What 7mm cartridge is the F/O National Team using?

[TonyR]

I have a 7X64 Brenneke which is very similar to a straight 280REM. I think the barrel is on the fast side but it gives me over 3000fps with the 180VLD and good vertical at 3000 fps. I shoot it at 2900 fps but it takes just over a grain less powder to make 2900 than my Shehane does. I plan to "Improve" it if the next barrel isn't as fast but anything in the 280 class is worth considering

 

[expiper]

Hi Laurie,,,good to see somone who is quik load and puter savvy...crankin out the numbers.....I fire form with Universal Clays and toilet paper (no -bullet) and see no additional bbl. wear from this procedure....as stated .020"wear at near 1000 rds...I (poor working guy) dont start to worry till I see .060" erosion...cant afford to change bbls every month or so.....my chamber is short so that the 30-06 brass doesnt have excessive clearance at the case mouth....the 30-06 brass was the whole premise for this project......but you culd use a std length reamer and use 280 AI Nozler factory brass .((with my chamber I hav to trim em to get em in the gun)) the 30-06 Lapua/Win brass is ~ 2.484 outa the box...when I squeeze em down to .284/7mm size they grow to 2.494 ((with a false shoulder on the neck like you do a Dasher--just leave enuff of an interference fit that you have to palm the bolt closed))and then when FF'd they suck back to a 2.474 aprox. length with lots of clearance in a 2.500 chamber....and never need trimmed....with a dozen re-loads on my Win. cases they havent grown more than .002-.003" !!!!.....Its realllll simple and realllllll good....Roger
PS...I shoot this combo in a Panda F-class SHORT action with cone breaching...feeds smooth as silk.....it ejects a spent round out the load window effortlessly.....you only need a long action if you want a repeater....

 

[Laurie]

expiper.

Thanks for the information - I've copied and saved it on my PC. It's really good of you to pass your experience on - saves learning the hard way! I'm getting keen on the 280 / 280AI idea.

Laurie

 

[JabaliHunter]

Interesting stuff guys! The .280AI is a very attractive proposition...
I think Lapua should make brass (please!)

 

[Baron B58]

I think Lapua should make straight 284 brass; now that will be real nice !. The 284 Win is still the one I would pick; less brass flow due to shorter case and no fireforming of case shoulders as with the 280AI plus you get more or less the same speeds. Remember that accuracy wise the short powder stack cartridges seem to outperform the long ones. Why pick a 280AI if you start from scratch?

 

[Laurie]

plus you get more or less the same speeds [Baron B58]

If you look at my water capacity table above, you'll see that the .280AI has around 8% greater capacity than the 'straight' .284 and is very close to the SAUM which an increasing number of people regard as having the ideal capacity for long-range competitive shooting with the 7mm. The key seems to be to achieve 2,950 fps or thereabouts with good accuracy using 180s, rather less than possible with the WSM version but providing much better barrel life.

Simple physics says that all other things being equal, a straight .284 simply cannot produce the same performance as the .280AI or SAUM. Yes, it is a efficient design and offers a good compromise between barrel life and performance, but the take-up in F-Class has been low outside of South Africa, because it is just a little lacking in the performance department. I like the idea of the 280 based numbers because it allows SAUM or near SAUM performance on the cheap - existing bolt-face and no need to change to one with a magnum diameter, readily available and reasonably priced dies (unlike the Shehane which rermains a custom order) and Lapua .30-06 brass at a very much lower price than the Norma SAUM equivalent.

Apart from the extra work involved in case preparation, the .280's downside is case length / COAL. You never do get anything for nothing though.

 

[TonyR]

No problem loading my 7X64 with the 180s seated out in the neck through a short action single shoot and the empties eject fine; so I don't believe that a long action would be necessary for any of the 280 class rounds.

 

[Laurie]

No problem loading my 7X64 with the 180s seated out in the neck through a short action single shoot and the empties eject fine; so I don't believe that a long action would be necessary for any of the 280 class rounds.

Tony,

I agree completely. With the .308 Win COALs I run in my Barnard F/TR action, I can't eject any live round through the port - no problemo, simply remove bolt with cartridge on the end of it. I'm in the same position with a factory Savage 12 F-Class rifle that simply wouldn't perform in its original 6.5-284 chambering, but is now a great performer in 6.5X55mm with a Bartlein barrel on it. It won't eject a live round though - so what on a competition / bench rifle? If I go down the .280 route, it'll be one of this pair that gets the 7mm barrel put on.

 

[TonyR]

Laurie. If you do, you might look for some RWS brass. It's hard to find over here but I built the Brenneke because I did find the RWS in that cartridge. Pricey stuff but it has not doisappointed. The weights vary about like Lapua but the loaded round runout has been exceptionally good using standard Redding F/L sizing dies. I did turn the necks to get the neck tension I wanted and speced the reamer to work with the specific die part number. Not a bad way to go. I believe that the RWS is made in 280 Rem and should be available on your side of the pond. Well worth your consideration.

 

[Laurie]

Tony,

we can get RWS brass here, but usually special order and VERY expensive - even more so than Norma. Lapua is much more readily available (I live only 30 minutes drive from the importer / distributor too which is a big help). Most people only order RWS brass when it's the only, or glaringly obvious choice - 6mm Swiss Match, 8X68mm (to form 7mm BooBoo etc) and suchlike. The only exception is .308W now that RUAG / RWS is loading the cartridge with the original 155gn Sierra MK (#2155) for the British NRA under contract and it is being sold at a very reasonable price with supplies of once-fired cases around at very low prices too for those who don't insist on virgin brass.

Thanks for the tip though.