but I do have the odd occasion I can't be arsed.i have to master the neck turning next.ive done some just taking some scrapings off.ive not done the tight neck turning.ive got the gear but not all the idea

[gbal]

Neil,

Accurate Shooter "Neck Turning Basics" by German Salazar

 

most all the ideas and how to do it

 

g